JP2015217709A - Brake control system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce an energy loss required for hydraulic regeneration of an accumulator.SOLUTION: An accumulator pressure, which is accumulated in an accumulator 102, is so made that an M/C pressure,which is equal to or higher than a W/C pressure usually used, is generated, and an M/C pressure, which is lower than a maximum pressure required as a W/C pressure, is generated. When a required W/C pressure is not generated in an M/C pressure generated by pressurizing assistance of an accumulator pressure, the W/C pressure is increased by an actuator 50 for brake fluid pressure control. Thus, an energy loss required for hydraulic regeneration of the accumulator 102 can be reduced, thereby improving an energy-saving effect.

Description

  The present invention relates to a vehicle brake device (hereinafter simply referred to as a brake device) having a hydro booster.

  2. Description of the Related Art Conventionally, for example, as disclosed in Patent Document 1, there is a brake device having a hydro booster that assists in pressurization of an operating force of a brake pedal. In this type of brake device, an auxiliary pressurizing source that generates brake fluid pressure to be applied to the hydro booster by accumulating brake fluid pressure within a predetermined pressure range in an accumulator (ACC) is provided. Specifically, a brake device having a hydro booster includes a pressure sensor, a motor, and a pump in addition to an accumulator as an auxiliary pressure source. Then, pressure is detected by a pressure sensor so that the brake fluid pressure stored in the accumulator (hereinafter referred to as accumulator pressure) falls within a predetermined pressure range, and when the accumulator pressure is low, the brake fluid generated by the pump is driven by driving the motor. The suction / discharge operation is performed.

  In a brake device having such a hydro booster, a master pressure is generated by pushing a master piston built in a master cylinder (hereinafter referred to as M / C) based on the accumulator pressure. Then, the braking force is generated by transmitting the M / C pressure to the wheel cylinder (hereinafter referred to as W / C) as the W / C pressure. At this time, the accumulation target pressure of the accumulator pressure is set to a value that can supply the maximum pressure required as the W / C pressure.

JP 2009-023553 A

  However, since the normal W / C pressure is lower than the maximum pressure required as the W / C pressure, the difference between the normal W / C pressure and the target value accumulated in the accumulator is large. There was an energy loss required for accumulating.

  That is, conventionally, an accumulator pressure that can generate a braking force larger than the braking force generated by the friction coefficient between the tire and the road surface has been guaranteed. Specifically, a high accumulator pressure is ensured so that a desired braking force can be generated even when the friction coefficient between the friction material and the brake rotor decreases. The friction coefficient between the friction material and the brake rotor is reduced under limited conditions such as during hydroplaning and heat fade. The setting of the accumulator pressure as described above is for guaranteeing the brake under such a limited condition, and no pressure assist is performed using the accumulator pressure during the normal friction coefficient. For this reason, it is an energy loss to always store a high accumulator pressure even during normal times.

  An object of this invention is to provide the brake device which has the hydro booster which can reduce the energy loss required for the pressure accumulation of an accumulator in view of the said point.

  In order to achieve the above object, in the first aspect of the present invention, the master cylinder pressure is determined based on the first pressure detecting means (S100) for detecting the accumulator pressure and the accumulator pressure detected by the first pressure detecting means. Pressure estimation means (S105) for estimating the maximum master cylinder pressure that is the maximum value generated, second pressure detection means (S110) for detecting the master cylinder pressure, and master cylinder pressure detected by the second pressure detection means Becomes a set value smaller than the maximum master cylinder pressure estimated by the pressure estimating means, the first motor driving means (S125) for starting rotation of the motor and the master cylinder pressure detected by the second pressure detecting means are pressure estimated. When the maximum master cylinder pressure estimated by the means is reached, the wheel cylinder is pressurized by the brake fluid pressure control actuator. That the pressure control means (S140), is characterized in that it comprises a.

  As described above, when the required W / C pressure cannot be generated by the M / C pressure generated by the pressure assist of the accumulator pressure, the brake hydraulic pressure control actuator increases the W / C pressure. ing. Therefore, even if the M / C pressure higher than the W / C pressure that is normally used is generated as the accumulator pressure accumulated in the accumulator, the M / C pressure smaller than the maximum pressure required as the W / C pressure is It can be generated. Thereby, it becomes possible to reduce the energy loss required for accumulator pressure accumulation, and the energy saving effect can be improved.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

It is the figure which showed schematic structure of the brake device 1 for vehicles concerning 1st Embodiment of this invention. It is a flowchart of the brake control which brake ECU70 performs. It is a flowchart of the brake control which brake ECU70 demonstrated in 2nd Embodiment of this invention performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments shown in the drawings will be described below. A brake device according to an embodiment of the present invention will be described. First, the basic configuration of the hydraulic circuit of the brake device according to the present embodiment will be described with reference to FIG. Here, an example in which the brake device according to the present invention is applied to a vehicle constituting a hydraulic circuit for front and rear piping will be described, but the present invention can also be applied to a vehicle such as an X piping.

  As shown in FIG. 1, a hydro booster 12 to which a brake hydraulic pressure from an auxiliary pressurizing source 100, which will be described later, is transmitted is connected to a brake pedal 11 as a brake operating member, and these are the sources of the brake hydraulic pressure. Is connected to the M / C 13. With this configuration, when the brake pedal 11 is operated, the operation force of the brake pedal 11 is assisted by the hydro booster 12 to generate a large M / C pressure exceeding the operation force of the brake pedal 11.

  Specifically, when the brake pedal 11 is depressed, the pressure boosting assistance by the hydro booster 12 is applied, and a master piston (not shown) disposed in the M / C 13 is pressed. Thereby, the same M / C pressure is generated in the primary chamber and the secondary chamber partitioned by the master piston. The M / C pressure is transmitted to each of the W / Cs 14, 15, 34, and 35 through the brake fluid pressure control actuator 50.

  The M / C 13 is provided with a master reservoir 13a having passages communicating with the primary chamber and the secondary chamber, and the brake fluid is supplied from the master reservoir 13a to the auxiliary pressurizing source 100. Further, excess brake fluid is returned from the hydro booster 12 to the master reservoir 13a. The brake pedal 11 is provided with a stroke sensor 11a, and the stroke sensor 11a can detect the operation amount of the brake pedal 11.

  The brake fluid pressure control actuator 50 has a first piping system 50a and a second piping system 50b, and is integrated by assembling various parts to an aluminum block (not shown). Yes. The first piping system 50a is a rear system that controls the brake fluid pressure applied to the left rear wheel RL and the right rear wheel RR, and the second piping system 50b is the brake fluid pressure that is applied to the left front wheel FL and the right front wheel FR. It is assumed to be a front system.

  In addition, since the basic composition of each system | strain 50a, 50b is the same, below, the 1st piping system 50a is demonstrated and description is abbreviate | omitted about the 2nd piping system 50b.

  The first piping system 50a transmits the M / C pressure described above to the W / C 14 provided in the left rear wheel RL and the W / C 15 provided in the right rear wheel RR, and generates a W / C pressure. A conduit A is provided.

  In addition, the pipe A is controlled to be in a communication state and a differential pressure state, so that the first pipe on the M / C 13 side on the upstream side and the W / C 14 on the 15th side on the downstream side are controlled. A first differential pressure control valve 16 that controls the differential pressure between the two pipes is provided. The first differential pressure control valve 16 is in a communicating state during normal braking when the driver operates the brake pedal 11 (when vehicle motion control such as collision avoidance control or skid prevention control is not executed). The valve position is adjusted. When a current flows through the solenoid coil provided in the first differential pressure control valve 16, the valve position is adjusted so that the larger the current value, the larger the differential pressure state.

  When the first differential pressure control valve 16 is in the differential pressure state, only when the brake fluid pressure on the W / C 14, 15 side is higher than the M / C pressure by a predetermined level or more, the M / Brake fluid flow to the C13 side is allowed. For this reason, the W / C 14, 15 side is always maintained so as not to be higher than the predetermined pressure by the M / C 13 side. Further, a check valve 16 a is provided in parallel with the first differential pressure control valve 16.

  The pipeline A branches into two pipelines A1 and A2 on the W / C 14 and 15 side downstream of the first differential pressure control valve 16. The pipeline A1 is provided with a first pressure increase control valve 17 that controls the increase of the brake fluid pressure to the W / C 14, and the pipeline A2 is a first pressure that controls the increase of the brake fluid pressure to the W / C 15. A two pressure increase control valve 18 is provided.

  The first and second pressure increase control valves 17 and 18 are constituted by two-position solenoid valves that can control the communication / blocking state. Specifically, the first and second pressure-increasing control valves 17 and 18 are in communication when the control current to the built-in solenoid coil is zero (when not energized), and the control current is supplied to the solenoid coil. It is a normally open type that is controlled to be in a shut-off state when a current is applied (when energized).

  In the pipeline A, the first and second pressure-increasing control valves 17 and 18 and the pipeline B serving as a pressure-reducing pipeline connecting the pressure regulating reservoirs 20 between the W / Cs 14 and 15 are controlled in communication / blocking states. The 1st pressure reduction control valve 21 and the 2nd pressure reduction control valve 22 which are comprised by the 2 position solenoid valve which can be each arrange | positioned. These first and second pressure reducing control valves 21 and 22 are cut off when the control current to the built-in solenoid coil is zero (when no power is supplied), and when the control current is passed through the solenoid coil ( It is a normally closed type that is controlled to be in a communicating state when energized.

  A conduit C serving as a reflux conduit is disposed between the pressure regulating reservoir 20 and a conduit A serving as a main conduit. The pipe C is provided with a self-priming pump 19 driven by a motor 60 that sucks and discharges brake fluid from the pressure regulating reservoir 20 toward the M / C 13 side or the W / C 14, 15 side. The pump 19 is constituted by a gear pump such as a trochoid pump that is superior in quietness compared to a piston pump, for example. The motor 60 is driven by controlling energization to a motor relay (not shown).

  A conduit D serving as an auxiliary conduit is provided between the pressure regulating reservoir 20 and the M / C 13. Brake fluid is sucked from the M / C 13 by the pump 19 through this pipe D, and discharged to the pipe A through the pipe C. Brake fluid is supplied, and the W / C pressure of the target wheel is increased.

  Further, the pipe E is provided with a pressure sensor 61 so that the M / C pressure can be detected.

  In addition, although the 1st piping system 50a was demonstrated here, the 2nd piping system 50b is also the same structure, The 2nd piping system 50b is also provided with the structure similar to each structure with which the 1st piping system 50a was equipped. Yes. Specifically, the second differential pressure control valve 36 and the check valve 36a corresponding to the first differential pressure control valve 16 and the check valve 16a, the third corresponding to the first and second pressure increase control valves 17 and 18, respectively. , Corresponding to the fourth pressure-increasing control valves 37, 38, the third and fourth pressure-reducing control valves 41, 42 corresponding to the first and second pressure-reducing control valves 21, 22, the pump 39 corresponding to the pump 19, and the reservoir 20. There are reservoirs 40, conduits E-H corresponding to conduits A-D. However, for the W / C 14, 15, 34, and 35 in which each system 50a, 50b supplies brake fluid, the capacity of the second piping system 50b serving as the front system is larger than that of the first piping system 50a serving as the rear system. There may be a difference. In the case of such a configuration, a larger braking force can be generated on the front side.

  Further, as shown in FIG. 1, the hydraulic circuit of the brake device according to the present embodiment includes an auxiliary pressurizing source 100 in addition to the brake hydraulic pressure control actuator 50. The auxiliary pressurization source 100 includes a hydraulic pump 101, an accumulator 102, an electric motor 103, a pressure sensor 104, a relief valve 105, and the like.

  The hydraulic pump 101 is provided in the pipe line I connecting the master reservoir 13a and the hydro booster 12, and is driven by the electric motor 103, and sucks and discharges the brake fluid in the master reservoir 13a. The brake fluid discharged from the hydraulic pump 101 is supplied to the accumulator 102. The hydraulic pump 101 is configured by a gear pump such as a trochoid pump, for example.

  An accumulator 102 is also provided in the pipeline I, and is disposed on the discharge side of the hydraulic pump 101 in the pipeline I, and accumulates brake fluid pressure based on the discharge of brake fluid by the hydraulic pump 101. The brake fluid pressure accumulated in the accumulator 102 corresponds to the accumulator pressure, and is transmitted to the hydro booster 12 as a brake fluid pressure for assisting in pressurizing the operation force of the brake pedal 11.

  The electric motor 103 is driven in response to the accumulator pressure falling below a predetermined lower limit value to increase the accumulator pressure, and is stopped in response to the accumulator pressure exceeding a predetermined upper limit value. Thereby, the accumulator pressure is maintained in a predetermined pressure range.

  The pressure sensor 104 is for monitoring the accumulator pressure, and is provided on the discharge side of the hydraulic pump 101 in the pipeline I. The electric motor 103 is driven based on the detection signal of the pressure sensor 104 so that the accumulator pressure detected by the pressure sensor 104 is always kept within a predetermined range.

  The relief valve 105 is provided in a pipeline J connecting the suction side and the discharge side of the hydraulic pump 101 in the pipeline I. The relief valve 105 maintains a shut-off state until the pressure difference between the brake fluid pressure on the discharge side and the brake fluid pressure on the suction side of the hydraulic pump 101 reaches a predetermined value, and is relieved when the predetermined value is reached. Therefore, the differential pressure should not exceed a predetermined value. This prevents the accumulator pressure from becoming too high.

  The hydraulic circuit of the brake device according to the present embodiment is configured by the structure as described above. Furthermore, the brake device according to the present embodiment includes an electronic control device (hereinafter referred to as a brake ECU) 70 for brake control for controlling the hydraulic circuit configured as described above. The brake ECU 70 receives detection signals from pressure sensors 61 and 104 and a wheel speed sensor (not shown), performs various calculations based on these signals, and controls the control valves 16 to 18, 21, 22, 36 to 38, 41, and 42. And the motor 60 are controlled. Thereby, the pressurization assistance of M / C pressure is performed, and the W / C pressure generated in W / C14, 15, 34, 35 of each wheel FL-RR is adjusted.

  Hereinafter, details of the control executed by the brake ECU 70 will be described. Note that the brake ECU 70 performs various vehicle motion controls (anti-lock brake control and side slip prevention control) for vehicle stabilization based on the wheel speed obtained from the detection signal of the wheel speed sensor and the estimated vehicle body speed obtained from the wheel speed. Etc.). However, since these controls are the same as those in the prior art, only the controls that characterize the present application will be described here.

  In the brake device according to the present embodiment, control is performed to reduce energy loss required for accumulating the accumulator 102. That is, the accumulator pressure to be accumulated in the accumulator 102 is set to a value lower than the maximum pressure required as the W / C pressure. When the W / C pressure equal to or higher than the M / C pressure generated by the assist of the accumulator pressure is required, the brake fluid pressure control actuator 50 is operated to operate the W / C 14, 15, 34, 35 can be pressurized.

  For example, by detecting the accumulator pressure accumulated in the accumulator 102 with the pressure sensor 104, the value at which the pressurizing assist force by the hydro booster 12 is maximized can be found. Therefore, the maximum M / C pressure that can be generated is calculated from the value, and when the measured value of the M / C pressure by the pressure sensor 61, that is, the W / C pressure at that time approaches the maximum M / C pressure, the brake The hydraulic pressure control actuator 50 is controlled to pressurize the W / Cs 14, 15, 34, and 35. Specifically, a differential pressure instruction to the first and second differential pressure control valves 16 and 36, that is, a current having a magnitude corresponding to the generated differential pressure is supplied, and the motor 60 is driven to drive the pumps 19 and 39. To increase the W / C pressure by pump pressurization. In this way, even when the hydraulic pressure equal to or higher than the maximum M / C pressure is required as the W / C pressure, the W / C pressure can be increased by pump pressurization in the region where the maximum M / C pressure is exceeded. You can

  Regarding the rotation instruction of the motor 60 at this time, for example, the rotation is started when the M / C pressure becomes higher than the W / C pressure (for example, 0.3 G) that is normally used. The motor 60 is rotated before reaching the M / C pressure. As described above, the rotation instruction to the motor 60 is issued before the differential pressure instruction to the first and second differential pressure control valves 16 and 36, so that the response delay of pressurization can be suppressed.

  Specifically, the brake ECU 70 performs the above-described control by performing an operation based on a flowchart at the time of brake control shown in FIG. Note that the various processes shown in the flowchart of FIG. 2 are executed at predetermined control cycles during brake operation.

  First, in step 100, the accumulator pressure is measured. That is, the detection signal of the pressure sensor 104 is input, and the accumulator pressure is measured from this detection signal. Then, it progresses to step 105 and estimates the maximum M / C pressure. The maximum M / C pressure is the maximum pressure of the M / C pressure obtained when the accumulator pressure generated at that time is used as auxiliary pressure, and is a value determined by the specifications of the hydro booster 12 and the like. From this, it can be estimated from the accumulator pressure measured in step 100.

  Next, the process proceeds to step 110, and the actually generated M / C pressure is measured. That is, the detection signal of the pressure sensor 61 is input, and the M / C pressure is measured from this detection signal. In step 115, the brake operation amount is measured. Specifically, the detection signal of the stroke sensor 11a is input, and the pedal stroke is measured as a brake operation amount.

  Then, the routine proceeds to step 120, where it is determined whether or not the M / C pressure is higher than a predetermined set pressure. The set pressure here is a hydraulic pressure that is a threshold value of the M / C pressure for instructing the rotation of the motor 60, and is set to a value smaller than the maximum M / C pressure so that a response delay in pressurization can be suppressed. ing. If the determination is affirmative, the routine proceeds to step 125. If the determination is negative, it is not necessary to pressurize the W / C 14, 15, 34, 35 using the brake fluid pressure control actuator 50. Return to step 100.

  In step 125, the motor rotation start is instructed. That is, the motor 60 is driven by energizing the motor 60 by energizing the motor relay that controls the energization of the motor 60.

  Thereafter, the process proceeds to step 130, where the target pressure of the W / C pressure (hereinafter referred to as the W / C target pressure) is set from the pedal stroke that is the brake operation amount measured in step 115. The relationship of the W / C target pressure with respect to the pedal stroke is predetermined as a desired brake characteristic, and is stored as a map or an arithmetic expression. For this reason, the W / C target pressure corresponding to the pedal stroke is derived from a map or an arithmetic expression.

  Then, the process proceeds to step 135, where it is determined whether or not the M / C pressure measured in step 110 is equal to or greater than the maximum M / C pressure. If the determination is affirmative, the process proceeds to step 140 and the first and second differential pressure controls. A differential pressure instruction for the valves 16 and 36 is issued, and a differential pressure is generated by the first and second differential pressure control valves 16 and 36. At this time, supply to the first and second differential pressure control valves 16 and 36 so as to generate a differential pressure corresponding to the M / C pressure (= maximum M / C pressure) subtracted from the W / C target pressure. The current is controlled. As a result, the W / C pressure is increased from the M / C pressure by the brake fluid discharged from the pumps 19 and 39 based on the drive of the motor 60, and the M / C pressure has reached the maximum M / C pressure. Even in this case, it becomes possible to generate the W / C pressure more than that.

  As described above, in this embodiment, although the M / C pressure higher than the W / C pressure that normally uses the accumulator pressure accumulated in the accumulator 102 is generated, it is required as the W / C pressure. An M / C pressure smaller than the maximum pressure is generated. Then, when the required W / C pressure cannot be generated by the M / C pressure generated by the pressure assist of the accumulator pressure, the brake hydraulic pressure control actuator 50 increases the W / C pressure. Yes. Therefore, the energy loss required for accumulating the accumulator 102 can be reduced, and the energy saving effect can be improved.

  In addition, the rotation of the motor 60 is started when the M / C pressure becomes higher than the W / C pressure normally used, and the motor 60 is rotated before the M / C pressure reaches the maximum M / C pressure. The situation is assumed. Thereby, it becomes possible to instruct the rotation of the motor 60 before instructing the differential pressure to the first and second differential pressure control valves 16 and 36, and the response delay of pressurization can be suppressed.

  Further, when the W / C pressure is increased, the pumps 19 and 39 are driven at a pressure higher than the normally used W / C pressure, and the frequency of use increases. For this reason, it is preferable that the pumps 19 and 39 are constituted by a gear pump excellent in silence as in this embodiment.

(Second Embodiment)
A second embodiment of the present invention will be described. This embodiment can cope with the case where the accumulator 102 has insufficient pressure compared to the first embodiment, and the other aspects are the same as those of the first embodiment. Only the different parts will be described.

  As described above, since the accumulator pressure is always detected in the brake device, it is possible to detect that the accumulated pressure in the accumulator 102 is insufficient. Therefore, even when the accumulator 102 has insufficient pressure accumulation, a desired W / C pressure is generated by applying pressure on the brake hydraulic pressure control actuator 50 side.

  Specifically, the brake ECU 70 performs an operation based on the flowchart at the time of brake control shown in FIG. 3, so that in addition to the control described in the first embodiment, control when the accumulated pressure of the accumulator 102 is insufficient. Is also going.

  First, in step 100, the accumulator pressure is measured as in step 100 of FIG. Then, the process proceeds to step 145, and it is determined whether or not the accumulator pressure measured in step 100 is within a set range. The setting range here indicates that the pressure is sufficient as the accumulator pressure, that is, the pressure that can generate the M / C pressure necessary to generate the normally used W / C pressure. If the accumulator pressure is within the set range, the normally used W / C pressure can be generated. Therefore, in steps 105 to 140, the same control as in the first embodiment is performed. If a negative determination is made in step 145, the processing after step 150 is performed.

  Basically, the motor rotation start is instructed in step 150, the M / C pressure is measured in step 155, the brake operation amount is measured in step 160, and the W / C target pressure is set in step 165. Each of these processes is performed in the same manner as steps 125, 115, and 130 described above. Then, the process proceeds to step 170, where a differential pressure instruction for the first and second differential pressure control valves 16 and 36 is issued as a differential pressure based on the M / C pressure measured in step 155, and the first and second differential pressure controls are performed. A differential pressure is generated by the valves 16 and 36. Thus, the W / C pressure is increased above the M / C pressure by the brake fluid discharged from the pumps 19 and 39 based on the drive of the motor 60. Accordingly, since the accumulator pressure is insufficient, even when only an insufficient M / C pressure is generated, the W / C pressure can be generated more than that.

  As described above, when the accumulator pressure is insufficient, a motor rotation instruction is issued regardless of whether the M / C pressure is higher than the set pressure, and the M / C pressure is set to the maximum M / C pressure. Even if not, the first and second differential pressure control valves 16 and 36 generate a differential pressure. As a result, a desired W / C pressure can be generated even when the accumulator pressure is insufficient, such as when the accumulator 102 fails.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in the above-described embodiment, the pedal stroke is used as the brake operation amount, but a pedaling force or an M / C pressure applied to the brake pedal 11 can be used. In the above embodiment, a gear pump is described as an example of the hydraulic pumps 19 and 39. However, other pumps such as a piston pump may be used if quietness is not taken into consideration.

  The steps shown in each figure correspond to means for executing various processes. That is, the part that executes the process of step 100 is the first pressure detecting means, the part that executes the process of step 105 is the pressure estimating means, the part that executes the process of step 110 is the second pressure detecting means, and the process of step 125 is executed. The portion to be executed corresponds to the first motor driving means. Further, the part that executes the process of step 130 corresponds to the target pressure setting means, the part that executes the process of step 140 corresponds to the pressurizing control means, and the part that executes the process of step 150 corresponds to the second motor driving means.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle brake device, 11 ... Brake pedal, 11a ... Stroke sensor, 12 ... Hydro booster, 13 ... M / C, 14, 15, 34, 35 ... W / C, 16, 36 ... First, second difference Pressure control valve, 19, 39 ... Pump, 50 ... Brake hydraulic pressure control actuator, 60 ... Motor, 70 ... Brake ECU, 80 ... M / C pressure sensor, 100 ... Auxiliary pressurization source

Claims (5)

A brake operating member (11) operated by a driver;
A hydro booster (12) for assisting in pressurizing the operating force of the brake operating member;
A master cylinder (13) for generating a master cylinder pressure according to the operating force of the brake operating member based on the pressurization assistance by the hydro booster;
A wheel cylinder (14, 15, 34, 35) for generating a braking force based on the master cylinder pressure;
From the main pipeline (A, E) connecting the master cylinder and the wheel cylinder, a differential pressure control valve (16, 36) for controlling the differential pressure between the master cylinder and the wheel cylinder, and the master cylinder A pump (19, 39) for sucking brake fluid and discharging it to the wheel cylinder side of the differential pressure control valve in the main line; and a motor (60) for driving the pump; A brake fluid pressure control actuator (50) for controlling the wheel cylinder pressure applied to
An accumulator pressure is accumulated in the accumulator (102) by driving the hydraulic pump (101), and an auxiliary pressurizing source for transmitting the accumulator pressure to the hydrobooster in order to assist the pressurization by the hydrobooster. 100), and a brake device comprising:
First pressure detecting means (S100) for detecting the accumulator pressure;
Pressure estimating means (S105) for estimating a maximum master cylinder pressure that is a maximum value generated as the master cylinder pressure based on the accumulator pressure detected by the first pressure detecting means;
Second pressure detection means (S110) for detecting the master cylinder pressure;
First motor driving means for starting rotation of the motor when the master cylinder pressure detected by the second pressure detecting means becomes a set value smaller than the maximum master cylinder pressure estimated by the pressure estimating means (S125). When,
When the master cylinder pressure detected by the second pressure detection means reaches the maximum master cylinder pressure estimated by the pressure estimation means, the pressure control means pressurizes the wheel cylinder by the brake fluid pressure control actuator. (S140) and a vehicle brake device.   When the master cylinder pressure detected by the second pressure detecting means reaches the maximum master cylinder pressure estimated by the pressure estimating means, the pressurizing control means sets the differential pressure control valve to a differential pressure state. The vehicular brake device according to claim 1. A target pressure setting means (S130) for setting a target pressure of a wheel cylinder pressure to be generated in the wheel cylinder by the pressure control means based on an operation amount of the brake operation member;
The vehicular brake device according to claim 2, wherein the pressurization control means sets a differential pressure generated by the differential pressure control valve based on the target pressure set by the target pressure setting means. .   The target pressure setting means sets the target pressure as an operation amount of the brake operation member based on any one of a stroke amount, a load or the master cylinder pressure of the brake operation member. Item 4. The vehicle brake device according to Item 3. Determining means (S145) for determining whether or not the accumulator pressure detected by the first pressure detecting means is within a predetermined set range;
The said determination means has a 2nd motor drive means (S150) which starts rotation of the said motor, if the said accumulator pressure is not in the said setting range, The Claim 1 thru | or 4 characterized by the above-mentioned. The brake device for vehicles as described in any one.

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