JP4433622B2 - Brake control device for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle braking control device, and more particularly, to an automatic hydraulic pressure generating device that generates a brake hydraulic pressure regardless of an operation of a brake pedal and applies a braking force to each wheel, and when an accelerator operation is released. Further, the present invention relates to a vehicle brake control device that generates a brake fluid pressure from an automatic fluid pressure generator and applies a braking force to each wheel.
[0002]
[Prior art]
Various types of vehicle braking control devices that apply braking force to each wheel independently of the operation of the brake pedal are known. When the accelerator operation is released, the brake hydraulic pressure is generated from the automatic hydraulic pressure generator. In addition to so-called engine braking, a braking control device that applies braking force to each wheel is also known. Further, Japanese Patent Application Laid-Open No. 10-236290 has a purpose of preventing a shift shock at the time of downshift in a power-off state, foreseeing shift down of an automatic transmission, and a predetermined time elapses after completion of the shift down. Until now, a braking force addition control means for automatically applying a braking force to the braking device, and an additional amount limiting means for reducing the additional amount of the braking force by the braking force addition control means during the downshifting are provided. A vehicle braking control device has been proposed.
[0003]
Japanese Laid-Open Patent Publication No. 7-108913 relates to a braking control device that estimates a road surface condition during traveling based on a deceleration generated in a vehicle when a predetermined braking control is executed. In view of the action of the engine brake, the brake hydraulic pressure supplied to the wheel cylinder during braking control is set to be smaller as the shift position is lower, and braking control is performed with the set brake hydraulic pressure. A braking control device that estimates a road surface state based on deceleration has been proposed.
[0004]
[Problems to be solved by the invention]
The braking control disclosed in the above-mentioned JP-A-7-108913 is such that the brake hydraulic pressure is set to be smaller as the shift position is lower, and the braking control disclosed in JP-A-10-236290 is also a downshift. The amount of addition of braking force is reduced during the execution of the above. In other words, in any publication, when the shift position (shift position) is a relatively large gear ratio (compared to a relatively small gear ratio), the braking control is performed so that the vehicle decelerates with a small deceleration. It is supposed to be done. This is because it is intended to reduce the shock at the time of downshifting, but it cannot be denied that a vehicle equipped with an automatic transmission tends to be contrary to the intention of the driver.
[0005]
In particular, when the braking force is automatically applied regardless of the operation of the brake pedal, the driver's intention should be given priority. For example, as described in the above publication, the shift position (shift position) is a relative position. If the braking control is performed so that the vehicle decelerates at a relatively small deceleration when the gear ratio is set to a large gear ratio, at least the braking force is ensured without depending on the operation of the brake pedal during engine braking. In that respect, it cannot be said to be in line with the driver's will. Therefore, the brake feeling desired by the driver when the accelerator operation is released is not achieved.
[0006]
Accordingly, the present invention provides an automatic transmission that includes an automatic transmission and generates a brake fluid pressure from an automatic fluid pressure generator regardless of the operation of the brake pedal. It is an object to be able to secure a brake feeling in line with the intention of the company.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides an automatic transmission for setting a plurality of shift positions with respect to travel of a vehicle and an accelerator pedal of the vehicle released from an operation state as described in claim 1 An accelerator release detecting means for detecting this, an automatic hydraulic pressure generating device for generating brake fluid pressure and applying a braking force to each wheel independently of the operation of the brake pedal, and the accelerator pedal operated by the accelerator release detecting means When it is detected that the vehicle has been released from the state, the vehicle braking control device includes a control unit that controls the automatic hydraulic pressure generator so as to apply a braking force to each wheel. When the transmission is in a gear position with a relatively large gear ratio, the vehicle decelerates with a large deceleration compared to when the gearbox is in a gear position with a relatively small gear ratio. It is obtained by the configuration of controlling the automatic hydraulic pressure generator.
[0008]
The control means may change the automatic transmission from a first shift position having a relatively small gear ratio to a second shift position having a relatively large gear ratio. Compared to the deceleration at the time, the deceleration when the first shift position or the second shift position is changed to the third shift position having a gear ratio larger than that of the second shift position becomes larger. In this way, the automatic hydraulic pressure generator may be controlled.
[0009]
The automatic hydraulic pressure generating device according to claim 3, wherein at least a vacuum booster that operates in response to an operation of the brake pedal, a master cylinder that is driven by the vacuum booster and generates a brake hydraulic pressure, A booster driving device for driving the vacuum booster irrespective of the operation of the brake pedal, and the control means detects that the accelerator pedal is released from the operating state by the accelerator release detecting means. Then, the booster driving device can be driven to drive the vacuum booster.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, as shown in FIG. 1, the master cylinder MC is boosted via the vacuum booster VB in accordance with the operation of the brake pedal BP, and the brake fluid in the master reservoir LRS is boosted, and the wheels FR, RL and wheels The master cylinder hydraulic pressure is output to the two brake hydraulic pressure systems on the FL and RR sides, and so-called X piping is configured. The master cylinder MC is a tandem master cylinder having two pressure chambers. One pressure chamber is connected to a brake fluid pressure system on the wheels FR and RL side, and the other pressure chamber is a brake fluid on the wheels FL and RR sides. It is connected to the pressure system. The vacuum booster VB will be described later with reference to FIG.
[0011]
In the brake hydraulic system on the wheel FR, RL side of the present embodiment, one pressure chamber is connected to the wheel cylinders Wfr, Wrl via the main hydraulic path MF and its branched hydraulic paths MFr, MFl, respectively. . The branch hydraulic pressure paths MFr and MFl are respectively provided with normally open type two-port two-position electromagnetic on-off valves PC1 and PC2 (hereinafter simply referred to as electromagnetic valves PC1 and PC2). Further, normally-closed two-port two-position electromagnetic on-off valves PC5 and PC6 (hereinafter simply referred to as electromagnetic valves PC5 and PC6) are connected to the discharge-side branch hydraulic pressure paths RFr and RFl connected to the wheel cylinders Wfr and Wrl, respectively. Is interposed, and the discharge hydraulic pressure channel RF where the branch hydraulic pressure channels RFr and RFl merge is connected to the auxiliary reservoir RS1.
[0012]
Further, check valves CV1 and CV2 are interposed in parallel with the electromagnetic valves PC1 and PC2, respectively. The check valves CV1 and CV2 allow the flow of brake fluid in the direction of the master cylinder MC and restrict the flow of brake fluid in the direction of the wheel cylinders Wfr and Wrl. The check valves CV1 and CV2 are connected via the check valves CV1 and CV2. The brake fluid in the wheel cylinders Wfr, Wrl is configured to be returned to the master cylinder MC and thus to the master reservoir LRS. Thus, when the brake pedal BP is released, the hydraulic pressure in the wheel cylinders Wfr, Wrl can quickly follow the decrease in hydraulic pressure on the master cylinder MC side.
[0013]
In the brake hydraulic system on the wheel FR, RL side, a hydraulic pump HP1 is interposed in a hydraulic path MFp communicating with the branch hydraulic paths MFr, MF1 upstream of the solenoid valves PC1, PC2, and the suction thereof The auxiliary reservoir RS1 is connected to the side via a check valve CV5. The hydraulic pump HP1 is driven by one electric motor M together with the hydraulic pump HP2, and is configured to introduce brake fluid from the suction side, increase the pressure to a predetermined pressure, and output from the discharge side. The auxiliary reservoir RS1 is provided independently of the master reservoir LRS of the master cylinder MC, and can also be referred to as an accumulator. The auxiliary reservoir RS1 includes a piston and a spring, and can store brake fluid having a capacity necessary for various controls. It is configured.
[0014]
The discharge side of the hydraulic pump HP1 is connected to the electromagnetic valves PC1 and PC2 via the check valve CV6 and the damper DP1, respectively. The check valve CV5 blocks the flow of brake fluid to the auxiliary reservoir RS1 and allows a reverse flow. The check valve CV6 regulates the flow of the brake fluid discharged through the hydraulic pump HP1 in a certain direction, and is normally configured integrally with the hydraulic pump HP1. Note that a damper DP1 is disposed on the discharge side of the hydraulic pump HP1, and a proportioning valve PV1 is interposed in a hydraulic pressure path leading to the wheel cylinder Wrl on the rear wheel side.
[0015]
Similarly, in the brake fluid pressure system on the wheels FL, RR side, normally open type 2-port 2-position electromagnetic on-off valves PC3, PC4, normally-closed 2-port 2-position electromagnetic on-off valves PC7, PC8, check valve CV3, CV4, CV7, CV8, auxiliary reservoir RS2, damper DP2, and proportioning valve PV2 are provided, and hydraulic pump HP2 is driven by electric motor M together with hydraulic pump HP1.
[0016]
Thus, the solenoid valves PC1 to PC8 constitute a hydraulic control valve device, and these solenoid valves PC1 to PC8 are driven and controlled by the electronic control unit ECU, and various controls such as traction control and braking steering control are performed. It is. For example, regarding the hydraulic pressure control of the wheel cylinder Wfr of the wheel FR, the opening / closing valve PC1 is set to the open position and the opening / closing valve PC5 is set to the closed position in the pressure increasing mode (and during normal braking operation), and is opened / closed in the pressure reducing mode. The valve PC1 is in the closed position and the on-off valve PC5 is in the open position. In the holding mode, both the on-off valves PC1 and PC5 are in the closed position.
[0017]
Although not shown, the electronic control unit ECU of the present embodiment includes a microcomputer including a processing unit, a memory ROM, a RAM, an input port, an output port, and the like that are connected to each other via a bus. Then, output signals from wheel speed sensors, brake switches, front wheel steering angle sensors, yaw rate sensors, lateral acceleration sensors, throttle sensors, etc. (all not shown) are input from the input ports to the processing units via the amplification circuits. It is configured. In addition, a control signal is output from the output port via a drive circuit.
[0018]
Further, as the accelerator release detecting means of the present invention, an accelerator switch AS that is turned on / off in response to the operation and release of the accelerator pedal AP is connected to the electronic control unit ECU. The release can be detected. Instead of the accelerator switch AS, an accelerator opening sensor (not shown) for detecting the operation amount of the accelerator pedal AP may be provided, or an output signal of a throttle sensor (not shown) may be used. Good.
[0019]
In the electronic control unit ECU, a program used for various processes including the flowchart shown in FIG. 3 is stored in the memory ROM, and the processing unit executes the program while an ignition switch (not shown) is closed. Is temporarily stored in the memory RAM. It should be noted that a plurality of microcomputers may be configured for each control such as throttle control or a combination of related controls as appropriate, and electrically connected to each other.
[0020]
Next, the vacuum booster VB is configured as shown in FIG. 2, and at least a booster driving device BD for automatically driving the vacuum booster VB when the brake pedal is not operated is provided. The basic configuration of the vacuum booster VB is the same as that of the prior art. A constant pressure chamber B2 and a variable pressure chamber B3 are formed by the movable wall B1, and the movable wall B1 is integrally connected to the power piston B4. The constant pressure chamber B2 is always connected to an intake pipe (shown by EG in FIG. 1) of the engine so that a negative pressure is introduced. The power piston B4 is connected to an output rod B10 via a fixed core D2 and a reaction disk B9, which will be described later, and the output rod B10 is connected to a master cylinder MC.
[0021]
In the power piston B4, there is provided a valve mechanism B5 including a vacuum valve V1 for intermittently communicating between the constant pressure chamber B2 and the variable pressure chamber B3, and an air valve V2 for intermittently communicating between the variable pressure chamber B3 and the atmosphere. It has been. The vacuum valve V1 includes an annular valve seat V11 formed on the power piston B4 and an elastic valve body V12 that can be attached to and detached from the annular valve seat V11. The air valve V2 includes an elastic valve seat V21 attached to the elastic valve body V12, and a valve body V22 that can be attached to and detached from the elastic valve seat V21. The valve body V22 is connected to an input rod B6 that can be interlocked with the brake pedal BP, and is urged in a direction to be seated on the elastic valve seat V21 by the urging force of the spring B7. Further, the elastic valve body V12 of the vacuum valve V1 is biased in the direction of seating on the annular valve seat V11 and the elastic valve seat V21 of the air valve V2 is applied in the direction of seating on the valve body 22 by the biasing force of the spring B8. It is energized.
[0022]
Thus, the vacuum valve V1 and the air valve V2 of the valve mechanism B5 are opened and closed according to the operation of the brake pedal BP (FIG. 1), and according to the operating force of the brake pedal BP between the constant pressure chamber B2 and the variable pressure chamber B3. As a result, a differential pressure is generated, and an output amplified in accordance with the operation of the brake pedal BP is transmitted to the master cylinder MC.
[0023]
The booster driving device BD has a linear solenoid D1, a fixed core D2, and a movable core D3. The linear solenoid D1 sucks the movable core D3 toward the fixed core D2 when energized. The electronic control unit ECU shown in FIG. Is electrically connected. The fixed core D2 is disposed between the power piston B4 and the reaction disk B9, and can transmit force from the power piston B4 to the reaction disk B9. The movable core D3 is disposed so as to face the fixed core D2 in the linear solenoid D1, and a magnetic gap D4 is formed between the movable core D3 and the fixed core D2. The movable core D3 is engaged with the valve body V22 of the air valve V2, and when the movable core D3 moves relative to the fixed core D2 in the direction of decreasing the magnetic gap D4, the valve body V22 of the air valve V2 moves integrally. Is configured to do. The booster drive device BD is configured to be able to switch between a drive position where the variable pressure chamber B3 communicates with the atmosphere and a release position where the drive position is released regardless of the operation of the brake pedal BP. In the release position, the vacuum booster VB is driven by the valve mechanism B5 according to the brake pedal operation.
[0024]
The input rod B6 includes a first input rod B61 and a second input rod B62. The first input rod B61 is integrally connected to the brake pedal BP. The second input rod B62 can move relative to the first input rod B61, and can be configured to transmit force to the output rod B10 side via the key member B11 by the power piston B4. Therefore, when only the second input rod B62 is driven forward, the first input rod B61 is left behind, and a so-called pedal remaining mechanism is constituted by these first and second input rods B61 and B62.
[0025]
Thus, the automatic booster VB, the booster driving device BD, and the master cylinder MC constitute an automatic hydraulic pressure generator, and this automatic hydraulic pressure generator automatically pressurizes the control target wheel at least when the brake pedal is not operated. The operation of the vacuum booster VB and the like when performing control (for example, deceleration control of the present invention, traction control and braking steering control) will be described below.
[0026]
When the automatic pressurization control is started by the electronic control unit ECU, the linear solenoid D1 is energized, the movable core D3 moves to the magnetic gap D4 side, and the valve body V22 of the air valve V2 resists the biasing force of the spring B7. It moves integrally with the movable core D3. As a result, the elastic valve body V12 of the vacuum valve V1 is seated on the annular valve seat V11 by the spring B8, and the communication state between the variable pressure chamber B3 and the constant pressure chamber B2 is blocked. Thereafter, since the valve body V22 of the air valve V2 further moves, the valve body V22 is detached from the elastic valve seat V21, and the atmosphere is introduced into the variable pressure chamber B3. As a result, a differential pressure is generated between the variable pressure chamber B3 and the constant pressure chamber B2, and the power piston B4, the fixed core D2, the reaction disk B9, and the output rod B10 move forward to the master cylinder MC (FIG. 1) side. The brake fluid pressure is automatically output from the cylinder MC.
[0027]
Then, after the power piston B4 is engaged with the key member B11, the second input rod B62 engaged with the key member B11 advances integrally with the power piston B4. At this time, since the forward force of the power piston B4 is not transmitted to the first input rod B61, the initial position is maintained. That is, the brake pedal BP is maintained at the initial position while the vacuum booster VB is automatically driven by the booster driving device BD.
[0028]
For example, at the time of traction control, for example, by the intermittent control of the electromagnetic on-off valves PC1 and PC5 in accordance with the acceleration slip state of the wheel FR, any one of the fluid pressures of sudden pressure increase, pulse pressure increase, pulse pressure decrease and hold is applied to the wheel cylinder Wfr. The control mode is set. As a result, braking torque is applied to the wheel FR, the rotational driving force is limited, acceleration slip is prevented, and traction control can be performed appropriately. Similarly, acceleration slip prevention control is performed for the wheel FL.
[0029]
On the other hand, when the operation of the accelerator pedal AP is released while the vehicle is running, the engine brake is activated. In addition, as described below with reference to FIG. 3, the booster drive device BD is driven, Deceleration control is performed by the vacuum booster VB. First, in step 101, it is determined whether or not the accelerator operation is turned off from the on state. That is, if it is determined that the output of the accelerator switch AS is turned on in the previous calculation cycle and is turned off in the current calculation cycle, the accelerator pedal AP is released from the operation state. In step 102, it is determined whether or not the shift is down.
[0030]
The automatic transmission (not shown) according to the present embodiment has, for example, four forward speeds and one reverse speed. With respect to the forward movement, an overdrive (OD) drive is performed in order from a gear position with a small gear ratio to a gear position with a large gear ratio. Range (D), second range (2nd), and low range (L) shift positions are set. These shift positions can be detected by a shift switch (not shown) provided on a shift lever (not shown), but are detected by other means such as estimation based on the relationship between the vehicle speed and the engine speed. It is good as well. Thus, in step 102, it is determined whether or not the shift lever (not shown) has been switched from a shift position with a small gear ratio to a shift position with a large gear ratio, that is, whether or not the shift lever has been shifted down.
[0031]
If it is determined in step 102 that the shift is not down, the process proceeds to step 104 and subsequent steps. That is, if there is no shift change, the process proceeds to one of steps 104, 106, and 108 depending on the shift position at that time, and if the shift is up during engine braking, depending on the shift position after the shift up. First, when overdrive (OD) is determined in step 103, the process proceeds to step 104, and the drive current (referred to as booster output Bf) for driving the linear solenoid of the booster drive device BD is set to the value Kod for overdrive. The If it is determined at step 105 that the drive range is (D), the routine proceeds to step 106 where the booster output Bf is set to the drive range value Kd.
[0032]
The value Kd for the drive range (D) is set larger than the value Kod for the overdrive (OD) (Kod <Kd), and the driving amount of the booster driving device BD and thus the driving force of the vacuum booster VB becomes large. Therefore, the master cylinder hydraulic pressure increases and the braking force on each wheel increases, so the vehicle decelerates with a large deceleration. If it is determined in step 107 that the second range is (2nd), the process proceeds to step 108, where the booster output Bf is set to the second range value K2 (Kd <K2). Accordingly, in the second range (2nd), the drive amount of the booster drive device BD becomes larger than in the drive range (D), and the braking force for each wheel increases. If it is determined in step 101 that the accelerator operation remains on, the process proceeds to step 109 where the booster output Bf is set to zero.
[0033]
On the other hand, when it is determined in step 102 that the gear has been shifted down, the process proceeds to one of steps 111 and 113 according to the change mode at that time. First, if it is determined in step 110 that the gear has been shifted down from the overdrive (OD) to the drive range (D) (change from the first shift position to the second shift position according to the present invention), the process proceeds to step 111. The booster output Bf is set to the value Khd for high speed shift down.
[0034]
Next, when the gear is shifted down from the drive range (D) to the second range (2nd) (change from the second shift position to the third shift position of the present invention) or from the overdrive (OD) to the second range ( 2nd), when the gear is shifted down (change from the first gear shift position to the third gear shift position of the present invention), the routine proceeds from step 112 to step 113, where the booster output Bf is set to the value Kh2 for low speed shift down. Is set. The value Kh2 for low speed shift down is set to be larger (Kh2> Khd) than the value Khd for high speed shift down, and the driving amount of the booster drive device BD and hence the driving force of the vacuum booster VB becomes large. As the hydraulic pressure increases and the braking force on each wheel increases, the vehicle decelerates with a large deceleration. The relationship between the shift down values Kh2 and Khd and the aforementioned values K2 and Kd is set to Kh2> K2 and Khd> Kd, for example. In the case of a shift down other than the above (for example, drive range (D) to low range (L)), the booster output Bf is left as it is.
[0035]
FIG. 4 shows an example of a time chart according to the present embodiment. For example, when a vehicle running with overdrive (OD) is turned off at t1, the booster output Bf is set to Kod and booster driving is performed. The device BD is driven. As a result, the deceleration Dod is added to the deceleration of the vehicle due to the normal engine brake indicated by the broken line, resulting in a large deceleration, resulting in a brake feeling according to the driver's intention. When the shift is shifted down from the overdrive (OD) to the second range (2nd) at t2, the booster output Bf is set to Kh2 and the booster driving device BD is driven. As a result, a deceleration Dh2 (> Dod) is added to the deceleration of the vehicle due to the engine brake after the normal downshift indicated by the broken line, resulting in a large deceleration. Brake feeling.
[0036]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects. That is, in the vehicle braking control apparatus according to claim 1, when the automatic transmission is in the shift position with a relatively large gear ratio, the reduction is larger than when the automatic transmission is in the shift position with a relatively small gear ratio. Since the automatic hydraulic pressure generator is controlled so that the vehicle decelerates at a speed, even in the case of an automatic transmission vehicle, when the accelerator operation is released, a large deceleration is obtained according to the shift position. Good brake feeling can be ensured according to the intention.
[0037]
In the device according to claim 2, the deceleration when the automatic transmission is changed from the first shift position having a relatively small gear ratio to the second shift position having a relatively large gear ratio. In comparison, the automatic hydraulic pressure generator is set so that the deceleration when the shift position changes from the first shift position or the second shift position to the third shift position with a gear ratio larger than that of the second shift position becomes large. Since the control is performed, it is possible to ensure a good brake feeling particularly in line with the driver's intention during the downshift.
[0038]
Moreover, if comprised as described in Claim 3, an automatic hydraulic pressure generator can be comprised simply and cheaply, and, thereby, can ensure a favorable brake feeling according to a driver's intention easily. Can do.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a vehicle braking control apparatus according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of a vacuum booster used in an embodiment of the present invention.
FIG. 3 is a flowchart showing processing for setting a solenoid drive current of a booster drive device according to a shift position of an automatic transmission and a downshift mode in an embodiment of the present invention.
FIG. 4 is a time chart showing an example of a booster output and a deceleration state at the time of downshifting in one embodiment of the present invention.
[Explanation of symbols]
BP brake pedal, AP accelerator pedal,
VB vacuum booster, BD booster drive,
MC master cylinder, HP1, HP2 hydraulic pump,
LRS master reservoir, RS1, RS2 auxiliary reservoir,
Wfr, Wfl, Wrr, Wrl Wheel cylinder, ECU Electronic control unit,
FR, FL, RR, RL wheel, PC1-PC8 solenoid valve

Claims (3)

An automatic transmission that sets a plurality of shift positions for vehicle travel, an accelerator release detecting means that detects that the accelerator pedal of the vehicle is released from the operating state, and brake fluid regardless of the operation of the brake pedal An automatic hydraulic pressure generator for generating pressure and applying braking force to each wheel, and applying braking force to each wheel when the accelerator release detecting means detects that the accelerator pedal is released from the operating state In the vehicle braking control device having the control means for controlling the automatic hydraulic pressure generating device, the control means is configured such that when the automatic transmission is at a gear position with a relatively large gear ratio, The automatic hydraulic pressure generator is controlled so that the vehicle decelerates with a large deceleration compared to when the gear is in a gear position with a small gear ratio. Apparatus. An automatic transmission that sets a plurality of shift positions for vehicle travel, an accelerator release detecting means that detects that the accelerator pedal of the vehicle is released from the operating state, and brake fluid regardless of the operation of the brake pedal An automatic hydraulic pressure generator for generating pressure and applying braking force to each wheel, and applying braking force to each wheel when the accelerator release detecting means detects that the accelerator pedal is released from the operating state In the vehicle braking control device having the control means for controlling the automatic hydraulic pressure generating device, the control means is configured so that the automatic transmission is relative to the first shift position having a relatively small gear ratio. A gear larger than the second shift position from the first shift position or the second shift position as compared to the deceleration when the gear position is changed to the second shift position with a large gear ratio. Brake control apparatus for a vehicle third deceleration when the change in the shift position of and controlling said automatic hydraulic pressure generator such that the larger the. The automatic hydraulic pressure generator includes at least a vacuum booster that operates according to the operation of the brake pedal, a master cylinder that is driven by the vacuum booster to generate brake hydraulic pressure, and is independent of the operation of the brake pedal. A booster driving device that drives the vacuum booster, and the control means drives the booster driving device when the accelerator release detecting means detects that the accelerator pedal is released from the operating state. The vehicle braking control apparatus according to claim 1 or 2, wherein the vacuum booster is driven.

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