JP2002249034A - Brake control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure brake feeling corresponding to the intention of a driver at the time of releasing accelerator operation, in a brake control device which is equipped with an automatic transmission and which generates brake hydraulic pressure from an automatic hydraulic pressure generating device independent of the operation of a brake pedal. SOLUTION: When release of an accelerator pedal of a vehicle from an operation condition is detected, the brake hydraulic pressure is generated from the automatic hydraulic pressure generating device to apply braking force to respective wheels independent of the operation of the brake pedal. Especially, when the automatic transmission is in a shifting position with a relatively large gear ratio (for example, a second range), the automatic hydraulic pressure generating device is controlled so that the vehicle may be decelerated at larger deceleration than that when the automatic transmission is in a shifting position with a relatively small gear ratio (for example, a drive range).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking control device for a vehicle, and more particularly to an automatic hydraulic pressure generating device for generating a brake hydraulic pressure regardless of the operation of a brake pedal and applying a braking force to each wheel. The present invention relates to a braking control device for a vehicle that generates a brake fluid pressure from an automatic fluid pressure generating device when an accelerator operation is released, and applies a braking force to each wheel.

[0002]

2. Description of the Related Art Various types of vehicle braking control devices for applying a braking force to each wheel independently of the operation of a brake pedal are known, and automatic hydraulic pressure generation is performed when an accelerator operation is released. There is also known a brake control device that generates a brake fluid pressure from a device and applies a braking force to each wheel in addition to a so-called engine brake. Further, JP-A-10-236
Japanese Patent Laid-Open No. 290 discloses an object of preventing a shift shock during a downshift in a power-off state, predicting a shift-down of an automatic transmission, and applying a braking device until a predetermined time elapses after the shift-down is completed. A braking control device for a vehicle including a braking force addition control unit that automatically adds a braking force to the vehicle and an addition amount limiting unit that reduces the amount of braking force applied by the braking force addition control unit during downshifting. Proposed.

Japanese Patent Laid-Open Publication No. Hei 7-108913 discloses a braking control device which 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 fact that a larger engine brake acts, the brake hydraulic pressure supplied to the wheel cylinder during braking control is set smaller as the shift position is lower, and braking control is performed with the set brake hydraulic pressure. There has been proposed a braking control device for estimating a road surface state based on the deceleration that has occurred.

[0004]

SUMMARY OF THE INVENTION The above-mentioned JP-A-7-108
In the braking control disclosed in Japanese Patent Application Laid-Open No. 913, the brake oil pressure is set to be lower as the shift position is lower. The braking control disclosed in Japanese Patent Application Laid-Open No. 10-236290 is also restricted during the downshift. This is to reduce the amount of additional power. That is, in any of the publications, when the shift position (shift position) has a relatively large gear ratio (compared to when the gear ratio is relatively small), the braking control is performed such that the vehicle is decelerated 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 driver's intention.

[0005] In particular, when the braking force is applied automatically regardless of the operation of the brake pedal, the driver's intention should be given priority. When the gear ratio is set to a relatively large gear ratio, the braking control is performed so that the vehicle decelerates at a relatively small deceleration at least in a state where the vehicle does not depend on the operation of the brake pedal during engine braking. In terms of securing power, it cannot be said that it is in line with the driver's intention. Therefore, the brake feeling desired by the driver when the accelerator operation is released is not obtained.

Accordingly, the present invention relates to a vehicle brake control device that includes an automatic transmission and generates a brake fluid pressure from an automatic fluid pressure generator irrespective of the operation of a brake pedal when the accelerator operation is released. It is another object of the present invention to ensure a brake feeling according to the driver's intention.

[0007]

In order to solve the above-mentioned problems, the present invention provides an automatic transmission for setting a plurality of shift positions with respect to the running of a vehicle, and an automatic transmission for the vehicle. Accelerator release detecting means for detecting that the accelerator pedal is released from the operating state, an automatic hydraulic pressure generating device for generating brake hydraulic pressure independently of operation of the brake pedal and applying a braking force to each wheel, A brake control device for a vehicle, comprising: control means for controlling the automatic hydraulic pressure generation device so as to apply a braking force to each wheel when release of the accelerator pedal is detected by release detection means. In the above, when the automatic transmission is in a shift position with a relatively large gear ratio, the control means may have a larger reduction than when the automatic transmission is in a shift position with a relatively small gear ratio. The vehicle is obtained by a structure for controlling the automatic hydraulic pressure generator to decelerate in degrees.

[0008] The control means may be arranged so that the automatic transmission has a relatively small first gear ratio.
From the first shift position or the second shift position, compared to the deceleration at the time of changing from the shift position of the second shift position to the second shift position of a relatively large gear ratio. The automatic hydraulic pressure generator may be controlled so that the deceleration when changing to the third shift position with a large gear ratio is large.

According to a third aspect of the present invention, the automatic hydraulic pressure generating device includes a vacuum booster that operates at least in response to an operation of the brake pedal, and a master that is driven by the vacuum booster to generate a brake hydraulic pressure. A cylinder and a booster driving device that drives the vacuum booster independently of the operation of the brake pedal are provided, and the control unit releases the accelerator pedal from the operating state by the accelerator release detection unit. When it is detected, the booster driving device is driven to drive the vacuum booster.

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First, as shown in FIG.
In response to the operation of the brake pedal BP, the master cylinder MC is boosted via the vacuum booster VB, and the brake fluid in the master reservoir LRS is pressurized and the wheels F
The master cylinder hydraulic pressure is configured to be output to two brake hydraulic systems on the R and RL sides and the wheels FL and RR sides, and a so-called X pipe is configured. The master cylinder MC is a tandem type master cylinder having two pressure chambers. One of the pressure chambers is connected to the brake hydraulic system on the wheels FR and RL, and the other pressure chamber is the brake fluid on the wheels FL and RR. It is connected to the pressure system. The vacuum booster VB will be described later with reference to FIG.

In the brake hydraulic system for the wheels FR and RL of this embodiment, one of the pressure chambers is connected to the wheel cylinders Wfr and Wrl via a main hydraulic pressure passage MF and branch hydraulic pressure passages MFr and MFl, respectively. Have been. Branch hydraulic path M
Fr and MFl respectively include normally open two-port two-position solenoid valves PC1 and PC2 (hereinafter simply referred to as solenoid valves PC1 and PC2).
2). Further, a discharge-side branch hydraulic pressure path R connected to and connected to the wheel cylinders Wfr and Wrl.
A normally closed type two-port two-position solenoid on-off valve PC5, PC6 (hereinafter, simply referred to as solenoid valve PC5, PC6) is interposed in each of Fr and RFl, and the drainage fluid in which branch hydraulic pressure lines RFr and RFl merge. The pressure line RF is connected to the auxiliary reservoir RS1.

Further, check valves CV1 and CV2 are provided in parallel with the solenoid valves PC1 and PC2, respectively. Check valve CV
1, CV2 permits the flow of brake fluid in the direction of the master cylinder MC and restricts the flow of brake fluid in the direction of the wheel cylinders Wfr, Wrl. The wheel cylinder Wfr is controlled via these check valves CV1, CV2. , Wr
1 is configured to return the brake fluid in the master cylinder MC and thus the master reservoir LRS. Thus, when the brake pedal BP is released, the hydraulic pressure in the wheel cylinders Wfr, Wrl becomes equal to the master cylinder MC
Can quickly follow the hydraulic pressure drop on the side.

In the brake hydraulic system for the wheels FR and RL, a branch hydraulic pressure path M is provided upstream of the solenoid valves PC1 and PC2.
A hydraulic pump HP1 is interposed in a hydraulic passage MFp connected to Fr and MFl, and an auxiliary reservoir RS1 is connected to a suction side of the hydraulic pump HP1 via a check valve CV5. The hydraulic pump HP1 is provided with one electric motor M together with the hydraulic pump HP2.
, The brake fluid is introduced from the suction side, boosted 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 a required amount of brake fluid for various controls. It is configured.

The discharge side of the hydraulic pump HP1 is provided with a check valve CV
6 and the solenoid valves PC1, PC2 via the damper DP1, respectively.
It is connected to the. Check valve CV5 is an auxiliary reservoir RS1
To prevent the flow of the brake fluid to the opposite direction and allow the reverse flow. The check valve CV6 is connected to the hydraulic pump HP1.
This restricts the flow of the brake fluid discharged through the hydraulic pump in a certain direction, and is usually integrally formed in the hydraulic pump HP1. Note that a damper D is provided on the discharge side of the hydraulic pump HP1.
A proportioning valve PV1 is provided in a hydraulic pressure path to the wheel cylinder Wrl on the rear wheel side.

Similarly, in the brake hydraulic system on the side of the wheels FL and RR, a normally open two-port two-position solenoid valve PC
3, PC4, normally closed 2-port 2-position solenoid on-off valve PC
7, PC8, check valve CV3, CV4, CV7, CV8,
An auxiliary reservoir RS2, a damper DP2, and a proportioning valve PV2 are provided, and a hydraulic pump HP2
Is driven by the electric motor M together with the hydraulic pump HP1.

The above-described solenoid valves PC1 to PC8 constitute a hydraulic pressure control valve device.
The electronic control unit ECU controls the driving of the PCs 1 to 8 to perform various controls such as traction control and braking steering control. For example, regarding the hydraulic pressure control of the wheel cylinder Wfr of the wheel FR, the on-off valve PC1 is in the open position and the on-off valve PC5 is in the closed position in the pressure increasing mode (and during normal brake operation), and is opened and closed in the pressure reducing mode. The valve PC1 is set to the closed position and the open / close valve PC5 is set to the open position. In the holding mode, both the open / close valves PC1 and PC5 are set to the closed position.

Although not shown, the electronic control unit ECU of this embodiment includes a microcomputer including a processing unit, a memory ROM, a RAM, an input port, an output port, and the like, which are interconnected via a bus. . Then, output signals of a wheel speed sensor, a brake switch, a front wheel steering angle sensor, a yaw rate sensor, a lateral acceleration sensor, a throttle sensor and the like (all not shown) are input to the processing unit from the input ports via the amplifier circuits. Is configured. The output port is configured to output a control signal via a drive circuit.

Further, as an accelerator release detecting means of the present invention, an accelerator switch AS which 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 from the operation state can be detected. Note that, 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.

In the electronic control unit ECU, programs for various processes including the flow chart shown in FIG. 3 are stored in the memory ROM, and the processing unit executes the programs while an ignition switch (not shown) is closed. And temporarily stores the variable data required for executing the program in the memory RAM. Note that a plurality of microcomputers may be configured for each control such as throttle control or a suitable combination of related controls, and may be electrically connected to each other.

Next, the vacuum booster VB is configured as shown in FIG. 2, and a booster driving device BD for automatically driving the vacuum booster VB at least when the brake pedal is not operated is provided therein. The basic configuration of the vacuum booster VB is the same as the conventional one, and a constant pressure chamber B2 and a variable pressure chamber B3 are formed by a movable wall B1,
The movable wall B1 is integrally connected to the power piston B4. The constant pressure chamber B2 is always connected to the engine intake pipe (EG in FIG. 1).
(Indicated by)) to introduce a negative pressure. 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, so that a force can be transmitted. The output rod B10 is connected to the master cylinder MC.

In the power piston B4, there is a vacuum valve V for interrupting communication between the constant pressure chamber B2 and the variable pressure chamber B3.
1 and an air valve V2 for interrupting communication between the transformation chamber B3 and the atmosphere. The vacuum valve V1 includes an annular valve seat V11 formed on the power piston B4, and an elastic valve body V12 detachable from the annular valve seat V11. The air valve V2 includes an elastic valve seat V21 mounted on the elastic valve body V12 and the elastic valve seat V21.
21 is provided with a detachable valve body V22. Valve V22
Is connected to an input rod B6 which can be interlocked with the brake pedal BP, and the elastic valve seat V2 is actuated by the urging force of a spring B7.
1 is urged in the seating direction. Also, the spring B8
Of the elastic valve element V1 of the vacuum valve V1
2 is urged in the direction of sitting on the annular valve seat V11, and the elastic valve seat V21 of the air valve V2 is urged in the direction of sitting on the valve body 22.

In response to the operation of the brake pedal BP (FIG. 1), the vacuum valve V1 and the air valve V2 of the valve mechanism B5 open and close, and the operating force of the brake pedal BP is applied between the constant pressure chamber B2 and the variable pressure chamber B3. Is generated, and as a result, the output amplified by the operation of the brake pedal BP is transmitted to the master cylinder MC.

The booster driving device BD has a linear solenoid D1, a fixed core D2 and a movable core D3. The linear solenoid D1 connects the movable core D3 to the fixed core D2 when energized.
The electronic control unit EC shown in FIG.
U is electrically connected. The fixed core D2 is disposed between the power piston B4 and the reaction disc B9, and is moved from the power piston B4 to the reaction disc B9.
The force can be transmitted to The movable core D3 is disposed in the linear solenoid D1 so as to face the fixed core D2, and a magnetic gap D4 is formed between the movable core D3 and the fixed core D2. The movable core D3 is provided with a valve body V22 of the air valve V2.
When the movable core D3 moves relative to the fixed core D2 in a direction to decrease the magnetic gap D4, the valve body V22 of the air valve V2 moves integrally. The booster drive device BD is configured to be able to switch between a drive position for communicating the variable pressure chamber B3 with the atmosphere and a release position for releasing the drive position irrespective 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 operation of the brake pedal.

The input rod B6 is 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 is relatively movable with respect to the first input rod B61, and is configured to be able to transmit a force to the output rod B10 via the key member B11 by the power piston B4. Therefore, the second input rod B6
When only 2 is driven forward, the first input rod B61 is left, and these first and second input rods B61, B62 are left.
This constitutes a so-called pedal remaining mechanism.

Thus, an automatic hydraulic pressure generating device is constituted by the vacuum booster VB, the booster driving device BD, and the master cylinder MC, and the automatic hydraulic pressure generating device controls at least the wheel to be controlled when the brake pedal is not operated. The operation of the vacuum booster VB and the like when performing the automatic pressurization control (for example, the traction control and the brake steering control including the deceleration control of the present invention) will be described below.

When the automatic pressurization control is started by the electronic control unit ECU, the linear solenoid D1 is energized, the movable core D3 moves toward the magnetic gap D4, and the air valve V
The second valve body V22 moves integrally with the movable core D3 against the urging force of the spring B7. As a result, the spring B
8, the elastic valve body V12 of the vacuum valve V1 is seated on the annular valve seat V11, and the communication between the variable pressure chamber B3 and the constant pressure chamber B2 is cut off. Thereafter, the valve element V2 of the air valve V2
2 further moves, the valve element V22 is separated 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.

The power piston B4 is connected to the key member B.
After engaging with the key member 11, the second input rod B62 engaging 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 first input rod B61 is maintained at the initial position. 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.

For example, at the time of traction control, for example, the solenoid on-off valve PC
1, wheel cylinder Wfr by intermittent control of PC5
In response, any of the hydraulic pressure control modes of rapid pressure increase, pulse pressure increase, pulse pressure decrease, and holding is set. As a result, a braking torque is applied to the wheels FR to limit the rotational driving force,
Acceleration slip is prevented, and traction control can be appropriately performed. Acceleration slip prevention control is similarly performed on wheel FL.

On the other hand, while the vehicle is running, the accelerator pedal AP
Is released, the engine brake is actuated. In addition, the booster driving device BD is driven and the vacuum booster VB performs deceleration control as described below with reference to FIG. First, in step 101, it is determined whether or not the accelerator operation has been turned off from the on state. That is, the accelerator switch A
If the output of S is determined to be off in the current calculation cycle from the state determined to be on in the previous calculation cycle, the accelerator pedal AP has been released from the operating state. Proceeding to 102, it is determined whether a downshift has occurred.

The automatic transmission (not shown) of the present embodiment
For example, with four forward speeds and one reverse speed, with respect to forward movement, overdrive (OD), drive range (D), second range (2nd), low range (L) ) Is 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 may be that. Thus, in step 102, it is determined whether or not a shift lever (not shown) has been switched from a gear position with a small gear ratio to a gear position with a large gear ratio, that is, whether or not a shift down has been performed.

If it is determined in step 102 that the downshift is not performed, the process proceeds to step 104 and subsequent steps.
That is, if there is no shift change, the process proceeds to any of steps 104, 106, and 108 according to the shift position at that time, and if the shift is performed during engine braking, according to the shift position after the upshift. First, if it is determined in step 103 that overdrive (OD) has occurred, the process proceeds to step 104, where the booster driving device BD
The driving current (referred to as booster output Bf) for driving the linear solenoid is set to a value Kod for overdrive. If it is determined in step 105 that the drive range is the drive range (D), the process proceeds to step 106, where the booster output Bf is set to the drive range value Kd.

The value Kd for the drive range (D) is set to be larger (Kod <Kd) than the value Kod for the overdrive (OD), and the driving amount of the booster driving device BD and, consequently, the driving force of the vacuum booster VB. Becomes larger, the master cylinder hydraulic pressure increases accordingly, and the braking force on each wheel increases, so that the vehicle decelerates at a large deceleration. If it is determined in step 107 that the range is the second range (2nd), the process proceeds to step 108, where the booster output Bf
Is set to the value K2 for the second range (Kd <K2). Therefore, in the second range (2nd), the drive amount of the booster driving device BD becomes larger than in the case of the drive range (D), and the braking force on each wheel increases. If it is determined in step 101 that the accelerator operation is still in the on state, the process proceeds to step 109, where the booster output Bf is set to 0.

On the other hand, when it is determined in step 102 that the shift-down has been performed, the process proceeds to one of steps 111 and 113 according to the change at that time. First, in step 110, downshifting from overdrive (OD) to drive range (D) is performed (first according to the present invention).
Is determined to have been changed from the shift position to the second shift position), the routine proceeds to step 111, where the booster output Bf is set to the value Khd for high-speed downshifting.

Next, when downshifting 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 overdrive (OD). If the gear is shifted down to the second range (2nd) (change from the first gear shift position to the third gear shift position of the present invention), the process proceeds from step 112 to step 113, where the booster output Bf is set to the low gear shift down. It is set to the value Kh2. Value Kh2 for low speed shift down
Is larger than the high speed downshift value Khd (Kh2> Khd)
The driving amount of the booster driving device BD, and thus the driving force of the vacuum booster VB, increases, and the master cylinder hydraulic pressure increases accordingly, and the braking force on each wheel increases. I do. The values Kh2, Khd for the downshift and the values K2, K
The relationship of d is set to, for example, Kh2> K2 and Khd> Kd. In the case of a downshift other than the above (for example, from the drive range (D) to the low range (L)), the booster output Bf remains unchanged.

FIG. 4 shows an example of a time chart according to the present embodiment. For example, when the accelerator operation is turned off at time t1 for a vehicle running in overdrive (OD), the booster output Bf becomes Kod. Thus, the booster driving 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. Then, at t2, when the gear is shifted down from the overdrive (OD) to the second range (2nd), the booster output Bf is set to Kh2, and the booster driving device BD is driven. As a result, the 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. It becomes a brake feeling.

[0036]

Since the present invention is configured as described above, the following effects can be obtained. That is, in the vehicle braking control device according to the first aspect, when the automatic transmission is in the shift position with a relatively large gear ratio, the automatic transmission is greatly reduced compared to when the automatic transmission is in the shift position with a relatively small gear ratio. Since the automatic hydraulic pressure generating device is controlled so that the vehicle decelerates at the speed, a large deceleration can be obtained according to the shift position when the accelerator operation is released also in the vehicle of the automatic transmission, and the driver's Good brake feeling according to the intention can be secured.

In the apparatus according to the second aspect,
Compared to the deceleration when the automatic transmission changes from the first shift position with a relatively small gear ratio to the second shift position with a relatively large gear ratio, the first shift position or the second shift position is compared. Since the automatic hydraulic pressure generating device is controlled so that the deceleration when changing from the position to the third shift position with a gear ratio larger than that of the second shift position is large, especially during downshifting, A good brake feeling according to the driver's intention can be secured.

Further, according to the third aspect of the present invention, the automatic hydraulic pressure generator can be simply and inexpensively configured, so that a good brake feeling according to the driver's intention can be easily achieved. Can be secured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a vehicle braking control device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a part of a vacuum booster provided in one embodiment of the present invention.

FIG. 3 is a flowchart illustrating a process of setting a solenoid drive current of a booster drive device according to a shift position of an automatic transmission and a downshift mode in one embodiment of the present invention.

FIG. 4 is a time chart illustrating an example of a booster output and a deceleration state during downshifting according to the embodiment of the present invention.

[Explanation of symbols]

BP brake pedal, AP accelerator pedal, VB
Vacuum booster, BD booster drive, M
C 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 wheels, PC1 to PC8 solenoid valve

Claims (3)

[Claims] 1. An automatic transmission for setting a plurality of shift positions with respect to traveling of a vehicle, accelerator release detecting means for detecting that an accelerator pedal of the vehicle is released from an operation state, and operation of a brake pedal. An automatic hydraulic pressure generating device that generates brake hydraulic pressure independently and applies a braking force to each wheel, and when the accelerator release detecting means detects that the accelerator pedal has been released from the operating state,
In a vehicle braking control device including a control unit that controls the automatic hydraulic pressure generation device so as to apply a braking force to each wheel, the control unit may control the automatic transmission to change a gear ratio of a relatively large gear ratio. A brake control device for a vehicle, wherein the automatic hydraulic pressure generation device is controlled such that the vehicle decelerates at a larger deceleration when the vehicle is in a shift position with a relatively small gear ratio. . 2. An automatic transmission for setting a plurality of shift positions with respect to traveling of a vehicle, accelerator release detecting means for detecting that an accelerator pedal of the vehicle is released from an operation state, and operation of a brake pedal. An automatic hydraulic pressure generating device that generates brake hydraulic pressure independently and applies a braking force to each wheel, and when the accelerator release detecting means detects that the accelerator pedal has been released from the operating state,
In a vehicle braking control device including a control unit that controls the automatic hydraulic pressure generation device so as to apply a braking force to each wheel, the control unit may control the automatic transmission to have a relatively small gear ratio. Compared to the deceleration at the time of changing from the first shift position to the second shift position with a relatively large gear ratio, the deceleration from the first shift position or the second shift position to the second shift position A brake control device for a vehicle, wherein the automatic hydraulic pressure generation device is controlled so that the deceleration when the gear shifts to a third shift position with a larger gear ratio is increased. 3. The automatic hydraulic pressure generator includes a vacuum booster that operates at least in response to operation of the brake pedal, a master cylinder that is driven by the vacuum booster to generate brake hydraulic pressure, A booster driving device that drives the vacuum booster irrespective of the operation, wherein the control means detects that the accelerator pedal has been released from the operating state by the accelerator release detection means, 3. The brake control device for a vehicle according to claim 1, wherein the vacuum booster is driven by driving a device.