Brake control device for a vehicle

Abstract

To achieve brake control excellent in both of vibration noise characteristic and responsiveness.SOLUTION: A control unit 11 of a brake control device sets a discomfort index that operation sound volume makes an occupant feel discomfort from a difference between the operation sound volume transmitted from a HCU 8 to the inside of a cabin and a background noise level in the cabin, sets a pressure rising gradient correction factor which makes required pressure rising gradient to the HCU 8 gentle on the basis of the occupant discomfort index, sets target pressure rising gradient by correcting the required pressure rising gradient with the pressure rising gradient correction factor, and calculates necessary regenerative torque compensating shortage of brake torque from a difference between the required pressure rising gradient and the target pressure rising gradient. The control unit 11 makes the HCU 8 and an inverter 5 perform a cooperative operation with the target pressure rising gradient and the necessary regenerative torque.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a brake control device for a vehicle that relatively reduces the operating noise generated when frictional braking force is generated by a hydraulic brake and ensures quietness in the vehicle interior.

Background Art

[0002] Vehicles are equipped with various systems that automatically operate the brakes, such as vehicle handling stability control (VDC: Vehicle Dynamics Control) to eliminate unstable behavior during driving, a torque vectoring function that actively adjusts the distribution of driving force between the left and right drive wheels, and a brake holding function (AVH: Auto Vehicle Hold) that maintains the stopped state of the vehicle.

[0003] When brake control by these systems intervenes during driving or deceleration, noise and vehicle body vibration (NV: Noise and Vibration) caused by the operation of actuators and valves that control brake hydraulic pressure occur.

[0004] In conventional vehicles with an engine as the drive source and equipped with a transmission, even if noise and vibration occur due to the operation of actuators that control brake hydraulic pressure, the level of background noise (background vibration) caused by engine noise, transmission noise, etc. is dominant. Therefore, even when noise and vibration caused by the operation of the brake system occurred, it rarely gave discomfort to the passengers.

[0005] However, as the drive source becomes electrified and the background noise becomes the fan noise of the air conditioner in the vehicle interior, the volume of the audio, the conversation of the passengers, etc., and the background noise level relatively decreases. Therefore, the noise and vibration caused by the operation of the brake system relatively become prominent and give discomfort to the passengers. Furthermore, if the drive source becomes an in-wheel motor and the transmission becomes unnecessary, the noise and vibration associated with the operation of the brake system become even more prominent, increasing the discomfort given to the passengers.

[0006] As a countermeasure, for example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2018-34537), when the differential pressure between the brake hydraulic pressure (master pressure) generated by operating the master cylinder by the brake control unit and the brake hydraulic pressure (brake pressure) supplied to the wheel cylinder is large, vibration noise is generated. Due to this, a technique is disclosed in which the master pressure is interlocked so as to become the target value of the brake pressure, and the differential pressure is eliminated to reduce vibration noise (NV).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the technique disclosed in Patent Document 1, since the master pressure is always controlled to be interlocked with the brake pressure, there is a problem in responsiveness. Therefore, in the technique disclosed in Patent Document 1, when emphasizing the responsiveness of the brake, it is switched to a mode of controlling the brake pressure by conventional brake control.

[0009] Therefore, in the technique disclosed in Cited Document 1, since the mode excellent in NV characteristics and the mode excellent in response characteristics are switched, it is impossible to realize brake control having both of them.

[0010] An object of the present invention is to provide a brake control device for a vehicle capable of realizing brake control excellent in both vibration noise characteristics and responsiveness.

Means for Solving the Problems

[0011] In a brake control device for a vehicle including a hydraulic brake operation unit that operates a hydraulic brake to apply a braking force to the vehicle, a regeneration operation unit that performs a regeneration operation of a motor generator to apply a braking force to the vehicle, and a control unit that causes the hydraulic brake operation unit and the regeneration operation unit to cooperate, the control unit includes an operation sound volume estimation unit that estimates an operation sound volume propagated from the brake operation unit into the vehicle interior based on a required pressure increase gradient and a required hydraulic pressure when the brake operation unit operates the hydraulic brake, a background noise level estimation unit that estimates a background noise level in the vehicle interior, a passenger discomfort index setting unit that sets a discomfort index indicating that a passenger feels discomfort with the operation sound volume from a difference between the operation sound volume estimated by the operation sound volume estimation unit and the background noise level estimated by the background noise level estimation unit, a pressure increase gradient correction value setting unit that sets a pressure increase gradient correction value for moderating the required pressure increase gradient based on the passenger discomfort index set by the passenger discomfort index setting unit, a target pressure increase gradient setting unit that corrects the required pressure increase gradient with the pressure increase gradient correction value set by the pressure increase gradient correction value setting unit to set a target pressure increase gradient, and a required regeneration torque calculation unit that calculates a shortage of braking torque from a difference between the required pressure increase gradient and the target pressure increase gradient set by the target pressure increase gradient setting unit and calculates a required regeneration torque for compensating for the shortage. The control unit causes the hydraulic brake operation unit and the regeneration operation unit to cooperate with each other based on the target pressure increase gradient set by the target pressure increase gradient setting unit and the required regeneration torque calculated by the required regeneration torque calculation unit.

Advantages of the Invention

[0012] According to the present invention, the control unit sets a discomfort index indicating that a passenger feels discomfort with the operation sound volume from a difference between the operation sound volume propagated from the brake operation unit into the vehicle interior and the background noise level in the vehicle interior, sets a pressure increase gradient correction value for moderating the required pressure increase gradient based on the passenger discomfort index, corrects the required pressure increase gradient with the pressure increase gradient correction value to set a target pressure increase gradient, and calculates a required regeneration torque for compensating for a shortage of braking torque from a difference between the required pressure increase gradient and the target pressure increase gradient. Then, since the control unit causes the hydraulic brake operation unit and the regeneration operation unit to cooperate with each other based on the target pressure increase gradient and the required regeneration torque, it is possible to realize brake control excellent in both vibration and noise characteristics and responsiveness.

Brief Description of the Drawings

[0013]

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Embodiments for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The host vehicle M shown in FIG. 1 is an electric four-wheel drive vehicle, and includes a front motor generator (FM / G) 1 and a rear motor generator (RM / G) 2 as power sources. Further, the output shaft 1a of the FM / G 1 is connected to the drive shafts 3l and 3r of the front drive wheels Fl and Fr via a front differential (abbreviated as "front diff") Df. Furthermore, the output shaft 2a of the RM / G 2 is connected to the drive shafts 4l and 4r of the rear drive wheels Rl and Rr via a rear differential (abbreviated as "rear diff") Dr.

[0015] The FM / G1 and RM / G2 are connected to the battery 6 via the inverter 5. The inverter 5 converts the DC power from the battery 6 into AC power to drive the FM / G1 and RM / G2, causing the front drive wheels Fl, Fr and the rear drive wheels Rl, Rr to generate tractive force. Also, when decelerating, the inverter 5 causes the FM / G1 and RM / G2 to function as generators, converting the AC power regenerated by the FM / G1 and RM / G2 into DC power to charge the inverter 5. Therefore, the inverter 5 has the function as the regenerative operation unit of the present invention.

[0016] When FM / G1 functions as a generator, a regenerative braking force due to regenerative braking is applied to the front drive wheels Fl, Fr. Similarly, when RM / G2 functions as a generator, a regenerative braking force due to regenerative braking is applied to the rear drive wheels Rl, Rr.

[0017] Also, hydraulic brake mechanisms 7 are respectively provided for the front drive wheels Fl, Fr and the rear drive wheels Rl, Rr. Each hydraulic brake mechanism 7 is a well-known friction brake device such as a disc brake or a drum brake, and the piston of the wheel cylinder is actuated by the brake hydraulic pressure supplied from a hydraulic control unit (HCU) 8 serving as a hydraulic brake operation unit to apply a hydraulic braking (friction braking) force.

[0018] The HCU 8 includes a hydraulic pressure generating device composed of a pressure boosting pump, an accumulator, etc., a pressure regulating control valve that adjusts the hydraulic pressure during braking and supplies it to the wheel cylinder of each hydraulic brake mechanism 7, and an on-off control valve that opens and closes the hydraulic circuit that supplies the brake hydraulic pressure to each hydraulic brake mechanism 7, as well as other actuators and valves.

[0019] The above-described inverter 5 and HCU 8 are operated by control signals from a control unit 11 serving as a control section. It should be noted that the brake control device of the present invention functions with the FM / G1, RM / G2, INV5, hydraulic brake mechanism 7, HCU8, and control unit 11.

[0020] This control unit 11 is composed of a microcontroller including a CPU, a RAM, a ROM, a rewritable non-volatile memory (flash memory or EEPROM), and peripheral devices. Programs and fixed data necessary for the CPU to execute each process are stored in the ROM. Also, the RAM is provided as a work area for the CPU, and various data in the CPU are temporarily stored. Note that the CPU is also called an MPU (Microprocessor) or a processor. Alternatively, a GPU (Graphics Processing Unit) or a GSP (Graph Streaming Processor) may be used instead of the CPU. Or, the CPU, GPU, and GSP may be selectively combined and used.

[0021] Furthermore, the control unit 11 acquires from the inverter 5 the current values, voltage values flowing through each of the FM / G1 and RM / G2, and detection signals from various sensors necessary for controlling both the FM / G1 and RM / G2. Also, the control unit 11 obtains the required driving force or required braking force necessary for controlling the running or braking of the host vehicle M based on the detection signals from the various sensors described above. Then, based on the required braking force, a regeneration cooperative braking control is performed by outputting a regeneration brake signal and a hydraulic brake signal to the inverter 5 and the HCU8, respectively.

[0022] Examples of the automatic braking control executed by the control unit 11 include VDC control, torque vectoring control, and AVH control. When these automatic braking controls are executed in the control unit 11, noises (vibrations) such as noises and NV caused by the operation of the boost pump provided in the HCU8 and the operation of the actuator and valve occur. In particular, in the host vehicle M using each of the FM / G1 and RM / G2 as a drive source, since the level of the background noise (background vibration) in the vehicle interior is low, the noise (vibration) associated with the operation of the HCU8 relatively gives discomfort to the occupants.

[0023] Therefore, the control unit 11 calculates the discomfort index received by the occupant from the difference between the operating volume of the HCU 8 during hydraulic braking (frictional braking) and the background noise (background vibration) level at that time, suppresses the pressure increase gradient (pressure increase speed) of the hydraulic brake according to this discomfort index, and compensates for the shortage with the regenerative braking force. Note that a microphone 12 for detecting the noise level in the vehicle interior is connected to the control unit 11.

[0024] The regenerative cooperative brake control executed by this control unit 11 is executed according to the regenerative cooperative brake control routine shown in FIG. 2. This routine is repeatedly executed at a predetermined calculation cycle when the system is started. First, in step S1, it is checked whether there is a brake control instruction from the automatic brake control system that executes VDC control, torque vectoring control, AVH control, etc. If there is no brake control instruction, the routine is exited as it is.

[0025] On the other hand, when it is determined that the behavior of the host vehicle M is unstable during curve driving and it is determined that a brake control instruction is output from the automatic brake control system, the process proceeds to step S2 to check whether the remaining charge [%] of the battery 6 is below the specified value. This remaining charge is estimated, for example, from the detection value of a SOC sensor (not shown) that detects the state of charge (SOC) of the battery 6. The specified value is a value for determining whether the battery 6 can be charged by regenerative power generation by FM / G1 and RM / G2, and is set to about 70 - 80 [%], for example.

[0026] If the remaining charge exceeds the preset value, it is determined that sufficient regenerative braking cannot be obtained, and the routine is exited. If the remaining charge is below the specified value, it is determined that regeneration is possible, the process proceeds to step S3 to set the target pressure increase gradient, and the process proceeds to step S4 to set the regenerative cooperative control amount and then the routine is exited.

[0027] The process in step S3 is executed according to the target boost gradient setting subroutine shown in FIG. 3. In this subroutine, first, in step S11, the required value (required boost gradient) of the boost gradient of the brake fluid pressure at the start of braking and the required brake fluid pressure (required pressure) set in the automatic brake control system are read. As shown in FIG. 5, the maximum value (high) and the minimum value (low) are set for the boost gradient, and the maximum value (high) and the minimum value (low) are also set for the required pressure. Therefore, the brake fluid pressure is set to any value within the region surrounded by the line from the maximum value of the boost gradient to the maximum value of the required pressure and the line from the minimum value of the boost gradient to the minimum value of the required pressure.

[0028] Next, proceed to step S12, and based on the required boost gradient and the required pressure set in the brake control system, estimate the operating volume of the HCU8 with reference to the operating volume estimation map. FIG. 6 shows the concept of the operating volume estimation map. This map uses the required boost gradient and the required pressure as parameters, and the operating volume propagated into the vehicle interior of the HCU8 is obtained for each vehicle type in advance through experiments, simulations, etc., and is stored as fixed data in a non-volatile memory or the like. In this map, as the required boost gradient and the required pressure increase, a large operating volume value propagated into the vehicle interior is set. Note that the process in this step S12 corresponds to the operating volume estimation unit of the present invention.

[0029] Thereafter, proceed to step S13, and based on the required boost gradient and the required pressure, set the emergency level [%] during the operation of the brake control system with reference to the emergency level map. FIG. 7 shows the concept of the emergency level estimation map. This map uses the required boost gradient and the required pressure as parameters, and the emergency level [%] of the brake control is obtained in advance through experiments, simulations, etc., and is stored as fixed data in a non-volatile memory or the like. In this map, as the required boost gradient is a steep gradient and the required pressure increases, the emergency level is set higher.

[0030] Therefore, for example, when the host vehicle M has a tendency to oversteer or understeer when entering a high-speed curve road and the VDC control is activated to eliminate unstable behavior, the required pressure increase gradient is steep and the required hydraulic pressure is large, so the urgency is estimated to be high. On the other hand, in the braking control in the deceleration section before the intersection associated with a red signal or the like or the braking control during following driving, the required pressure increase gradient is gentle and the required hydraulic pressure is small, so the urgency is estimated to be low. Note that the processing in this step S13 corresponds to the urgency setting unit of the present invention.

[0031] Also, when proceeding to step S14, the in-vehicle noise detected by the microphone 12 installed in the vehicle interior is read, and the in-vehicle background noise (in-vehicle background noise) level is estimated. Here, the background noise refers to the noise in the vehicle interior excluding the target operating sound, and the target in this embodiment is the operating sound from the HCU8. Examples of the in-vehicle background noise include wind noise, road noise, air conditioner blowing sound, output sound from the audio speaker, wiping sound due to wiper operation, and conversations of passengers. If this in-vehicle background noise level becomes low, the operating sound from the HCU8 relatively becomes an annoying unpleasant sound. Therefore, for example, by installing the microphone 12 near the headrest of the seat where the driver is seated, the in-vehicle background noise level can be estimated more accurately. Note that the processing in this step S14 corresponds to the background noise level estimation unit of the present invention.

[0032] Next, proceed to step S15. Based on the difference between the operating sound from the HCU8 (HCU operating volume) estimated in step S12 and the ambient noise level estimated in step S14, refer to the discomfort index table to estimate the discomfort index (occupant discomfort index) given to the occupant. Fig. 8 shows the concept of the discomfort index table. In this table, the difference between the HCU operating volume and the ambient noise level is shown on the horizontal axis, and the occupant discomfort index is shown on the vertical axis. Incidentally, in this table, the occupant discomfort index is shown in 9 levels from 0 to 8, and when (HCU operating volume - ambient noise level) ≤ inaudible level (for example, about 10 [dB]), all discomfort indices are set to 0. Also, a discomfort index of less than 1 to 2 means the HCU operating sound can be heard but is not bothersome, a discomfort index of less than 2 to 4 means the HCU operating sound is somewhat bothersome, and a discomfort index of 4 to 8 is set to a level where the HCU operating sound is very bothersome. Note that the processing in this step S15 corresponds to the occupant discomfort index setting unit of the present invention.

[0033] Thereafter, when proceeding to step S16, based on the urgency estimated in step S13 and the occupant discomfort index set in step S15, set the boost gradient correction rate [%] as the boost gradient correction value by referring to the boost gradient correction rate map. Fig. 9 shows the concept of the boost gradient correction rate map. This map sets the ratio of how much the brake hydraulic pressure can be replaced with regenerative braking force using the urgency and the occupant discomfort index as parameters, and is a fixed value obtained in advance from experiments, simulations, etc. and stored in a non-volatile memory or the like. Note that the processing in this step S16 corresponds to the boost gradient correction value setting unit of the present invention.

[0034] The boost gradient correction rate is set to a smaller ratio as the urgency is higher and the occupant discomfort index is higher. That is, in the automatic brake control system, the urgency is prioritized even if the occupant discomfort index is high. Also, this boost gradient correction rate is set to a small value when the urgency is low and the occupant discomfort index is low. Furthermore, in the region where both the urgency and the discomfort index gradually increase, the boost gradient correction rate is set to 0 [%], that is, no correction.

[0035] In this embodiment, the boost gradient correction rate is set in three levels, large, medium, and small, according to the degree of relaxation in response to the urgency and the passenger discomfort index, but it is not limited to this. Incidentally, although it is set to about large = 60 [%], medium = 40 [%], and small = 20 [%], this is not limiting either, and it can be set as appropriate. Therefore, for example, when performing automatic braking control in a deceleration section in front of a traffic signal, if the urgency is low and the vehicle interior is quiet and the background noise level is low, the boost gradient correction rate is set small. On the other hand, when the VDC control is activated when the host vehicle M enters a high-speed curve as described above, since the urgency is high, the passenger gradient correction rate becomes 0 [%] regardless of the passenger discomfort index. As the boost gradient correction value, in addition to the boost gradient correction rate, a correction coefficient, a correction gain, or a correction amount may be used.

[0036] After that, when proceeding to step S17, the required boost gradient is corrected by the boost gradient correction rate to set the target boost gradient, and then proceed to step S4 in FIG. 2.

[0037] That is, when the required boost gradient is ΔPi [Pa / s] and the boost gradient correction rate is kp [%], the target boost gradient Pt [Pa / s] is Pt←(1-kp / 100)·ΔPi This processing in step S17 corresponds to the target boost gradient setting unit of the present invention.

[0038] Then, proceed to step S18, and output a drive signal corresponding to this target boost gradient Pt to the HCU8. Then, the HCU8 boosts the brake hydraulic pressure until it reaches the required hydraulic pressure Ph at the target boost gradient Pt. As a result, this brake hydraulic pressure is supplied to the hydraulic brake mechanism 7, and each drive wheel Fl, Fr, Rl, Rr is braked by frictional braking.

[0039] Next, when proceeding to step S4 in FIG. 2, the regenerative cooperative control amount is set. The setting of this regenerative control amount is executed in the regenerative cooperative control amount setting subroutine shown in FIG. 4. In this subroutine, first, in step S21, the required pressure increase gradient ΔPi and the required hydraulic pressure Ph set in the automatic brake control system, and the target pressure increase gradient ΔPt set in step S17 of FIG. 3 are read. Then, until the target pressure increase gradient ΔPt reaches the required hydraulic pressure Ph, the difference between the required pressure increase gradient ΔPi and the target pressure increase gradient ΔPt, and after the required pressure increase gradient ΔPi reaches the required hydraulic pressure Ph, the braking torque shortage in the area hatched in FIG. 10 is calculated from the difference between this required hydraulic pressure Ph and the target pressure increase gradient ΔPt. In this case, the characteristics of the braking torque with respect to the brake hydraulic pressure are stored in the non-volatile memory in advance. Therefore, the shortage of braking torque can be set based on the braking torque characteristics from the difference between the required pressure increase gradient ΔPi or the required hydraulic pressure Ph and the target pressure increase gradient ΔPt.

[0040] Next, proceed to step S22 to calculate the required regenerative torque for compensating the shortage of the braking torque. Note that since this required regenerative torque is calculated for each operation cycle, as a result, the required regenerative torque is increased at a predetermined torque gradient until the required hydraulic pressure is reached. Note that the processes in steps S21 and S22 correspond to the required regenerative torque calculation unit of the present invention.

[0041] Thereafter, proceed to step S23, output the current command value for obtaining the required regenerative torque to the inverter 5, and exit the routine. The inverter 5 regeneratively operates the FM / G1 and RM / G2 based on the current command value from the control unit 11 to compensate for the shortage of the braking torque applied to each drive wheel Fl, Fr, Rl, Rr.

[0042] For example, as shown in FIG. 10, when both the required hydraulic pressure and the urgency during the operation of the HCU8 are low and the occupant discomfort index is high, the boost gradient correction rate increases, so that the target boost gradient becomes gentler than the required boost gradient. As a result, the hatched area in the figure becomes the area of the required regenerative torque for compensating for the shortage of the braking torque. Thereby, the operating volume of the HCU8 is suppressed, and the discomfort given to the occupant can be reduced. After the required regenerative torque reaches the required hydraulic pressure, the required regenerative torque is relatively decreased until the brake hydraulic pressure reaches the required hydraulic pressure.

[0043] As described above, when the automatic brake control system such as VDC operates in the control unit 11, the operating volume propagated from the HCU8 into the passenger compartment is estimated based on the required boost gradient and the required hydraulic pressure of the brake hydraulic pressure supplied from the HCU8. Then, based on the difference between this operating volume and the ambient noise level in the passenger compartment, a discomfort index (occupant discomfort index) indicating how much the occupant feels discomfort with the operating sound of the HCU8 is set. When the urgency of the automatic brake control system is low, the boost gradient correction rate is set according to the occupant discomfort index, and the required boost gradient of the brake hydraulic pressure is set low with this boost gradient correction rate, so that the operating volume propagated from the HCU8 into the passenger compartment is suppressed. As a result, good vibration and noise characteristics (quietness) can be obtained.

[0044] In addition, since the shortage of the braking torque due to the friction braking is compensated by the regenerative torque, no response delay occurs, and excellent brake controllability can be obtained. Further, when the urgency of the automatic brake control system is high, the boost gradient correction rate is set to 0 [%], and the friction braking by the brake hydraulic pressure is preferentially operated, so that high safety can be obtained.

[0045] Note that the present invention is not limited to the above-described embodiments. For example, the control unit 11 may be configured to directly control and operate an electric brake booster instead of the HCU8. The vehicle to be adopted may be a front-wheel drive vehicle or a rear-wheel drive vehicle. In this case, the regenerative cooperative control is performed on the drive wheel side.

Description of Reference Numerals

[0046] 1… Front motor generator, 2… Rear motor generator, 1a, 2a… Output shafts, 3l, 3r, 4l, 4r… Drive shafts, 5… Inverter, 6… Battery, 7… Hydraulic brake mechanism, 8… Hydraulic control unit (HCU), 11… Control unit, 12… Microphone, Fl, Fr… Front drive wheels, M… Own vehicle, Ph… Required hydraulic pressure, Pt… Target boost gradient, Rl, Rr… Rear drive wheels, ΔPi… Required boost gradient, ΔPt… Target boost gradient

Claims

1. A hydraulic brake operation unit that operates a hydraulic brake to apply a braking force to a vehicle, a regeneration operation unit that performs a regeneration operation of a motor generator to apply a braking force to the vehicle, and a control unit that causes the hydraulic brake operation unit and the regeneration operation unit to cooperate with each other In a brake control device for a vehicle comprising: The control unit is an operation sound volume estimation unit that estimates an operation sound volume propagated from the hydraulic brake operation unit into the vehicle interior based on a required pressure increase gradient and a required hydraulic pressure when the hydraulic brake operation unit operates the hydraulic brake; a background noise level estimation unit that estimates a background noise level in the vehicle interior; an occupant discomfort index setting unit that sets an occupant discomfort index based on a difference between the operation sound volume estimated by the operation sound volume estimation unit and the background noise level estimated by the background noise level estimation unit, and at which an occupant feels discomfort with the operation sound volume; a pressure increase gradient correction value setting unit that sets a pressure increase gradient correction value for moderating the required pressure increase gradient based on the occupant discomfort index set by the occupant discomfort index setting unit; a target pressure increase gradient setting unit that corrects the required pressure increase gradient with the pressure increase gradient correction value set by the pressure increase gradient correction value setting unit to set a target pressure increase gradient; a required regeneration torque calculation unit that calculates a shortage of braking torque from a difference between the required pressure increase gradient and the target pressure increase gradient set by the target pressure increase gradient setting unit, and calculates a required regeneration torque for compensating for the shortage; and the control unit causes the hydraulic brake operation unit and the regeneration operation unit to cooperate with each other based on the target pressure increase gradient set by the target pressure increase gradient setting unit and the required regeneration torque calculated by the required regeneration torque calculation unit. A brake control device for a vehicle, characterized in that.

2. The control unit further includes an emergency level setting unit that estimates an emergency level of a brake operation based on the required hydraulic pressure and the required pressure increase gradient, and the pressure increase gradient correction value setting unit sets the pressure increase gradient correction value based on the emergency level set by the emergency level setting unit and the occupant discomfort index set by the occupant discomfort index setting unit. A brake control device for a vehicle according to claim 1, characterized in that.

3. The emergency level set by the emergency level setting unit is set higher as the required hydraulic pressure is higher and the required pressure increase gradient becomes steeper. A brake control device for a vehicle according to claim 2, characterized in that.

4. The occupant discomfort index setting unit sets the occupant discomfort index higher as the ambient noise level estimated by the ambient noise level estimating unit becomes lower than the operating noise level estimated by the operating noise level estimating unit. The brake control device for a vehicle according to any one of claims 1 to 3, characterized in that.

5. The required regenerative torque calculation unit calculates a shortage of braking torque from the difference between the required pressure increase gradient and the required hydraulic pressure and the target pressure increase gradient until the required hydraulic pressure is reached. The brake control device for a vehicle according to any one of claims 1 to 4, characterized in that.

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