JPS6378867A - Antiskid control device - Google Patents

Abstract

PURPOSE:To ensure a proper brake pressure control and the controllability, by controlling a brake pressure respectively individually of the first front wheel and its diagonally rearward positioned second rear wheel while in common of the second front wheel and its diagonally rearward positioned first rear wheel. CONSTITUTION:A brake pressure is controlled for a right front wheel FR and a left rear wheel RL respectively individually by oil hydraulic control valve units 4, 5 and for a left front wheel FL and a right rear wheel RR in common by an oil hydraulic control valve unit 3. In case, for instance, that a vehicle is driven running on a snow-covered road winding a chain only on the front wheel, when the rear wheel tends to be locked by depressing a brake pedal 1, a control circuit 14, on the basis of a wheel rotary speed signal from sensors 10, 11, 12R, 12L, decreases a fluid pressure from a master cylinder 2 by the oil hydraulic control valve unit 5, and an excessive slip of the left rear wheel RL is prevented before occurrence. Since the front wheel is not influenced by the control of said brake pressure, controllability is surely ensured by the three wheels. In this way, the proper control of the brake pressure and the controllability can be ensured by at least the three wheels.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is directed to the prevention of wheel locking due to rotational slip of the wheels with respect to the road surface and high brake pressure when braking while the vehicle is running.
The present invention relates to an anti-skid control device that prevents wheels from rotating (stopping), and particularly to an anti-skid control device suitable for front-wheel drive vehicles (vehicles with an engine mounted in the front of the vehicle body and driving the front wheels).

(Conventional technology) When the road surface is wet or frozen,
If you apply the brakes while the vehicle is moving, the wheels may slip against the road surface, causing the wheels to stop quickly and the vehicle to slide on the road surface. It can happen sometimes. If the wheels of the vehicle stop (lock) even though the vehicle is moving forward, steering becomes difficult and a vehicle accident is likely to occur.

Therefore, in the past, the slip ratio 5 = i - wheel rotation speed / vehicle speed was calculated from the vehicle speed and wheel rotation speed during braking, and when the slip ratio during braking was a predetermined value of 81 or more, the brake pressure was lowered (depressurized) to I'm trying to recover the rotation. Note that the vehicle speed cannot be accurately detected when the vehicle is slipping. Therefore, in the case of four wheels, the highest wheel rotational speed is used as the reference speed for considering the vehicle speed. This type of anti-skid control was developed, for example, in
It is disclosed in Japanese Patent Application No. 71 and Japanese Patent Application Laid-open No. 59-206248.

In addition, the brake pressure can be continuously increased and held using the wheel speed deviation and wheel acceleration/deceleration as parameters.

Anti-skid control is disclosed in Japanese Patent Application No. 59-67212, in which continuous pressure reduction, pressure reduction, or pressure increase is determined, and wheel brake pressure is increased/decreased duty-controlled based on the determined duty.

This type of anti-skid control is preferably performed for each of the four wheels. However, the brake energizing unit for adjusting the brake pressure of the wheel brakes is composed of relatively complicated valve devices such as a bypass valve, an actuator valve, a pressure increasing/decreasing solenoid valve, and a slow/slow switching solenoid valve. Anti-skid systems that individually control brake pressure for each wheel require a large number of mechanical and electrical elements, making the vehicle expensive.

Therefore, conventionally, in a vehicle that has an engine mounted in the front of the vehicle body and drives the rear wheels, for example, as shown in Fig. 12,
The brake pressure of the front wheels (front right wheel FR and front right wheel FL), which have a large effect on steering performance, is individually controlled by one brake energizing unit 4 and 3, respectively, and the rear wheels have a small effect on steering performance. , both wheels (rear right wheel RR and rear left wheel R
L) is provided with one brake energizing unit 5 in common,
Brake pressure is controlled in common for both wheels.

In this conventional example, only three d brake energizing units are required. An example of this is disclosed in the aforementioned Japanese Patent Publication No. 48-8071.

In the case of an FF vehicle, as shown in FIG. 13, one brake energizing unit 4 commonly controls the brake pressure of the front right wheel FR and rear left wheel RL, and the other brake energizing unit 3 controls the brake pressure of the front right wheel FR and the rear left wheel RL. The brake pressures of the front right wheel FL and the rear right wheel RR are commonly controlled. That is, the brake hydraulic system is configured as an X pipe, and the brake pressures of all axes are controlled by two brake energizing units. In addition, PV
1 and PV2 are proportional control wells (pressure ratio setting valves) for setting the brake pressure ratio between the front wheel brake and the rear wheel brake. An example of this is disclosed in the aforementioned Japanese Patent Laid-Open No. 59-206248.

(Problems to be Solved by the Invention) In the case of a front-wheel drive vehicle, the brake distribution for the front wheels is as large as approximately 80%, so if the brakes on the front wheels fail, the brakes of the vehicle will essentially become ineffective. Therefore, the brakes are controlled separately for the right and left front wheels so that even if one front wheel brake fails, the brakes on the other front wheel will work, and in order to ensure operability, as mentioned above, For example, when the front wheel is wrapped with a chain and the rear wheel is not wrapped with a chain and the brake is stepped on, the brake pressure on the front wheel is large, and anti-skid control is performed based on the rotational speed of the front wheel. Then the rear axle will lock up immediately. If the rear wheels lock up, the vehicle becomes unstable,
Generates spin etc. Anti-skid control based on the rotational speed of the rear wheels (relaxing the brake pressure when the rear axle is about to lock up) requires the brake pressure to be considerably relaxed, which reduces the front wheel's braking force and lengthens the control distance. The inherent benefits of skid control are not provided. In the anti-skid control system disclosed in JP-A-59-206248, brake pressure is controlled based on the rotational speed of the front wheels when the front wheels are rotating, and based on the rotational speed of the rear wheels when the front wheels are locked. Although explained, the aforementioned problems are not improved.

On the other hand, when an anti-skid control system as shown in FIG. 12 is set in a front-wheel drive vehicle, if the brakes on the rear axle cannot be applied due to a failure in the rear wheel brake system, the stability of the vehicle decreases and spins are likely to occur.

An object of the present invention is to improve the above-mentioned problems in a vehicle in which an engine is mounted at the front of the vehicle and the front wheels are driven. In other words, to avoid simultaneous locking of both front wheels,
The purpose is to avoid simultaneous locking of both rear axles and to ensure vehicle braking and steering ability even if one brake system fails.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes, as in the past, brake instruction means; and reference speed detection means;
and at least a first front wheel, a second rear wheel, and a second front wheel.
A means for detecting the rotational speed of the wheel, a brake pressure instruction from the brake instruction means, and a first method including at least pressure reduction.
A first brake energizing means for controlling the brake pressure of the brake attached to the first front wheel in response to a control instruction; a brake pressure instruction from the brake instruction means, and a second control instruction including at least pressure reduction. , a second brake energizing means for controlling the brake pressure of a brake attached to a second rear wheel diagonally behind the first front wheel in response to a brake pressure instruction from the brake instruction means; a third brake that controls the brake pressure of a brake pressure pipe communicating with the brake of the second front wheel and the brake of the first rear wheel diagonally behind the second front wheel in response to a third control instruction including pressure reduction; and a first brake biasing means for instructing the brake pressure in accordance with the reference speed and the rotational speed of each wheel. 2nd or 3rd control instruction to 1st
．． Brake control means for applying to the second or third brake control means;

That is, one system of the X piping is equipped with two brake energizing units (first and second brake energizing means) for controlling the brake pressures of the front wheels and the rear axle, respectively, so that the brake pressures can be controlled individually. However, the other system is provided with one brake energizing unit (third brake energizing means) in the same way as in the conventional system, and is configured to control the brake pressure in common for the front and rear axles.

(Function) According to this, the brake pressure of the first front wheel (for example, the front right wheel) and the second rear wheel diagonally behind it (the rear left wheel) is individually controlled, and the second front wheel (the front left wheel) is individually controlled. brake pressure is commonly controlled for the first rear wheel (rear right wheel) diagonally behind the rear wheel.

For example, if the brake is stepped on when the front wheel is wrapped around the front wheel but not the rear axle, and the rear axle is about to lock up, the brake pressure on the second rear wheel is lowered, and the brake pressure on the second rear wheel is reduced. Excessive slip of the rear wheel is prevented, and the second rear wheel
Since such brake pressure control of the wheels does not affect the brake pressure of the front wheels, excessive slipping of both front wheels is also prevented, and steering performance is maintained in at least three wheels. If the common brake pressure control for the second front wheel and the first rear wheel is the same as the conventional
Even if a problem similar to piping anti-skid control occurs, the brake pressure of the first front wheel and the second rear wheel diagonally behind it is controlled to an appropriate level, so the minimum braking force and steering performance are maintained. Ru.

Even if one of the front wheels and the rear wheel diagonally behind it (X pipe 2 In a preferred embodiment of the present invention, the first brake energizing means and the second brake energizing means are connected to the first output port of the brake master cylinder (e.g. M /cF), and the third brake energizing means is connected to the second output port (M/cR).

According to this, even if one of the brake systems breaks down, the front axle and rear wheel brakes located diagonally are healthy, so the control and steering performance of the vehicle is ensured.

Common brake pressure control for the second front wheel and the first rear wheel.
In a preferred embodiment of the present invention, in order to minimize the same problems as the conventional X-piping anti-skid control and ensure as high braking and steering performance as possible for these wheels, the means for detecting the rotational speed of all wheels is The rotational speed shall be detected; the brake control means shall issue a third control instruction to instruct depressurization when the first rear wheel is in a predetermined depressurization region and this continues for a predetermined time T2, and the brake control means shall issue a third control instruction to depressurize; Tri, Tri<Tr2. When the predetermined pressure reduction region continues and the pressure reduction instruction continues, the third control instruction corresponding to the second front wheel is returned.

According to this, the common brake pressure control for the second front wheel and the first rear wheel is mainly based on the anti-skid control based on the rotational speed of the second front wheel, and the first rear wheel continues during Tr2. When a lock is about to occur, the brake pressure is reduced to reduce rear wheel slip, which is based on the rotational speed of the first rear wheel, and if this continues during the Tri, the brake is switched to a brake based on the rotational speed of the second front wheel. It is returned to anti-skid. In other words, if the first rear wheel becomes locked continuously while anti-skid control is being performed for the second front wheel, the anti-skid control is based on the second front wheel during Tr2, and then the anti-skid control is performed based on the second front wheel during Tr2. The reference wheels are switched in a time-sharing manner such that anti-skid control (pressure reduction) is based on the first rear wheel during the period of Tr2, anti-skid control is based on the second front wheel during the next Tr2, and so on. Even in this case, T
r2) Since it is Tri, priority is given to anti-skid based on the second front wheel. As mentioned above, the first front wheel and the second rear wheel are individually anti-skid controlled to ensure basic braking force and basic steering performance. Even in the common brake pressure control, the anti-skid control of the second front wheel and the anti-skid control of the first rear wheel are balanced, so the stability of the brake and the stability of the steering performance due to the anti-skid control are further improved.

Other objects and features of the invention will become apparent from the following description of embodiments with reference to the drawings.

〔Example〕

FIG. 1a shows a system configuration of an embodiment of the present invention.

In this embodiment, anti-skid control is performed independently for the front old wheel FR and the rear left wheel RL.

Anti-skid control is performed on the front wheel FL and rear right wheel RR all at once, but FL is given priority (in normal conditions, anti-skid control is applied to FL), and when the RR wheel locks, it is temporarily controlled to release the anti-skid control. Anti-skid control is performed for RR. In this case, since it is necessary to know the rotational speed of each of the four wheels, a speed sensor 10°11.12R and a 12L
It has. Each of these sensors consists of a magnetic gear coupled to a wheel, a permanent magnet core fixed opposite to the gear, and a voltage wound around this core with a frequency corresponding to the rotation of the gear. An electric coil is generated;
It consists of These sensors 10, 11, 12R
and 12L generated voltages 51 to S4 are applied to the electronic control device 14.

When the brake pedal 1 is depressed, the brake operation detection switch BSW, which is open when the brake pedal is not depressed, is closed. A status signal indicating whether the switch BSW is open or closed is provided to the electronic control unit 14.

Brake fluid pressure is applied from the brake master cylinder 2 to the brake fluid pressure ports (3a) of the brake fluid pressure control valve units 3, 4, and 5. The hydraulic pressure of the control output port (3b) of the brake hydraulic pressure control valve units 3, 4, and 5 is applied to the brake wheel cylinder 7 of the front right wheel FR, the brake wheel cylinder 6 of the front left wheel FL, and the rear left wheel RL, respectively. is applied to the brake wheel cylinder 9. The output hydraulic pressure of the brake hydraulic pressure control valve unit 3 is applied to the brake wheel cylinder 8 of the rear right wheel RR via the proportional control valve PVI.

The output pressure of the power hydraulic pressure source device PPS, that is, the accumulated pressure of the accumulator 17, is applied to the power hydraulic ports (3d) of the bypass valve devices of the brake hydraulic pressure control valve units 3, 4, and 5. Power hydraulic port (3k) of the hydraulic control valve device of brake hydraulic control valve units 3, 4 and 5
Each of the solenoid switching valve devices 5OLI.

Pressure at the output ports of 5OL2 and 5OL3 is applied.

Brake fluid pressure control valve units 3, 4 and 5 all have the same configuration. FIG. 1b shows the configuration of the control valve unit 3. The control valve unit 3 includes bypass valve devices (3a to 3).
h) and hydraulic control valve devices (3i to 3k).

The bus pass control valve device includes a coil storage space that communicates with a brake hydraulic pressure port 3a and accommodates a compression coil spring 3f, and a control output port 3b that communicates with this space and a valve operation that accommodates a ball valve (valve member) 3e. Room.

An operator operating space that communicates with this chamber and the control input port 3C and through which an operator integrated with the piston 3h passes, and the piston 3
It has a piston operating space that houses the piston h and communicates with the power hydraulic port 3d.

The hydraulic pressure control valve device includes a valve operating chamber that communicates with a brake hydraulic pressure port 31 and houses a compression coil spring 30 and a ball valve 3Q, and a valve operating chamber that communicates with a control input port 3C that communicates with a piston 3.
A hydraulic control chamber 3j through which an integrated operator passes.

It also has a piston operating space that accommodates the piston 3n and communicates with the power hydraulic port 3k.

When a predetermined power hydraulic pressure is applied to port 3d (
During normal operation), the piston 3h moves to the right compared to the illustrated state, the ball valve 3e moves to the right against the force of the spring 3f, and the control output port 3b is connected to the control input port 3c.
is connected to. Furthermore, in a state where anti-skid control is not substantially performed (a state where the electromagnetic switching valve 5OLI is in the first state (de-energized) and shown in FIG. 1a), power hydraulic pressure is applied to the port 3k, and the piston 3n is in the first state. It has moved to the right from the state shown in Figure 1b, and the ball valve 3Q has moved to the right, and the brake fluid pressure ports 3a and 3i-pressure control chamber 3
The wheel cylinder 6 communicates with the mask cylinder 2 through a path of j-control input port 3C-working chamber 3g-control output port 3b-wheel cylinder 6.

When skid prevention control is not being performed, brake fluid pressure is applied to the wheel cylinder 6 through this route even when the brake is depressed and the brake fluid rises. Even in this state,
As will be described later, it is monitored whether or not there is a possibility that a skid will occur. Briefly speaking, if the possibility of skidding is high, the electromagnetic switching valve 5OLI is energized to reduce the pressure in a predetermined energization pattern. When energizing for reduced pressure, the output port of the electromagnetic switching valve 5OLI, that is, the power hydraulic port of the hydraulic pressure control valve device)
3k becomes the drain pressure, the piston 3n moves to the left, and as a result, the ball valve 3Q cuts off between the brake hydraulic pressure port 31 and the hydraulic pressure control chamber 3j, the volume of the hydraulic control chamber 3j increases, and the The pressure decreases and this is passed through the control input port 3c-control output port 3b to the wheel cylinder 6.
As a result, the brake fluid pressure in the wheel cylinder 6 decreases,
Brake force weakens.

When the output power hydraulic pressure of the power hydraulic pressure source device PPS decreases (in an abnormal state), the piston 3h of the bypass valve device moves to the left, and the ball valve 3e moves to the left, as shown in FIG. 1b. In this way, the control output port 3b and the control input port 3c are cut off, and the brake hydraulic pressure port 3a and the control output port 3b are communicated (bypass). In this state, brake fluid pressure from the mask cylinder 2 is directly applied to the wheel cylinder 6.

Brake fluid pressure control valve units 4 and 5 have exactly the same configuration as unit 3, and also include electromagnetic on-off valves 5QL2゜5OL.
3 has exactly the same configuration as 5OLI. Therefore, the application of brake fluid pressure to wheel cylinder 7 and the application of brake fluid pressure to wheel cylinders 8 and 9 are similar to the application of brake fluid pressure to wheel cylinder 6 described above.

However, control such as reducing, increasing, and holding the brake fluid pressure to the wheel cylinders by anti-skid control is performed by the wheel cylinder 7 of the front right wheel FR, the wheel cylinder 6 of the front left wheel FL, and the wheel cylinder of the rear left wheel RL. This is done independently for each of the three cylinders 9. As will be described later, the wheel cylinder 8 of the rear right wheel RR is roughly subordinated to the brake pressure control of the wheel cylinder 9 of the front left wheel FL, and when the rear right wheel RR is in a wheel lock state, the wheel cylinder 8 of the rear right wheel RR temporarily controls the brake pressure of the wheel cylinder 9 of the front left wheel FL. Brake pressure control is given to the right wheel FL.

Referring again to FIG. 1a. The brake fluid pressure input ports 3a of the first and second brake fluid pressure units 4 and 5 are
The front brake pressure port M/cF (first output port) of the brake master cylinder 2 and the third brake hydraulic unit 3 are connected to the rear brake pressure output port M/cR (second output port). That is, FR and R
L is connected to M/c F in units 4 and 5, and FL and RR are connected to M/c R in unit 3, forming an X piping.

Even if there is a failure in the M/c F system, the M/c R
The FL and RR brakes connected to the system work, and the braking and steering performance of the vehicle is ensured by the diagonally positioned front wheels FL and rear axle RR. Even if there is a failure in the M/c R system, the FR and RL brakes connected to the M/c F system will work, and the diagonally positioned front wheels FR and rear axle RL will ensure vehicle braking and steering performance. . The power hydraulic pressure source device PPS includes a reservoir R5V and a bomb 16. It mainly consists of an accumulator 17 and an electric motor 15, and the power hydraulic port (3d) of the bypass valves of units 3 to 5 and the high pressure input port (fin) of the electromagnetic switching valve devices 5QLI to 5OL3 are connected to the output port 17o of this device PPS. In addition, the low pressure port Lout of the electromagnetic switching valve devices 5QLI to 5OL3 is connected to the drain port 17d of the device PPS.
is connected. When the hydraulic pressure of the accumulator 17 is lower than a predetermined pressure, the pressure detection switch PS is opened and a high level signal is given to the electronic control unit 14;
A signal is given.

Briefly, when switch PS is open (low pressure), electronic control unit 14 energizes motor energizing relay RLY to energize motor 15 to drive pump 16, and when switch PS
When closed (high voltage), relay RLY is deenergized and motor 1
5 and stops the pump 16. In addition, this is to prevent the motor from turning on and off in short cycles.

The pressure detection switch PS is opened by the motor energization control described later (
Even after switching from low pressure (low pressure) to close (high pressure), the motor 15 is kept energized for 3 seconds, and the motor 15 is stopped at a pressure higher than the pressure at which the switch PS is closed.

The electromagnetic switching valve devices 5QLI to 5OL3 can linearly control the position of the flow path switching piston or plunger using the energized current value, and connect the high hydraulic pressure input port Hin to the output port (3k) without energizing to increase the pressure. connection), maximum current value 1
At max, the output port (3k) is connected to the low pressure port Lout (reduced pressure connection), and at an intermediate value between de-energized and Imax, the output port (3k) is shut off (held) from both the high hydraulic pressure input port Hin and the low pressure port Lout. It is something.

Since the position of the flow path switching plunger of the electromagnetic switching valve devices 5QLI to 5OL3 is linear in accordance with the energizing current value,
In the anti-skid control described later, 5OLI to 5OL3
In the first state (pressure increase connection), the current value applied to Itnax is set to 078, and in the second state (hold), Im
The current value applied to ax is set to 278, and in the third state (reduced pressure connection), the current value applied to Imax is set to 778.

In addition, the reason why 8 is used as the denominator in the control of 5QLI to 5OL3 is that 3 is used in the energizing current value specification code of 5QLI to 5OL3.
This is because bits are assigned. The numerator indicates a value (decimal number) expressed by 3-bit data.

The microprocessor 13 of the electronic control unit 14 outputs a code specifying such a current value, the code is converted into an analog signal by an A/D converter in the electronic control unit 14, and the analog signal is converted to an analog signal by a linear amplifier. The signal is amplified and the electromagnetic switching valves [5QL1 to 5OL3 are energized at a level corresponding to the analog signal level.

A linear amplifier has a power voltage of
Power supply voltage is applied through main relay MRY.

When main relay MRY is open, the output of the linear amplifier is zero (de-energized), regardless of the output code of microprocessor 13.

Since the microprocessor 13 of the electronic control device 14 has a position of the splitter linearly in accordance with the current value, 5OLI is used in the anti-skid control described later.

The control of 5QL2 is such that in the first state (pressure increase connection), the current value is set to 0/8 with respect to Imax, and in the second state (hold)
In the third state (reduced pressure connection), the applied current value is set to 2/8 with respect to Imax, and in the third state (reduced pressure connection), the applied current value is set to 7/8 with respect to Imax.

The control of 5OL3 is lll1a in the first state (pressure increase connection).
The current value for x is 074, the second state (hold) is 1/4 the current value for Imax, and the third state is
The state (reduced pressure connection) is to set the current value to Imax by 3/
It is set at 4.

In addition, the reason why 8 is used as the denominator in the control of 5OLI and 5OL2 is that 3 is used in the energizing current value specification code of 5OLI and 5OL2.
This is because bits are assigned. The numerator indicates a value (decimal number) expressed by 3-bit data. 4 under control of 5OL3
is used as the denominator because 2 bits are assigned to the energizing current value designation code of 5OL3. The numerator indicates a value (decimal number) expressed as 2-bit data.

A code specifying such a current value is output by the microprocessor 13 of the electronic control device 14, and in the electronic control device 14, the code is converted into an analog signal by an A/D converter, and the analog signal is converted into an analog signal. The signal is amplified by a linear amplifier, and the electromagnetic switching valve devices 5QLI to 5QL3 are energized at a level corresponding to the analog signal level.

A power supply voltage is applied to the linear amplifier as a power voltage through the main relay MRY.

When main relay MRY is open, the output of the linear amplifier is zero (de-energized), regardless of the output code of microprocessor 13.

Basic data for calculating the wheel speed by executing an interrupt every time a pulse obtained by shaping the wheel speed detection voltage arrives, counting up the arriving pulse and determining the elapse of time. Create. In addition to interrupts, calculation of wheel speed.

Creation of anti-skid control basic data, energization control, temperature estimation and protection control of the compressor motor 15.

It performs continuous long-term pressure reduction monitoring, protection control, anti-skid control (energization control of electromagnetic switching valves 5DLI to 5OL3), etc.

FIG. 2 shows the energization pattern of 5QLI to 5DL3 during anti-skid control. Referring to FIG. 2, before the start of control, the electromagnetic switching valve devices 5QLI to 5OL3 are not energized (same as the pressure increase state: 078 output energization).

At this time, for example, referring to unit 3 (FIG. 1b), mask cylinder 2 - brake hydraulic port 31 -
The wheel cylinder 6 communicates with the mask cylinder 2 through the path of hydraulic pressure control chamber 3j - control input port 3c - working chamber 3g - control output port 3b - wheel cylinder 6, and a normal brake hydraulic pressure loop (no anti-skid control) is established. loop) is formed, and the pistons 3h and 3n are located at the rightmost possible end.

The pressure increase energization pattern in the state where anti-skid control is entered is the energization pattern shown in the second column of Figure 2, and the energization pattern is 24 m.
078 energized for 5ec (same as non-energized: pressure increase) 9th 6m
3/8 to speed up the transition to the hold state for 5ec
Energization (passing type in the hold direction) and the next 42m
One unit is 72m5ec with 278 energization (hold) for 5ec.

The continuous pressure increase of the 3rd fm is brought about by continuous de-energization. As shown in the fourth column, the hold energization pattern is a continuation of 278 energizations, and the duration is indefinite and is determined depending on the results of status reading and calculation in anti-skid control, which will be described later, or in other words, the occasional situation.

As shown in the fifth column, the depressurization energization pattern of 5OLI and 5OL2 is such that one unit is 778 energizations (depressurization) for 48 m5ec and 278 energizations (hold) for the next 72m5ec.

The continuous reduced pressure in column 6 is brought about by continuous 778 energizations.

Desired pressure increase patterns and pressure decrease patterns can be obtained by various combinations of the above-described energization patterns.

For example, one unit pressure increase pattern (72πSeC or 5
4m5ec) is repeated continuously, the UP shown in Figure 3 is obtained.
As in C, the pressure increase is brought about at a fast rate.

A short hold period following a unit pressure increase pattern will result in a slightly slower rate of pressure increase as in the UP old case in Figure 3, and furthermore, a slight hold period following a unit pressure increase pattern will result in a slightly slower rate of pressure increase as in the UP old case in Figure 3. A long hold period results in a slow rate of pressure build-up, such as UPH2 in FIG.

Similarly, in the case of pressure reduction, by adding a hold period to one unit of pressure reduction and varying the length of this hold period, a pressure reduction pattern with a desired falling rate can be obtained. The concept of setting the pressure increase and decrease speeds is as described above, but in this embodiment, the hold time (see columns 2 and 5 in Figure 2) is constant, and the times of pressure increase and decrease energization are varied depending on the situation. Depending on the situation, change the length to be longer or shorter to obtain the desired pressure increase or decrease speed.

Note that even when executing a single unit pressure increase or decrease pattern, or even when in the hold state, if it is determined that it is necessary to shift to another control mode by reading the status, calculating, etc., that pattern will be executed at that time. is stopped and the next required pattern is executed.

When the brake pedal 1 is depressed and the switch BSIN is closed, anti-skid control is started under the condition classification shown in FIG. 4a. In Fig. 4a, the area marked as pressure increase hold means that the pressure increase setting state (0/8 energization: no anti-skid control) is held as is (278 energization), and is indicated by a thick downward slope to the left. The region shown is the region where the brake pressure is assumed to be insufficient and the pressure is increased continuously (pressure increase before the start of control: see FIG. 2).

After the anti-skid control (pressure increase hold) is entered in the area division shown in FIG. 4a, various control modes are entered in the condition division shown in FIG. 4b (pressure increase or pressure increase hold state). In Fig. 4b, the thick downward sloping line indicates the condition area where continuous decompression occurs, the thin downward sloping line indicates the area where pressure decreases, the thin downward sloping line to the left indicates the area where pressure increases, and the thick downward sloping line indicates the condition area where pressure continues to decrease. Areas proceeding to continuous pressure increase are shown, and white indicates areas proceeding to hold.

When proceeding to depressurization or depressurization hold, the process proceeds to various control modes according to the condition classification shown in FIG. 4c. The inclined lines etc. in FIG. 40 indicate areas similar to those in FIG. 4b.

The reason why the region to which the next step is to proceed during pressure reduction or pressure reduction hold (Fig. 4c) is shifted to the upper right than the region to which the next step is to be carried out during pressure increase or amplification hold (Fig. 4b) is due to the difference between pressure increase and pressure reduction. This is to provide hysteresis to prevent control switching.

Next, an outline of the anti-skid control by the microprocessor 13 will be explained with reference to FIG.
Estimate calculation is performed on s'. The reference vehicle speed Vs' is the higher of the average wheel speed of the front wheels and the average wheel speed of the rear axle. When the brake pedal 1 is not depressed, the control reference vehicle speed Vs is made to match the reference vehicle speed Vs'. In addition, when the reference vehicle speed Vg' decreases, the control reference vehicle speed Vg'
Calculated value reduced by 1.3G deceleration and reference vehicle speed Vg
', the higher one is set as the control reference vehicle speed Vg, and the time to set the value calculated by deceleration at 1.3G as the control reference vehicle speed Vg is 96 m.
When it reaches 5ec, the higher of the calculated value reduced by the deceleration of 0.15G and the reference vehicle speed Vs' is set as the control reference vehicle speed Vs.

Therefore, based on the acceleration/deceleration Dv of each wheel and the deviation ΔVs between the wheel speed and the control reference vehicle speed vs, either Pressure increase, pressure decrease, and hold control is performed under the condition classification shown in FIG. 4c (when the current control is in the pressure reduction mode or pressure reduction hold mode).

As shown in Figures 4b and 4C, the deviation ΔVs is Δ
When V2 = ΔVs/2 or more (when the deviation ΔVs of the wheel speed Va from the control reference vehicle speed Vg is large: when the wheel slip is large), the pressure is continuously reduced regardless of the wheel acceleration/deceleration Dv. In other words, priority is given to determining the next control mode based on the deviation ΔVs, and the brake pressure is lowered at high speed.

If the control reference vehicle speed is less than 8 km/h, all-wheel anti-skid control is not necessary, so 5QLI to 5OL3
Cut off the electricity. 8Km/h or more but +n to 10
If it is less than /h, there is no need for front wheel anti-skid control, and in order to ensure the directional stability of the vehicle, 5O
Power is cut off to LI and 5OL2, and anti-skid control for only the front wheels is stopped.

So that the hydraulic pressure of the accumulator 17 is equal to or higher than a predetermined pressure,
When the pressure is low, the motor 15 is energized when the switch PS is opened, and when the pressure is high, the motor 1 is energized when the switch PS is closed.
5 is considered to be a stop, but while the motor is energized, the estimated motor temperature value is counted up in a predetermined pattern described later, and while the motor is stopped, it is counted down, and when the estimated motor temperature value reaches a predetermined high value, the motor is stopped. . Thereafter, the estimated motor temperature value is counted down, and when the estimated motor temperature value reaches a predetermined low value, the motor is energized if the motor energization is required.

The above-mentioned anti-skid control is performed only when the average wheel speed Va of the rear axles RR and RL exceeds 20 km/h. This is done because changing the brake pressure using anti-skid control at low speeds has no particular effect and may even increase the braking distance, which can be dangerous. When anti-skid control is entered at a wheel speed exceeding 20 km/h, anti-skid control is stopped for both the front and rear axles when the control reference vehicle speed is less than 8 km/h (estimated at wheel speed of 5 km/h), and the anti-skid control is stopped at a wheel speed of 10 km/h. h
The reason why anti-skid control for only the front axle is stopped at speeds below 20 Km/h (estimated at 7 KIII/h at wheel speeds) is that the situation judgment for anti-skid control at speeds above 20 Km/h is accurate and subsequent misjudgments are avoided. Low = 31- The safety of anti-skid control is high, and once anti-skid control is activated, it is generally better to continue it until the car stops, which improves the driving stability of the car and the feel of the brakes. By being smooth. For example, if the anti-skid control stops at 20 km/h, the car will react differently to driving operations at that point, making it difficult to drive.

The reason why the speed at which anti-skid control is stopped for the front wheels and rear axle is set to 10 km/h and 8 km/h, respectively, and the vehicle speed for the front wheels is slightly higher, is to improve the directional stability of vehicle driving. When anti-skid control is entered and the car decelerates, the brake force on the rear wheels is first increased, and then the brake force on the front axle is increased, which makes steering easier and prevents the car from swaying. do not have.

If anti-skid control is performed as it is during acceleration slipping, such as when the accelerator is depressed and the brake is depressed, there is a risk that pressure reduction control will be applied and no braking will occur. Therefore, in the above-mentioned anti-skid control, the microprocessor 13 compares the wheel speeds of the rear wheels (wheels not driven by the engine) and the front wheels (wheels driven by the engine) to determine whether there is an acceleration slip. Anti-skid control is not performed when

In addition, in the above-mentioned anti-skid control, the microprocessor 13 monitors the duration of the pressure reduction mode, and when the duration of the pressure reduction mode is long (braking on a road with a low friction coefficient μ (hereinafter referred to as a low μ road)), the microprocessor 13 monitors the duration of the pressure reduction mode. , slow down the speed of pressure increase to restore brake pressure and wait for wheel speed to return. This is to avoid early locking, which is likely to occur if the pressure increase rate is high on a low μ road.

In the anti-skid control described above, if the duration of the depressurization mode exceeds a predetermined time, the microprocessor 13 refers to the wheel speed Va and determines whether the wheel speed is restored (increased).
When this happens, it is not considered abnormal and the depressurization mode scheduled for control continues. If the wheel speed Va has not recovered, it is determined that there is an abnormality and the pressure reduction mode is stopped after a predetermined period of time.

In the above-mentioned anti-skid control, the repetition cycle of pressure increase and decrease in the anti-skid control is set to the unsprung level so that the vibration of the braking force due to repeated increases and decreases in the brake fluid pressure does not synchronize or resonate with the unsprung vibration of the vehicle. It is made to be larger than the period of vibration.

The rear right wheel RL is independently anti-skid controlled, but the rear right wheel RR is controlled by adjusting the brake pressure generated by the anti-skid control of the front left wheel FL to the brake pressure for the rear wheel using a proportional control valve PVI. is applied, so the front left wheel F
It is also conceivable that the rear right wheel RR may lock during the L anti-skid control. For example, if you wrap a cheno around the front shaft,
This type of lock is likely to occur when the cheno is not wrapped around the rear shaft. In order to avoid such a lock as much as possible, the microprocessor 13 controls the rear right wheel RR to
When the brake pressure is continuously in a predetermined pressure reduction required region near the lock for a period of 2, the brake pressure control for the front left wheel FL is switched to the brake pressure control for the rear right wheel to perform pressure reduction. There is a high probability that locking of the rear right wheel RR will be avoided due to this pressure reduction.

Therefore, if the rear right wheel RR leaves the predetermined pressure reduction area after setting this pressure reduction, or if Tri (Tri
When this pressure reduction is performed for <Tt2), the anti-skid control of the front left wheel FL is restored.

Next, details of control by the microprocessor 13 will be explained with reference to a flowchart shown in the drawings.

When the power is turned on, the microprocessor 13
Execute the main routine shown in the figure and cancel the interrupt mask there. Note that this microprocessor 13 has four interrupt ports 81 to S4, among which ports S1 and S
Ports 3 and S4 can be set to enable or disable interrupt execution using interrupt mask control, but port S2 is a port that cannot be controlled by mask, and when the power is turned on, an interrupt is triggered by a signal to this port. When a signal change occurs, interrupt processing is executed.

First, the interrupt processing operation at port S1 will be explained with reference to FIG. 6a. When the signal Sl (speed pulse obtained by binarizing the voltage generated by the speed sensor 10 of the front left wheel FR) falls from the high level H to the low level L while the interrupt mask of the port S1 is released. The flip-flop of port S1 is set to execute the interrupt processing shown in FIG. 6a. That is, first, the flip-flop must be reset to wait for the next signal change (from H to L).Step 1: Hereinafter, only numbers will be written. The numbers in parentheses below indicate the step numbers), then the pulse number counter N
' to be counted up by 12), then the current time To
The value To-TI obtained by subtracting the previous time T1, that is, the elapsed time from the previous time, is compared with 6 m5ec (3).

If the elapsed time is less than 6m48C, the process returns to the step before entering the current interrupt. If the elapsed time is 6 m5ec or more, the elapsed time To-T1 is stored in the time interval register T4), the current time is updated in the previous time register T15), and the pulse number counter N'
6) Store the value N' in the pulse number register N.
, initialize the pulse number counter N' (7). And F indicates that more than 6m5ec has passed since the last time.
Set the R6msec end flag (8) and return to the step before the interrupt.

In addition, if the clock pulse is constantly counted and 6m5ec is counted inside the microprocessor 13, 6m
Set the flag OCF indicating that 5 ec has passed and return to the initial state (count time 0) and count up again in the same way 6
The internal counter with m5ec period and the clock pulse are constantly counted and 64m5ec is counted.
Set the flag TOF indicating the progress and return to the initial state (count time 0) and count up again 64m5
There is an internal counter for the ec period, and the current time To is this 6
It is obtained from the count value of a counter with a cycle of 4111 seconds.

Therefore, T and -T1 may be negative, but if they are negative, To+64m5ec-Tl is set as ro-T1.

Due to the interrupt control described above, when the FR6msec end flag is set, the number of pulses that arrived at port S1 during the time (6 msec or more) stored in time interval register T is stored in pulse number register N. Therefore, the time at which pulse counting was newly started is stored in the previous time register T1.

The rotational speed (wheel speed) of the front wheel FR is obtained by multiplying N/T by a constant, and the wheel speed can be determined based on the contents of registers T and N. The wheel speed is determined by referring to the flag in the main routine (Fig. 7b) to be described later.
Calculated when the c end flag is set.

Interrupt processing at interrupt ports S3 and S3 (6th
c and 6d) also interrupt processing at port S1 (
Since it is exactly the same as FIG. 6a), the explanation will be omitted.

The interrupt processing of interrupt port S2 is shown in FIG. 6b.

In this interrupt processing, first, the presence or absence of the initialization end flag is checked, and if it is not present, the process returns to the main routine. If there,
Steps 1-16 are exactly the same as steps 2-8 in Figure 6a.
Execute. As a result, this interrupt processing is not executed unless initialization has been completed.

Through the interrupt processing described above, data for wheel speed calculation is transferred to registers T and N at a cycle of 6III seconds or more.
The memory will be updated. Note that the interrupt is executed on the condition that there is a change in the speed detection pulse (Sl-S4), so the interrupt is not executed when the vehicle is stopped, and when the wheel speed is extremely low and the speed detection pulse period When is greater than 64 m5ec, the speed calculation value based on the data in registers T and N has no reliability at all. Therefore, the vehicle speed sensors 10゜11.12L and 12R should be set at a minimum speed of 30m5ec at the planned minimum speed of the vehicle.
It is said that voltage oscillations with a period less than ec are generated.

As a result, when the vehicle is running at this minimum speed, if the 6m5ec end flag is set, the data in the time interval register T indicates a value longer than 30m5ec (shorter than 50+++sec. In steps 147 to 15g in Figure 10a, the data To -TI in register T is referenced and it is
Longer than 5ec<50m When the value is shorter than 5ec, it is the lowest speed, and in order to set the detected wheel speed data to 0, register N is set to 0 (register N is cleared). Note that, although this minimum speed does not necessarily correspond to the vehicle speed of 0, there is no problem in calculating and controlling the vehicle with this minimum speed as 0 in terms of anti-skid control. As will be described later, since the minimum wheel speed referred to in the control is 7.7 Km/h or around it, the wheel speed (minimum speed) for setting O in the register N may be about 5 Km/h or less.

7a and 7b show the control main routine of the microprocessor 13.

To explain this main routine, when the power is turned on, the microprocessor 13 performs initialization in steps 17-24.

During this initialization, various registers, timers, and counters.

Clear the flags, etc., set the input port to the signal wait state, set the standby signal to the output port, turn on the main relay MRY, cancel the interrupt mask of ports S1, S3, and S4, and initialize. Set the conversion end flag, set the current time (count value of the 64 msec internal counter) in register T1, and set the time interval register T as follows.
Speed calculation value N/T (Actually, it is multiplied by a constant)
is set to a value of 32tnsec, which is considered to be essentially 0.

This initialization enables interrupt processing operations of the interrupt ports 51 to S4.

Next, the microprocessor 13 refers to the presence or absence of the flag OCF indicating the count over of the 6m5ec internal counter (25), and if it is present, the microprocessor 13 performs subroutine OCFMAi (anti-skid control: hereinafter, not only actual brake pressure control but also brake pressure control). It also includes control of state reading, calculation, state judgment, etc. until entering the step. Proceed to 27 and 64m5e
cReference is made to the presence or absence of a flag TOF indicating that the internal counter has overcounted.

If TOF is present, subroutine TOFMAi (motor energization control) is executed.

Details are shown in Figures 9a and 9b. ) (28), and if it exits or there is no TOF, the warning flag is set by referring to the presence or absence of a warning flag (a flag that is set when an abnormality is determined; described later) (29). Without it, the electromagnetic switching reduction device 5QLI~
Refer to the activation state of each 5OL3, and if the depressurization is not energized, clear the count registers 5QLI on counter, 5QL2 on counter, and 5QL3 on counter for monitoring the depressurization energization time of each of 5OLI, 5OL2, and 5OL3 (35 ). 5OLI.

If either 5OL2 or 5OL3 is energized under reduced pressure,
Referring to the count value 31.32), if the duration is 5 seconds or more, the decrease in brake fluid pressure continues for a long time, so in step 33a, the wheel acceleration/deceleration Dv is set to a predetermined value -0,
Compare with 2G. If it is greater than -0.2G, the wheel speed Va has recovered due to pressure reduction (deceleration has stopped) and can be considered normal, so proceed to step 36, but Dv is -0.
, 2G or less, the pressure reduction takes a long time and the return of the wheel speed is abnormally slow. Therefore, to avoid no-braking, the abnormality flag VRNFLG should be set (33), the main relay MRY should be turned off, and the electromagnetic switching valve device should be set. 5OLI, 5OL
2, 5OL3 are all de-energized (pressure increased), motor relay RLY is turned off, and energization of motor 15 is stopped (
34).

When there is a warning flag (29), when the on counter is cleared (35), or when the main relay MRY
and when motor relay RLY is turned off (34),
The input of the port BS (whether or not the brake pedal 1 is depressed) is read (36), and the read state is compared with the memory contents of the BS register (37). The initial state (no pressing of the brake pedal 1) is set.

If the comparison results do not match, it means that the brake pedal 1 has changed from not being depressed to being depressed, or vice versa. Therefore, the BS change counter will be increased by 1 count.
8), check whether the count value is 5 or more (39)
, 5 or more, the process proceeds to the next step 42, passes through the subsequent control steps, and then returns to steps 36-37. In this way, when we check the mismatch five times, the count value is 5 (we looked it up five times, and the state was the same all five times). The new state of the petal 1 is memorized (41), the BS change counter is cleared for the next reading decision (41), and the process proceeds to the next step 42. If the same reading is not obtained five times after detecting a discrepancy, it is assumed that the brake has not been depressed or released sufficiently or that the switch is simply chattering, and the process proceeds from step 37 to step 41 to clear the BS counter. , B.S.
The contents of the register are not changed to the state read. By reading the state and updating the memory in this manner, the changed state is stored in the BS register only when the brake pedal 1 changes from not being depressed to definitely being depressed or vice versa.

The next steps 42, 43, 44 and 45 are the same as the previously described steps 25, 26, 27 and 28, respectively, and therefore will not be described here.

After passing through step 45 and proceeding to steps 46 and 47, the contents of the priority counter are referred to, and if the value of the priority counter is 1, the process proceeds to step 48 in Figure 7b, and if it is 2, the process proceeds to step 51 in Figure 7b. If it is 3, the process goes to step 54 in FIG. 7b, and if it is not any of 1 to 3, the process goes to step 56B in FIG. 7c. From steps 46 to 66, the speed pulse number count value N and time interval T obtained by the interrupt processing (Figs. 6a to 6c) are
The wheel speed is calculated based on the following.

Note that if the 6m5ec end flag is not set in the interrupt process, the speed calculation data is not ready, so the 6m5ec end flag is not set.
The wheel speed is calculated only when the m5ec end flag is set.

If the wheel speeds of the front old wheel FR, front wheel FL, rear right wheel RR, and rear left wheel RL are all calculated, the calculation will take a relatively long time, resulting in a control delay, especially 6 II lsec.
Anti-skid control OCFMAi is executed every time the internal counter times out, and motor energization control TOFMAi is executed every time the 64m5ec internal counter times out.
Therefore, in calculating the wheel speed after step 46, only the wheel speed is calculated at the maximum when the 6m5ec end flag is set (that is, the 6m5ec end flag is set). I have to. In this case, if the wheel speed calculations of the front old wheel FR, front wheel FL, rear right wheel RR, and rear left wheel RL are fixed, then
The probability of entering the calculation will be different for each ring.

Therefore, by using the priority counter (register) and going through the same speed calculation flow (steps 46 to 64), step 64
The priority counter is incremented by 1, and when it exceeds a predetermined count value, it is initialized (set to 1). Therefore, when the priority counter is 1, step 48
Proceed to step 1 and refer to the presence or absence of the FL6msec end flag, and if it is found, proceed to calculate the speed of the FL (front left wheel), and when that is completed, increase the priority counter by 1 (64).
. When there is no FL6msec end flag, RL
Refer to the presence or absence of the 6 msec end flag (49), and if it is present, proceed to the RL speed calculation, and when that is completed, the priority counter is incremented by 1 (64). RL, 6rns
If there is no ec end flag, refer to the FR6msec end flag (50), and if there is, proceed to FR speed calculation (57-63), and when that is completed, the priority counter is incremented by one (64). If there is no FR6msec end flag, refer to the RR6msec end flag (50A), and if there is one, proceed to the speed calculation of R1'l, and when that is completed, the priority counter is incremented by one count.

In this way, if the priority counter is 1 when entering steps 46 and 47, as described above, FL6msec
End flag reference (48), RL6msec end flag reference (49), FR6msec end flag reference (50), and RR6msec end flag reference (50)
A), so when the priority counter is 1, the calculation priority order is FL, RL, FR, and RR.

However, when the priority counter content is 2, RL6ms
ec end flag reference (51), FR6msec end flag reference (52), RR6msec end flag reference (53), and FL6m+ec end flag reference (
53A), so when the priority counter is 2, the calculation priority order is RL, FR, RR.

It is FL.

Further, when the priority counter is 3, the PR6msec end flag is referenced (54) and the RR6msec end flag is referenced (55).

Reference to FL6msec end flag (56) and RL6
Since the process proceeds to refer to the msec end flag (56A), when the priority counter is 3, the calculation priority order is FR, RR, F.
L, RL.

Furthermore, when the priority counter is 4, RR6msec
The process proceeds with reference to the end flag (56B), reference to the FL6msec end flag (56C), reference to the RL6msec end flag (56D), and reference to the FR6msec end flag (56E), so when the priority counter is 4,
The calculation priority order is RR, FL, RL, and FR.

Due to the above priority shift, the speeds of each axis are calculated in the same order. In any case, if there is a FL6msec end flag, proceed to FL speed calculation.

If there is an RL6msec end flag, the process proceeds to RL speed calculation, and if there is a FR6msec end flag, steps 57~
The process proceeds to the speed calculation of FR 63, and when the RR6msec end flag is present, the process proceeds to the speed calculation of RR.

In the FR speed calculation, the 6m5ec end flag set in the interrupt processing (Figure 6a) is cleared for the next data processing57), and the data N of the pulse number counter N is
is set in the accumulator register for the next calculation (58).

Next, in step 59, constant multiplication AX of wheel speed = AN/T
A subroutine (MULVV) that performs N is executed.

FIG. 8a shows a subroutine for constant multiplication Mutvww. In this case, the number of pulses N is 70 compared to 10.
), if it does not exceed 10, leave N unchanged; if it exceeds it, then change the number of pulses N to 10 because it is larger than the maximum speed corresponding value.
(71). Then calculate AXN (72
). A is a constant. Next, the AN value is memorized (73),
Steps 74 to 77, which are the same as steps 25 to 45, are executed, and the process returns to step 60, where the time interval T is set in the accumulator register.

Next, in step 61, the AN/T division subroutine (Di
VVW).

FIG. 8b shows the subroutine DiVVV. In this case, calculate Vw=AN/T and memorize the calculated value Vw as the FR wheel speed (78.79), Steps 25 to 2
Execute steps 80 to 83 with the same contents as 8, return to the original, and set Vv to the accumulator register in step 62.
Set. Next, in step 63, an average value (smoothed value) calculation subroutine DiGFiL is executed.

FIG. 8c shows the average value calculation subroutine DiGFiL. In this case, smoothed value Va=(Vw −2+ 2 Vw −1+Vw) /
4 (84), then the acceleration/deceleration Dv of the smoothed value Va.
=(Va-Va-1)/T is calculated (85). Note that V W -1 is the previous calculated value, V W -2 is the previous calculated value, and Va, . . . 1 is the previous calculated value. In the following, Va will be referred to as wheel speed, and Dv will be referred to as acceleration/deceleration.

Next, update memory to Vati-Va-t register.8
6), Steps 87 to 87 with the same content as Steps 25 to 28
Execute step 90, return to step 64, increment the priority counter by 1 as described above (64), check whether the count value is 5 or not (65),
If it is not, leave it as is; if it is 5, update the count value to 1 (66), then average speed of FR and RL (front) (Va of FR + Va of FL)/2,
Then, the average speed of RR and RL (rear) (Va of RR)/2 is calculated and compared between the two (67).

If the average speed of the front is larger than the average speed of the rear, the average vehicle speed of the front should be set to the reference vehicle speed Vs69),
When the average speed of the front is less than the average speed of the rear, set the average rear speed to the reference vehicle speed Vs68)
, then return to step 25 again and perform step 25 described above.
Run the following: Repeat this below.

In the control main flow explained above, step 2
If the flag is set to O at each of 5, 42, 74, and 80.87,
If there is a CF, the next step is to execute the subroutine OCFMi that performs anti-skid control, and in step 27,
Temporary Nifrag TOF at 44, 76, 82, and 89 respectively.
If so, the next step is to execute a subroutine TOFMAi for controlling motor energization.

As explained above, OCF is set when the 6m5ec internal counter times out, and TOF is set when the 6m5ec internal counter times out.
Set when the m5ec internal counter times out. As mentioned above, the presence or absence of these flags is referenced in many steps, and if they are present, anti-skid control or motor energization control is started accordingly, so the anti-skid control OCFMAi is practically executed at a 6m5ec cycle. The motor energization control is effectively 64 m.
It will be executed every 5ec.

First, the motor energization control TOFMAi is
This will be explained with reference to the flowchart shown in FIG.

Proceeding to motor energization control, the microprocessor 13:
First, the TOF flag is cleared and the presence or absence of warning flag 51 (lag) is referred to (91). This flag is set when an abnormality is detected, which will be described later.

If there is no warning flag, the flashing counter is cleared and motor relay RLY is turned on in step 106.

Proceeds to off reference, but if there is a warning flag, the seventh
Decompression abnormality continuation flag W set in step 33 in Figure a
The presence or absence of RNFLG is checked (93), and the sensor warning flag is checked (94b).

If VRNFLG is present, set the 3-time blinking pattern data in the register 94a); if the sensor warning flag is present, set the 2-time blinking pattern data in the register 94c), main relay MRY, motor relay RLY
And the electromagnetic switching valve devices 5QLI to 5OL3 are de-energized (95). In other words, the anti-skid control (brake fluid pressure control) is set to a state (abnormality safe state).

Then, in steps 96 to 105, the warning lamp ldL is turned on for 0.5 seconds, turned off for the next 0.5 seconds, and turned on for the next 0.5 seconds as the subsequent steps progress. Controls the blinking of the awning lamp WL. After this blinking for 5 seconds, the light goes out. However, if WRNFLG is still present after 5 seconds, the blinking control is performed in the same way as described above, so that while the result WRNFLG is present, the warning lamp blinks three times at a one-second cycle every five seconds.

This blinking stops when VRNFLG is cleared. If there is a sensor warning flag, it will blink twice.

Both when this flashing control is not performed and when it is performed (during flashing control), the motor L/-RLY
(7) Refer to on and off, (106;
When FLG is set, it is turned off in step 95), and when it is off (motor stopped), the contents of the estimated temperature register Tm are compared with 40 (estimated temperature 40°C), and if it exceeds 40 (the ambient (because the temperature difference is large and the temperature decreases quickly), the contents of the estimated temperature register Tl11 are updated to the value obtained by subtracting 3 from the current value (108
).

When the content of the estimated temperature register Tm is 40 or less, compare it with 20 (estimated temperature 20°C) (109)
.

When the temperature is higher than 20, the contents of the estimated temperature register Tm are
It is updated to a value obtained by subtracting 2 from the current value (110).

Estimated temperature register T! When the contents of ll are 20 or less, a value obtained by subtracting 1 from the contents of the estimated temperature register Tm is updated to the estimated temperature register Tm (111).

If the updated memory value is smaller than 0, the contents of the estimated temperature register are updated (cleared) to 0 (112, 113).

If you update in this way, then compare the contents of the updated estimated temperature register Tm with 20ll"l), and if it is smaller than 2o, the motor energization will be stopped because the estimated motor temperature value is 80 or more and there is a risk of overheating. Clears the motor-on prohibition flag, which is set when motor energization is prohibited.

This means that motor energization is prohibited at an estimated temperature value of 80, and this prohibition is canceled when the estimated temperature value becomes less than 20. The reason why a large hysteresis is provided for inhibiting and canceling motor energization in this manner is to take into consideration the stability of control and the braking feeling of the vehicle driver. If you try to cancel the motor energization control prohibition at high temperature,
In addition, there is a high possibility that the temperature will quickly rise to the prohibition temperature, which will result in repeated prohibitions and cancellations, which will not only make automatic control unstable, but also cause the driver's braking sensation to change from time to time, increasing the possibility of trouble. Because it will be.

Next, the process proceeds to step 124, where the warning flag is referenced. If the motor relay RLY is on in step 106 described above, the motor is being energized, so the contents of the estimated temperature register Tm are compared with 40 (116).
If it exceeds 40, the motor temperature is relatively high, heat dissipation is large, and the rate of temperature rise is small, so a value obtained by adding 2 to the contents of the estimated temperature register Tm is updated and stored in the estimated temperature register Tm (117). When the content of the estimated temperature register Tm is less than 40, the content of the estimated temperature register Tm is compared with 20 (118), and when it exceeds 20, the value obtained by adding 3 to the content of the estimated temperature register Tm is used as the estimated temperature register. Update memory is stored in Tm (119). If the contents of the estimated temperature register Tm are 20 or less, the estimated temperature register T
The value obtained by adding 4 to the contents of m is updated and stored in the estimated temperature register Tm (120).

Next, set the updated value in the estimated temperature register Tm to 8.
0, and if it exceeds 80, the estimated temperature register Tm
The contents of the memory are updated to 80 (122), and it is assumed that the motor 15 is overheating, and in order to ensure the safety of the motor,
The motor-on prohibition flag is set (123), and the presence or absence of the warning flag is checked in step 124.

If there is a warning flag in step 124, the motor relay RLY is turned off (130), the extended 3-sec timer is cleared, and the process proceeds to step 133. However, if there is no warning flag, the presence or absence of the motor-on prohibition flag is checked. (125), similarly to 130), turn off the motor relay RLY, clear the extended 3 sec timer, and proceed to step 133. However, if there is no motor on prohibition flag, the open/closed state of the pressure switch Ps is read, and whether the pressure is low or high pressure is detected. Check the state (126), and if the pressure is low, turn on the motor relay RLY (132) and proceed to step 133. If it is in a high voltage state, refer to the on/off of motor relay RLY (127), but if it is not on (which is fine), the process proceeds to step 133. If it is on, it should be turned off, but if the extension timer is not set, set it. If set, the extension timer will be incremented by 1 (64msec) (128), and the value will be 3 seconds or more (300msec).
0/64 or more) 129) If not, the process proceeds to step 133 to continue the moat relay on. If the time has exceeded 3 seconds, motor relay RLY is turned off (130) and the extension timer is cleared. In this way, in a low pressure state (switch PS open), motor 1
The reason why the motor continues to be energized for 3 seconds even after the pressure increases and the switch PS is closed is to provide hysteresis in energizing and stopping the motor. If these 3 seconds are omitted, the motor 15 is energized as soon as the accumulator pressure drops slightly, and when it rises slightly, the motor 15 is immediately stopped and the motor 15 is turned on.

This is to prevent the number of off-times from becoming too large.

Proceeding to step 133, the microprocessor 13:
The code set as an output at the output port 5OL3 is referred to to see if it indicates depressurization energization. If it does not indicate reduced pressure energization, the 5QL3 on counter is cleared (134) and the process proceeds to step 137. If it indicates depressurization energization, the presence or absence of the RL pressure down stop flag is checked (135), and if so, the process proceeds to step 137.

If this is not done, the 5QL3 on counter will increase by 1 count (64
msec) (136) and proceeds to step 137.

Proceeding to step 137, the microprocessor 13 refers to the code set as an output at its output port 5OLI to determine whether or not the code indicates depressurization energization. If it does not indicate reduced pressure energization, the 5QL1 on counter is cleared (138) and the process proceeds to step 141. If the flag indicates depressurization energization, the presence or absence of the FL pressure cast flag is checked (139), and if so, the process proceeds to step 141. If it is not there, the 5QL1 on counter will be set to 1 because the pressure is being energized (brake fluid pressure is being reduced).
The count is increased (64 msec) (140) and the process proceeds to step 141.

Proceeding to step 141, the microprocessor 13 refers to the code set as an output at its output port 5OL2 to determine whether or not the code indicates depressurization energization. If it does not indicate reduced pressure energization, the 5QL2 on counter is cleared (142), and the routine returns to the original routine from which motor energization control was entered (return). If it indicates depressurization energization, the presence or absence of the FR press-in stop flag is checked (143), and if there is, the routine returns to the original routine from which motor energization control was entered (return). If it is not there, the pressure is being energized (brake fluid pressure is being reduced), so it is 5QL.
2-on counter is counted up by 1 (64msec)
(136), and returns to the original routine from which motor energization control was entered.

By the motor energization control TOFMAi described above, the motor 15 is energized when the accumulator pressure becomes lower than a predetermined pressure, and the motor 15 is stopped 3 seconds after the accumulator pressure reaches the predetermined pressure. While the motor 15 is energized, the estimated motor temperature value is increased at a speed corresponding to the range to which the estimated value belongs, and when the motor 15 is stopped, it is decreased at a speed corresponding to the range to which the estimated value belongs.

When the estimated motor temperature exceeds a predetermined value of 80, a motor on prohibition flag is set to stop the energization of the motor 15. After setting this flag, when the estimated motor 59 temperature becomes less than 20, the flag is set. is cleared to enable motor energization. In addition, when the brake fluid pressure is being reduced, among the 5QLI to 5QL3 on counters for monitoring the duration of pressure reduction, the electromagnetic switching valve devices 5QLI to 5O are displayed when the pressure reduction is energized.
Count up those corresponding to L3.

In the above-mentioned main routine, the contents of these 5QLI to 5QL3 on counters are referred to, and if it is longer than 5 seconds, the abnormality continues, so a flag WRN indicating abnormal decompression continues is set.
Set FLG. If this is set,
Motor energization control controls blinking of warning lamp WL, and for abnormality protection, main relay MRY, motor relay RLY, and electromagnetic switching valve device SQL 1 to 5O are activated.
Turn off all L3.

Next, the anti-skid control OCF M A i will be explained with reference to FIGS. 10a to 1id.

As mentioned above, the microprocessor 13 has a size of substantially 6 m5.
Proceed to anti-skid control ○CF M A i at the ec cycle. Proceeding to this anti-skid control OCF M A i, it clears the 160-flag OCF indicating the time-out of the 6 m5ec internal counter (145), resets the 6 m5ec internal counter 146), and performs the following operations as explained in the interrupt processing. The contents of the previous time register T1 assigned to the RR are stored in the memory (146A), and the time interval T of the RR explained in the interrupt processing is compared with 30m5ec and 5Qmsec (146B). If T is between them, the subsequent wheel speed calculation (7th
In order to simplify the calculation in Figure b), the contents of the pulse number register N are set to 0 (clear) (146C). and RR6
The msec end flag is set (1460). R.L.,
Similarly, steps 147 to 1 are performed for FR and FL.
50, determine the wheel speed O at 151-154 and 155-158, and if it is 0, set N to 0, and 6IIls
Set the ec end flag.

Next, the microprocessor 13 registers the BS register (7a
Refer to the data (159) in which the state read by changing the brake switch BS in the figure is stored in memory), and if it is L (brake not depressed), set the pressure increase mode counter to 3, and set the pressure decrease counter. and clear the low μ flag (160). That is, Pleikipetal 1
Initializes the status register for anti-skid control when is depressed (H).

Next, the reference vehicle speed Vs (see steps 67 to 69 in Fig. 7b) is compared with the front (F) average wheel speed Va (16
1). If it is different from the F average wheel speed Va, the reference speed Vs should be the average wheel speed of the rear (R) wheels (the R wheel speed is higher than the F wheel speed), so the process proceeds to step 174. , when the reference vehicle speed Vs is equal to the F average wheel speed Va, the F wheel speed is higher than the R wheel speed (because there is a possibility of acceleration slipping).
, RR speed and 0.875Vs (Vs = Front Va)
162), and if the RR speed is smaller than 0.875Vs, the possibility of acceleration slip is even higher, so the RL speed is compared with 0.875Vs (Vs = front Va) (163). If the RL speed is smaller than 0.875Vs, it is assumed that there is an acceleration slip, and an acceleration slip flag is set (164). If the RR speed is 0.875Vs or more or the RL speed is 0.875Vs or more, it is assumed that there is no acceleration slip and the process proceeds to step 171 to clear the acceleration slip flag.

In step 161 described above, the reference vehicle speed Vg (see steps 67 to 69 in Fig. 7b) is compared with the F wheel speed Va, and if the reference vehicle speed Vg is different from the F wheel speed Va, the reference speed Vs is determined by the average wheel speed of the R wheels (R wheel speed). speed is higher than F wheel speed)
Therefore, the process proceeds to step 174, where the reference speed Vs and the average speed of the R wheels are compared (17
4). If the reference speed Vs and the R average speed do not match, the acceleration slip judgment cannot be made (the data is not yet complete), so clear the acceleration slip flag (
171). If they match (R average speed is higher than F average speed), compare the standard speed Vs with 30Rm/h (1
75).

30R with brake off and R speed higher than F speed
At vehicle speeds above m/h, the RR and RL speeds are each compared to 0.75Vs (175A, 176),
When the RR speed or RL speed is 0.75Vs or more, the vehicle speed sensors 10, 11, 12R.

170) Clear the acceleration slip flag (171). If the RR speed and RL speed are less than 0.75Vs, compare the FR speed with 1.25Vs and 0.75vs (177.178), and if the FR speed is 1 or 25Vs higher, or 0.75
If it is smaller than Vs, the vehicle speed sensors 10, 11, 12R,
170) Clear the acceleration slip flag (171). When the FR speed is in the range of 1.25Vs to 0.75Vs, it is considered normal and no acceleration slip has occurred, so the acceleration slip flag is cleared (171).

When the reference speed Vs' is less than 30Rm/h (1
75), the reference speed Vs' is compared with 20Rm/h (179).

If the reference speed is less than 20 Rm/h, the acceleration slip flag is cleared (171).

When the speed is 20Rm/h or more, the RR speed, RL speed, FR speed, and FL speed are each compared with 5Km8, and if it is 5Km/h or less, the condition that has progressed so far is brake off, and the R average speed is 20Rm/ greater than F speed
h or more and the wheel speed is abnormally low compared to this, so at least one of the vehicle speed sensors 10, 11, 12R, 12L is abnormal and a sensor warning flag should be set. 170) Clear the acceleration slip flag. (
171).

Now, when it is determined that there is an acceleration slip and the acceleration slip flag is set (164), the RR speed and RL speed are respectively compared to 20Rm/h (165, 166), 20
At speeds exceeding Rm/h, the speed difference between RR and RL is small, so let's compare RR speed and RL speed.167.168)
, if the difference between the two is too large, the vehicle speed sensors 10, 11, 12
Assuming that at least one of R and 12L is abnormal, the sensor warning flag is set (170) and the acceleration slip flag is cleared (171). If the difference between the two is small,
Assuming that the sensor is normal and the state determination is correct, a control reference vehicle speed at the start of anti-skid control when the brake is on is set (169). This is done by setting the reference vehicle speed Vg in the control reference vehicle speed register.

When the brake is turned on, as shown in Fig. 5, control starts from deceleration region I, so as a standby preparation state, a flag indicating deceleration region ■ is set, and RL, FL
, clear the FR OCR (anti-skid required flag), clear the mode counter, control counter, high μ flag, slip counter, deceleration area counter, etc. (172
). Note that the state in which the high μ flag is cleared is the state in which the low μ flag is set. That is, when the acceleration slip flag is set (164), the low μ flag is set (164).
172). Next, the electromagnetic switching valve devices 5QLI to 5OL3 are de-energized (173), and this anti-skid control OCF
Return to the control step before entering MAi
do.

Enter anti-skid control OCFMAi, step 1
When BS=H in step 59 (brake depression), proceed to step 183 in Fig. 10b and refer to the presence or absence of the acceleration slip flag (183), otherwise, in step 188, the anti-skid control required flag OCR is set. Refer to the presence or absence of.

When there is an acceleration slip flag, the front wheels are slipping, so the R average wheel speed should be set to the reference vehicle speed Vs'' (184), and this reference vehicle speed Vs is compared with the F wheel speed (185).The F speed is Vs'. If it is smaller than , the acceleration slip state is no longer present, so the acceleration slip flag is cleared (187), and the presence or absence of the anti-skid control required flag OCR is referred to (188).

If the F speed is Vs' or more, there is a possibility that the vehicle is under acceleration slipping, but if the brake is on (BS = H) is 300
Please refer to whether or not more than m5ec has passed.186) If it has, there is a possibility that the F speed is higher than the reference speed Vs' (R average speed) due to rear wheel braking rather than acceleration slip. Since it is high, the acceleration slip flag is cleared (187), and the presence or absence of the anti-skid control required flag OCR is checked (188).

Now, in step 188, the anti-skid control necessary flag is set to OC.
The presence or absence of R (one assigned to each of FL, FR, and RL) is checked, and if it does not exist, the process proceeds to the anti-skid necessity determination shown in FIG. 10d, and at least one OCR is detected. Step 1 of Figure 10c
Proceed to brake fluid pressure control below 89.

First, the determination of whether anti-skid control is necessary will be explained with reference to FIG. 10d. First, the pressure increase mode counter is set to 3 (228), and the control reference vehicle speed Vs is compared with 20 km/h (229).

Since there is no need to start anti-skid control when the control reference vehicle speed Vs is 20 km/h or less, the process proceeds to step 169 in FIG. 10b and updates the control reference vehicle speed Vs.

In this case, the reference vehicle speed Vs' at that time is updated and stored in the control reference vehicle speed register.

If the control reference vehicle speed Vs exceeds 20 km/h, it is necessary to perform anti-skid control (brake fluid pressure control) depending on the situation, so steps 230 to 2 in Fig. 10d are performed.
At step 31, the control reference vehicle speed is updated to the one for braking. That is, if the control reference vehicle speed is calculated and decelerated at a deceleration of 1.3G, the calculated value is compared with the actual reference vehicle speed Vs', and the higher one is set as the control reference vehicle speed Vg (this is the area shown in FIG. 5). I). Next, in steps 233-238, the fourth a
It is determined in which of the anti-skid control condition categories at the start of brake-on shown in the figure, and if the condition is in the region marked as pressure increase hold in Figure 4a, steps 239 to 24
Pressure increase hold mode flag FLUPH, FRUPH at 4
Or, set RLUPH and set the anti-skid control required flag OCR to perform anti-skid control for the front right wheel (FRCONT), anti-skid control for the front left wheel (FLCONT), or anti-skid control for the rear left wheel as shown in Fig. 10c. Proceed to control (RRCONT).

Note that even if it is determined in step 234 or 238 that RL is in the pressure increase region, it is determined whether pressure reduction is set for preventing or releasing RR lock (will be described later) (there is a sudden pressure reduction flag for RR). is checked (235A), and if it is set, do not set the pressure increase.

Furthermore, when the pressure is in the continuous pressure increase region shown in FIG. 4a, the electromagnetic switching valve devices 5QLI to 5OL3 are in the pressure increase (non-energized) state at this point, so there is nothing to do and the anti-skid control is continued. Return to the control step before entering OCFMAi. Therefore, even if the brake is turned on, if the pressure is continuously increased as shown in FIG. is applied, the brake fluid pressure increases as the output fluid pressure of the mask cylinder 2 increases, the braking force increases, and eventually advances to the pressure increase hold region shown in FIG. 4a,
Therefore, through steps 233 to 244, the pressure increase hold mode flag FLUPH, FRUPH, or RLUPH is set, and the anti-skid control necessary flag OCR is set.

Now, set the pressure increase hold flag FLUPH, FRUPH or RLUPH, and set the anti-skid control required flag F.
Anti-skid control FLCONT, FRCONT or R by setting LOCR, FROCR or RLOCR
Proceed to LCONT, then anti-skid control OC
Return to the control step before entering FMAi)
Furthermore, if the anti-skid control OCFMAi is executed and the control is executed up to step 18g, the anti-skid control required flag OCR is set at this point (the anti-skid control FLCONT, FRCO is set more than once).
NT or RLCONT), the process advances from step 188 to step 189 to check whether the deceleration area is in the deceleration region ■. 1 in deceleration region I (see Figure 5)
．． Compare the value calculated by decelerating the control reference speed with 3G deceleration and the actual reference speed 190), and if the actual reference speed is larger than the calculated value, update the memory in the register with the actual reference vehicle speed as the control reference speed 191), Proceeding to step 196, the area 1 control counter is cleared. If the calculated speed is higher than the actual reference vehicle speed, the area I control counter is counted up by 1 (6 msec) L (193), and the content of the area I counter is compared with 96 m5ec (194).

If the content of the area I control counter is 96 m5ec or more, the area ■ control flag is set to calculate deceleration at a deceleration of 0.15G, and the area I control counter is cleared (195). Clear (19
6) If it is not 96m5ec or more, the area control flag is not changed in order to calculate deceleration at 1.3G.

Next, in step 197, the electromagnetic switching valve devices 5QL1 to 5O
Please refer to the energization amount specification code to L3 197, 199,
201), when reducing pressure is energized (7/8 energizing), the reduced pressure counter is incremented by 1 count (6 msec) (1
98, 200, 202).

When the reduced pressure is not energized, and when the reduced pressure counter is incremented by 1 count because the reduced pressure is energized, the control reference vehicle speed is set to 8 + n/h (203), 8 km/h.
If it is less than h, in order to end anti-skid control for all wheels, clear the anti-skid control required flag OCR, set the depressurization stop flag, and clear the control counter (210), all of the electromagnetic switching valve devices 5QLI to 5OL3. is de-energized and returns to the control step before entering the anti-skid control OCFMAi (return).

When the control reference vehicle speed is 8 km/h or more, the control reference vehicle speed is compared with 10 km/h (204). If the control reference vehicle speed is less than 10 km/h, only the anti-skid control for the front wheels is terminated, so the anti-skid control required flag OCR for FR and FL is cleared, and the FR and FL
The decompression stop flag is set and the control counter is cleared (208). And electromagnetic switching valve devices 5OLI and 5O
With L2 de-energized, the process proceeds to rear anti-skid control RLCON on the condition that the RL anti-skid control required flag RLOCR exists.

Now, in step 189, if the deceleration is not in the deceleration area ■ (that is, in the area ■), the deceleration calculation was performed as a deceleration of 0.14G. If it is larger, set the calculated value to the control reference speed 216), area ■ Count up the control counter by 1 (6 msec) L/ (217), refer to the presence or absence of the low μ flag 21B) If it is not there, there will be less slipping. Check whether 200m5ec has passed since the brake was turned on.219) If 200m5ec has elapsed, then the braking must be working, so compare the control reference speed with 7.7Km/h and make sure the speed is lower than 7.7Km/h. If it is smaller, proceed to step 214, set the area I control flag, clear the area ■ control flag (214), and clear the area ■ control counter (214).
15). Then, the process returns to step 197.

When there is a low μ flag, 200m5 from the brake on
ec has not elapsed or the control reference vehicle speed is 7, 7
When the speed is over Km/h, the brake is turned on by 30
Referring to whether 0+n5ec has elapsed (220
), if it has elapsed, set the low μ flag and clear the high μ flag 222), if it has not elapsed, skip this step 222 and refer to the elapsed time of area ■ from the contents of the area ■ control counter. (223, 224).

The elapsed time is 100, 200, 300, 450,
When the value is 600, 750, 900 or 1200m5ec, the presence or absence of the low μ flag is checked (225), and the low μ
When there is a flag, all wheel speed Va is compared with the control reference speed to check whether all the differences are within β, and when there is no low μ flag, it is checked whether all the differences are over γ (2
26, 227). If all values are within β or γ, the process proceeds to step 214, where the area control flag is set in area I, and the area ■ control flag is cleared (215). If the difference is not within β or within γ, the process returns to step 197 without changing the area control flag. When the elapsed time is 1500 msec, the area is changed to area I.

For other elapsed times, the process advances to step 197 and waits for one hour to elapse.

"Setting the control reference vehicle speed" in steps 189 to 227 described above is executed only when the OCR is set, and the elapsed time from the brake ON is executed.

Based on the correlation of the elapsed time of each region, the presence or absence of the low μ flag (presence or absence of slip), the reference vehicle speed Vg, the calculation speed of the predetermined deceleration, etc., the time series control reference vehicle speed and the speed region I or ■
, is determined.

Therefore, in the case of region (2), that is, when the reference vehicle speed (estimated vehicle speed) is decreasing as shown in FIG. 5, it is determined in steps 190 to 195 whether the conditions for transition to region (2) are satisfied.

In region ■, that is, when the reference speed (estimated vehicle speed) Vs has recovered as shown in FIG.
12-227--In step 197, it is determined whether the conditions for returning to area (3) are satisfied.

Setting the control reference vehicle speed explained above (189 to 227)
During the anti-skid control, the control reference vehicle speed is set and updated, and when the pressure is being reduced, the duration of the pressure reduction is counted.

Anti-skid control (brake fluid pressure control) of the front right wheel FR in steps 205 to 207 in Fig. 10c FRCONT
and anti-skid control (brake fluid pressure control) for the rear left wheel RL (RLCONT) are virtually the same.Anti-skid control (brake fluid pressure control) for the front left wheel FL FLC
ONT is also almost the same as the anti-skid control for the front right wheel FR, but the FL brake pressure is applied to the rear right wheel RR via the proportional control valve P■1, and then the anti-skid control for the right wheel RR is applied. Minimum anti-skid control, i.e. RR
In order to prevent wheel locking and release the wheel lock in a manner that does not impede the anti-skid control of the front left wheel FL as much as possible, it is necessary to determine whether the RR depressurization required region exists and to determine the presence or absence of the RR decompression required region and the time period in which the region exists = 75. If RR continues to exist in the area requiring decompression for Tr2 after checking =, etc., then for a longer period of Tri,
In order to prevent or release the RR lock, the 5OLI is energized under reduced pressure.

Therefore, the anti-skid control (brake fluid pressure control) flow is shown in Figures 11a to 11c for a typical FRCONT for the front right wheel, and FLC for the front left wheel with changes.
The ONT is shown in Figure 1.id.

First, let's start with the typical anti-skid control F for the front right wheel.
RCONT will be explained with reference to FIGS. 11a to 1ie.

When proceeding to FRCONT, the microprocessor 13 sets the control address of the electromagnetic switching valve device 5OL2 to 2.
45), increase the control counter by 1 count 246), and increase the FR wheel speed Va with respect to the control reference vehicle speed Vs.
Calculate the difference ΔVs = Vs − Va, and find that ΔVs is 0
(247) whether the wheel speed Va is higher than the control reference vehicle speed Vg. ΔVs is smaller than 0 (
wheel speed is higher than the control reference vehicle speed) and the presence or absence of the anti-skid control required flag OCR (FLOCR),
Without it, anti-skid control (brake fluid pressure control)
Since there is no need to energize the solenoid switching valve device 5OLI (0
/8 energization output), and the process proceeds to step 267, which will be described later.

If the control required flag FLOCR is present, refer to the presence or absence of the low μ flag (258), and if there is no low μ flag, compare the acceleration/deceleration Dv of the wheel speed (acceleration for positive, deceleration for negative) with 12G259), 12G If ΔVs is less than 0 and the acceleration/deceleration is 12, as shown in FIGS. 4b and 4c,
When exceeding G, the pressure is continuously increased regardless of the current brake fluid pressure control mode (normal brakes that do not require anti-skid control in this state: 5OL2 continuous de-energization)
), clear the pressure increase mode counter to 260.
), the process proceeds to step 262, which will be described later.

When there is a low μ flag or acceleration/deceleration Dv is 12G
If the pressure is below, it is in the pressure increase region regardless of whether you refer to FIG.
Since it is necessary to control the energization pattern for pressure increase (during control) shown in the second column of the figure, it is determined whether or not the pressure increase mode has already been entered by referring to the flag (261).

If the pressure increase mode is not set, set the pressure increase mode flag FRUPS here (262), and set the electromagnetic switching valve device 5QL2 to 0/8 output energization (263: pattern in the left column of the second column in Figure 2). checking).

Next, a pressure reduction stop flag is set (264), and a pressure increase mode counter is set (265). In this case, when the value of the pressure increase mode counter is O, it is set to 1,
If it is 1, set it to 2, and if it is 3, leave it as 3. When entering this control for the first time, the previous step 2
Since the pressure increase mode counter is set to 3 at step 28 (FIG. 10d), in this case, the content of the pressure increase mode counter is not changed at step 265.

Next, anti-skid control required flag OCR (FROCR)
266) Clear the control counter 267) and proceed to the next control step 207 (return).

If the pressure increase mode is set, it means that the pressure increase mode has already been entered, so steps 261 to 26
Proceed to step 8, refer to the elapsed time since entering the pressure increase mode (268), and the elapsed time is 6 m5ec (set the pressure increase mode (262, 263), then set the next cycle (6 ms).
ec) later entered OCFMAi], the contents of the decompression counter are referred to in steps 269 and 271, and if the contents of the decompression counter are 500m5ec or more, the slip is large and the brake fluid pressure has been reduced for a long time. Since the pressure is being reduced, the low μ flag is set, and in order to reduce the pressure increase rate (shorten the O/8 energization time in pressure increase mode), first count up the control counter by 1 (6 msec). (Add progress) L (270
), the value obtained by subtracting 48m5ec from the contents of the decompression counter is updated and set in the decompression counter.

Next, count up another 2 (add 12 msec elapsed)
(273). The content of the decompression counter is 500m5ec
If it is less than 48m5ec or more, the low μ flag is set and the control counter is counted up by 2 (12ms
ec progress) (273). Then, the value obtained by subtracting 48m5ec from the contents of the decompression counter (remaining production reduction amount deducted by pressure increase) is updated and set in the decompression counter (2
74).

When the content of the decompression counter is smaller than 48 m5ec, the control counter is not counted up and the decompression counter is cleared (272). In this case, 6
By clearing the pressure reduction counter, the pressure increase of m5ec is offset from the production decrease.

By the above control counter count-up processing, the pressure increase is set (262, 263) and then 6m5
When ec has passed, depending on the previous depressurization state (road friction coefficient), if the depressurization state was long (low μ), the low μ flag is set, and the pressure is increased (078 energization:
Count the elapsed time (de-energized) longer than the actual elapsed time (control counter), and shorten the actual time of pressure increase energization (078 energized: refer to the pattern in the left column of the second column in Figure 2). (Slows the rise in pressure). In other words, the pressure increase time is set according to μ.

If it is not 611ISeC in step 268, refer to the elapsed time since entering the pressure increase mode in steps 275, 277, 279 and 282, and if it is 24m5ec (4 counts), the energization instruction code of the electromagnetic switching valve device 5OLI is set to 378 energization. Change the level to something that indicates - 3
If it is 0m5ec (5 counts), set the energization instruction code to 2.
/8 Changed to indicate the energization level, 72m5ec
or more (12 counts or more), steps 262-2
67, reset the pressure increase mode flag FLUPS, set the energization instruction code to 078 energization level (non-energization), and control the pressure increase mode again (see 21 in Figure 2).
1 left column).

When it is less than 72m5ec (12 counts), further Δ
Compare Vs with 0 (276), and if it is less than O, proceed to the next step (207) (return), but if it is more than 0, the pressure increase mode is set at this point, so step 4b
In order to determine which control mode to transition to as shown in the figure (condition classifications referred to in pressure increase mode and pressure increase hold mode), the next control mode in the pressure increase mode and pressure increase hold mode shown in Figure 11b is determined. move on.

Note that the reason why the judgment does not proceed to the next control mode when ΔVs
Next control mode classification conditions in pressure increase hold mode (No. 4b)
(Figure) are exactly the same, so in steps 247 to 259, the next control mode is determined and transferred when ΔVs<O, and only when ΔVs≧O, the pressure increase mode/pressure increase hold mode is activated as described above. In order to determine the control mode to which the transition should be made, as shown in Figure 4b (condition classifications referred to in pressure increase mode and pressure increase hold mode), the next control mode in the pressure increase mode and pressure increase hold mode shown in Figure 11b is determined. Proceed to the determination.

As a result of comparing ΔVs with 0 in step 247, ΔVs
If ≧0, compare ΔVs with 1/2Vs (reference vehicle speed)248), and if ΔVs is larger than that, the next control mode will be continuous pressure reduction regardless of the current control mode, so set the pressure reduction mode flag FLDPS. Set 249)
, set 5OLI to 778 energization 250), clear the pressure increase mode counter 251), and proceed to step 266.

If ΔVs is less than 1/2Vs (reference vehicle speed), compare Dv with 20G (252), and if Dv is greater than 20G (because the next control mode is continuous pressure increase), compare the reference speed Vs with 30Km/h. If Vs is large, the high μ flag is set, the low μ flag is cleared (254), the pressure increase mode counter is cleared (255), and the process proceeds to step 262. Vs
is smaller than 30 Km/h, the μ flag is left as is and the process proceeds to step 255.

If Dv is smaller than 20G, step 299 (11th
Proceed to Figure c).

When proceeding to the determination of the next control mode in the pressure increase mode/pressure increase hold mode shown in FIG. = Vs - Va 8Km/
h, and if ΔVs is greater than that, the pressure reduction mode flag FLDPS is set (249), and the electromagnetic switching valve device 5
Set the OLI to 778 energization (250), clear the boost mode counter (251), and proceed to step 266. If ΔVs is less than 8 Km/h, refer to the contents of the pressure increase mode counter (289, 290), and if it is 1 (entering the first pressure increase mode after executing the pressure reduction mode more than once), Since the pressure increase may be continued as it is, the process returns (transition to step 207). If the content of the pressure increase mode counter is 2 (the second pressure increase mode control has been started after executing the pressure reduction mode more than once), the value of the pressure increase mode counter is 5.
OLI is energized (hold energized after pressure increase 0/8):
291)
If energization is in progress, the process returns to continue increasing the pressure (to complete one cycle of pressure increase energization). If the current is not being applied, it means that the required pressure increase has been completed, so the process proceeds to step 249 for pressure reduction mode control. When the content of the pressure increase mode counter is 3, it means that the pressure increase mode is being executed for the first time after the brake is turned on. (This is caused by leaving it at 3), and the next control determination is depressurization mode (
(see FIG. 4b), the process proceeds to step 249 and subsequent steps for pressure reduction mode control.

In this way, in the pressure increase mode control for the first time after the brake is turned on, the reason why the next control mode is determined to be the pressure decrease mode and then immediately proceeds to the pressure decrease mode control is to prevent pressure increase too much (wheel lock). be. After that, when the pressure reduction mode control is executed at least once (this clears the pressure increase mode counter), in the subsequent pressure increase, the pressure increase mode control must be repeated at least twice as described above. This is to make the brake fluid pressure longer, and as a result, when there is a pressure reduction, the pressure reduction time will inevitably become longer, and the period of rise and fall of the brake fluid pressure will be lengthened. By making it longer in this way, the vibration period of the braking force due to the vertical movement of the brake fluid pressure becomes significantly longer than the period of the vehicle's unsprung vibration, which causes amplification of the unsprung vibration due to resonance, synchronization, etc. No. In other words, once the pressure is increased, the pressure increase mode control (left column of the second column in FIG. 2) is repeated twice in succession to prevent resonance with unsprung vibration.

Even in these two consecutive pressure increase mode controls, the brake fluid pressure has been lowered once by the previous pressure reduction, so there is no risk of the pressure being increased too much (wheel lock).

Referring again to step 282 in Figure 11b. If the wheel acceleration/deceleration Dv is equal to or greater than 14G in step 282, Dv is compared with 12G (283). Dv is 12G
If it is smaller than α, compare ΔVs with α (292), and if it is greater than α, the next control mode is continuous pressure reduction or pressure reduction, and in any case, the pressure reduction mode should be executed, so step 28
Step 8 proceeds to continue pressure increase or pressure decrease mode control in the same manner as the condition determinations from step 288 onwards.

When it is less than α, the next control mode is hold (currently pressure increase mode, pressure increase hold: hold after pressure increase, brake fluid pressure is held in the increased state), so step 294) Set the flag to indicate pressure increase hold mode via 293.
8 energization 295) Proceed to step 266. Note that when the process proceeds to step 293 after the next 6 m5 ec, the pressure increase hold mode has been set, so the process returns from step 293.

In other words, when the pressure increase hold mode is entered, until the condition becomes other than the hold mode by referring to the condition classification in Fig. 4b,
Continue holding.

Refer again to step 283. Dv in step 283
If it is 12G or more, compare ΔVs with α (284), and if it is smaller than α, the next control mode will be pressure increase, so check whether the current mode is pressure increase mode or pressure increase hold mode (297). , 298), if it is the pressure increase mode, it returns as is, and if it is the pressure increase hold mode, it proceeds to step 262 to set the pressure increase mode.

If ΔVs is greater than or equal to α in step 284, ΔVs is compared with β (285). If ΔVs is smaller than β, Dv is compared with −1.3G in order to determine whether the hold mode or pressure increase mode should be selected (296). If Dv is smaller than -1.3G, the hold mode (pressure increase hold mode) should be selected, so in step 293 and subsequent steps, the current mode is referred to and if the current mode is the pressure increase mode, the pressure increase hold mode is selected. Set the mode 294), 5O
Set LI to 2/8 energization (295), step 26
Proceed to step 6. If the current mode is the pressure increase hold mode, no change is required and the process returns.

If Dv is -1.3G or more, it is necessary to set the pressure increase mode, and the current control mode is referred to, and if it is the pressure increase mode, it returns as is, and if it is the pressure increase hold mode, it goes to step 262. Proceed (297, 298).

Refer to step 285 again. At step 285 ΔV
If s is greater than β, compare ΔVs with γ286),
If ΔVs is larger than γ, the next control mode is the pressure reduction mode, so the process proceeds to step 288.

When ΔVs is less than γ, Dv is compared with 6G287)
, If Dv is 6G or less, the next control mode is the pressure reduction mode, so the process proceeds to step 288.

If Dv exceeds 6G, the next control mode is the pressure increase mode, so the process advances to step 297.

Next, the determination of the next control mode in the pressure reduction mode and pressure reduction hold mode from step 309 onward in FIG. 11c will be explained.

The current mode is referred to (309), and if it is the decompression mode, the duration of the decompression mode is read from the contents of the decompression counter and compared with 120 m5ec (323).

If 120m5ec or more has passed, one cycle of depressurization control (
This means that the left column of column 5 in Figure 2 has been completed.
Proceed to step 245. When it is less than 120m5ec, the content of the decompression counter is changed to 48m5ec (decompression energization time:
324), 48m5e
If c, set 5OLI to 278 energization (hold) 325) L, Proceed to step 313, 48m
If it exceeds 5ec, the process advances to step 313. In step 313, Dv is compared with -1 and 3G, and Dv is -1.
, 3G or less, Dv is compared with -12G in step 327, and if Dv is greater than -12G, the process proceeds to step 330. If Dv is less than 112G, refer to the high μ flag, and if it is present, proceed to step 328; otherwise, step 2
Proceed to step 49.

Now, if it is determined in step 309 that the mode is not the reduced pressure mode, it is checked whether the mode is the reduced pressure hold mode or not (310), and if it is not the reduced pressure hold mode (this is impossible), the process returns. When in decompression hold mode,
Refer to the contents of the control counter and compare it (decompression hold time) with 150m5ec (312), 1
If it is 50 m5ec or more, it is considered that the pressure reduction is insufficient, and the process proceeds to step 249, where the pressure reduction mode is set. 150m5e
If it is less than c, Dv is -1, compared to 3G (313)
, Dv is -1.3G or less, it is a depressurization or continuous depressurization, so the process proceeds to step 327. If it exceeds -1.3G, ΔVs is compared with α (314). If ΔVs is smaller than α, the next control mode is the pressure increase mode, and the process proceeds to step 262 and subsequent pressure increase settings.

When ΔVs is greater than α, Dv becomes -0.3 compared to 6G.
15) If Dv is -0.6G or less, the next control mode is pressure reduction mode or continuous pressure reduction mode, so step 33
Go to 0 to set decompression mode. Dv is -0.6G
If it exceeds β, ΔVs is compared with β in step 316, and if ΔVs is smaller than β, the process proceeds to step 262 and subsequent steps to set the pressure increase mode. If ΔVs is greater than or equal to β, Dv is compared with O,'6G in step 317, and Dv is 0.6G.
If it is below, the process proceeds to step 330, but Dv is 0.6G.
If Dv exceeds 6G, compare Dv with 6G318), and if Dv exceeds 6G, compare ΔVg with γ329), γ
If this is the case, the next control mode is the reduced pressure hold mode, so the process proceeds to step 320. If it is less than γ, the pressure is increased, and the process proceeds to step 262, where the pressure increase mode is set.

When Dv is 6G or less in step 318, Δ
Compare Vs with γ (319), and if it is greater than or equal to γ, the next control mode is the pressure reduction mode, and the process proceeds to step 330. γ
If it is less than that, it is in decompression hold mode, so step 3
Proceed to set vacuum hold mode below 20.

As explained above, the parameter classification for determining the next control mode is determined in steps 248, 282 to 291 and 299 to 32 as shown in FIG. 4b and FIG.
As shown in 2, first determine the acceleration/deceleration by ΔVs, then set the acceleration/deceleration reference value individually for each division of ΔVs, and if it is large, set a rough reference value according to ΔVs, and then set the reference value more roughly than the reference value. Rather, the determination is made based on ΔVs, and where ΔVs is small, a fine reference value is set so that the determination is made based on acceleration/deceleration Dv rather than ΔVs. This provides stable and appropriate anti-skid control. ΔVs
In the region >(1/2)·Vs, it is considered that the wheel slip is large and immediate pressure reduction is required, so the process proceeds to pressure reduction without referring to acceleration/deceleration Dv (248-249). Δ
In the region of Vs>(1/2)·Vs, the reference value of acceleration/deceleration Dv is set to infinity.

In the pressure increase mode or pressure increase hold mode, the next control mode is determined according to the flow in FIG. 11b based on the data in FIG. The next control mode is determined in the flow of 328, and in FIGS. 4b and 4c, the acceleration/deceleration G that differentiates between pressure reduction and hold, the acceleration/deceleration G that differentiates between hold and pressure increase, and pressure increase and pressure decrease are Since the acceleration/deceleration G to be classified is set to the low acceleration side in Fig. 4b and to the high acceleration side in Fig. 40, there is no high frequency switching from pressure increase to pressure decrease or vice versa. This eliminates vehicle vibration and the driver's sense of abnormality. Furthermore, since a hold area (pressure reduction hold, pressure increase hold) is inserted between the pressure reduction area and the pressure increase area, the probability that brake pressure control will suddenly change from pressure increase to pressure reduction or vice versa is low. Therefore, vibration is less likely to occur, and power hydraulic pressure is consumed less. After brake pedal 1 is depressed, anti-skid control (brake fluid pressure control) is entered on the condition that the estimated vehicle speed is 20 km/h or higher, which is the first value, and anti-skid control is activated when it is less than 2 (lK+n/h). It doesn't fit in.

This is step 1 if there is a step on the plate I.
59 to step 183 and then step 18
4 to 187, the presence or absence of the anti-skid required flag OCR is checked in step 188, and if it is not present (anti-skid control has not yet entered), the process proceeds to step 228 and then to step 229, where the control reference vehicle speed is set. is 2
If the speed does not exceed 0 km/h, the process returns to step 169 and does not enter anti-skid control, but it is determined whether anti-skid is necessary on the condition that the speed exceeds 20 km/h (steps 233 to 244). A flag OCR indicating this is set in step 240, 242 or 244, and the anti-skid control (brake fluid pressure control) 20
5, 206 or 207.

Once anti-skid control is entered, if brake pedal 1 is continuously depressed (anti-skid required flag OC
R is set), in step 203 the control reference vehicle speed is compared with 8 Km/h (end speed regarding rear axle anti-skid control: second value), and in step 204 the control reference vehicle speed is set to 10/Km ( When the control reference vehicle speed becomes less than 10/Km (compared with the end speed for anti-skid control of the front axle (second value)), the flag OCR is cleared to end the anti-skid control of the front wheels, and the electromagnetic switching valve device 5
OLI and 5QL2 are de-energized and the control reference vehicle speed is 8KI.
When the speed becomes less than Il/h, the flag OCR is cleared and the electromagnetic switching valve devices 5OLI, 5OL2, and 5OL3 are de-energized in order to end anti-skid control for the front and rear wheels, so when the speed is 20 km/h or more. Once anti-skid control (brake fluid pressure control) is started, anti-skid control continues for the front wheels until the estimated speed becomes less than 10 km/h, and for the rear axle until the estimated speed becomes less than 8 km/h. This anti-skid control is effective for 20km
/h or more, the initial state detection of the control is accurate, and since it continues continuously according to a predetermined logic, it has high continuity and stability, so it does not give the driver a sense of abnormality. and does not significantly increase braking distance. Anti-skid control will not start when the brake pedal 1 is depressed at a speed of 20+n/h or less, but since the speed is low, the possibility of wheel lock is low, and the driver's brake operation is sufficient to respond to the situation. In addition, even if the wheels lock, the speed will be low, so the operability and stability of driving are higher than when the anti-skid control is applied even at speeds of 20 km/h or less.

FR anti-skid control FRCONT explained above
An anti-skid control RLCONT similar to RLCONT is similarly performed for RL.

Next, the anti-skid control FLCONT for the front left wheel FL will be explained with reference to FIG.

In this FLCONT, first, the FRCO shown in Fig. 11a is
Similar to steps 245 and 246 of NT, set the control address of the electromagnetic switching valve device 5OLI (245A)
, increments the control counter by 1 (24
6A). And steps 247A, 340 to 342, 344 to prevent RR lock, which are different from FRCONT.
Execute 355. FRCONT steps 247-3
FL anti-skid control, which is completely similar to the control in step 30, is executed in step 343.

First, to explain the difference, that is, the control operation for preventing RR lock, in step 247A, ΔVs(
It is checked whether the deviation of the RR speed from the reference speed exceeds Vs/2 (Vs is the reference speed). That is,
Check whether RR is in the high slip region (rapid depressurization required region: thick line descending to the right in FIGS. 4b and 4c). If not exceeded (not in the region requiring rapid depressurization), the RR lock flag is cleared (354), the RR rapid deceleration flag is cleared (355), and the process proceeds to step 343. Step 246 in Figure ■lc
Exactly the same control as FRCONT of ~330 is performed for FL. For example, if you are driving on a snowy road and stepping on the brake with the front wheel wrapped with a chenno but not the rear wheel,
Since the slip rate of the front left wheel FL is low and pressure increase is set in the anti-skid control (343), the rear right wheel R
The slip rate of R is high, and ΔVs of RR is Vs/2 (V
If s exceeds the reference speed), the presence or absence of the RR lock flag is checked in step 340, and if there is no RR lock flag, the RR lock flag is set (344), the timer Tr2 is set (345), and the process proceeds to step 343. and ΔVs of RR
continues to exceed Vs/2 (Vs is the reference speed),
Since the RR lock flag is set, it waits for Tr2 to time out (342). That is, ΔV of RR
Even if s exceeds Vs/2 (Vs is the reference speed), the process does not immediately proceed to the setting of sudden pressure reduction for preventing RR lock (346 to 352). When Tr2 times out, ΔVs of RR
Since the state in which the speed exceeds Vs/2 (Vg is the reference speed) has continued for more than Tr2, proceed to the setting of sudden pressure reduction to prevent RR lock (346 to 352), and first set the FL pressure reduction mode FLDPS.346 ), set the RR sudden pressure reduction flag 346), set timer T r 1 348), set 5OLI to 7/8 energization (6W in Figure 2) 349), clear the pressure increase mode counter. do(
350), sets the FL OCR and clears the control counter (352). As a result, brake pressure reduction of RR (and FL) is started. After that, check whether the RR ΔVs continues to exceed V+/2 (Vs is the reference speed) (247A), and if it does not exceed it, clear the RR lock flag (354), and clear the RR rapid decompression flag (355A). ) Proceeding to step 343, FL anti-skid control is performed, and in this control, the energization bias of 5OLI is switched from the 778 bias for rapid pressure reduction to the energization bias for FL brake pressure control. After setting the sudden pressure reduction to prevent RR lock, RR's ΔVs continues to exceed Vs/2 (Vs is the reference speed), and when Tri finally elapses, RR's ΔVs exceeds Vs/2 (Vs is the reference speed). 354), clear the RR rapid decompression flag (35).
5) Proceed to step 343 to perform FL anti-skid control, and in this control, the energization bias of 5OLI is switched from 7/8 bias for rapid pressure reduction to energization bias for FL brake pressure control, and then Also, when proceeding to FLCONT, proceeding from step 247A to 340-344-345, 3
Proceed to step 43. Therefore, when the FL anti-skid control in step 343 causes the RR to reach the region where rapid depressurization is required, the FL anti-skid control during Tr2 is
During ri, rapid pressure reduction for RR lock prevention or lock release is performed, and during the next Tr2, FL anti-skid control is executed by repeated switching. Tri(Tr
Since it is set to 2, the common brake pressure control for FL and RR is mainly based on the FL anti-skid control (this is the same as the FR anti-skid control FRCONT described above), and the R
When R is about to lock, the brake pressure is suddenly reduced to lower the RR slip, and if this continues for a maximum of T'rl, the anti-skid control is returned to FL, using time-division switching control.

By setting the brake hydraulic system and anti-skid control as explained above, even if a simple brake control hydraulic system using three sets of brake pressure control units is adopted, FR and RL
In addition to controlling the appropriate brake pressure with individual anti-skid control to ensure base braking force and base steering performance, this common brake pressure control for FL and RR also allows
Since the L and RR anti-skid controls are balanced, the stability of the brake and the stability of the steering performance due to the anti-skid control are further improved.

In the above embodiment, common brake pressure control is applied to FL and RR, but it is also possible to perform independent brake pressure control on each of FL and RR, and to perform common brake pressure control on FR and RL. good.

〔Effect of the invention〕

As described above, the present invention individually controls the brake pressure of the first front wheel (for example, FR) and the second rear wheel (RL) diagonally behind the front wheel, and Since the rear first wheel (RR) is configured to perform common brake pressure control, there are three sets of brake pressure biasing units (3, 4).
, 5), and the brake pressure is independently controlled for the first front wheel and the second rear wheel, which are in diagonal positions, and in addition, at least one of the second front wheel and the first rear wheel is effective. Since the brake pressure is controlled accurately, appropriate brake pressure control and steering performance are ensured for at least three wheels.

[Brief explanation of the drawing]

FIG. 1a is a block diagram showing the system configuration of an embodiment of the present invention, and FIG. 1b is a sectional view showing details of the configuration of the hydraulic pressure control valve unit 3 shown in FIG. 1a. FIG. 2 is a plan view showing the energization pattern in which the microprocessor 13 energizes the electromagnetic switching valve devices 5QLI to 5QL3 in the brake fluid pressure control of the embodiment, and FIG. 3 shows the brake fluid obtained by combining various energization patterns. A graph showing how the pressure increases and decreases; FIG. 4a is a graph showing the relationship between the vehicle running state and the control mode when anti-skid control is entered;
Fig. 4b is a graph showing the next control mode in light of vehicle running conditions when anti-skid control is being performed in pressure increase mode or pressure increase hold mode, and Fig. 4c is a graph showing anti-skid control in pressure reduction mode or pressure reduction hold mode. This is a graph showing the next control mode to proceed to during anti-skid control in light of vehicle running conditions, and FIG. It is a chart. 6a, 6b, 6c and 6d are flowcharts showing the interrupt processing operation of the microprocessor 13, and FIGS. 7a and 7b are flowcharts showing the interrupt processing operation of the microprocessor 13.
Figures 8a, 8b and 8c are flowcharts showing the subroutine for calculating wheel speeds, and Figures 9a and 9b are for motor-equipped vehicles. Flowchart showing control (subroutine), No. 10a
, IOB, FIG. 10c, and FIG. 10d are flowcharts showing anti-skid control (subroutine),
Figures 11a and 11b. Figures 11e and 11d show anti-skid control (electromagnetic switching valve device energization control: subroutine) that actually controls brake fluid pressure during anti-skid control (Figures 10a, 10b and 10c). It is a flowchart. FIGS. 12 and 13 are block diagrams showing the configuration of a conventional anti-skid control brake hydraulic system. 1: Brake petal 2 Brake master cylinder (1,
2 nib brake instruction means) 3: Hydraulic pressure control valve unit (third brake energizing means) 4:
Hydraulic pressure control valve unit (first brake energizing means) 5: Hydraulic pressure control valve unit (second brake energizing means) 3a to 3h:
Bypass valve devices 31 to 3n: hydraulic control valve devices 6.7, 8.9 Ni brake wheel cylinder 10.1
1, 12R, 12L: Speed sensor (means for detecting wheel rotational speed) 13: Microprocessor (reference speed detection means; brake control means) 14: Electronic control device 15: Electric motor 16: Pump 17: Accumulator pps Ni brake fluid Pressure source device RLY: Motor relay MR'/: Main relay 1i1L: Warning lamp BSV Ni-brake operation detection switch PS: Pressure detection switch BSV: Reservoir voice 4a figure Lf: ■S°3%2g Temperature 0.3 Kmh figure 4b Romoto-IL/Do N Dojo Kosui Shil Masugo Sugigo JVs: Vs -Va ■a: Kurumahima contract. VS: System #f Grave quasi-shaku figure 4c - et nl - East figure 98 "Ku yen"

Claims (4)

[Claims] (1) Brake instruction means: A first control unit that controls the brake pressure of the brake attached to the first front wheel in response to a brake pressure instruction from the brake instruction means and a first control instruction that includes at least pressure reduction. Brake energizing means: energizing the brake attached to the second rear wheel diagonally behind the first front wheel in response to a brake pressure instruction from the brake instruction means and a second control instruction including at least pressure reduction. Second brake energizing means for controlling brake pressure; Braking of the second front wheel and diagonal biasing of the second front wheel in response to a brake pressure instruction from the brake instruction means and a third control instruction including at least pressure reduction. A third brake energizing means for controlling the brake pressure of the brake pressure pipe communicating with the brake of the rear first wheel; at least the first front wheel, the second rear wheel, and the second front wheel.
means for detecting the rotational speed of the wheels; reference speed detection means; or brake control means for applying it to the third brake control means; an anti-skid control device comprising: (2) The brake instruction means is a brake master cylinder that generates brake instruction hydraulic pressure to the first output port and the second output port in response to depression of the brake pedal;
The anti-skid according to claim 1, wherein the brake energizing means and the second brake energizing means are connected to the first output port, and the third brake energizing means is connected to the second output port. Control device. (3) The means for detecting the rotational speed includes means for detecting the rotational speed of the first rear wheel; the brake control means sends a third control instruction to reduce the pressure when the first rear wheel is in a predetermined pressure reduction region. Tr shall be given a specified period of time from that instruction.
The anti-skid control device according to claim 1, wherein if this pressure reduction instruction is continued for a period of 1, the control instruction is returned to the third control instruction corresponding to the second front wheel. (4) The means for detecting rotational speed includes means for detecting the rotational speed of the first rear wheel;
If the third control instruction continues for
2. The anti-skid control device according to claim 1, wherein when the predetermined pressure reduction region continues for 2 and the pressure reduction instruction is continued, the anti-skid control device returns to the third control instruction corresponding to the second front wheel.