JP4131343B2 - Brake control device for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle brake control device.
[0002]
[Prior art]
A general automobile is equipped with a booster (a booster) that assists a braking force generated by depressing a brake pedal. Here, particularly for beginners, there are cases where sufficient depression cannot be performed in an emergency. Therefore, an emergency brake device has been proposed for assisting the booster device to obtain a stronger braking force.
[0003]
On the other hand, in recent automobiles, in the brake operation of the driver, it is detected from the slip rate of the wheel whether or not the wheel is likely to be locked, and when this state is detected, the brake fluid pressure of the wheel is released and the braking force is increased. An ABS (Anti-Skid Brake System) device that suppresses the lock of the wheel by reducing it is mounted.
[0004]
Japanese Patent Application Laid-Open No. 4-135958 discloses a method for changing a target slip ratio in accordance with a depression state of a brake pedal with respect to ABS control during turning of a vehicle.
[0005]
[Problems to be solved by the invention]
However, during normal braking, the load on the front wheels is greater than that of the rear wheels, so the rear wheels are more likely to slip than the front wheels. For this reason, when the ABS is operated, the rear wheel brake fluid pressure is controlled to be reduced as compared with the front wheel brake fluid pressure to suppress the rear wheel slip. However, when the emergency brake device is activated and the ABS is activated, there is a possibility that the braking distance may be increased due to the decrease in the brake fluid pressure.
[0006]
The present invention has been made in view of the above-described problems, and an object thereof is to provide a vehicle brake control device that can improve the stability by suppressing the slip of the rear wheel during normal operation and improve the braking performance when the emergency brake device is operated. It is to be.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, a vehicle brake control device of the present invention has the following configuration. That is,
Braking force assisting means for increasing the braking force of the wheel when the brake state quantity is greater than or equal to a predetermined amount; and slip suppression means for reducing the wheel braking force and suppressing wheel slip when the wheel slip rate is greater than or equal to a predetermined value; A brake control device for a vehicle comprising: a rear wheel slip suppression means for reducing a rear wheel braking force to suppress a rear wheel slip when a braking force is applied; The slip suppression means increases the degree of suppression of the operation of the rear wheel slip suppression means when traveling at a high speed or traveling on a road surface having a low friction coefficient when the brake state quantity is a predetermined amount or more .
[0008]
Preferably, the slip suppression means changes the predetermined value to be larger when the brake state quantity becomes a predetermined quantity or more.
[0009]
Preferably, the slip suppression means changes the increasing rate of the braking force of the rear wheel slip suppression means in the increasing direction when the brake state quantity becomes a predetermined amount or more.
[0010]
Preferably, the slip suppression means operates the rear wheel slip suppression means when the deceleration of the vehicle body is equal to or greater than a predetermined deceleration, and the predetermined deceleration when the brake state quantity exceeds a predetermined amount. Change to be larger.
[0012]
Preferably, the vehicle further includes determination means for determining that an emergency is required to increase the braking force when the brake state amount is equal to or greater than a predetermined amount.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[Mechanical structure of ABS controller]
FIG. 1 is a block diagram showing a mechanical configuration of the ABS control device according to the present embodiment.
[0014]
As shown in FIG. 1, in the vehicle according to this embodiment, the left and right front wheels 11 and 12 are driven wheels, the left and right rear wheels 13 and 14 are drive wheels, and the output torque of the engine 15 is changed from the automatic transmission 16 to the propeller shaft. 17, it is transmitted to the left and right rear wheels 13 and 14 via the differential 18 and the left and right drive shafts 19 and 20.
[0015]
Each of the wheels 11 to 14 includes brake devices 21 to 24 having discs 21a to 24a that rotate integrally with the wheels and calipers 21b to 24b that receive the supply of braking pressure and brake the rotation of the discs 21a to 24a. 24 is provided.
[0016]
The brake control system for operating the brake devices 21 to 24 is based on the main booster 27 and the sub booster 47 that increase the depression force of the brake pedal 26 by the driver, and the pedaling force pressure increased by the boosters 27 and 47. And a master cylinder 28 for generating braking pressure. A front wheel braking pressure supply line 29 extending from the master cylinder 28 is branched into a left front wheel braking pressure supply line 29a and a right front wheel braking pressure supply line 29b, and is connected to calipers 21a and 22b of the brake devices 21 and 22, respectively. It is connected. The left front wheel braking pressure supply line 29a is provided with a first valve unit 30 comprising an electromagnetic on-off valve 30a and an electromagnetic relief valve 30b. The right front wheel braking pressure supply line 29b has an electromagnetic on-off valve 31a. And a second valve unit 31 comprising an electromagnetic relief valve 31b.
[0017]
A rear wheel braking pressure supply line 32 extending from the master cylinder 28 is provided with a third valve unit 30 including an electromagnetic on-off valve 33a and an electromagnetic relief valve 33b. The rear wheel brake pressure supply line 32 branches downstream of the third valve unit 33 into a left rear wheel brake pressure supply line 32a and a right rear wheel brake pressure supply line 32b. , 24 are connected to calipers 23a, 24b.
[0018]
In the present embodiment, the brake pressure of the brake device 22 of the right front wheel 12 is adjusted by the first channel that adjusts the brake pressure of the brake device 21 of the left front wheel 11 by the operation of the first valve unit 30 and the operation of the second valve unit 31. A second channel for adjustment and a third channel for adjusting the braking pressure of the brake devices 23 and 24 of the left and right rear wheels 13 and 14 by operation of the third valve unit 33 are provided, and these channels are controlled independently of each other. It has come to be. Then, the first to third valve units 30, 31, and 33 adjust the braking pressure.
[0019]
The control 34 for controlling the first to third channels includes a brake state signal from the brake sensor 35 that detects whether or not the brake pedal 26 is depressed, a depression amount and a depression speed of the brake pedal, and wheels 11 to 14. The wheel speed signal from the wheel speed sensors 37 to 40 for detecting the rotation speed of the vehicle and the steering angle signal (steering amount, steering speed) from the steering angle sensor 41 are input, and ABS control is performed in parallel for each channel. To do it.
[0020]
Based on the wheel speed of each wheel 11-14, the control unit 34 increases / decreases the braking pressure of each wheel 11-14 by the first to third valve units 30, 31, 33 according to a predetermined ABS control start threshold, The ABS control start threshold value is corrected or prohibited from being corrected, and the on / off valves 30a, 31a, 33a and the relief valves 30b, 31b, 33b of the first to third valve units 30, 31, 33 are controlled to be opened / closed by duty control. It has become. The brake fluid discharged from the relief valves 30b, 31b, 33b is returned to the reservoir tank 28a of the master cylinder 28 via a drain line (not shown).
[Mechanical configuration of emergency brake control system]
Hereinafter, for convenience of explanation, the brake control by the booster (main booster) at the normal time is referred to as “boost control”, and the assist control for the booster at the time of emergency is referred to as “emergency brake control”.
[0021]
FIG. 2 is a block diagram illustrating a mechanical configuration of the emergency brake control device for a vehicle according to the embodiment of the present invention.
[0022]
As shown in FIG. 2, the emergency brake control device for a vehicle according to the present embodiment includes a main booster 27 and a sub booster 47 connected in series. The main booster 27 and the sub booster 47 are provided between the brake pedal 26 and the master cylinder 28.
[0023]
The main booster 27 is provided with a diaphragm 27a urged leftward in the figure by a return spring in the shell, and a diaphragm chamber 27b partitioned by the diaphragm 27a has a vacuum pressure or a vacuum pump in the intake manifold of the engine. The vacuum pressure is supplied through the check valve 59.
[0024]
Similarly, the sub-booster 47 includes a diaphragm 47a urged leftward in the figure by a return spring in the shell, and an air chamber 57 is connected to the diaphragm chamber 47b partitioned by the diaphragm 47a.
[0025]
A vacuum pressure is supplied to the air chamber 57 via a check valve 59 and a vacuum valve 55, and atmospheric pressure is supplied via an atmospheric pressure valve 49. The vacuum valve 55 and the atmospheric pressure valve 49 are composed of duty solenoid valves, and the opening degree of the valves 49 and 55 is duty-controlled by the control unit 34. As will be described later, the control unit 34 changes the boost ratio of the sub booster 47 to the main booster by controlling the opening of each valve. The control unit 34 includes a general central processing unit (CPU), a ROM storing a control program, a RAM storing a vehicle speed, a brake depression amount, and the like, a time timer, and the like.
[0026]
The brake pedal 26 and the master cylinder 28 are connected by rods 28a extending through the central portions of the diaphragms 27a and 47a provided in the main booster 27 and the sub booster 47, and both the diaphragms 27a are connected to the rod 28a. , 47a are engaged at the center.
[0027]
Therefore, when both the diaphragm chambers 27b and 47b become negative pressure, the center portions of the respective diaphragm chambers 27b and 47b are displaced rightward in the figure against the urging force of the respective return springs. In addition to the pressure, an emergency brake pressure is applied to the rod 28a.
[0028]
The pedal pressure of the brake pedal is applied to the piston of the master cylinder 28 by synthesizing the boost pressure of the main booster 27 and the emergency brake pressure of the sub booster 47, and by making the emergency brake pressure by the sub booster 47 variable, The boost pressure as a whole is changed.
[0029]
The front wheel braking pressure supply line 29 extending from the master cylinder 28 is branched into a left front wheel braking pressure supply line 29a and a right front wheel braking pressure supply line 29b, and is connected to calipers 21b and 22b of the brake devices 21 and 22, respectively. It is connected.
[0030]
A rear wheel braking pressure supply line 32 extending from the master cylinder 28 is branched into a left rear wheel braking pressure supply line 32a and a right rear wheel braking pressure supply line 32b, and calipers 23b of the brake devices 23 and 24 are provided. , 24b.
[0031]
In addition, the same number is attached | subjected to the same structure as the ABS control apparatus of FIG. 1, and description is abbreviate | omitted.
[0032]
The control unit 34 includes a brake state signal from the brake sensor 35, a chamber pressure signal from the pressure sensor 58 that detects the pressure in the air chamber 57, a vehicle speed signal from the vehicle speed sensor 71 that detects the vehicle speed, and a depression of the accelerator pedal 73. An accelerator depression amount signal is input from an accelerator stroke sensor 74 that detects the amount. The control unit 34 outputs a vacuum pressure control signal and an atmospheric pressure control signal for controlling the duty solenoid for the vacuum valve 55 and the atmospheric pressure valve 49.
[0033]
In addition to the stroke sensor, a pedal depression force pressure sensor or the like may be applied as the brake sensor.
[0034]
The control unit 34 calculates the depression amount and depression speed of the brake pedal based on the brake state signal of the brake pedal. When the pedal depression amount and the pedal depression speed become larger than a predetermined threshold, the boost magnification (emergency brake pressure) in the sub booster 47 is determined, and the target pressure value in the air chamber 57 is set to obtain this boost magnification. Then, the duty ratio between the vacuum pressure control signal output to the vacuum valve 55 and the atmospheric pressure valve 49 and the atmospheric pressure control signal is calculated from the target pressure value, and the vacuum value is set so that the pressure value in the air chamber 57 approaches the target pressure value. The duty of the valve 55 and the atmospheric pressure valve 49 is controlled. This duty control takes the form of feedback control that approaches the target pressure value using the vacuum pressure and the atmospheric pressure.
[0035]
In addition to the apparatus using the pneumatic actuator of the present embodiment, a configuration using a hydraulic actuator may be used. In this case, an emergency brake hydraulic valve may be provided downstream of the master cylinder instead of the vacuum valve, the atmospheric pressure valve, the sub booster, and the air chamber.
[Control procedure of emergency brake control device]
Next, the control procedure by the emergency brake control device of this embodiment will be described.
[0036]
FIG. 3 is a flowchart showing a control procedure of the emergency brake control device according to the present embodiment.
[0037]
As shown in FIG. 3, when the process is started, the control unit 34 takes in a brake state signal from the brake sensor 35 in step S <b> 2. In step S4, the depression amount and depression speed of the brake pedal 26 by the driver are calculated from the brake state signal. In step S6, it is determined whether or not the flag FBA has been reset. This flag FBA indicates whether or not emergency brake control is being performed. When FBA is set (FBA = 1), an emergency brake control state is indicated. When FBA is not set (FBA = 0), an emergency brake non-control state is indicated. . If the flag FBA is reset in step S6, the process proceeds to step S8 to determine whether or not an emergency brake control start condition is satisfied. This emergency brake control start condition is determined based on whether or not the depression amount and the depression speed of the brake pedal 26 are equal to or greater than a predetermined threshold value. If the emergency brake control start condition is satisfied in step S8, the flag FBA is set in step S10, and the opening amounts of the atmospheric pressure valve and the vacuum valve are set to predetermined boost magnifications in steps S12 and S14.
[0038]
If the flag FBA is set in step S6, the process proceeds to step S16 to determine whether or not the emergency brake control end condition is satisfied. This emergency brake control end condition is determined based on whether or not the depression amount and the depression speed of the brake pedal 26 are equal to or less than a predetermined threshold value. If the emergency brake control end condition is satisfied in step S16, the atmospheric pressure valve and the vacuum valve are closed in steps S18 and S20, and the flag FBA is reset in step S22.
[0039]
Further, if the emergency brake start condition is not satisfied in step S8, the atmospheric pressure valve and the vacuum valve are closed in steps S24 and S26.
[Control procedure of ABS control device]
Next, a control procedure by the ABS control device will be described.
[0040]
4 to 5 are flowcharts showing a control procedure of the ABS control apparatus according to the present embodiment.
[0041]
As shown in FIGS. 4 and 5, when the process is started, in step S32, signals are taken from the sensors. In step S34, the friction coefficient μ of the road surface is calculated. In step S36, the slip ratio of each wheel is calculated. In step S38, an ABS control start threshold value Sa and a target slip ratio Sb are calculated. In step S40, it is determined whether or not the flag FBA is set. If the flag FBA is set in step S40, the process proceeds to step S41, and if it is reset, the process proceeds to step S46. In step S41, it is determined whether the vehicle is traveling at a high speed by determining whether the vehicle speed V is equal to or higher than a predetermined value V0. If the vehicle speed V is greater than or equal to the predetermined value V0 in step S41, the process proceeds to step S43, and if it is below the predetermined value V0, the process proceeds to step S42. In step S42, it is determined whether the vehicle is traveling on a low μ road by determining whether the friction coefficient μ calculated in step S34 is equal to or less than a predetermined threshold value μ1. If the friction coefficient μ is equal to or smaller than the predetermined threshold μ1 in step S42, the process proceeds to step S44, and if the friction coefficient μ exceeds the predetermined threshold μ1, the process proceeds to step S43.
[0042]
In step S43, the vehicle is running at a high speed, and a predetermined value A is added to the ABS control start threshold Sa to correct the direction in which it is difficult to intervene in the ABS control. In step S44, the vehicle is traveling on a low μ road, and a predetermined value B is added to the ABS control start threshold Sa to correct the direction in which it is difficult to intervene in the ABS control. Here, the predetermined value B is set to a value larger than the predetermined value A (B> A), and is set to be less likely to intervene in ABS control during low-μ road traveling than during high-speed traveling.
[0043]
In step S46, it is determined whether or not the flag FABS has been reset. This flag FABS indicates whether or not ABS control is in progress. When FABS is set (FABS = 1), the ABS control state is indicated. When FABS is reset (FABS = 0), the ABS non-control state is indicated. If the flag FABS is reset in step S46, the process proceeds to step S48, and it is determined whether or not the wheel slip ratio S is greater than or equal to the ABS control start threshold value Sa. The slip ratio S of the wheel is calculated by, for example, an average value of the slip ratio of each wheel. If the wheel slip ratio S is greater than or equal to the ABS start threshold value Sa in step S48, the process proceeds to step S50, the flag FABS is set, and in step S52, the first to third valve units 30, 31, 33 are used to move to the brake devices 21-24. The braking pressure is reduced to converge the slip ratio S to the target slip ratio Sb.
[0044]
If the flag FABS is set in step S46, the process proceeds to step S54, and it is determined whether or not the wheel slip ratio S is equal to or less than the target slip ratio Sb. If the slip ratio S of the wheel is equal to or less than the target slip ratio Sb in step S54, the process proceeds to step S56, where the first to third valve units 30, 31, and 33 increase the braking pressure to the brake devices 21 to 24 to perform slip. It converges to the target slip ratio Sb.
[0045]
In step S58, it is determined whether or not the pressure increase continuous time t has exceeded a predetermined time t1. If the pressure increase continuous time t has not exceeded the predetermined time t1 in step S58, the process returns. If the pressure increase continuous time t has exceeded the predetermined time t1 in step S58, the flag FABS is reset in step S60 and the process returns. .
[0046]
If the wheel slip rate S exceeds the target slip rate Sb in step S54, the process proceeds to step S62. In step S62, whether or not the difference between the wheel slip rate S and the target slip rate Sb is equal to or greater than a predetermined value α. Determine. If the difference between the slip ratio S of the wheel and the target slip ratio Sb is equal to or larger than the predetermined value α in step S62, the braking pressure applied to the brake devices 21 to 24 by the first to third valve units 30, 31, and 33 in step S64. To reduce the slip ratio S to the target slip ratio Sb.
[0047]
Further, if the difference between the wheel slip ratio S and the target slip ratio Sb is less than the predetermined value α in step S62, it is determined in step S66 whether or not the wheel acceleration Δv is equal to or greater than the first value va. If the wheel acceleration Δv is greater than or equal to the first value va in step S66, the brake pressure to the brake devices 21 to 24 is increased by the first to third valve units 30, 31, and 33, and the slip ratio S is determined as the target slip ratio. Converge to Sb.
[0048]
If the wheel acceleration Δv is lower than the first value va in step S66, the process proceeds to step S70 to determine whether the wheel acceleration Δv is equal to or less than the second value vb. If the wheel acceleration Δv is equal to or less than the second value vb in step S70, the braking pressure to each brake device 21-24 is reduced by the first to third valve units 30, 31, 33 in step S72, and the slip ratio S is determined. It converges to the target slip ratio Sb. On the other hand, if the wheel acceleration Δv exceeds the second value vb in step S70, the braking pressures to the brake devices 21 to 24 are held by the first to third valve units 30, 31, and 33 in step S74.
[Rear wheel ABS control procedure]
Next, rear wheel ABS control will be described.
[0049]
In this rear wheel ABS control, if the brake is operated normally during forward travel, the load on the front wheel becomes larger than that of the rear wheel, so the ground contact area with respect to the road surface of the rear wheel becomes smaller and the rear wheel slips than the front wheel. It becomes easy to do. For this reason, as shown in FIG. 9, during ABS control, the brake fluid pressure of the rear wheel is controlled to be reduced compared to the brake fluid pressure of the front wheel, so that the increase rate of the brake fluid pressure of the rear wheel is reduced. The slip of the wheel is suppressed.
[0050]
6 to 7 are flowcharts for explaining the rear wheel ABS control procedure.
[0051]
As shown in FIGS. 6 and 7, when the process is started, in step S <b> 82, signals are taken from each sensor. In step S84, the vehicle body deceleration D is calculated. In step S86, it is determined whether the flag FBA is set. If the flag FBA is set in step S86, the process proceeds to step S88, and if it is reset, the process proceeds to step S92. In step S92, the emergency brake is not controlled, and the rear wheel ABS control start threshold D0 and the rear wheel target slip ratio S0 are corrected (D0 ← D0A, S0 ← S0A).
[0052]
In step S88, it is determined whether the vehicle is traveling at a high speed by determining whether the vehicle speed V is equal to or higher than a predetermined speed V0. If the vehicle speed V is greater than or equal to the predetermined value V0 in step S88, the process proceeds to step S94, and if it is below the predetermined value V0, the process proceeds to step S90. In step S90, it is determined whether the vehicle is traveling on a low μ road by determining whether the friction coefficient μ calculated in step S34 is equal to or less than a predetermined threshold value μ1. If the friction coefficient μ is equal to or smaller than the predetermined threshold μ1 in step S90, the process proceeds to step S94. If the friction coefficient μ exceeds the predetermined threshold μ1, the process proceeds to step S96.
[0053]
In step S94, the vehicle is traveling at a high speed and traveling on a low μ road, and the rear wheel ABS control start threshold D0 and the rear wheel target slip ratio S0 are corrected (D0 ← D0B, S0 ← S0B). In step S96, neither high-speed traveling nor low-μ road traveling is performed, and the rear wheel ABS control threshold D0 and the rear wheel target slip ratio S0 are corrected (D0 ← D0C, S0 ← S0C). Here, the magnitudes of the correction values D0A, D0B, D0C of the rear wheel ABS control threshold D0 are set to D0A <D0B <D0C, and the magnitudes of the correction values S0A, S0B, S0C of the rear wheel target slip ratio S0 are S0A <. S0B <S0C is set. Further, the relationship between the rear wheel target slip ratio S0 and the vehicle body deceleration D in the rear wheel ABS control is set so that the target slip ratio S0 increases in proportion to the vehicle body deceleration D as shown in FIG. The
[0054]
As a result, as shown in FIG. 9, the rear wheel ABS control start threshold D0 is corrected so as to increase when the emergency brake control device is activated, so that the rear wheel slip is suppressed during normal operation, and the emergency brake control device is activated. The braking performance can be improved by making it difficult to intervene in the rear wheel ABS control.
[0055]
Further, by setting the correction values D0A, D0B, D0C of the rear wheel ABS control threshold D0 to D0A <D0B <D0C, the rear wheel ABS control intervention is performed during high-speed driving and / or low-μ road driving. The braking distance can be shortened by increasing the degree of suppression of the braking force and suppressing the rear wheel ABS control intervention.
[0056]
In step S98 shown in FIG. 7, it is determined whether the vehicle body deceleration D is equal to or greater than the rear wheel ABS control start threshold D0 set in step S92, S94, or S96. If the vehicle body deceleration D is greater than or equal to the rear wheel ABS control start threshold D0 in step S98, the process proceeds to step S100. If the vehicle body deceleration D is less than the rear wheel ABS control start threshold D0, the process proceeds to step S106.
[0057]
In step S100, the flag FEBD is set. This flag FEBD indicates whether or not the rear wheel ABS is being controlled. When FEBD is set (FEBD = 1), the rear wheel ABS control state is set. When FEBD is not set (FEBD = 0), the rear wheel ABS is not controlled. Represents a state.
[0058]
In step S102, it is determined whether or not the rear wheel slip ratio S is equal to or greater than the target slip ratio S0 in the rear wheel ABS control set in step S92, S94 or S96. If the slip ratio S of the wheel is greater than or equal to the rear wheel target slip ratio S0 in the rear wheel ABS control in step S102, the process proceeds to step S104, and if it is less than the rear wheel target slip ratio S0, the process proceeds to step S112.
[0059]
In step S104, the third valve unit 33 reduces the braking pressure applied to the rear wheel brake devices 23, 24 to converge the rear wheel slip ratio S to the target slip ratio S0.
[0060]
In step S112, it is determined whether or not the rear wheel slip ratio S is less than a value obtained by subtracting a predetermined value α from the rear wheel target slip ratio S0. If the rear wheel slip ratio S falls below the value obtained by subtracting the predetermined value α from the rear wheel target slip ratio S0 in step S112, the braking pressure to the rear wheel brake devices 23, 24 is reduced by the third valve unit 33 in step S114. The rear wheel slip ratio S is converged to the target slip ratio S0. If the rear wheel slip ratio S is not less than the value obtained by subtracting the predetermined value α from the rear wheel target slip ratio S0 in step S112, the third valve unit 33 holds the braking pressure to the rear wheel brake devices 23, 24 in step S116. To do.
[0061]
On the other hand, in step S106, it is determined whether or not the flag FEBD is set. If the flag FEBD is set in step S106, the process proceeds to step S108, and if it is reset, the process returns.
[0062]
In step S108, it is determined whether or not the vehicle speed V is zero (stopped) or the brake depression amount is zero (the foot is released from the brake pedal). If the vehicle speed V is zero or the brake depression amount is zero in step S108, it is determined that the rear wheel ABS control termination condition is satisfied, and the routine proceeds to step S110, where the flag FEBD is reset. If the vehicle speed V is not zero or the brake depression amount is not zero in step S108, the process proceeds to step S102.
[0063]
In step S111, the braking pressure of the rear wheels is gradually reduced to a pressure corresponding to a brake depression amount of zero.
[0064]
Note that the present invention can be applied to modifications or variations of the above-described embodiment without departing from the spirit of the present invention.
[0065]
【The invention's effect】
As described above, according to the first aspect of the present invention, the slip suppression means can prevent the rear wheel slip when traveling at a high speed or traveling on a road surface having a low friction coefficient when the brake state quantity is equal to or greater than a predetermined amount. By increasing the degree of suppression of the operation of the suppression means, the braking distance can be shortened by suppressing the intervention of the rear wheel ABS control when the emergency brake control device is operating and during high speed traveling or low μ road traveling .
According to the second aspect of the present invention, the slip suppression means brakes the vehicle by making it difficult to intervene in the ABS control by changing the brake state amount so that the predetermined value becomes larger when the brake state amount exceeds the predetermined amount. Performance can be improved.
[0066]
Further, according to the invention of claim 3, the slip suppression means changes the increase rate of the braking force of the rear wheel slip suppression means in the increasing direction when the brake state quantity becomes a predetermined amount or more. The braking performance can be improved by making it difficult to intervene in the wheel ABS control.
[0067]
According to the invention of claim 4, the slip suppression means operates the rear wheel slip suppression means when the deceleration of the vehicle body is equal to or greater than the predetermined deceleration, and when the brake state quantity exceeds the predetermined amount, By changing the predetermined deceleration so as to increase, braking performance can be improved by making it difficult to intervene in the rear wheel ABS control due to the vehicle body deceleration.
[0069]
In addition, according to the invention of claim 5 , further comprising a determination means for determining that an emergency is required to increase the braking force when the brake state quantity is greater than or equal to a predetermined quantity, thereby providing braking during emergency brake control. The distance can be shortened.
[0070]
[Brief description of the drawings]
FIG. 1 is a block diagram showing a mechanical configuration of an ABS control device according to the present embodiment.
FIG. 2 is a block diagram showing a mechanical configuration of the vehicle emergency brake control device according to the embodiment of the present invention.
FIG. 3 is a flowchart showing a control procedure of the emergency brake control device according to the present embodiment.
FIG. 4 is a flowchart showing a control procedure of the ABS control device according to the present embodiment.
FIG. 5 is a flowchart showing a control procedure of the ABS control device according to the present embodiment.
FIG. 6 is a flowchart showing a rear wheel ABS control procedure of the present embodiment.
FIG. 7 is a flowchart showing a rear wheel ABS control procedure of the present embodiment.
FIG. 8 is a diagram showing a relationship between a rear wheel target slip ratio and a vehicle body deceleration.
FIG. 9 is a diagram illustrating rear wheel ABS control.
[Explanation of symbols]
21-24 ... Brake device 30 ... 1st valve unit 31 ... 2nd valve unit 33 ... 3rd valve unit 34 ... Control unit

Claims (5)

Braking force assisting means for increasing the braking force of the wheel when the brake state quantity is greater than or equal to a predetermined amount; and slip suppression means for reducing the wheel braking force and suppressing wheel slip when the wheel slip rate is greater than or equal to the predetermined value; A vehicle brake control device comprising:
The slip suppression means includes rear wheel slip suppression means for reducing the braking force of the rear wheel to suppress the slip of the rear wheel when a braking force is applied,
The slip suppression means increases the degree of suppression of the operation of the rear wheel slip suppression means when traveling at a high speed or on a road surface having a low friction coefficient when the brake state quantity is a predetermined amount or more. A vehicle brake control device.   2. The vehicle brake control device according to claim 1, wherein the slip suppression unit changes the predetermined value so as to increase when the brake state amount becomes a predetermined amount or more. 3.   2. The vehicle according to claim 1, wherein the slip suppression unit changes an increasing rate of a braking force of the rear wheel slip suppression unit in an increasing direction when the brake state amount becomes a predetermined amount or more. Brake control device.   The slip suppression means operates the rear wheel slip suppression means when the deceleration of the vehicle body is equal to or greater than a predetermined deceleration, and increases the predetermined deceleration when the brake state quantity exceeds a predetermined amount. The vehicle brake control device according to claim 1, wherein the vehicle brake control device is changed.   5. The apparatus according to claim 1, further comprising a determination unit that determines that an emergency is required to increase the braking force when the brake state amount is a predetermined amount or more. Brake control device for vehicles.

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