JP2000255407A - Hydraulic brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always properly control wheel cylinder pressure by providing a response characteristic detecting means for detecting a response characteristic of solenoid valves, and correcting a driving signal according to the detected response characteristic in a hydraulic brake device for controlling the wheel cylinder pressure via the solenoid valves. SOLUTION: Solenoid valves for controlling supply/discharge of a brake fluid to wheel cylinders 44, 46 of left/right front wheels are controlled by an ECU 10. In detecting a response characteristic of holding solenoids 36, 38 and pressure reducing solenoids 52, 54 of the respective solenoid valves to a driving signal from this ECU 10, when an IG switch 84 is turned on, a shift lever is in a P range and a parking brake switch 88 is in an ON state, respective solenoids are driven to be turned on and off in the prescribed duty ratio. A change degree of wheel cylinder pressure, that is, a pressure increasing gradient and a pressure reducing gradient are determined from output of hydraulic sensors 80, 82. The response characteristic is determined according to this change degree correct the driving signal according to the detected response characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake device, and more particularly, to a hydraulic brake device having an electromagnetic valve communicating with a wheel cylinder and controlling the wheel cylinder pressure based on a drive signal applied to the electromagnetic valve. About.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open Publication No.
As disclosed in No. 8, a hydraulic brake device capable of executing antilock brake control (hereinafter, referred to as ABS control) is known. The ABS control is a control for increasing or decreasing a wheel cylinder pressure generated in a wheel cylinder in order to prevent a wheel from slipping on a road surface. The above-mentioned conventional apparatus is provided with a hydraulic pressure adjusting means communicating with the wheel cylinder, and realizes ABS control by increasing or decreasing the wheel cylinder pressure based on a drive signal applied to the hydraulic pressure adjusting means.

[0003]

By the way, even if a drive signal is given to the fluid pressure adjusting means, the fluid pressure adjusting means is properly driven in accordance with the drive signal due to a manufacturing error or the like of the fluid pressure adjusting means. In other words, the response characteristic of the hydraulic pressure adjusting means to the drive signal may not be the desired characteristic. When such a fluid pressure adjusting means is mounted on a vehicle, the wheel cylinder pressure may not be appropriately increased or decreased, and the slip state of the wheels may not be quickly released. In this regard, in the above-described conventional hydraulic brake device, the response characteristics of the hydraulic pressure adjusting means are not considered, and an appropriate wheel cylinder pressure may not be generated in the wheel cylinder.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a hydraulic brake capable of appropriately controlling a wheel cylinder pressure even when a response characteristic of a hydraulic pressure adjusting means does not become a desired characteristic. It is intended to provide a device.

[0005]

The above object is achieved by the present invention.
In a hydraulic brake device comprising an electromagnetic valve communicating with a wheel cylinder and controlling a wheel cylinder pressure based on a drive signal applied to the electromagnetic valve, a response characteristic detection for detecting a response characteristic of the electromagnetic valve Means and a drive signal correcting means for correcting the drive signal in accordance with the response characteristic.

In the present invention, the wheel cylinder pressure is controlled based on a drive signal applied to the solenoid valve. The response characteristic detecting means detects a response characteristic of the solenoid valve. The drive signal applied to the solenoid valve is corrected according to the response characteristic detected by the response characteristic detecting means. Therefore, even when the response characteristics of the solenoid valve do not become the desired characteristics, it is possible to guide an appropriate wheel cylinder pressure to the wheel cylinder.

According to a second aspect of the present invention, in the hydraulic brake device according to the first aspect, the response characteristic detecting means detects a change in the wheel cylinder pressure with respect to a predetermined drive signal. This is achieved by a hydraulic brake device characterized by detecting the response characteristic.

In the present invention, the response characteristic detecting means detects a response characteristic of the solenoid valve based on a change in wheel cylinder pressure with respect to a predetermined drive signal. When the response characteristic of the solenoid valve is low, the wheel cylinder pressure gradually increases or decreases as compared with a desired gradient. On the other hand, when the response characteristic of the solenoid valve is excessively high, the wheel cylinder pressure is increased or decreased more quickly than the desired gradient. Therefore, the response characteristic of the solenoid valve can be grasped based on the change in the wheel cylinder pressure with respect to the predetermined drive signal. The drive signal applied to the solenoid valve is corrected according to the response characteristics. Therefore, according to the present invention, the wheel cylinder pressure can be appropriately controlled even when the response characteristic of the solenoid valve does not become the desired characteristic.

[0009]

FIG. 1 is a system configuration diagram of a hydraulic brake device according to an embodiment of the present invention. The hydraulic brake device according to the present embodiment includes an electronic control unit (hereinafter referred to as an ECU).
The ECU 10 is controlled by the ECU 10 to generate a braking force for braking the wheels.
FIG. 1 shows only portions of the hydraulic brake device of the present embodiment that correspond to the left and right front wheels FL and FR.

The hydraulic brake device according to the present embodiment includes a brake pedal 12. A brake switch 14 is provided near the brake pedal 12. The brake switch 14 outputs an ON signal to the ECU 10 when the brake pedal 12 is depressed. EC
U10 determines whether or not the brake pedal 12 is depressed based on the output signal of the brake switch 14.

A vacuum booster 16 is connected to the brake pedal 12. Vacuum booster 16
When the brake pedal 12 is depressed, an assist force having a predetermined boosting ratio with respect to the brake depression force is generated. The vacuum booster 16 has a master cylinder 1
8 is fixed. The master cylinder 18 includes a first hydraulic chamber 20 and a second hydraulic chamber 22 therein.
In addition, a reservoir tank 24 is provided above the master cylinder 18. The first hydraulic chamber 20 and the second hydraulic chamber 22 in the master cylinder 18 are connected to the brake pedal 12.
If the depression of the tank has been released, the reservoir tank 24
When the brake pedal 12 is depressed, the reservoir tank 24 is disconnected. When the brake pedal 12 is depressed, a master cylinder pressure Pm / c corresponding to the assist force transmitted from the vacuum booster 16 is generated in the first hydraulic chamber 20 and the second hydraulic chamber 22.

The first hydraulic chamber 20 and the second hydraulic chamber 22 in the master cylinder 18 are provided with a first hydraulic passage 26 and a second hydraulic chamber 26.
The hydraulic passage 28 communicates. The first hydraulic passage 26 is a hydraulic passage provided for the left and right front wheels FL, FR, while the second hydraulic passage 28 is a hydraulic passage provided for the left and right rear wheels RL, RR. It is a pressure passage. First hydraulic passage 26
There is no difference between the hydraulic circuit communicating with the hydraulic circuit and the hydraulic circuit communicating with the second hydraulic passage 28 in the configuration. Therefore, in the following description, the configuration and operation of the hydraulic circuit communicating with the first hydraulic passage 26 will be described.

A high-pressure passage 32 communicates with the first hydraulic passage 26 via a master cut solenoid 30. The master cut solenoid 30 maintains the valve open state in a normal state,
The solenoid valve is a two-position solenoid valve that is closed when a drive signal is supplied from the ECU 10. A relief valve 34 is arranged in parallel with the master cut solenoid 30.
When the hydraulic pressure on the high pressure passage 32 side becomes higher than a predetermined relief pressure as compared with the hydraulic pressure on the first hydraulic pressure passage 26 side, the relief valve 34 switches the first hydraulic pressure passage from the high pressure passage 32 side. This is a constant pressure release valve that allows only the flow of the brake fluid toward the 26th side.

The control hydraulic pressure passages 40 and 42 communicate with the high-pressure passage 32 via a left front wheel holding solenoid (hereinafter, referred to as SFLH) 36 and a right front wheel holding solenoid (hereinafter, referred to as SFRH) 38. Hereinafter, these solenoids are collectively referred to as “holding solenoid SF * H”. The SFLH 36 and the SFRH 38 are two-position solenoid valves that maintain a valve-open state in a normal state and are closed when a drive signal is supplied from the ECU 10. Wheel cylinders 44, 46 provided on the left and right front wheels FL, FR communicate with the control hydraulic pressure passages 40, 42, respectively. SFLH3 is provided between the wheel cylinders 44 and 46 and the high pressure passage 32.
Check valves 48 and 50 are arranged in parallel with the 6 or SFRH 38. Check valves 48 and 50 are mounted on wheel cylinder 4
This is a one-way valve that allows only the flow of the brake fluid from the side of the high pressure passage 32 from the side of the high pressure passage 32.

A left front wheel pressure reducing solenoid (hereinafter, referred to as SFLR) 52 and a right front wheel pressure reducing solenoid (hereinafter, referred to as SFRR) 54 are connected to the wheel cylinders 44, 46. Hereinafter, when these solenoids are collectively referred to, they are referred to as “pressure reducing solenoid SF * R”. SFLR52
And SFRR 54 maintain the valve closed state under normal conditions, and
This is a two-position solenoid valve that is opened when a drive signal is supplied from U10. SFLR52 and SFR
A pressure reducing passage 56 communicates with R54.

An auxiliary reservoir 58 communicates with the pressure reducing passage 56. The auxiliary reservoir 58 has a piston 60 and a spring 62 therein, and the spring 6
By elastically deforming 2, a predetermined amount of brake fluid can be stored. The auxiliary reservoir 58 includes
The suction passage 66 communicates via the check valve 64. The check valve 64 is a one-way valve that allows only the flow of brake fluid from the auxiliary reservoir 58 to the suction passage 66.

The suction passage 66 communicates with the suction side of a pump 70 via a check valve 68 and a first through a reservoir cut solenoid (hereinafter, referred to as SRCF) 72.
It communicates with the hydraulic passage 26. The check valve 68 is a one-way valve that allows only the flow of brake fluid from the suction passage 66 toward the suction side of the pump 70. Also, SRC
F72 is a two-position solenoid valve that keeps the valve closed in a normal state, and is opened when a drive signal is supplied from the ECU 10. The discharge side of the pump 70 communicates with the high-pressure passage 32. The pump 70 sucks the brake fluid from the auxiliary reservoir 58 or the suction passage 66 and discharges the sucked brake fluid to the high-pressure passage 32 at a predetermined discharge pressure.

Wheel speed sensors 74 and 76 are provided near the left and right front wheels FL and FR, respectively. The wheel speed sensors 74 and 76 output pulse signals to the ECU 10 at a cycle corresponding to the wheel speed Vfl of the left front wheel FL and the wheel speed Vfr of the right front wheel FR. The ECU 10 detects the wheel speeds Vfl, Vfr of each wheel based on the output signals of the wheel speed sensors 74, 76. Then, the ECU 10 estimates the vehicle speed SPD based on the wheel speeds Vfl and Vfr of each wheel, and calculates the slip ratio generated on the wheels.

A hydraulic pressure sensor 78 is provided in the first hydraulic pressure passage 26. The hydraulic pressure sensor 78 is connected to the first hydraulic pressure passage 26.
, Ie, a signal corresponding to the master cylinder pressure generated by the master cylinder 18 is output to the ECU 10. The ECU 10 detects the master cylinder pressure Pm / c based on the output signal of the hydraulic pressure sensor 78. The control hydraulic passages 40 and 42 are provided with hydraulic pressure sensors 80 and 82, respectively.
Are arranged. The hydraulic pressure sensor 80 is connected to the control hydraulic pressure passage 4.
0, that is, the wheel cylinder pressure P of the left front wheel FL.
While outputting a signal corresponding to wc / fl to the ECU 10, the hydraulic pressure sensor 82 also sends a signal corresponding to the internal pressure of the control hydraulic pressure passage 42, that is, a signal corresponding to the wheel cylinder pressure Pwc / fr of the right front wheel FR to the ECU 10. Output. The ECU 10 detects the wheel cylinder pressures Pwc / fl and Pwc / fr generated on each wheel based on the output signals of the hydraulic pressure sensors 80 and 82.
Hereinafter, the wheel cylinder pressure of each wheel is generally referred to as wheel cylinder pressure Pwc / **.

The ECU 10 is connected to an ignition switch (hereinafter referred to as an IG switch) 84 of the vehicle and a shift position sensor 86 for outputting a signal corresponding to the position of the shift lever of the automatic transmission. ECU1
0 indicates whether or not the IG switch 84 is on based on the output signal of the IG switch 84, and operates the shift lever to the parking range (P range) based on the output signal of the shift position sensor 86. It is determined whether or not the operation has been performed.

A parking brake switch (hereinafter, referred to as PKB) 88 is connected to the ECU 10. The PKB 88 outputs an ON signal when the parking brake of the vehicle is operated, that is, is operated to generate a braking force, and the parking brake is not operated, that is, the braking force is released. Is a switch that outputs an off signal when operated. EC
U10 determines whether or not the parking brake of the vehicle is operating based on the output signal of the PKB 88.

Next, the operation of the hydraulic brake system according to the present embodiment will be described. The hydraulic brake device according to the present embodiment has a normal function of generating a braking force according to a brake operation amount (hereinafter, referred to as a normal brake function), and a predetermined value (hereinafter, referred to as a normal brake function) applied to one of the wheels during the brake operation. An antilock brake function (hereinafter, referred to as an ABS function) that reduces the slip rate of the wheel when an excessive slip rate exceeding the predetermined value (hereinafter, referred to as “start slip rate”) occurs.

The normal braking function is realized by turning off all the solenoid valves provided in the hydraulic brake device and turning off the pump 70 as shown in FIG. Hereinafter, the control for realizing the normal brake function is referred to as normal brake control. When such a state is realized, the wheel cylinders 44, 46
The master cylinder 18 communicates with the first hydraulic chamber 20 via the high-pressure passage 32, the high-pressure passage 32, and the first hydraulic passage 26.
In this case, a wheel cylinder pressure equal to the master cylinder pressure Pm / c is guided to the wheel cylinders 44 and 46. Therefore, according to the hydraulic brake device of the present embodiment, it is possible to generate a braking force according to the brake operation amount in a normal state.

The ABS function is realized by activating the pump 70 and driving the holding solenoid SF * H and the pressure reducing solenoid SF * R as follows. Hereinafter, control for realizing the ABS function is referred to as ABS control. The ECU 10 starts the ABS control when an excessive slip rate exceeding a predetermined start slip rate occurs on any of the wheels under a situation where the brake pedal 12 is depressed. Hereinafter, the wheels on which the ABS control is executed are referred to as A
It is called BS target wheel. Then, the ABS control is continued for the ABS target wheel until a predetermined ABS control end condition is satisfied.

The ECU 10 calculates the ABS target wheel
Set the holding solenoid SF * H to the closed state (ON state),
The pressure reducing solenoid SF * R is set to the valve open state (ON state). When such a state is realized, the wheel cylinders 44,
46 is shut off from the high-pressure passage 32 and communicates with the auxiliary reservoir 58. In this case, the wheel cylinder 4
The brake fluid in the tanks 4 and 46 flows toward the auxiliary reservoir 58, and the wheel cylinder pressure is reduced. Hereinafter, this state is referred to as a decompression mode. The decompression mode is continuously executed for a predetermined time.

When the pressure reducing mode is executed, the brake fluid supplied to the auxiliary reservoir 58 is pumped up by the pump 70 being operated, and the high pressure passage 32
Is discharged. A part of the brake fluid discharged from the pump 70 into the high-pressure passage 32 is consumed by being supplied to the wheel cylinders 44 and 46, and the rest is returned to the master cylinder 18.

After the above-described decompression mode is completed, the ECU 10 increases the wheel cylinder pressure of the ABS target wheel at a predetermined gradient by combining the following two modes. The increase in the wheel cylinder pressure is continued until the slip ratio of the ABS target wheel reaches the start slip ratio again. EC
U10 is the holding solenoid S for the ABS target wheel.
F * H is opened (OFF state) and the pressure reducing solenoid S
F * R is set to a valve closed state (OFF state). When such a state is realized, the wheel cylinders 44 and 46 are disconnected from the auxiliary reservoir 58 and are electrically connected to the master cylinder 18. In this case, the wheel cylinder pressure is increased toward the master cylinder pressure. Hereinafter, this state is referred to as a pressure increase mode.

The ECU 10 calculates the ABS target wheel
Set the holding solenoid SF * H to the closed state (ON state),
The pressure reducing solenoid SF * R is set to a valve closed state (off state). When such a state is realized, the wheel cylinders 44,
46 is shut off from both the auxiliary reservoir 58 and the master cylinder 18. In this case, the wheel cylinder pressure is maintained without increasing or decreasing. Hereinafter, this state is referred to as a holding mode.

According to the ABS control, the wheel cylinder pressure of the ABS target wheel can be controlled to an appropriate pressure without generating an excessive slip ratio on the wheel.
Therefore, according to the hydraulic brake device, when the driver performs the brake operation, it is possible to generate a large braking force on all the wheels without locking any of the wheels.

Incidentally, even if a drive signal is supplied to the holding solenoid SF * H and the pressure reducing solenoid SF * R, the holding solenoid SF * H
In some cases, the pressure reducing solenoid SF * R is not properly driven in response to the drive signal, that is, the response characteristic of the solenoid to the drive signal from the ECU 10 does not show desired characteristics. When such a situation occurs, a desired wheel cylinder pressure is not generated on the wheels, and much time is required for the wheel slip ratio to fall to an appropriate range. Therefore, in order to properly execute the ABS control, the ECU of the holding solenoid SF * H and the pressure reducing solenoid SF * R is required to execute the ABS control.
It is appropriate to grasp the response characteristic to the drive signal from 10 and correct the drive signal supplied to the solenoid according to the response characteristic so that a desired wheel cylinder pressure is generated.

Therefore, in the system of this embodiment, every time the IG switch 84 of the vehicle is turned on, the ECU 10
To holding solenoid SF * H and pressure reducing solenoid SF
* A drive signal is supplied for a predetermined time to R, and it is determined whether or not those solenoids operate properly in accordance with the drive signal. Hereinafter, the IG switch 84
Is turned on, a series of processing executed as described above is referred to as an initial check.

FIG. 2 shows a holding solenoid SF * H and a pressure reducing solenoid SF * for a drive signal from the ECU 10.
4 shows a flowchart of an example of a control routine executed by the ECU 10 in the hydraulic brake device of the present embodiment to detect a response characteristic of R. The routine shown in FIG. 2 is a routine that is repeatedly started each time the processing is completed.
When the routine shown in FIG.
0 is executed.

In step 100, it is determined whether or not the IG switch 84 is on, the shift lever has been operated to the P range, and the PKB 88 has output an on signal. As a result, when the above condition is satisfied, it can be determined that the vehicle has stopped reliably. In this case, even if the wheel cylinder pressure is changed, no inconvenience occurs. Therefore, when such a determination is made, the process of step 102 is executed next. On the other hand, if it is determined that the above condition is not satisfied, the current routine is terminated without any further processing.

In step 102, a process is executed for setting the holding solenoid SF * H to the closed state (ON state) and setting the pressure reducing solenoid SF * R to the open state (ON state) for the ABS target wheel. When the process of step 102 is performed, a state is formed in which the brake fluid in the wheel cylinders 44 and 46 flows out toward the auxiliary reservoir 58.

In step 104, the above-mentioned step 102
After the execution of the above processing, it is determined whether or not a predetermined time t0 has elapsed. The predetermined time t0 is equal to the time when the pressure reducing solenoid S
This is the time when the wheel cylinder pressure is expected to be sufficiently reduced by opening the valve of F * R. The processing of step 104 is
It is repeatedly executed until it is determined that the above condition is satisfied. The valve open state of the pressure reducing solenoid SF * R is maintained for a predetermined time t.
0 If continued, the wheel cylinder pressure will drop to a predetermined pressure. When the process of step 104 is completed, the process of step 106 is performed next.

In step 106, the pressure reducing solenoid SF
A process is executed in which * R is closed (off state) and the holding solenoid SF * H is duty-driven at a predetermined duty ratio. In step 108, a process for bringing the pump 70 into an operating state is executed. When the process of step 108 is performed, the wheel cylinder pressure Pwc / ** is increased at a gradient corresponding to the above-described predetermined duty ratio.

At step 110, the hydraulic pressure sensors 80, 8
2, the pressure increase gradient Ka of the wheel cylinder pressure Pwc / ** is detected. FIG. 3 shows the holding solenoid S
The pressure increasing gradient Ka of the wheel cylinder pressure Pwc / ** detected when F * H is duty-driven. Step 11
In step 2, it is determined whether the wheel cylinder pressure Pwc / ** is equal to or higher than a predetermined pressure P0. The process of step 112 is repeatedly executed until it is determined that Pwc / ** ≧ P0 holds. As a result, if it is determined that Pwc / ** ≧ P0 holds, the process of step 114 is executed next.

In step 114, a process for bringing the pump 70 into a non-operation state is executed. In step 116, a process is performed in which the holding solenoid SF * H is closed (on) and the pressure reducing solenoid SF * R is duty-driven at a predetermined duty ratio. When this step 114 is executed, the wheel cylinder pressure Pwc / ** is reduced at a gradient according to the above-mentioned predetermined duty ratio.

In step 118, the hydraulic pressure sensors 80, 8
2, a pressure reduction gradient Kr of the wheel cylinder pressure Pwc / ** is detected. FIG. 4 shows a decompression solenoid S
F * R indicates a pressure reduction gradient Kr of the wheel cylinder pressure Pwc / ** detected when the duty driving is performed. According to the above processing, it is possible to grasp the degree of change in the wheel cylinder pressure Pwc / ** when the holding solenoid SF * H and the pressure reducing solenoid SF * R are driven at a predetermined duty ratio. That is, according to the present embodiment, the holding solenoid SF
The response characteristics of * H and the pressure reducing solenoid SF * R to the drive signal from the ECU 10 can be grasped.

FIG. 5 shows a flowchart of an example of a control routine executed by the ECU 10 in the hydraulic brake system of the present embodiment to realize the ABS control. The routine shown in FIG. 5 is a routine that is repeatedly driven each time the processing ends. When the routine shown in FIG. 5 is started, first, the process of step 130 is executed. In step 130, it is determined whether or not the ABS control start condition is satisfied. Specifically, in a situation where the vehicle speed SPD exceeds a predetermined value, it is determined whether or not a slip ratio exceeding a start slip ratio has occurred for any of the wheels due to the brake operation. As a result, if it is determined that the ABS control start condition is not satisfied, the current routine is terminated without any further processing. On the other hand, when it is determined that the ABS control start condition is satisfied, the process of step 132 is executed next.

In step 132, the absolute value of the pressure reduction gradient Kr detected by the routine shown in FIG. 2 is equal to or larger than a value (Kr0-α) obtained by subtracting a predetermined value Kr0 by α, and
It is determined whether or not the value is equal to or smaller than a value (Kr0 + α) obtained by adding α to the predetermined value Kr0. The predetermined value Kr0 is a pressure reduction gradient of the wheel cylinder pressure Pwc / ** estimated to be realized when the pressure reduction solenoid SF * R is driven at the above-described predetermined duty ratio. If Kr0−α ≦ | Kr | ≦ Kr0 + α holds, it can be determined that the pressure reducing solenoid SF * R has a desired response characteristic. In this case, the pressure reducing solenoid S
It is appropriate to drive F * R at the above-mentioned predetermined duty ratio. Therefore, if it is determined that Kr0−α ≦ | Kr | ≦ Kr0 + α is satisfied, the process of step 134 is executed next.

On the other hand, if Kr0−α ≦ | Kr | ≦ Kr0 + α does not hold, it can be determined that the pressure reducing solenoid SF * R does not have the desired response characteristics. In this case, it is appropriate to correct the duty ratio of the drive signal supplied to the pressure reducing solenoid SF * R. Therefore, Kr0−α ≦ | Kr
If it is determined that | ≦ Kr0 + α is not established, the process of step 136 is executed next.

In step 134, the pressure reducing solenoid SF
A process for setting the command current Ir to * R to a predetermined value I1 as usual is executed. When the process of step 134 ends, the process of step 138 is executed next. In step 136, the command current Ir to the pressure reducing solenoid SF * R
Is performed by multiplying the predetermined value I1 by the predetermined value Kr0 and the absolute value and ratio of the pressure reduction gradient Kr detected by the routine shown in FIG. Step 13
When the processing of step 6 is executed, the command current Ir decreases as the absolute value of the detected pressure reduction gradient Kr increases, that is, as the speed of reducing the wheel cylinder pressure increases, while the absolute value of the pressure reduction gradient Kr increases. Is smaller, the command current Ir
Becomes larger. When the processing of step 136 is completed,
Next, the process of step 138 is performed.

FIG. 6A is a diagram for comparing a triangular wave of a predetermined cycle with a command current Ir to the pressure reducing solenoid SF * R. FIG. 6B shows a decompression solenoid SF.
FIG. 9 is a diagram illustrating a drive signal having a duty ratio according to a command current Ir to * R. When the command current Ir to the pressure reducing solenoid SF * R is the predetermined value I1, a drive signal is supplied to the pressure reducing solenoid SF * R for a time corresponding to the region I shown in FIG.

When the command current Ir to the pressure-reducing solenoid SF * R increases (indicated by a thick line in FIG. 6A), the pressure-reducing solenoid SF * R has a region I as shown in FIG. The drive signal is supplied longer by the time corresponding to the regions II and III as compared with the case of FIG. On the other hand, when the command current Ir to the pressure reducing solenoid SF * R decreases, a drive signal for a shorter time is supplied to the pressure reducing solenoid SF * R than in the case of the region I. Therefore, according to this method, the larger the absolute value of the pressure reduction gradient Kr of the wheel cylinder pressure Pwc / ** at the time of the initial check, the larger the ABS
The duty ratio of the drive signal supplied to the pressure reducing solenoid SF * R during control can be reduced, and the duty ratio of the drive signal can be increased as the absolute value of the pressure reduction gradient Kr is smaller.

In step 138, the holding solenoid SF
* H is in the valve closed state (ON state). Step 13
When the process of No. 8 is executed, the wheel cylinders 44 and 46 and the master cylinder 18 are shut off. Step 140
Then, at a duty ratio corresponding to the command current Ir calculated in the above step 134 or 136, the pressure reducing solenoid S
F * R is duty-driven. When the process of step 140 is executed, the conduction state between the wheel cylinders 44 and 46 and the auxiliary reservoir 58 is switched at the above-described duty ratio, and the wheel cylinder pressure Pwc / ** is reduced by an appropriate pressure reduction gradient. Will be done.

In step 142, the above-mentioned step 140
It is determined whether or not a predetermined period of time tsh has elapsed after the processing of (1) is executed. The predetermined time tsh is a time during which the decompression mode is continued. The processing in step 142 is performed for a predetermined time tsh.
Is repeatedly executed until it is determined that has elapsed. If the predetermined time tsh has elapsed, it can be determined that the decompression mode has ended in the ABS control. In this case, it is necessary to increase the wheel cylinder pressure Pwc / ** by repeating the holding mode and the pressure increasing mode as the next stage. Therefore, if it is determined that the predetermined time tsh has elapsed after the execution of the processing of step 140, the processing of step 144 is executed next.

In step 144, the pressure reducing solenoid SF
* R is set to a valve closed state (off state). Step 14
When the process of No. 4 is executed, the conduction state between the wheel cylinders 44 and 46 and the auxiliary reservoir 58 is cut off, and the wheel cylinder pressure Pwc / ** is maintained at a predetermined pressure. In step 146, the pressure increase gradient Ka detected by the routine shown in FIG. 2 is calculated by subtracting a predetermined value Ka0 by β (Ka0−
β) or more and not more than a value (Ka0 + β) obtained by adding β to the predetermined value Ka0. The predetermined value Ka0 is a pressure increase gradient of the wheel cylinder pressure Pwc / ** estimated to be realized when the holding solenoid SF * H is driven at the above-described predetermined duty ratio. Ka0-β≤Ka
If ≦ Ka0 + β holds, the holding solenoid SF * H
Has the desired response characteristics. In this case, it is appropriate to drive the holding solenoid SF * H at the above-described predetermined duty ratio. Therefore, Ka0−β ≦ K
If it is determined that a ≦ Ka0 + β holds, the process of step 148 is executed next.

On the other hand, if Ka0−β ≦ Ka ≦ Ka0 + β does not hold, it can be determined that the holding solenoid SF * H does not have the desired response characteristics. In this case, it is appropriate to correct the duty ratio of the drive signal supplied to the holding solenoid SF * H. Therefore, Ka0−β ≦ Ka ≦ Ka0
If it is determined that + β does not hold, then step 1
50 processing is executed.

In step 148, the holding solenoid SF
The process for setting the command current Ia to * H to the predetermined value I2 is executed as usual. When the process of step 148 is completed, the process of step 152 is performed next. In step 150, the command current Ia to the holding solenoid SF * H
Is multiplied by the ratio of the predetermined value Ka to the predetermined pressure Ka0 and the pressure increase gradient Ka detected by the routine shown in FIG. 2 as described above. When the process of step 150 is executed, the command current decreases as the pressure increase gradient Ka increases, that is, as the speed of increasing the wheel cylinder pressure increases, whereas the command current increases as the pressure increase gradient Ka decreases. Become.

Command current Ia to holding solenoid SF * H
Becomes smaller, the duty ratio of the drive signal supplied to the holding solenoid SF * H decreases. When the command current Ia to the holding solenoid SF * H increases, the duty ratio of the drive signal increases. Accordingly, as the pressure increase gradient Ka of the wheel cylinder pressure Pwc / ** at the time of the initial check is larger, the duty ratio of the drive signal supplied to the holding solenoid SF * H during the ABS control can be reduced, and the pressure increase gradient Ka Is smaller, the duty ratio of the drive signal can be increased.

When the processing of step 150 is completed,
Next, the process of step 152 is executed. Step 15
In step 2, the holding solenoid SF * H is duty-driven at a duty ratio corresponding to the command current Ia calculated in steps 148 and 150. When the process of step 152 is executed, the conduction state between the wheel cylinders 44 and 46 and the master cylinder 18 is switched at the above-described duty ratio, and the wheel cylinder pressure Pwc / ** is increased with an appropriate pressure increasing gradient. You.

In step 154, it is determined whether or not the condition for terminating the ABS control is satisfied. The condition for terminating the ABS control is satisfied when the depression of the brake pedal 12 is released, when the slip ratios of all the wheels are reduced to an appropriate range, when the vehicle speed SPD becomes sufficiently low, and the like. If it is determined that the ABS control end condition is not satisfied as a result of the above determination, the process returns to step 132 again.
Is performed. On the other hand, when it is determined that the condition for terminating the ABS control is satisfied, the process of step 156 is executed.

In step 156, the holding solenoid SF
* H is in the valve open state (OFF state). This step 15
When the process of step 6 is completed, the current routine is completed.
According to the above-described processing, the drive for supplying the pressure to the holding solenoid SF * H and the pressure reducing solenoid SF * R in accordance with the magnitude of the pressure increasing gradient Ka and the pressure decreasing gradient Kr obtained by executing the routine shown in FIG. The duty ratio of the signal can be corrected. When the duty ratio of the drive signal is corrected, that is, when the time during which the holding solenoid SF * H and the pressure reducing solenoid SF * R are in the on state is corrected, the wheel cylinder is moved from the high pressure passage 32 through the solenoid. The amount of brake fluid flowing toward 44 and 46 is increased or decreased, and the pressure increasing gradient and the pressure decreasing gradient of the wheel cylinder pressure change. Therefore, according to the present embodiment, the holding solenoid SF * H and the pressure reducing solenoid SF
* Even if R does not have the desired response characteristics, a desired pressure can be generated in the wheel cylinder by correcting the drive signal supplied to those solenoids.
Therefore, according to the hydraulic brake device of the present embodiment, it is possible to quickly release the slip state of the wheels.

In the above embodiment, the holding solenoid SF * H and the pressure reducing solenoid SF * R are provided in the first embodiment.
The ECU 10 corresponds to the “solenoid valve” described above.
Executes the processing of steps 110 and 118 so that the "response characteristic detecting means" of claim 1 executes the processing of step 136 instead of the processing of step 134, and step 148. By executing the processing of step 150 in place of the processing of (1), the "drive signal correcting means" of claim 1 is realized.

In the above embodiment, the duty ratio of the drive signal supplied to the holding solenoid SF * H and the pressure reducing solenoid SF * R is corrected.
The "drive signal correcting means" according to claim 1 is realized, but the present invention is not limited to this. In a hydraulic brake device in which these solenoids are linear solenoids, the drive is supplied to the linear solenoids. The “drive signal correction means” may be realized by correcting the magnitude of the exciting current.

In the above-described embodiment, a drive signal having a predetermined duty ratio is supplied to the holding solenoid SF * H and the pressure reducing solenoid SF * R at the time of the initial check, and the pressure reduction gradient of the wheel cylinder pressure which changes at that time is supplied. And the pressure increase gradient is recognized as a response characteristic of the holding solenoid SF * H and the pressure reducing solenoid SF * R to the drive signal. However, the present invention is not limited to this. The amount of change in the wheel cylinder pressure that changes during the predetermined time, or the amount of change in the degree of opening detected by the device is provided. , The response characteristics of the holding solenoid SF * H and the pressure reducing solenoid SF * R.

In the above embodiment, the pressure increasing gradient K of the wheel cylinder pressure Pwc / ** at the time of the initial check is determined.
a and the holding solenoid SF * according to the pressure reduction gradient Kr.
Although the duty ratio of the drive signal supplied to H and the pressure reducing solenoid SF * R is linearly increased or decreased, the present invention is not limited to this, and the duty ratio may be corrected stepwise.

Further, in the above embodiment, the holding solenoid SF * H and the pressure reducing solenoid SF * R used for the ABS control are limited, but the present invention is not limited to this, and the vehicle behavior control is not limited to this. (VSC) and brake assist control (BA).

[0060]

As described above, according to the first and second aspects of the present invention, the wheel cylinder pressure can be appropriately controlled even when the solenoid valve does not have a desired response characteristic.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a hydraulic brake device according to an embodiment of the present invention.

FIG. 2 is a flowchart of an example of a control routine executed to detect response characteristics of a holding solenoid and a pressure reducing solenoid in the hydraulic brake device of the present embodiment.

FIG. 3 is a diagram showing a pressure-increase gradient Ka of a wheel cylinder pressure when a holding solenoid is duty-driven.

FIG. 4 is a diagram showing a pressure reduction gradient Kr of the wheel cylinder pressure when the pressure reduction solenoid is duty-driven.

FIG. 5 shows the ABS of the hydraulic brake device of the present embodiment.
5 is a flowchart of an example of a control routine executed to realize control.

FIG. 6A is a diagram for comparing a triangular wave of a predetermined cycle with a command current to a holding solenoid and a pressure reducing solenoid. FIG. 6B is a diagram illustrating a drive signal having a duty ratio according to a command current to the solenoid.

[Explanation of symbols]

 10 electronic control unit (ECU) 36 left front wheel holding solenoid (SFLH) 38 right front wheel holding solenoid (SFRH) 44, 46 wheel cylinder 52 left front wheel pressure reducing solenoid (SFLR) 54 right front wheel pressure reducing solenoid (SFRR)

Claims (2)

[Claims] 1. A hydraulic brake device comprising an electromagnetic valve communicating with a wheel cylinder and controlling a wheel cylinder pressure based on a drive signal applied to the electromagnetic valve, wherein a response characteristic detection for detecting a response characteristic of the electromagnetic valve. Means, and a drive signal correcting means for correcting the drive signal according to the response characteristic. 2. The hydraulic brake device according to claim 1, wherein the response characteristic detecting means detects the response characteristic based on a change in a wheel cylinder pressure with respect to a predetermined drive signal. Brake device.