JP2001260840A - Brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption and heat generation without lowering control quality in a brake control device. SOLUTION: In this brake control device, a wheel cylinder pressure is intensified by driving a pump 4, and the wheel cylinder pressure is reduced by opening an outside gate valve 3 on the other hand. When outputting a control signal to keep the liquid pressure of the wheel cylinder WC, a control signal having a duty ratio corresponding to the liquid pressure of the wheel cylinder WC is outputted. Accordingly, power consumption in the outside gate valve 3 can be reduced and generation of heat can be also suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a hydraulic pressure source other than a master cylinder, which mechanically generates pressure in response to a driver's operation, and applies a hydraulic pressure of this hydraulic pressure source to a wheel cylinder. The present invention relates to a brake control device that automatically controls a braking force by supplying and increasing the pressure of a wheel cylinder, maintaining the hydraulic pressure of a wheel cylinder, or releasing the hydraulic pressure of a wheel cylinder to another and reducing the pressure.

[0002]

2. Description of the Related Art In recent years, various brake control devices for controlling a braking force have been proposed. Controls in such a brake control device include an automatic braking control that automatically performs braking according to a distance between the vehicle and an oncoming obstacle such as a preceding vehicle, and a case where an overundersteer state or an overoversteer state occurs during a turn. Vehicle behavior that automatically controls the wheel cylinder fluid pressure of the outer front wheel and the inner rear wheel to generate braking force, thereby generating a yaw moment that returns the vehicle to the neutral steer direction, thereby stabilizing the behavior of the vehicle Control, torque-slip control that applies a braking force to the drive wheel when the drive wheel slips, and suppresses slippage, and by-wire control that detects braking operation by the driver and generates hydraulic pressure based on the detected value And assist control for assisting the braking operation by further increasing the brake fluid pressure generated by the driver's braking operation. There is.

[0003] In the various types of braking control described above, control quality is improved so that the driver does not feel uncomfortable. As a technique for improving the control quality of the braking control as described above, for example, a technique described in Japanese Patent Application Laid-Open No. 8-150909 is known. This conventional technology is a brake control device that automatically performs braking based on the distance between the vehicle and an obstacle such as a preceding vehicle. It is an object of the present invention to achieve both prevention and urgent braking during urgent braking. To this end, in this prior art,
First, a control deviation is obtained. Based on the control deviation, when the deviation is large, the proportional control gain is increased, and when the deviation is small, the proportional control gain is decreased. Therefore, when the control deviation is small, the hydraulic gradient becomes gentle and the "crank brake" can be prevented. On the other hand, when braking is urgent, that is, when the control deviation is large, the hydraulic gradient becomes steep, resulting in high responsiveness. Braking becomes possible, and the above object can be achieved.

[0004]

However, in the above-mentioned prior art, a signal having a constant duty ratio is always output as a control signal output to the solenoid valve when the hydraulic pressure is maintained. . For this reason, when the hydraulic pressure is maintained for a long time, the power consumption of the battery is increased, and the amount of generated heat is increased, which is disadvantageous in terms of durability. In particular, in recent years, the number of in-vehicle electrical devices has increased,
It is desired to reduce power consumption.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to reduce power consumption and heat generation in a brake control device without deteriorating control quality.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a wheel cylinder capable of arbitrarily adjusting the wheel cylinder pressure by increasing, holding, and reducing pressure on the wheel cylinder. Hydraulic pressure adjusting means having an electromagnetic valve which closes the wheel cylinder to hold the brake fluid when the pressure is held, running state detecting means for detecting the running state of the vehicle, and the running state detected by the running state detecting means. Braking control means for outputting a control signal to the hydraulic pressure adjusting means to perform pressure increase / hold / pressure reduction in accordance with a running state of the vehicle, and for executing a brake control for generating a desired braking force. In the brake control device, the brake control means outputs a control signal for maintaining the solenoid valve in a closed state when the hydraulic pressure adjusting means is operated for holding,
In addition, the control signal is a signal that changes the effective current value output to the solenoid valve to a higher value as the wheel cylinder pressure increases in accordance with the held wheel cylinder pressure.

According to a second aspect of the present invention, in the brake control device according to the first aspect, the traveling state detecting means is provided with an actual pressure detecting means for obtaining an actual pressure of a wheel cylinder, and the braking control means comprises: A target hydraulic pressure calculating means for calculating a target hydraulic pressure of the wheel cylinder based on an input from the traveling state detecting means, and an actual wheel cylinder pressure detected by the actual pressure detecting means at the time of the braking control is set to a target hydraulic pressure. It is characterized in that the hydraulic pressure adjusting means is operated so as to approach the target hydraulic pressure calculated by the calculating means.

According to a third aspect of the present invention, in the brake control device according to the second aspect, the actual pressure detecting means includes:
It is a means for calculating the actual wheel cylinder pressure based on the vehicle deceleration.

According to a fourth aspect of the present invention, in the brake control apparatus according to any one of the first to third aspects, the braking control executed by the braking control means includes a step of detecting a distance from a preceding vehicle based on an input from a traveling state detecting means. The automatic braking control is characterized in that a distance is obtained, and a braking force is generated to make the inter-vehicle distance an optimum value.

According to a fifth aspect of the present invention, in the brake control device according to the first to fourth aspects, a brake circuit connected to the wheel cylinder to supply brake fluid to the wheel cylinder, and a brake directed to the brake circuit are provided. A fluid pressure source for supplying a fluid, wherein the solenoid valve is a normally-open solenoid valve connected to a brake circuit for allowing the brake fluid of the wheel cylinder to escape to a low pressure circuit on a relatively low pressure side. The control means supplies the brake fluid from the hydraulic pressure source to the brake circuit at the time of pressure increase during braking control, temporarily or continuously closes the electromagnetic valve at the time of pressure reduction, and at the time of hold,
While stopping the supply of brake fluid from the hydraulic pressure source,
The solenoid valve is closed.

[0011]

According to the present invention, when the braking control means executes the braking control, when the wheel cylinder pressure is maintained, a control signal for maintaining the valve closed state toward the solenoid valve, for example, a duty ratio signal is output. I do. At this time,
This control signal controls the execution current value (duty ratio) as the holding pressure is higher and the execution current value (duty ratio) as the holding pressure is lower, in accordance with the wheel cylinder pressure to be held. Therefore, the control signal output to the solenoid valve is
The control signal can be a minimum execution current value (duty ratio) that can maintain the solenoid valve in the closed state against the holding pressure, thereby reducing power consumption and heat generation in the solenoid valve. While improving durability,
The effect that the control quality can be maintained by reliably maintaining the valve closed state is obtained.

According to the second aspect of the present invention, the brake control means calculates a target hydraulic pressure based on an input from the traveling state detecting means when the brake control is executed, and uses the actual wheel cylinder pressure as the target hydraulic pressure. Activate the hydraulic pressure adjusting means so as to approach them. In the control of the hydraulic pressure adjusting means, when the actual wheel cylinder pressure approaches the target hydraulic pressure, a control signal of an execution current value (duty ratio) corresponding to the actual wheel cylinder pressure is sent to the solenoid valve to maintain the wheel cylinder pressure. Is output. Therefore, highly accurate braking control according to the control request can be executed.

According to the third aspect of the present invention, the actual wheel cylinder pressure is calculated based on the vehicle deceleration. That is, there is a correlation between the braking force and the vehicle deceleration, and the actual wheel cylinder pressure can be obtained from the vehicle deceleration. Further, the vehicle deceleration can be obtained from a vehicle speed obtained from a wheel speed and a change in the vehicle speed. For example, the vehicle speed at the present time is Vn, the vehicle speed at one time in the past (meaning the time when the previous control routine was executed, for example, 10 msec before) is (Vn-1), and the vehicle speed at three times before is Where (Vn−3) and the vehicle speed (Vn−4) four times before, the deceleration G = [Vn + (Vn−1)] − [(Vn−3) +
(Vn-4)].

According to the fourth aspect of the present invention, at the time of the automatic braking control for maintaining the optimum inter-vehicle distance with the preceding vehicle, the above-mentioned electromagnetic valve of the hydraulic pressure adjusting means is controlled. In such a brake control device, it is possible to obtain an effect that the power consumption described above can be reduced and durability can be improved. According to the fifth aspect of the invention, during the braking control including the automatic braking control, the brake fluid is supplied from the hydraulic pressure source to the brake circuit to increase the pressure in the wheel cylinder, and the solenoid valve is opened. Then, the brake fluid in the brake circuit is released to the low pressure side to reduce the pressure.
When the holding is performed, the supply from the hydraulic pressure source is stopped, and the solenoid valve is closed.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) Embodiment 1 is an example corresponding to the first to fifth aspects of the present invention, and FIG. 1 is a brake circuit diagram showing a brake device of Embodiment 1. In the figure, M
C is a well-known cylinder which supplies brake fluid to the wheel cylinder WC via the brake circuits 1 and 2 when the brake pedal BP is depressed. In addition,
The master cylinder MC is provided with a reservoir RES for storing brake fluid.

The brake circuits 1 and 2 have a connection structure called a so-called X pipe. That is, the brake circuit 1 connects the wheel cylinder WC (FL) of the left front wheel and the wheel cylinder WC (RR) of the right rear wheel, and the brake circuit 2 connects the wheel cylinder WC (FR) of the right front wheel and the left rear wheel. It is configured to connect to a wheel cylinder WC (RL).

An out-side gate valve 3 as an electromagnetic valve of the embodiment is provided in the middle of the brake circuits 1 and 2. This out side gate valve 3 is connected to the brake circuit 1
2 is a normally open solenoid valve that switches between communication and shutoff.

The one-way valve 3a allows only the flow of brake fluid from the master cylinder MC side (hereinafter referred to as upstream) to the wheel cylinder WC side (hereinafter referred to as downstream) to the out side gate valve 3. Are provided in parallel.

In the brake circuits 1 and 2,
Downstream of the out-side gate valve 3, an inflow valve 5 including a solenoid-driven normally open ON / OFF valve is provided.
In the middle of the return circuit 10 connecting the position downstream of the inflow valve 5 and the reservoir 7, the solenoid-driven normally closed ON
An outflow valve 6 composed of an OFF valve is provided.

Further, a pump 4 is connected to the brake circuits 1 and 2 as a hydraulic pressure source other than the master cylinder MC (corresponding to the hydraulic pressure source according to the fifth aspect). The pump 4 serves as a brake fluid pressure source when the driver is not performing a braking operation, and also serves as a return pump when executing ABS control. Also, this pump 4
Is a plunger pump operated by a motor 8 and includes two plungers 4p, 4p, and a pump chamber 4r for performing suction / discharge by each of the plungers 4p, 4p via branched suction circuits 4a, 4b. In the brake circuits 1 and 2, the out-side gate valve 3
It is connected to a position further upstream and the reservoir 7. On the other hand, a discharge circuit 4c is connected to a position between the out-side gate valve 3 and the inflow valve 5 in the brake circuits 1 and 2. Further, the suction circuit 4b is provided with a check valve 4d for preventing the brake fluid from flowing in the direction of the reservoir 7. An ABS unit is constituted by the inflow valve 5, the outflow valve 6, the reservoir 7, the return circuit 10, and the suction circuit 4b. When a wheel lock is likely to occur during braking, the inflow valve 5 Is closed and the outflow valve 6 is opened to reduce the pressure of the wheel cylinder WC, both the inflow valve 5 and the outflow valve 6 are closed to maintain the hydraulic pressure of the wheel cylinder WC, and the inflow valve 5 is opened. At the same time, the outflow valve 6 can be closed to increase the pressure.

The suction circuit 4a is provided with an in-side gate valve 9 for switching communication between the suction circuit 4a and the suction circuit. The in-side gate valve 9 is constituted by a normally closed solenoid valve.

The operations of the two gate valves 3, 9, the inflow valve 5, the outflow valve 6, and the motor 8 are controlled by a control unit 11 as a braking control means. As shown in FIG. 2, the control unit 11 is connected to running state detecting means 13 including a wheel speed sensor 12 for detecting the running state of the vehicle, and will be described later based on an input from the running state detecting means 13. The ABS control and the automatic braking control are executed. Incidentally, the traveling state detecting means 13
Includes means for detecting a driving operation state of the driver, that is, a braking operation, a steering operation, and an accelerator operation.

The ABS control is a well-known control, and will be briefly described. In the present embodiment, the wheel speed sensor 1
The wheel lock during braking is determined based on the input from 2,
When the wheels are likely to lock, after reducing the wheel cylinder pressure to avoid wheel lock, the wheel speed of the target wheel is lower than the body speed by a predetermined value, the most effective speed for braking The pressure is reduced, maintained, and increased as appropriate so that the pressure is maintained.

The pressure reduction / holding / pressure increase in the ABS control is performed by closing the inflow valve 5 and opening the outflow valve 6 in the case of pressure reduction, and closing both valves 5 and 6 in the case of pressure reduction. The pressure increase is performed by opening the inflow valve 5 and closing the outflow valve 6. When the pressure is reduced, the brake fluid in the wheel cylinder WC is released to the reservoir 7, but the brake fluid accumulated in the reservoir 7 is
It is returned to the brake circuits 1 and 2 as needed based on the operation of the pump 4.

In this embodiment, automatic braking control is performed. This automatic braking control is performed by the running state detecting means 13.
Detects a running state based on an input from the vehicle and automatically generates a braking force.For example, a vehicle-to-vehicle distance with a preceding vehicle is detected, and the vehicle-to-vehicle distance becomes shorter than an ideal vehicle-to-vehicle distance corresponding to a vehicle speed. The control includes automatically generating a braking force when the vehicle is driven to keep the distance between vehicles at an ideal distance between vehicles.

When the above-described automatic braking control is performed, the brake fluid is discharged to the brake circuits 1 and 2 by opening the in-side gate valve 9 and operating the pump 4.
At this time, the inflow valve 5 and the outflow valve 6 are deactivated,
When the inflow valve 5 is kept open and the outflow valve 6 is kept closed, the wheel cylinder pressure is increased. In the present embodiment, although described later, the amount of pressure increase is controlled by performing pulse modulation control (hereinafter, referred to as PWM control) on the motor 8 (pump 4). On the other hand, when the out-side gate valve 3 is opened from this state, the brake fluid in the brake circuits 1 and 2 is released to the master cylinder MC side to reduce the pressure. In the present embodiment, the amount of pressure reduction is controlled by performing the opening amount of the out-side gate valve 3 by PWM control.

The automatic brake control includes, in addition to the automatic braking control described above, a torque slip control for generating a braking force on the drive wheel when a slip of the drive wheel is detected and preventing the drive wheel from slipping. A vehicle motion control for generating a braking force on a desired wheel to generate a yaw moment in a direction to return the vehicle to a neutral state when the vehicle is in an over-oversteer state or an over-understeer state; When a braking operation is performed by operating means that does not generate the master cylinder pressure and is provided other than the above, a target hydraulic pressure (target deceleration) is determined according to the braking operation, and a by-wire that generates a braking force according to the determined hydraulic pressure (target deceleration) Control or the like may be executed. By the way, in the case of the automatic braking control or the by-wire control, it is necessary to control the wheel cylinder pressure of all the wheels to the same pressure or to supply the hydraulic pressure to all the wheel cylinders WC while giving a predetermined hydraulic pressure difference between the front and rear wheels. On the other hand, in the case of vehicle motion control, a braking force may be generated only on one wheel. As for the torque slip control, the hydraulic pressure is supplied only to the wheel cylinder WC of the drive wheel.

Next, details of the above-described automatic braking control will be described with reference to the flowchart of FIG. First, in step 101, the target deceleration (corresponding to the target hydraulic pressure) G
It is determined whether or not T is larger than a preset hold prohibition threshold value GMAX, and if GT> GMAX, step 1 is executed.
In step 02, the hold prohibition flag F_GMAX is set to 1 and the feedback gain DGAINB is reset to 0. On the other hand, in step 101, GT
If ≤ GMAX, skip step 102 and proceed to step 103. In step 103, based on whether the target deceleration GT is greater than a preset off threshold THOFF, braking control is executed toward pressure reduction / holding / pressure increase processing according to the target deceleration GT. Judge whether or not
If GT> THOFF, the process proceeds to step 104 to execute processing toward the target deceleration GT, and GT ≦ THOFF
In the case of, it is determined that the braking control is unnecessary, and
Then, the process proceeds to step 4, where an OFF process for terminating the braking control is performed. That is, when the target deceleration GT is extremely small, the OFF process is performed, the pump 4 (motor 8) is stopped, the out-side gate valve 3 is opened, and the in-side gate valve 9 is closed. Things.

In step 104, a target deceleration gradient D which is a gradient from the current deceleration to the target deceleration GT.
It is determined whether or not to perform the rapid pressure increase based on whether the GT is less than a preset rapid increase threshold value THKYU,
Step 10 at the time of non-rapid pressure increase determination of DGT <THKYU
The routine proceeds to step 113, and when it is determined that DGT ≧ THKYU is rapidly increased, the routine proceeds to step 113. In this step 113, a rapid pressure increase process is performed. In this case, an output for opening the in-side gate valve 9 and an output with a duty ratio of 100% to the motor 8 are performed, and the out-side gate valve is output. 3
Is output at a duty ratio of 60%. As described above, in the present embodiment, when a rapid pressure increase is required, a high braking force can be generated to cope with this.

In step 105, the hold prohibition flag F_
It is determined whether or not GMAX is set, and F_GMA
If X = 1, the process proceeds to step 107, where F_GMAX ≠ 1
If (F_GMAX = 0), the process proceeds to step 106. In step 106, it is determined whether or not the target deceleration gradient DGT is larger than a pressure increase threshold DBIC, and DGT> DB
In the case of an IC, step 1 is performed to determine whether the pressure is increased or maintained.
07, and when DGT ≦ DBIC, the process proceeds to step 108 to determine whether the pressure is reduced or maintained.

In step 107, the control signal SIGCN
It is determined whether or not T is greater than a preset pressure increase holding threshold value DBIU, and if SIGCNT> DBIIU, the process proceeds to step 112 to execute a pressure increase process.
If SIGCNT ≦ DBIIU, the process proceeds to step 111 to execute a holding process. It should be noted that the pressure increase holding threshold D
BIU is set to a value on the reduced pressure side with respect to the normal holding area. When the pressure increasing process is performed in step 112, the output duty ratio D
UTY_P is set to a value fp (SIGC based on a duty characteristic map corresponding to the control signal SIGCNT shown in FIG.
NT), and the in-side gate valve 9 is maintained in the open state. Further, at this time, the out-side gate valve 3 is maintained in a closed state. At this time, the duty ratio DUTY_V output to the out-side gate valve 3 is set in the same manner as in the case of holding described later. The value fk (target hydraulic pressure signal) based on the characteristic map corresponding to the target hydraulic pressure shown in FIG.
The value is obtained by adding the holding duty margin Dα. That is, it is calculated by an arithmetic expression of DUTY_V = fk (target hydraulic pressure signal) + Dα. Further, the control signal SIGCNT
Is calculated from the following equation. SIGCNT = PGAINF × GT + DGAINF × D
GT + PGAINB × (GT-GL) + DGAINB ×
(DGT-DGL) where PGAINF is a feed forward P gain,
GT is target deceleration, DGINF is feedforward D gain, DGT is target deceleration gradient, PGAINB is feedback P gain, GL is vehicle deceleration, DGAIN
The B feedback D gain and DGL are vehicle deceleration gradients. The vehicle deceleration GL is 4 as shown in FIG.
After averaging the wheel speed signals from the wheels by the averaging processing unit a, differentiating by the differentiating unit b, and amplifying by the amplifying unit c, it can be obtained by performing band-pass processing with the low-pass filter d. Further, in the present embodiment,
By giving a predetermined gain to the vehicle deceleration GL by the gain processing unit e, a hydraulic pressure signal indicating the actual wheel cylinder pressure is formed and used for the processing in this flowchart.

In step 108, the target deceleration gradient DG
It is determined whether or not T is smaller than the pressure reduction threshold DBDC,
If DGT <DBDC, the process further proceeds to step 109, where the control signal SIGCNT is set to
It is determined whether or not the pressure is smaller than C. If YES is determined in both step 108 and step 109, the process proceeds to step 110 to perform the decompression process. On the other hand, NO is determined in either step 108 or step 109. If so, the process proceeds to step 111 to perform a holding process. In addition,
The pressure-reduction-time holding threshold value DBDC is set to a value on the pressure-increase side of the normal holding region.

When the pressure reduction process is executed in step 110, the in-side gate valve 9 is closed, the output duty ratio to the motor 8 (pump 4) is set to 0%, and the output duty ratio to the out-side gate valve 3 is further reduced. DUTY_
V is set based on a map corresponding to the control signal SIGCNT shown in FIG.

When the holding process is executed in step 111, in the present embodiment, the driving of the motor 8 (pump 4) is stopped, and the in-side gate valve 9 is closed.
Further, a duty ratio based on the holding pressure is output to the outside gate valve 3. That is, the output duty ratio for the out-side gate valve 3 is set to a value fk (target hydraulic pressure signal) based on a characteristic map corresponding to the target hydraulic pressure shown in FIG. Is added. That is, DUTY_V = fk
(Target hydraulic pressure signal) + Calculated by Dα.

After performing any one of steps 110 to 114, the process proceeds to step 115, where a feedback process is performed on the outside gate valve 3.

FIG. 8 is a time chart showing an operation example of the first embodiment. As shown in this figure, at the time of pressure increase,
Output duty ratio DUTY for out side gate valve 3
_V is changed according to the target hydraulic pressure, and at the time of holding, is maintained at a value corresponding to the target hydraulic pressure which is the actual wheel cylinder pressure at that time. Therefore, the lower the target hydraulic pressure, the lower the output duty ratio DUTY_V. Also,
When the pressure is reduced, an output duty ratio DUTY_V corresponding to the control signal SIGCNT is output. In this case,
The out-side gate valve 3 is opened by the wheel cylinder pressure and the urging force of a return spring (not shown).

As described above, in the present embodiment,
When closing the out-side gate valve 3, the duty ratio DUTY_V output toward the out-side gate valve 3 is controlled by the hydraulic circuit in the brake circuits 1 and 2 that closes the out-side gate valve 3 when the pressure is increased or reduced. Since the determination is made based on the map shown in FIG. 5 in accordance with the target hydraulic pressure as the pressure, the operation of the out-side gate valve 3 is minimized while the out-side gate valve 3 is reliably maintained in the closed state. And the power consumption and the amount of heat generation can be reduced while maintaining the control quality. FIG. 9 shows the relationship between the hydraulic pressure and the duty ratio at which the closed state of the out-side gate valve 3 can be maintained. In this manner, if the held hydraulic pressure decreases, the output duty ratio DUTY_V decreases. It can be kept low. Note that the duty ratio DUTY_V output to the solenoid valve may be corrected based on the coil temperature of the solenoid valve or the ambient temperature.

Further, in the present embodiment, the target deceleration G
When T is larger than the hold prohibition threshold value GMAX, the determination based on the target deceleration gradient in step 106 is skipped, and the process proceeds to step 107 to determine whether the pressure is increased or held, and at this time, the feedback D gain DGA
Since INB is reset to 0 and the control signal SIGCNT does not reflect the deviation between the target deceleration gradient and the vehicle deceleration gradient, the pressure is increased until the vehicle deceleration GL reaches the target deceleration GT, Without delay of response,
A high deceleration is reliably obtained, which also allows a high control quality to be obtained.

(Embodiment 2) Next, a brake device according to Embodiment 2 will be described. The brake device of the second embodiment is a so-called brake-by-wire type brake device in which the master cylinder MC is not provided and the wheel cylinder pressure is controlled using the hydraulic pressure of the pump as a hydraulic pressure source even during normal braking. The out-side gate valve 3 is the same as that of the first embodiment.
The same components as those of the first embodiment are used, and the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

FIG. 10 is a brake circuit diagram showing only one system in the brake device according to the second embodiment. The main structure is the same as that of the first embodiment. The difference from the first embodiment is that the out-side gate valve 3 is connected to the suction side of the pump 4 via a low-pressure circuit 201. Therefore, when the out-side gate valve 3 is opened, the hydraulic pressure of the brake circuit 1 is reduced. In addition, each valve 3,5,6
A control unit (not shown) for controlling the operation of the motor 8 is connected to a braking operation detecting means for detecting an operation of a brake pedal or a manual brake switch. When the driver performs the braking operation, the target hydraulic pressure and the control signal SIGCNT are obtained based on the detection values of the braking operation detecting means, and the out-side gate valve 3 and the motor 8 are PWM-controlled based on these values. Also,
As in the first embodiment, at the time of the ABS control, the inflow valves 5,
This controls the outflow valve 6 and the motor 8.

Although the embodiment has been described with reference to the drawings, the present invention is not limited to the configuration of the above embodiment. For example, the brake control device to which the present invention can be applied is not limited to the one described in the embodiment. Further, in the embodiment, the pressure increase amount is controlled by driving the motor 8 (pump 4) at the time of pressure increase. However, the electromagnetic valve provided in the circuit connecting the hydraulic pressure source and the wheel cylinder is provided. The control may be performed by opening and closing.

[Brief description of the drawings]

FIG. 1 is a brake circuit diagram showing a brake circuit in a brake control device according to a first embodiment.

FIG. 2 is a block diagram illustrating a configuration of a control unit according to the first embodiment.

FIG. 3 is a flowchart illustrating braking control according to the first embodiment.

FIG. 4 is a diagram illustrating a duty characteristic output to a pump in the first embodiment.

FIG. 5 is a diagram illustrating a duty characteristic output to the out-side gate valve at the time of pressure increase and holding in the first embodiment.

FIG. 6 is a duty characteristic diagram that is output to the out-side gate valve when the pressure is reduced in the first embodiment.

FIG. 7 is a block diagram showing a main configuration of the first embodiment.

FIG. 8 is a time chart showing an operation example of the first embodiment.

FIG. 9 is a characteristic diagram showing a relationship between a holding fluid pressure and a current value in the first embodiment.

FIG. 10 is a brake circuit diagram showing a brake circuit in a brake control device according to a second embodiment.

[Explanation of symbols]

 Reference Signs List 1 brake circuit 2 brake circuit 3 out-side gate valve 3a one-way valve 4 pump 4a suction circuit 4b suction circuit 4c discharge circuit 4d check valve 4p plunger 4r pump room 5 inflow valve 6 outflow valve 7 reservoir 8 motor 9 in-side gate valve 10 Return circuit 11 Control unit 12 Wheel speed sensor 13 Running state detecting means 201 Low pressure circuit BP Brake pedal MC Master cylinder RES Reservoir WC Wheel cylinder a Averaging unit b Differentiating unit c Amplifying unit d Low-pass filter e Gain processing unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yukihiko Inoue 1370 Onna, Atsugi-shi, Kanagawa F-term in Unisia Gex Co., Ltd. (Reference) 3D046 BB18 BB29 BB31 BB32 CC02 EE01 FF05 HH16 HH20 HH26 JJ21 LL23 LL38 LL50

Claims (5)

[Claims] 1. A valve closing means for increasing, holding and reducing pressure on a wheel cylinder to arbitrarily adjust the wheel cylinder pressure, and for closing brake fluid in the wheel cylinder at least when holding the wheel cylinder pressure. Hydraulic pressure adjusting means having an electromagnetic valve to perform; running state detecting means for detecting a running state of the vehicle; and controlling the hydraulic pressure adjusting means in accordance with the running state of the vehicle detected by the running state detecting means. A brake control unit that outputs a signal to execute pressure increase / hold / pressure reduction to execute a brake control for generating a desired braking force. The brake control unit includes a hydraulic pressure adjustment unit. When the holding operation is performed, a control signal for maintaining the solenoid valve in the closed state is output, and the control signal is output according to the wheel cylinder pressure to be held. A brake control device characterized in that the signal is a signal that changes an execution current value output to the solenoid valve to a higher value as the value of the brake control signal is higher. 2. The running state detecting means is provided with an actual pressure detecting means for obtaining an actual pressure of a wheel cylinder, and the braking control means detects a target hydraulic pressure of the wheel cylinder based on an input from the running state detecting means. A target hydraulic pressure calculating means for calculating, and the hydraulic pressure adjusting means for bringing the actual wheel cylinder pressure detected by the actual pressure detecting means at the time of the braking control closer to the target hydraulic pressure calculated by the target hydraulic pressure calculating means. The brake control device according to claim 1, wherein the brake control device is operated. 3. The brake control device according to claim 2, wherein said actual pressure detecting means is means for calculating an actual wheel cylinder pressure based on a vehicle deceleration. 4. The braking control executed by the braking control means includes determining an inter-vehicle distance from a preceding vehicle based on an input from a traveling state detecting means and generating a braking force to make the inter-vehicle distance an optimum value. 4. The brake control device according to claim 1, wherein the control is control. 5. A brake circuit connected to a wheel cylinder for supplying brake fluid to the wheel cylinder, and a fluid pressure source for supplying brake fluid to the brake circuit, wherein the solenoid valve is connected to the brake circuit. A normally-open solenoid valve that is connected to release the brake fluid of the wheel cylinder to a low-pressure circuit that is on a relatively low-pressure side. 2. The solenoid valve is temporarily or continuously closed when the pressure is reduced, and the supply of the brake fluid from the hydraulic pressure source is stopped and the solenoid valve is closed when the pressure is maintained. 5. The brake control device according to any one of items 1 to 4.