JP4045514B2 - Vehicle braking device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a braking device for a vehicle.
[0002]
[Prior art]
A general automobile is equipped with a booster or the like that assists a braking force generated by a depression operation of a brake pedal. Here, particularly for beginners, there are cases where sufficient depression cannot be performed in an emergency. Therefore, an emergency brake assist device has been proposed that assists the booster device that increases the auxiliary magnification of the booster device to apply a stronger braking force.
[0003]
In JP-A-7-156767, when the brake pedal is returned from the actuator position by a predetermined range or more, it is determined that the assist control is released, and the auxiliary magnification to the booster is returned to the auxiliary magnification by the normal booster. Are disclosed.
[0004]
[Problems to be solved by the invention]
However, in the conventional emergency brake assist device, as shown in FIG. 20, when the brake pedal is returned from the actuator position by a predetermined range or more and the brake depression amount pp becomes the predetermined threshold value pp1 or less, it is determined that the assist control is released. Therefore, for example, as shown in FIG. 21, when the brake is suddenly activated by the emergency assist intervention, the driver is surprised to loosen the brake pedal and assist the brake pedal when the brake depression amount decreases rapidly. It is conceivable that the control is released.
[0005]
The present invention has been made in view of the above-described problems, and its object is to correct the threshold value for assist control release determination according to not only the amount of depression of the brake pedal but also the operation speed of the brake pedal, so that the brake pedal It is an object of the present invention to provide a vehicle braking device that does not release assist control when it is suddenly returned.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, a vehicle braking device of the present invention has the following structure. That is,
Brake force assisting means for assisting the braking force generated according to the brake operation, an operation amount detecting means for detecting the brake operation amount, an operation speed detecting means for detecting the brake operation speed, the brake operation amount and the brake operation An emergency determination unit that determines an emergency in which it is necessary to assist the braking force according to the speed, and when the emergency determination unit determines an emergency, the assist operation by the brake force support unit is started. a boosting start control means for, when the brake operation amount is less than the predetermined amount, and assisting end control means for terminating the assisting operation by the braking force assisting means, the brake operation amount is the brake operation when less than a predetermined amount When the speed is equal to or higher than a predetermined speed, the end of the assist operation by the assist end control means is restricted, and the brake operation amount is not a predetermined amount. When the brake operating speed is less than the predetermined speed when the can and a control means for ending the assist operation by the assist termination control means.
[0008]
Preferably, the control means delays the end of the assisting operation for a predetermined time.
[0009]
Preferably, the control means gradually reduces the assisting force by the brake force assisting means when the brake operation speed is equal to or higher than a predetermined speed when the brake operation amount is less than a predetermined amount.
[0010]
Preferably, the control means continues the assisting operation by the brake force assisting means until the brake operation amount becomes zero.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[0014]
In the following, for convenience of explanation, the brake control by the booster at the normal time is called “boost control”, and the brake control of the emergency brake assist device for the booster at the time of emergency is called “assist control”. .
[Device configuration]
FIG. 1 is a block diagram of a vehicle braking apparatus according to an embodiment of the present invention.
[0015]
As shown in FIG. 1, the vehicle braking apparatus 1 of the present embodiment includes a main booster 13 and a sub booster 14 connected in series. The main booster 13 and the sub booster 14 are provided between the brake pedal 11 and the master cylinder 16.
[0016]
The main booster 13 is provided with a diaphragm 13a urged leftward in the figure by a return spring in the shell, and a diaphragm chamber 13b partitioned by the diaphragm 13a has a vacuum pressure or a vacuum pump in the intake manifold of the engine. The vacuum pressure is supplied through the check valve 19.
[0017]
Similarly, the sub-booster 14 includes a diaphragm 14a urged leftward in the figure by a return spring in the shell, and an air chamber 17 is connected to the diaphragm chamber 14b partitioned by the diaphragm 14a.
[0018]
A vacuum pressure is supplied to the air chamber 17 via the check valve 19 and the vacuum valve 15, and atmospheric pressure is supplied via the atmospheric pressure valve 9. The vacuum valve 15 and the atmospheric pressure valve 9 are composed of duty solenoid valves, and the opening degree of the valves 9 and 15 is duty-controlled by the control unit 10. As will be described later, the control unit 10 changes the assist magnification for the main booster by the sub booster 14 by controlling the opening of each valve. The control unit 10 includes a general central processing unit (CPU), a ROM that stores a control program, a RAM that stores vehicle speed, a brake depression amount, and the like, a timer, and the like.
[0019]
The brake pedal 11 and the master cylinder 16 are connected by a rod 16a extending through the central portion of each diaphragm 13a, 14a provided in the main booster 13 and the sub booster 14, and the both diaphragms 13a are connected to the rod 16a. , 14a are engaged at the center.
[0020]
Therefore, when both the diaphragm chambers 13b and 14b become negative pressure, the central portion of each diaphragm chamber 13b and 14b is displaced rightward in the figure against the urging force of each return spring. In addition to the pressure, an assist pressure is applied to the rod 16a.
[0021]
The brake pedal pressure force is applied to the piston of the master cylinder 16 by synergizing the assist pressure of the main booster 13 and the assist pressure of the sub booster 14, and the assist pressure by the sub booster 14 is made variable as a whole. The assist pressure is changed.
[0022]
The disc brake device 20 includes a brake disc 20a and a caliper 20b that are hydraulic and rotate together with the wheels. The caliper 20b holds a brake pad, and the brake pad is pressed against the brake disc with a pressure corresponding to the brake fluid pressure supplied from the master cylinder to the cylinder through the oil passage, thereby generating a braking force on the wheels.
[0023]
The illustrated disc brake device 20 is for a front wheel, and the brake fluid pressure for a not-shown rear wheel brake device is supplied from an oil passage through a proportioning valve 22.
[0024]
The control unit 10 detects the pedal depression amount detection signal pp from the stroke sensor 12 that detects the depression amount of the brake pedal 11, the chamber pressure sensor signal pc from the pressure sensor 18 that detects the pressure in the air chamber 17, and the vehicle speed. A vehicle speed signal v from the vehicle speed sensor 21 and an accelerator depression amount detection signal a from the accelerator stroke sensor 24 for detecting the depression amount of the accelerator pedal 23 are input. The control unit 10 also outputs a vacuum pressure control signal d1 and an atmospheric pressure control signal d2 for controlling the duty solenoid for the vacuum valve 15 and the atmospheric pressure valve 9. The control unit 10 receives an ON signal when the ignition switch 25 (IG switch) is turned on. In addition to the stroke sensor 12, a pedal depression force pressure sensor or the like may be applied as a sensor for detecting the depression amount of the brake pedal.
[0025]
The control unit 10 measures the pedal operation time tp of the brake pedal (the time when the pedal depression amount pp exceeds the predetermined amount pp0), and based on the pedal depression amount detection signal pp and the pedal operation time tp, the brake pedal operation speed pv1 or The pedal return speed pv2 is calculated. The pedal depression amount pp, the pedal operation time tp, and the pedal operation speeds pv1, pv2 are larger than the predetermined amounts pp 0 , pp 1 , the predetermined speeds pv10, pv20, and the predetermined time tp0 (in the case of pedal return). The boost magnification k (assist amount) in the sub booster 14 is determined on the basis of the time during which the booster is small, and a target pressure value in the air chamber 17 is set in order to obtain the boost magnification k. The duty ratio between the vacuum pressure control signal d1 and the atmospheric pressure control signal d2 output to the vacuum valve 15 and the atmospheric pressure valve 9 is calculated, and the vacuum valve 15 and the atmospheric pressure are adjusted so that the pressure value in the air chamber 17 approaches the target pressure value. The valve 9 is duty controlled. This duty control takes the form of feedback control that approaches the target pressure value using the vacuum pressure and the atmospheric pressure. Predetermined amount pp 0, pp 1, predetermined speed pv10, pv20, the predetermined time tp0 is changed according to the vehicle speed v as shown in FIGS. 7-11.
[0026]
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, a brake assist hydraulic valve may be interposed between the master cylinder and the proportioning valve instead of the vacuum valve, the atmospheric pressure valve, the sub booster, and the air chamber.
[Control processing]
Next, an assist control process by the vehicle braking device of the present embodiment will be described.
<Assist control intervention judgment processing>
FIG. 2 is a flowchart illustrating assist control intervention determination processing by the vehicle braking apparatus according to the present embodiment.
[0027]
As shown in FIG. 2, when the process is started, in step S2, the control unit 10 receives an ON signal from the IG switch 25, and determines whether the IG switch 25 has changed from OFF to ON. If the IG switch 25 has changed from OFF to ON in step S2, the process proceeds to step S4. If the IG switch 25 has not changed from OFF to ON, the process proceeds to step S6. In step S4, the flags F1 and F2 are reset. The flag F1 is a flag that is set to determine the start of the assist control, and the flag F2 is a flag that is set to determine whether or not the assist control has been executed at least once after the IG is turned on.
[0028]
In step S6, the control unit 10 reads from the ROM a predetermined amount pp1, pp0 that is a threshold of the pedal depression amount pp, a predetermined time tp0 that is a threshold of the pedal operation time tp, and a predetermined speed pv10, that is a threshold of the operation speeds pv1, pv2. Read pv20.
[0029]
In step S8, the pedal depression amount pp from the pedal stroke sensor 12 and the chamber pressure pc from the pressure sensor 18 are detected. In step S10, it is determined whether or not the flag F1 is set (F1 = 1?). If the flag F1 is not set in step S10 (NO in step S10), the process proceeds to step S12. If the flag F1 is set (YES in step S10), the process proceeds to step S70 described later.
[0030]
In step S12, it is determined whether the pedal depression amount pp exceeds zero, that is, whether the brake pedal is depressed. If the brake pedal is depressed in step S12 (pp> 0), the process proceeds to step S14. If the brake pedal is not depressed (pp = 0), the pedal operation time tp is reset in step S32, and then the process proceeds to step S2. Return and repeat this program again.
[0031]
In step S14, a pedal operation speed pv1 of the brake pedal is calculated. The pedal operation speed pv1 is calculated by dividing the difference between the current pedal depression amount and the previous depression amount (one cycle before the sampling time) by the sampling time (control cycle period) ΔT. The pedal operation speed pv1 may be calculated by interpolation using the previous data.
[0032]
In step S16, it is determined whether or not the pedal operation speed pv1 exceeds a predetermined amount pv10. If the pedal operation speed pv1 exceeds the predetermined amount pv10 in step S16 (YES in step S16), the process proceeds to step S18. If the pedal operation speed pv1 is equal to or less than the predetermined amount pv10 (NO in step S16), the pedal operation time tp in step S32 After resetting, the program returns to step S2 to repeat this program again.
[0033]
In step S18, it is determined whether or not the pedal depression amount pp exceeds a predetermined amount pp0. If the pedal depression amount pp exceeds the predetermined amount pp0 in step S18 (YES in step S18), the process proceeds to step S20. If the pedal depression amount pp is equal to or smaller than the predetermined amount pp0 (NO in step S18), step S32 pedal operation time tp is set. After resetting, it returns to step S2 and repeats this program again.
[0034]
In step S20, whether or not the flag F2 is set, that is, whether or not the pedal depression amount pp is equal to or less than the predetermined amount pp0 until the previous sampling, and whether or not the pedal depression amount pp exceeds the predetermined amount pp0 for the first time this time. Determine. If the flag F2 is not set in step S20 (YES in step S20), the process proceeds to step S22. If the flag F2 is set (NO in step S20), the process proceeds to step S26.
[0035]
In step S22, the flag F2 is set, and in step S24, the pedal operation time tp is set to one cycle ΔT (tp = ΔT). On the other hand, in step S26, the pedal operation time tp is added by ΔT for one cycle (tp = tp + ΔT).
[0036]
In step S28, it is determined whether or not the pedal operation time tp exceeds a predetermined time tp0. If the pedal operation time tp exceeds the predetermined time tp0 in step S28 (YES in step S28), the process proceeds to step S30. If the pedal operation time tp is less than the predetermined time tp0 in step S28, the process returns to step S2 and the program is executed again. repeat.
[0037]
In step S30, the flag F1 is set to set the assist control start state, and then the process returns to step S2 to repeat this program again.
<Assist control processing>
FIG. 3 is a flowchart for explaining an assist control process by the vehicle braking apparatus of the present embodiment.
[0038]
As shown in FIG. 3, when the process is started, in step S40, the control unit 10 determines whether or not the flag F1 is set, that is, whether or not the assist control is started. If the flag F1 is set in step S40 (F1 = 1), the process proceeds to step S42, and if the flag F1 is not set (F1 = 0), the process proceeds to step S44.
[0039]
In step S42, the boosting factor k by the sub booster 14 is set to the emergency factor 2. On the other hand, in step S44, the boost magnification k by the sub-booster 14 is set to a magnification 1 for normal boost control. The boost magnification k can be set to a large value according to the running state of the vehicle and the brake pedal depression state of the driver, for example, when the vehicle speed v is large and the pedal operation speed pv1 is large. As a result, the braking performance can be further improved when the deceleration request is large. Further, the boost magnification may be controlled so that braking by full braking or a predetermined braking force generation pattern is obtained.
[0040]
In step S46, the target chamber pressure pt corresponding to the boost magnification k is determined from the map representing the relationship between the boost magnification k and the target chamber pressure pt shown in FIG. In step S48, a chamber pressure deviation Δp is calculated. The chamber pressure deviation Δp is calculated by subtracting the boost pressure pc from the target chamber pressure pt (Δp = pt−pc). In step S50, it is determined whether or not the chamber pressure deviation Δp is equal to or less than the pressure control threshold value α. If the chamber pressure deviation Δp is equal to or smaller than the pressure control threshold value α in step S50 (YES in step S50), the process proceeds to step S52. If the chamber pressure deviation Δp exceeds the pressure control threshold value α (NO in step S50), the process proceeds to step S60. move on.
[0041]
In step S52, it is determined whether or not the chamber pressure deviation Δp is equal to or less than the pressure control threshold −α. If the chamber pressure deviation Δp is equal to or smaller than the pressure control threshold −α in step S52 (YES in step S52), the process proceeds to step S54, and if the chamber pressure deviation Δp exceeds the pressure control threshold −α (NO in step S52), step. Proceed to S64. In steps S50 and S52, a dead zone from the pressure control threshold value α to −α is set in the chamber pressure deviation Δp, and it is determined whether Δp> α, Δp <−α, and −α ≦ Δp ≦ α. is doing.
[0042]
In steps S54 and S56, it is determined that the chamber pressure deviation Δp is −α ≦ Δp ≦ α, which means that the boost pressure pc in the air chamber 17 is within the target range. In step S58, the vacuum pressure control signal d1 and the atmospheric pressure control signal d2 with a duty ratio of 0% are output and both valves are closed to set the air pressure in the air chamber 17. Hold pressure.
[0043]
In step S60, since it is determined that the chamber pressure deviation Δp is Δp> α, it means that the boost pressure pc in the air chamber 17 is too high, and the vacuum valve 15 is closed and the air pressure in the air chamber 17 is increased. In step S62, the duty ratio corresponding to the chamber pressure deviation Δp is determined from the map showing the relationship between the chamber pressure deviation Δp and the duty ratio shown in FIG. An atmospheric pressure control signal d2 corresponding to the duty ratio is output, and a vacuum pressure control signal d1 with a duty ratio of 0% for closing the vacuum valve 15 is output.
[0044]
Further, in step S64, since it is determined that the chamber pressure deviation Δp is Δp <−α, it means that the boost pressure pc in the air chamber 17 is too low, and the atmospheric pressure valve 9 is closed and the air chamber 17 is closed. In step S66, the duty ratio corresponding to the chamber pressure deviation Δp is determined from the map showing the relationship between the chamber pressure deviation Δp and the duty ratio shown in FIG. 16 , and step S58 is performed. Then, a vacuum pressure control signal d1 corresponding to this duty ratio is output, and an atmospheric pressure control signal d2 having a duty ratio of 0% for closing the atmospheric pressure valve 9 is output.
[0045]
According to the present embodiment described above, the pedal operation speed pv1 is greater than the predetermined speed pv10, the pedal depression amount pp is greater than the predetermined amount pp0, and the pedal depression time tp is greater than the predetermined time tp0 as the assist control start condition. Assist control is started when
[0046]
Accordingly, in addition to determining the start of the assist control based on the operation speed of the brake pedal (see FIG. 17), the start of the assist control is determined in consideration of the pedal depression amount and the depression time. When the vehicle is stepped on (see FIG. 18) or the pumping brake is performed (see FIG. 19), the assist control is not executed. And since the brakes are effective more than necessary, it is possible to prevent the driver from being surprised and the following vehicle approaching suddenly.
[0047]
If the pedal operation speed pv1, the pedal depression amount pp, and the pedal depression time tp are combined, for example, the pedal operation speed pv1 is larger than the predetermined speed pv10 and the pedal depression amount pp is larger than the predetermined amount pp0. Alternatively, the assist control start condition may be set so that the assist control is started when the pedal depression amount pp is larger than the predetermined amount pp0 and the pedal depression time tp is larger than the predetermined time tp0.
[0048]
<Assist control end determination process>
FIG. 4 is a flowchart for explaining the assist control end determination process by the vehicle braking apparatus of the present embodiment.
[0049]
As shown in FIG. 4, the process proceeds to step S70 after the process of step S58 shown in FIG. In step S70, the control unit 10 calculates the return speed pv2 of the brake pedal. This pedal return speed pv2 is calculated by dividing the difference between the previous depression amount (one cycle before the sampling time) and the current pedal depression amount by the sampling time (control cycle period) ΔT. The pedal return speed pv2 may be calculated by interpolation using the previous data.
[0050]
In step S72, the predetermined value pp1 is corrected according to the vehicle speed v from the map representing the relationship between the vehicle speed v and the predetermined amount pp1 that is the threshold of the pedal depression amount pp shown in FIG. The predetermined amount pp1 may be corrected according to the pedal return speed pv2 from the map showing the relationship between the pedal return speed pv2 and the predetermined amount pp1 shown in FIG.
[0051]
In step S74, it is determined whether or not the pedal return speed pv2 is smaller than a predetermined amount pv20. If the pedal return speed pv2 is smaller than the predetermined amount pv20 in step S74 (YES in step S74), the process proceeds to step S76. If the pedal return speed pv2 is equal to or greater than the predetermined amount pv20 (NO in step S74), the process proceeds to step S80.
[0052]
In step S76, it is determined that the pedal return speed pv2 is smaller than the predetermined amount pv20 and the brake pedal is slowly returned by the driver, and it is determined whether the pedal depression amount pp is smaller than the predetermined amount pp1. If the pedal depression amount pp is smaller than the predetermined amount pp1 in step S76 (YES in step S76), the process proceeds to step S78. If the pedal depression amount pp is equal to or larger than the predetermined amount pp1 (NO in step S76), step S40 shown in FIG. Return to, and continue assist control.
[0053]
In step S78, the assist control is terminated, and the flag F1 is reset (F1 = 0) in order to start the normal boost control by the main booster 13.
[0054]
In step S80, it is determined that the pedal return speed pv2 is greater than the predetermined amount pv20 and the driver has suddenly returned the brake pedal, and it is determined whether the pedal depression amount pp is smaller than the predetermined amount pp1. If the pedal depression amount pp is smaller than the predetermined amount pp1 in step S80 (YES in step S80), the process proceeds to step S82. If the pedal depression amount pp is equal to or larger than the predetermined amount pp1 (NO in step S80), step S40 shown in FIG. Return to, and continue assist control.
[0055]
In step S82, it is determined whether the pedal depression amount pp exceeds zero, that is, whether the brake pedal is depressed. If the brake pedal is depressed at Step S 8 2 (pp> 0) , and returns to step S40 shown in FIG. 3 continues the assist control, if the brake pedal is not depressed (pp = 0) Proceeding to step S78, the assist control is terminated, and the flag F1 is reset to start normal boost control (F1 = 0).
[0056]
In steps S74 to S80 described above, for example, the driver was surprised by the assist control and suddenly returned the brake pedal. However, the assist control is continued when the pedal depression amount is large, and the brake is depressed when the pedal depression amount is small. After determining whether or not the pedal is completely returned, the assist control is continued if the brake pedal is still depressed, and the assist control is ended if the brake pedal is fully returned.
[0057]
According to the present embodiment described above, as a condition for determining the end of the assist control, when the pedal depression amount pp becomes smaller than the predetermined amount pp1 in the slow return operation where the pedal return speed pv2 of the brake pedal is smaller than the predetermined speed pv20. Although the assist control is released (see FIG. 20), the assist control is not released until the pedal depression amount pp becomes zero in the case of a sudden return operation in which the pedal return speed pv2 of the brake pedal is larger than the predetermined speed pv20 (FIG. 21). reference).
[0058]
Therefore, even if the driver is surprised by the assist control due to an emergency deceleration behavior and the brake pedal is suddenly returned, the assist control is continued if the pedal depression amount is large, and conversely if the pedal depression amount is small, the brake pedal Is determined as the assist control end condition, it is surely executed in a situation where the assist control is necessary.
<Another embodiment>
In step S82 described above, whether or not the assist control is continued is determined based on whether or not the accelerator pedal 23 is depressed in addition to the depression amount pp of the brake pedal (accelerator pedal depression amount> 0?), Or the depression amount is Whether or not the predetermined amount or more has been reached, or whether or not the idle switch has been switched from on to off may be used as the determination material.
<Modification 1>
Next, with reference to FIG. 5, the modification 1 of the assist control completion | finish judgment process of this embodiment is demonstrated.
[0059]
FIG. 5 is a flowchart for describing a first modification of the assist control end determination process of the present embodiment.
[0060]
As shown in FIG. 5, if the determination in step S74 of FIG. 4 is NO, in step S90, the control unit 10 determines whether or not the pedal depression amount pp is smaller than a predetermined amount pp1. If the pedal depression amount pp is smaller than the predetermined amount pp1 in step S90 (YES in step S90), the process proceeds to step S92. If the pedal depression amount pp is equal to or larger than the predetermined amount pp1 (NO in step S90), step S40 shown in FIG. Return to, and continue assist control.
[0061]
In step S92, the counter t is incremented (t = t + 1). In step S94, it is determined whether the counter t has exceeded a predetermined value t0. If the counter t exceeds the predetermined value t0 in step S94 (YES in step S94), the process proceeds to step S98, the flag F1 and the counter t are reset, and the assist control is terminated. If the counter t does not exceed the predetermined value t0 in step S94 (NO in step S94), the process proceeds to step S96 to determine whether the pedal depression amount pp is zero, that is, whether the brake pedal is depressed. If the brake pedal is depressed in step S96 (pp> 0), the process returns to step S40 shown in FIG. 3 to continue the assist control. If the brake pedal is not depressed (pp = 0), step S98. Proceed to to end the assist control.
[0062]
In this modified example, since the assist control end condition (pp <pp1) is satisfied and the assist control end time is delayed by a predetermined time t0, the assist control is not released suddenly, Even if a person is surprised by the assist control and suddenly returns the brake pedal, the assist control is surely executed in a situation where the assist control is necessary.
<Modification 2>
Next, a second modification of the assist control end determination process of the present embodiment will be described with reference to FIG.
[0063]
FIG. 6 is a flowchart illustrating a second modification of the assist control end determination process of the present embodiment.
[0064]
As shown in FIG. 6, when the determination in step S74 of FIG. 4 is NO, in step S100, the control unit 10 determines whether or not the pedal depression amount pp is smaller than a predetermined amount pp1. If the pedal depression amount pp is smaller than the predetermined amount pp1 in step S100 (YES in step S100), the process proceeds to step S102. If the pedal depression amount pp is greater than or equal to the predetermined amount pp1 (NO in step S100), step S40 shown in FIG. Return to, and continue assist control.
[0065]
In step S102, the counter t is incremented (t = t + 1). In step S104, the magnification k1 of the boost magnification k corresponding to the counter t is determined from the map representing the relationship between the counter t and the magnification k1 shown in FIG. In step S106, it is determined whether or not the magnification k1 is 0.5. If the magnification k1 is 0.5 in step S106 (YES in step S106), the process proceeds to step S110, the flag F1 and the counter t are reset, and the assist control is ended. If the magnification k1 exceeds 0.5 in step S106 (NO in step S106), the process proceeds to step S108 to determine whether the pedal depression amount pp is zero, that is, whether the brake pedal is depressed. If the brake pedal is depressed in step S108 (pp> 0), the process returns to step S40 shown in FIG. 3 to continue the assist control, and if the brake pedal is not depressed (pp = 0), step S110. Proceed to to end the assist control. Here, the value of the magnification k1 of the boost magnification k in step S104 is set between 0.5 and 1, and the value of the boost magnification k is a value set between 1 and 2. For this reason, the case where the magnification k1 is 0.5 means a state where the boost magnification k is set between 0.5 and 1, that is, a state where normal boost control is executed. Further, the magnification k1 set in step S104 is multiplied by the boost magnification k set in steps S42 and S44 in FIG. 3 (k = k1 × k).
[0066]
In this modification, the boost magnification k is gradually decreased according to the elapsed time after the assist control end condition (pp <pp1) is satisfied, and the assist amount during the assist control is gradually decreased. Therefore, even if the driver is surprised by the assist control and suddenly returns the brake pedal, the assist control is surely executed in a situation where the assist control is necessary. .
[0067]
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.
[0069]
【The invention's effect】
As described above, according to the present invention, when the brake operation amount is less than the predetermined amount and the brake operation speed is equal to or higher than the predetermined speed , the assist operation is terminated, so the assist control is suddenly released. Even if the driver is surprised by the assist control and suddenly returns the brake pedal, the driver can be surely executed in a situation where the assist control is necessary.
[0070]
Further, preferably, the end of the assisting operation is delayed for a predetermined time, so that the assist control is not suddenly released, and even if the driver is surprised by the assist control and suddenly returns the brake pedal, the assist control is necessary. It is surely executed in a difficult situation.
[0071]
Preferably, when the brake operation amount is less than the predetermined amount, the assisting force is gradually decreased when the brake operation speed is equal to or higher than the predetermined speed. Even if the brake pedal is suddenly returned in surprise to the assist control, it is surely executed in a situation where the assist control is necessary.
[0072]
Further, preferably, the assisting operation is continued until the brake operation amount becomes zero, so that the assist control is surely executed in a situation where the assist control is necessary.
[0075]
[Brief description of the drawings]
FIG. 1 is a block diagram of a vehicle braking apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating assist control intervention determination processing by the vehicle braking device according to the present embodiment.
FIG. 3 is a flowchart illustrating an assist control process by the vehicle braking apparatus according to the present embodiment.
FIG. 4 is a flowchart illustrating assist control end determination processing by the vehicle braking device of the present embodiment.
FIG. 5 is a flowchart illustrating a first modification of the assist control end determination process of the present embodiment.
FIG. 6 is a flowchart illustrating a second modification of the assist control end determination process according to the present embodiment.
FIG. 7 is a map showing a relationship between a vehicle speed v and a predetermined speed pv10 as a threshold value of the pedal operation speed pv.
FIG. 8 is a map showing a relationship between a vehicle speed v and a predetermined amount pp0 as a threshold value of a pedal depression amount pp.
FIG. 9 is a map showing a relationship between a vehicle speed v and a predetermined time tp0 as a threshold value of a pedal operation time tp.
FIG. 10 is a map showing a relationship between a vehicle speed v and a predetermined speed pv20 as a threshold value of the pedal return speed pv2.
FIG. 11 is a map showing a relationship between a vehicle speed v and a predetermined amount pp1 as a threshold value of a pedal operation amount pp.
FIG. 12 is a map showing a relationship between a pedal return speed pv2 and a predetermined amount pp1 as a threshold for a pedal operation amount pp.
FIG. 13 is a map showing a relationship between an elapsed time t after the assist control end condition is satisfied and a magnification k1 multiplied by the boost magnification k.
FIG. 14 is a map showing the relationship between boost magnification k and target chamber pressure pt.
FIG. 15 is a map showing the relationship between the chamber pressure deviation Δp and the duty ratio of the atmospheric pressure valve.
FIG. 16 is a map showing the relationship between the chamber pressure deviation Δp and the vacuum valve duty ratio.
FIG. 17 is a diagram illustrating an operation at the time of assist control start determination.
FIG. 18 is a diagram for explaining an operation at the time of assist control start determination.
FIG. 19 is a diagram for explaining an operation at the time of assist control start determination.
FIG. 20 is a diagram for explaining an operation at the time of assist control end determination.
FIG. 21 is a diagram for explaining an operation at the time of determining the end of assist control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 9 ... Atmospheric pressure valve 10 ... Control unit 11 ... Brake pedal 12 ... Brake pedal stroke sensor 13 ... Main booster 14 ... Sub booster 15 Vacuum valve 16 ... Master cylinder 17 ... Air chamber 18 ... Pressure sensor 19 ... Check valve 20 ... Disc brake Device 21 ... Vehicle speed sensor 22 ... Proportioning valve 23 ... Accelerator pedal 24 ... Accelerator pedal stroke sensor

Claims (4)

Braking force assisting means for assisting the braking force generated according to the brake operation;
An operation amount detection means for detecting a brake operation amount;
An operation speed detecting means for detecting a brake operation speed;
Emergency determination means for determining an emergency in which it is necessary to assist the braking force according to the brake operation amount and the brake operation speed;
An assist start control means for starting an assisting operation by the brake force assisting means when the emergency determining means determines an emergency; and
An assistance end control means for ending the assisting operation by the braking force assisting means when the brake operation amount is less than a predetermined amount;
If the brake operation speed is greater than or equal to a predetermined speed when the brake operation amount is less than a predetermined amount, the end of the assist operation by the assist end control means is restricted, and when the brake operation amount is less than the predetermined amount, A vehicle braking apparatus comprising: a control means for ending the assisting operation by the assisting end control means when the brake operation speed is less than a predetermined speed . The braking device for a vehicle according to claim 1 , wherein the control means delays the end of the assisting operation for a predetermined time. The control means according to claim 1, wherein the amount of brake operation when the brake operating speed when less than the predetermined amount is equal to or higher than the predetermined speed, and wherein the gradually reducing the assist force according to the brake force assisting means A braking device for a vehicle according to claim 1. Wherein, until said brake operation amount becomes zero, the braking apparatus for a vehicle according to claim 2 or 3, characterized in that to continue assisting operation by the braking force assisting unit.

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