JPH115522A - Brake assist control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake assist control device corresponding to a difference between brake pedal operating characteristics of each driver, eliminating a temporal feeling of physical disorder associated with brake pedal operation and action of brake control, and decreasing necessity for setting a constant or the like of each vehicle. SOLUTION: In a control device 26 having a negative pressure chamber, valve element, atmospheric pressure passage part and a negative pressure booster 22 to drive a solenoid 5 at braking time to perform a brake assist, this control device is constituted such that, deceleration detected in a deceleration sensor 27, when a vehicle is braked, is learned, and in accordance with this learned deceleration, a threshold value determining whether the assist is performed or not is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an emergency in which a vehicle traveling ahead of a host vehicle is suddenly stopped or there is an obstacle in front of the host vehicle that may hinder the driving of the host vehicle. The present invention relates to a brake assist control device that sometimes assists a braking force corresponding to a driver's braking operation force to shorten a braking distance of a vehicle.

[0002]

2. Description of the Related Art As a conventional brake assist system, for example, there is the following one. U.S. Pat. No. 5,158,343 discloses a method of starting brake assist when a brake operation speed is equal to or higher than a predetermined value. In JP-A-7-76267, a threshold value of a brake pedal operation speed is calculated from a brake pedal stroke amount and a vehicle speed, and a brake pedal stroke amount when the brake pedal operation speed exceeds the threshold value is set as a starting point. A method of starting emergency brake assist when the pedal operation speed of a fixed pedal stroke does not fall below a threshold is disclosed. Also, Japanese Patent Application Laid-Open No. Hei 7-1567
In Japanese Patent Publication No. 86, a characteristic value for correcting a threshold value of a brake pedal operation speed is calculated from a maximum stroke amount and a maximum pedal speed of a brake pedal during braking, and learning control corresponding to a driver's pedal operation characteristic is performed to perform accurate control. A method for performing emergency brake assist is disclosed.

[0003]

However, in the above-described conventional brake assist system, the operation speed of the brake pedal is basically used as a criterion for determining whether or not to perform the brake assist. In an emergency case, a driver with a weak pedaling force may not be able to perform sufficient brake assist control because the brake pedal depressing speed is insufficient. If the driver is too fast, the brake assist control is activated, and there is a possibility that the driver will suddenly brake against the will of the driver. In addition, when the driver performs the brake pedal operation, there is a time delay before the deceleration occurs in the vehicle, but when the brake assist control is activated at the moment when the brake pedal is depressed, Since a sudden rise of the deceleration occurs, the driver may feel uncomfortable. Further, the method of calculating the threshold value of the brake pedal operation speed from the physical amount different from the brake pedal stroke amount and the vehicle speed by calculation requires a constant setting for each vehicle,
Therefore, tuning man-hours were required.

The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and in an emergency case where the vehicle must be suddenly braked, a driver who depresses the brake pedal insufficiently, It is possible to cope with differences in the brake pedal operation characteristics of each driver, such as a driver whose brake pedal depressing speed is extremely fast, not only in an emergency, but also for the operation of the brake pedal operation and the brake assist control. It is an object of the present invention to provide a brake assist control device that eliminates the accompanying time-related discomfort and further reduces the need to set constants for each vehicle.

[0005]

Means for Solving the Problems To achieve the above object, a brake assist control device according to claim 1 includes a negative pressure chamber, a vacuum valve that shuts off or opens a flow path between the variable pressure chamber, and an external device. An atmospheric pressure passage section that shuts off or opens a path to the variable pressure chamber; and a negative pressure booster that has a solenoid that shuts off or opens the vacuum valve and the atmospheric pressure passage section in response to energized currents. A deceleration detecting means for detecting a deceleration of the vehicle, a threshold value for judging the magnitude of the deceleration detected by the deceleration detecting means, and a deceleration detecting means for braking the vehicle. Control means for determining the magnitude relationship between the deceleration of the vehicle detected by the above and the threshold value, and performing brake assist control when the deceleration detected by the deceleration detection means exceeds the threshold value A deceleration learning unit that learns the deceleration detected by the deceleration detection unit; and a threshold change setting unit that changes and sets the threshold according to the deceleration learned by the deceleration learning unit. It is characterized by that. According to a second aspect of the present invention, there is provided the brake assist control device according to the first aspect, wherein the deceleration learning means is configured to decelerate the vehicle when the deceleration detected by the deceleration detection means is smaller than the threshold value. The threshold value change setting means changes the threshold value according to the maximum value of the deceleration learned by the deceleration learning means. According to a third aspect of the present invention, there is provided the brake assist control device according to the first aspect, wherein the deceleration learning means is configured to decelerate the vehicle when the deceleration detected by the deceleration detection means is smaller than the threshold value. The threshold value change setting means learns the average value of
The threshold value is changed and set according to the average value of the deceleration learned by the deceleration learning means. According to a fourth aspect of the present invention, there is provided the brake assist control device according to the first aspect, wherein the deceleration learning means is configured to decelerate the vehicle when the deceleration detected by the deceleration detection means is smaller than the threshold value. The threshold value change setting means changes the threshold value according to the average value of the deceleration that has become the most frequent frequency of the frequency distribution of the average value of the deceleration learned by the deceleration learning means. It is characterized by setting.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show an embodiment of the present invention. FIG.
FIG. 2 is a configuration diagram of a negative pressure booster. First, the configuration will be described. In FIG. 1, reference numeral 20 denotes a brake pedal operated by a driver, and reference numeral 21 denotes a brake stroke sensor for detecting an operation amount of the brake pedal 20 in FIG. Reference numeral 22 denotes a negative pressure booster, and reference numeral 5 denotes a solenoid, the details of which are shown in FIG. 23 is a master cylinder, 24 is each wheel, and its rotation speed is detected by a wheel speed sensor 25. Reference numeral 26 denotes a control device for performing brake assist, and details of the calculation processing thereof will be described later. 27 is a deceleration sensor, 28 is a brake switch, and 29 is a brake depression force sensor.

In the configuration of the negative pressure booster 22, the variable pressure chamber 1 and the negative pressure chamber 2 are partitioned by the power piston 10 for contracting the master cylinder 23 and the diaphragm 14 in FIG. The power piston 10 moves against the diaphragm return spring 15 due to a differential pressure generated between the variable pressure chamber 1 and the negative pressure chamber 2, and pushes the push rod 8 and the master cylinder 23 through the reaction disk 9.
And the boosted load is transmitted. The negative pressure chamber 2 communicates with an intake pipe and a vacuum pump of an engine (not shown) to generate a negative pressure. Transformation chamber 1 is power piston 1
0 can communicate with the negative pressure chamber 2 through the negative pressure passage 11;
When the opening of the negative pressure passage 11 is opened apart from the valve body 3 functioning as a vacuum valve, the opening communicates with the negative pressure chamber 2. Further, the variable pressure chamber 1 can communicate with the outside (atmosphere) through the atmospheric pressure passage portion 4 of the valve body 3, and the air passage passage portion 4 is separated from the valve seat 12 provided in the cylindrical plunger 7. When opened, it communicates with the atmosphere. In this case, the atmospheric pressure passage portion 4 of the valve element 3 and the valve seat 12 constitute an atmospheric valve.

When the brake is not operated, the valve seat 12 of the plunger 7 is seated on the atmospheric pressure passage portion 4 to close the atmospheric pressure passage portion 4 by the urging force of the return springs 13a and 13b, as shown in FIG. Since the negative pressure passage is opened apart from the pressure passage 11, the variable pressure chamber 1 and the negative pressure chamber 2 are communicated with each other, and the mutual pressures become equal. On the other hand, at the time of the brake operation, the plunger 7 supporting the return spring 13a is moved to the left with respect to the power piston 10 as the operating rod 6 interlocked with the depression of the brake pedal 20 (FIG. 1) is pushed into the power piston 10. When a predetermined stroke moves in the direction, the valve element 3 slides due to the elastic restoring force of the return spring 13a and closes the negative pressure passage 11. At the initial position of closing the negative pressure passage 11, the atmospheric pressure passage portion 4 is still closed, and when the plunger 7 is further moved from this position, the valve body 3 is moved to the negative pressure passage 11
Cannot move any further while seated in the opening of the plunger 7, the valve seat 12 of the plunger 7 separates from the valve body 3, and the atmospheric pressure passage 4 opens. As a result, the variable pressure chamber 1 is communicated with the atmospheric pressure, and the pressure piston generated between the variable pressure chamber 1 and the negative pressure chamber 2 causes the power piston 10 to move the diaphragm return spring 15.
To the left in the figure to urge the master cylinder 23 in the contracting direction to generate brake fluid pressure.

In order to perform brake assist in an emergency, the solenoid 5 for electromagnetically driving the plunger 7 is provided on the power piston 10 in the negative pressure booster 22. That is, when a predetermined drive current is supplied to the solenoid 5 by the control device 26, the plunger 7 is sucked leftward in the drawing against the spring 16 by the electromagnetic force of the solenoid 5, thereby closing the negative pressure passage 11 and the atmospheric pressure. The passage portion 4 moves to a position where the passage portion 4 is opened, whereby the power piston 10 urges the master cylinder 23 in the contracting direction.

Next, an emergency brake assist control in the above configuration will be described. FIG. 3 is a flowchart showing Embodiment 1 of the arithmetic processing of the control device 26,
This routine is an interrupt processing routine executed at a predetermined cycle.

In FIG. 3, in step S101, it is determined whether or not the driver is performing a brake operation. If the driver is performing a brake operation (brake ON), the process proceeds to step S102. When the brake operation is not performed (brake OFF), the process proceeds to step S121, the value of the assist flag indicating whether the brake assist control is being executed is set to 0 (0 indicates that the brake assist control is not being executed), and then step S123 is performed. Does not perform assist control. That is, if the brake assist control is being executed, the assist control ends. Here, the brake operation detection is performed according to FIG.
Brake switch 28 and brake depression force sensor 29 shown in FIG.
And so on.

In step S102, the deceleration sensor 27
The deceleration (G) of the vehicle detected is read and the process proceeds to step S103. In step S103, the value of the assist flag indicating whether or not the brake assist control is being executed is determined. If the assist flag = 1, that is, if the assist control is being executed, step S1 is executed.
The process proceeds to step S104, and if the assist flag = 0, that is, if the assist control is not being executed, the process proceeds to step S104.

In step S104, the deceleration (G) in the current braking is compared with the control threshold (G1). If the current deceleration (G) exceeds the control threshold (G1), the flow proceeds to step S105. If the current deceleration (G) is equal to or smaller than the control threshold (G1), the process proceeds to step S111.
Here, it is determined whether emergency braking or normal braking is performed by comparing the deceleration (G) by the driver's brake operation with the control threshold (G1). That is, if the current deceleration (G) exceeds the control threshold (G1), it is determined that emergency braking is performed, and assist control is performed in step S124 described below, and the current deceleration (G) is equal to or less than the control threshold (G1). If so, it is determined that the braking is normal, and the assist control is not performed in step S123 described later.

In step S105, it is determined whether brake assist control is possible. The determination on whether or not the brake assist control is possible is performed in a control availability determination routine shown in FIG.

In FIG. 6, in step S401, the current vehicle speed is compared with a predetermined value V1, and if the current vehicle speed exceeds the predetermined value V1, that is, if the current vehicle speed is in the middle or high speed range, the process proceeds to step S402. If the current vehicle speed is equal to or lower than the predetermined value V1, that is, if the current vehicle speed is in the low speed range, the process proceeds to step S405. In step S402, the gear position of the transmission is determined.
03, if not, go to step S405. In step S403, if the brake assist control has already been executed and the ABS is operating, it is determined whether or not the ABS operation has been completed. If the ABS operation has not been completed, the process proceeds to step S404, and the ABS If the operation has been completed, the process moves to step S405.
In step S404, the control continuation time of the brake assist control is determined. If the predetermined time t has not elapsed, the process proceeds to step S406, and if the predetermined time t has elapsed, the process proceeds to step S405. In step S405, the brake assist control is not performed. That is, if the brake assist control is being executed, the assist control ends. In step S406, brake assist control is performed. That is, if the brake assist control is being executed, the assist control is cascaded. If the assist control is not being executed, the assist control is started.

Returning to FIG. 3, when it is determined in step S105 that the brake assist control is to be performed in the control availability determination routine shown in FIG. 6, the process proceeds to step S122 to determine whether the brake assist control is being executed. Is set to 1 (1 indicates running),
Next, assist control is performed in step S124. That is, if the brake assist control is being executed, the assist control is continued, and if the assist control is not being executed, the assist control is started. If it is determined in step S105 that the brake assist control is not to be performed, the process proceeds to step S121, and the value of the assist flag indicating whether the brake assist control is being performed is set to 0 (0 indicates that the brake assist control is not being performed), Next, in step S123, the assist control is not performed. That is, if the brake assist control is being executed, the assist control ends.

In step S104 described above, when the deceleration (G) in the current braking is determined to be equal to or less than the control threshold value (G1) and the process proceeds to step S111, the deceleration (G) in the current braking and the deceleration in the past braking are determined. (Gm
ax), and if the current deceleration (G) exceeds the past maximum value of deceleration (Gmax), step S1 is performed.
12, the current deceleration (G) is set as the maximum value of the deceleration (Gmax), and the process proceeds to step S113. When the deceleration (G) in the current braking is equal to or smaller than the maximum value (Gmax) of the deceleration in the past braking, the process proceeds to step S121. In step S113, the maximum value (Gmax) of the deceleration set in step S112 described above.
Then, the control threshold value (G1) is changed and set using the control threshold change setting map shown in FIG. 7, and the process proceeds to step S121. Here, the deceleration that can be generated by the driver's braking operation in emergency braking is estimated from the maximum value of the deceleration in the driver's normal braking operation, and the control threshold (G1) is changed based on the estimated value. Set. Further, the control threshold change setting map shown in FIG. 7 may be corrected by a vehicle speed, a road surface friction coefficient, or the like.

Here, the basic concept of FIG. 7 is changed to the maximum value (Gma) of the deceleration in the normal brake operation of the driver of FIG.
The relationship between x) and the deceleration that can be generated by the driver's braking operation is determined by the braking operation in normal braking, the braking operation in emergency braking, and the braking operation in intermediate braking between normal and emergency. This is shown in the conceptual diagram separately divided into time.

In FIG. 8, for example, the maximum value (Gmax) of the deceleration in the normal brake operation of the driver is Gm.
In the case of ax1, the deceleration that can be generated by the driver's brake operation is Ga during normal brake operation.
1. Ga2 at the time of brake operation in intermediate braking between normal and emergency, and Ga3 at the time of brake operation in emergency braking
Becomes

When the brake assist control is performed as described above (step S124), a predetermined drive current is supplied to the solenoid 5 of the negative pressure booster 22, so that the negative pressure passage 11 is closed and the atmospheric pressure passage portion 4 is opened. The variable pressure chamber 1 moves and is communicated with the atmospheric pressure, and the power piston 10 urges the master cylinder 23 in the contracting direction by a pressure difference generated between the variable pressure chamber 1 and the negative pressure chamber 2 to generate a brake hydraulic pressure. .

On the other hand, when the brake assist control is not performed (step S123) and the brake assist control is being executed, the solenoid 5 of the negative pressure booster 22 is driven in the reverse manner to the case where the brake assist control is performed. The brake assist control ends. In addition, simply turning off the power supply to the solenoid 5 can reduce the return spring 1.
The negative pressure passage 11 is opened by the urging forces 3a and 13b, the atmospheric pressure passage portion 4 is closed, the contraction of the master cylinder 23 is released, and the brake assist control ends. In this routine, steps S106 to S110 and steps S114 to S120 are missing numbers.

Next, a second embodiment of the brake assist control according to the present invention will be described. In the first embodiment, when the control threshold value (G1) of the brake assist control is changed and set, the control threshold value (G1) is generated from the maximum value of the deceleration in the normal brake operation of the driver by the brake operation in the emergency braking of the driver. The control threshold (G1) is changed and set by estimating the obtained deceleration. In the present embodiment, the control threshold (G1) is changed and set based on the average value of the deceleration in the normal brake operation of the driver. I do.

Hereinafter, a description will be given based on a flowchart showing the second embodiment of FIG. In FIG. 4, step S
201 to step S205 and step S22
Steps 1 to S224 are the same as steps S101 to S105 and steps S121 to S124 described above, and a description thereof will be omitted. This routine is an interrupt routine that is executed at a predetermined cycle as in FIG. In step S211, the deceleration (G) in the braking by the normal brake operation at this time is accumulated (Gtotal).
At 212, the number of accumulations (Bcount) of the deceleration (G) in the current braking is counted, and the routine goes to Step S221.

In step S201 (the description is omitted) of the previous step, no brake operation is performed (brake OF
When it is determined to be F) and the process proceeds to step S213, the average deceleration (Gave) in the current braking (one braking immediately before the brake is turned off) is calculated using the values in the above steps S211 and S212. Then, the average deceleration (Gave) is further accumulated, and step S214 is performed.
Move to.

In step S214, the latest control threshold value determination (step S204) after the ignition of the vehicle is turned on or the previous determination that the deceleration (G) at that time exceeds the control threshold value (G1). The number of times of braking (brkcnt) from the determination after is determined, and step S
Move to 215.

In step S215, the aforementioned step S
The number of braking counted in 214 (brkcnt)
Has reached the specified number of times, the average of the average deceleration (Gave) in the single braking, that is, the average of a plurality of average decelerations (Gave), is calculated using the values of steps S213 and S214 described above. With the average deceleration (G
1ave), and the process moves to step S216. Here, in step S214 described above, the number of braking operations (b
If rkcnt) has not reached the specified number of times, although not shown, the processing of this step is not performed, and the processing proceeds to step S221 without performing the processing of the next step S216. Note that the past N times (fixed value) may be set as the number of times of braking (brkcnt) counted in step S214.

In step S216, similarly to step S113 of FIG. 3 in the first embodiment, the control threshold (G1) shown in FIG. 7 is calculated from the average deceleration (G1ave) calculated in step S215. The change is set by the threshold change setting map, and the process proceeds to step S221. Here, a deceleration that can be generated by the driver's emergency braking operation is estimated from the average value of the driver's normal braking operation, and the control threshold (G1) is changed based on the estimated value. Set.

As described above, when the brake assist control is performed (step S224) or when the brake assist control is not performed (step S223), the solenoid 5 of the negative pressure booster 22 is driven as in the first embodiment. In this routine, steps S206 to S210 and steps S217 to S220 are missing numbers. Further, the accumulation (Gtotal) of the deceleration (G) accumulated in step S211 and
The accumulated number of decelerations (G) counted in step S212 (Bcount) is the same as step S201 in the previous step.
In the determination of (description omitted), the process proceeds to step S213, where the average deceleration (Gave) is calculated and accumulated, and then cleared (not shown). Further, the average deceleration (Gave) calculated and accumulated in step S213, And step S
The braking frequency (brkcnt) counted in 214 is cleared after calculating the average deceleration (G1ave) in step S215 (not shown).

Next, a third embodiment of the brake assist control according to the present invention will be described. In the second embodiment, when the control threshold value (G1) of the brake assist control is changed and set, the control threshold value (G1) is generated based on the average value of the deceleration in the normal braking operation of the driver by the braking operation in the emergency braking of the driver. The control threshold (G1) is changed and set by estimating the obtained deceleration. In the present embodiment, the control threshold (G1) is based on the frequency distribution of the average value of the deceleration in the normal brake operation of the driver. Change the settings.

Hereinafter, a description will be given based on a flowchart showing the third embodiment of FIG. In FIG. 5, step S
Steps 301 to S305, steps S311 to S312, and steps S321 to S324 are the same as steps S101 to S324 described above.
105, steps S211 to S212, and steps S121 to S124, and a description thereof will be omitted. This routine is an interrupt routine that is executed at a predetermined cycle as in FIG.

In step S313, in step S301 (description omitted) of the previous step, it is determined that the brake operation is not performed (brake OFF), and when the process proceeds to step S313, the steps S311 (description omitted) of the previous step and step S313 are executed. The average deceleration (Gave) in the current braking (one braking immediately before the brake is turned off) is calculated using the value of S312 (the description is omitted), and the process proceeds to step S314.

In step S314, a frequency distribution is created for the average deceleration (Gave) calculated in step S313 in the previous step, for example, in one section of 0.05 g.
It moves to step S315. Here, as the number of average decelerations (Gave) at the time of obtaining the frequency distribution, the same number as the number of times of braking in step S214 in FIG. 4 in the second embodiment is used, but other values are set. Is also good.

In step S315, the above-described step S
The average deceleration (Gave) of the section with the highest frequency in the frequency distribution of the average deceleration (GaVe) created in 314 is obtained, and the process proceeds to step S316. Here, if the average deceleration (Gave) is not the specified number in step S314 described above, although not shown, the processing of this step is not performed, and the processing of the next step S316 is not performed, and step S321 is not performed. Move to.

In step S316, similarly to step S113 in FIG. 3 in the first embodiment or step S216 in FIG. 4 in the second embodiment, the average having the highest frequency obtained in step S315 is determined. Based on the deceleration (Gave), the control threshold (G1) is changed and set according to the control threshold change setting map shown in FIG. 7, and the process proceeds to step S321. Here, the deceleration that can be generated by the brake operation in emergency braking by the driver is estimated from the most frequent average deceleration in the normal brake operation of the driver, and the control threshold (G1) is determined based on the estimated value. Change settings. As described above, when the brake assist control is performed (step S324) or when the brake assist control is not performed (step S323), the solenoid 5 of the negative pressure booster 22 is driven as in the first embodiment. In this routine, steps S306 to S310 and steps S317 to S310 are performed.
320 is a missing number. In addition, the accumulation (Gtotal) of the deceleration (G) accumulated in step S311 and the accumulated number (Bcount) of the deceleration (G) counted in step 312 are determined in step S301 of the previous step.
In the determination of (Description omitted), the process proceeds to step S313, the average deceleration (Gave) is calculated and then cleared (not shown). Further, the frequency distribution of the average deceleration (Gave) created in step S314 is: This is cleared after the average deceleration (Gave) of the most frequent number is obtained in step S315 (not shown).

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the above-described embodiments, and there are design changes and the like within a range not departing from the gist of the present invention. This is also included in the present invention.

[0036]

According to the brake assist control device of the first aspect, the deceleration in the normal braking operation of the driver is learned, and the control threshold value of the brake assist control according to the learned deceleration is changed and set. In an emergency case where the vehicle must be braked suddenly, the driver may not be able to depress the brake pedal sufficiently, or not only in an emergency, but also at a driver whose brake pedal depressing speed is always very fast. The effect that it is possible to perform the brake assist control corresponding to the difference in the brake pedal operation characteristic is obtained, and the effect that the temporal discomfort associated with the operation of the brake pedal operation and the operation of the brake assist control can be eliminated. can get. According to the brake assist control device of the second aspect, the maximum value of the deceleration in the normal braking operation of the driver is learned, and the maximum value of the learned deceleration is generated by the braking operation in the emergency braking of the driver. The deceleration that can be estimated can be estimated, and the control threshold value of the brake assist control can be changed and set based on the estimated value,
The effect that the brake assist control corresponding to the difference in the brake pedal operation characteristics for each driver can be obtained is obtained. According to the brake assist control device of the third aspect, the average value of the deceleration in the normal brake operation of the driver is learned, and the average value of the learned deceleration is generated by the brake operation in the emergency braking of the driver. It is possible to estimate the deceleration that can be performed, change and set the control threshold value of the brake assist control based on the estimated value, and perform the brake assist control corresponding to the difference in the brake pedal operation characteristics for each driver. The effect is obtained. According to the brake assist control device of the fourth aspect, the frequency distribution of the average value of the deceleration in the normal brake operation of the driver is learned, and the frequency distribution of the average value of the learned deceleration is learned from the emergency distribution of the driver. Estimates the deceleration that can be generated by the brake operation during braking, and can change and set the control threshold value of the brake assist control based on the estimated value. Brake assist control corresponding to differences in brake pedal operation characteristics for each driver Is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of the present invention.

FIG. 2 is a configuration diagram of a negative pressure booster of the present invention.

FIG. 3 is a flowchart showing the first embodiment of the present invention.

FIG. 4 is a flowchart showing a second embodiment of the present invention.

FIG. 5 is a flowchart showing a third embodiment of the present invention.

FIG. 6 is a brake assist control availability determination routine.

FIG. 7 is a control threshold setting map.

FIG. 8 shows the maximum deceleration (Gmax) or the average deceleration (G1av) in the driver's normal brake operation.
e) or average deceleration of the most frequent number (Gave)
FIG. 5 is a conceptual diagram showing a relationship between the deceleration that can be generated by a driver's brake operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable pressure chamber 2 Negative pressure chamber 3 Valve 4 Atmospheric pressure passage 5 Solenoid 6 Operating rod 7 Plunger 8 Push rod 9 Reaction disk 10 Power piston 11 Negative pressure passage 12 Valve seat 13a Return spring 13b Return spring 14 Diaphragm 15 Diaphragm return spring Reference Signs List 16 spring 20 brake pedal 21 brake stroke sensor 22 negative pressure booster 23 master cylinder 24 each wheel 25 wheel speed sensor 26 control device that performs brake assist 27 deceleration sensor 28 brake switch 29 brake pedal force sensor

Claims (4)

[Claims] A vacuum valve for shutting off or opening a flow path between the negative pressure chamber and the transformation chamber; an atmospheric pressure passage section for shutting off or opening a flow path between the outside and the transformation chamber; A brake assist control device that includes a vacuum valve and a negative pressure booster including a solenoid that shuts off or opens the atmospheric pressure passage portion, and that drives the solenoid during braking; a deceleration detection unit that detects deceleration of the vehicle; A threshold value for determining the magnitude of the deceleration of the vehicle detected by the deceleration detecting means; and a magnitude relationship between the deceleration detected by the deceleration detecting means during vehicle braking and the threshold value. Control means for performing brake assist control when the deceleration detected by the speed detection means exceeds the threshold; deceleration learning means for learning the deceleration detected by the deceleration detection means; Brake assist control apparatus being characterized in that and a threshold change setting means for setting changes the threshold value according to the deceleration learned by degrees the learning means. 2. The deceleration learning means learns the maximum value of the deceleration of the vehicle when the deceleration of the vehicle detected by the deceleration detection means is smaller than the threshold value. 2. The brake assist control device according to claim 1, wherein a threshold value is changed and set according to a maximum value of the deceleration learned by the deceleration learning means. 3. The deceleration learning means learns an average value of the vehicle deceleration when the deceleration of the vehicle detected by the deceleration detection means is smaller than the threshold value. 2. The brake assist control device according to claim 1, wherein a threshold value is changed and set according to an average value of the deceleration learned by the deceleration learning means. 4. The deceleration learning means learns the frequency distribution of the average value of the deceleration of the vehicle when the deceleration of the vehicle detected by the deceleration detection means is smaller than the threshold value. 2. The brake according to claim 1, wherein the means changes the threshold value according to the average value of the deceleration that has become the most frequent frequency of the frequency distribution of the average value of the deceleration learned by the deceleration learning means. Assist control device.