JP2019031177A - Brake control device for vehicle - Google Patents

Abstract

To provide a brake control device that improves boosting responsiveness by using a simulator and that has improved reliability and is capable of restraining discomfort to a driver.SOLUTION: In a brake control device, liquid pressure of a pressure adjusting fluid passage is adjusted by an electric pump and a solenoid valve. The brake control device comprises: a simulator having a "reaction chamber connected to a master cylinder" and an "assistance chamber positioned on the opposite side of the reaction chamber with respect to a simulator piston" and imparting operational force; a separation unit having a "pressurization chamber connected to a wheel cylinder" and a "separation chamber positioned on the opposite side of the pressurization chamber with respect to a separation piston"; an assistance valve provided between the assistance chamber and the pressure adjusting fluid passage; and an open valve provided between the assistance chamber and a reservoir. When a braking operation is urgent, the assistance valve is put in an open position and the open valve is put in a closed position. When the braking operation is not urgent, the assistance valve is put in the closed position, and the open valve is put in the open position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a braking control device for a vehicle.

  Patent Document 1 discloses that a stroke simulator out is performed in accordance with the operation state of the driver's brake pedal (2) for the purpose of “improving the pressure response of the wheel cylinder while suppressing an increase in the size of the actuator”. The valve (24) is operated in the valve closing direction to pressurize the wheel cylinder (8) with the brake fluid flowing out from the stroke simulator (22), and the fluid in the wheel cylinder (8) or the first oil passage (11). When the pressure reaches a predetermined state, the stroke simulator out valve (24) is operated in the valve opening direction, and the brake fluid of the stroke simulator (22) is allowed to flow out to the low pressure portion while being limited to a predetermined flow rate. " Yes.

Further, Patent Document 1 describes the following.
(1) The discharge oil passages 16P and 16S constitute a communication passage that connects the first oil passages 11P and 11S to each other. The communication valve 26P is a normally closed electromagnetic valve (closed in a non-energized state) provided in the discharge oil passage 16P. The communication valve 26S is a normally closed electromagnetic valve provided in the discharge oil passage 16S. The pump 7 is connected to the wheel cylinders 8a to 8d via the communication passages (discharge oil passages 16P and 16S) and the first oil passages 11P and 11S, and brakes to the communication passages (discharge oil passages 16P and 16S). The wheel cylinder hydraulic pressure Pw can be increased by discharging the liquid.
(2) The third oil passage 13 is a first back pressure oil passage connecting the back pressure chamber R <b> 2 of the stroke simulator 22 and the first oil passage 11. Specifically, the third oil passage 13 branches from between the cut valve 21P and the solenoid-in valve 25 in the first oil passage 11P (oil passage 11B) and is connected to the back pressure chamber R2. The stroke simulator-in valve is a normally open solenoid valve (first simulator cut valve) provided in the third oil passage 13.
(3) When it is determined that the depression speed of the brake pedal 2 is fast), the auxiliary pressurization control can be executed. When the brake operation speed (pedal stroke speed ΔSp / Δt) is equal to or higher than a predetermined value α (a threshold value for determining start and end of auxiliary pressure control), it is determined that the predetermined sudden brake operation is being performed. The auxiliary pressurization control can be executed when the detected or estimated wheel cylinder hydraulic pressure Pw is equal to or lower than a predetermined value. When the detected or estimated wheel cylinder hydraulic pressure Pw is larger than the predetermined value Pw0, the normal wheel by the pump 7 is used. Execute cylinder pressurization control.

  In the apparatus of Patent Document 1, for example, a case where a fluid path failure occurs around the wheel cylinder 8a of the primary system is assumed. In this situation, when the auxiliary pressurization control (also referred to as “auxiliary control”) is executed, the brake fluid BF moved from the failure part to the pump 7 and the back pressure chamber R2 flows out of the apparatus. Is done. At this time, when the auxiliary control is executed, the piston 220 cannot be displaced any more (that is, full stroke). For this reason, the operation characteristics of the braking operation member BP (the relationship of the operation force Fp with respect to the operation displacement Sp) may change suddenly, and the driver may feel uncomfortable.

  Further, the normally closed communication valve 26P is set to the closed position so that the above-described failure portion is identified and the wheel cylinder hydraulic pressure Pw of the secondary system can be adjusted, and the discharge oil passage 16S and the third oil passage 13 The communication state is cut off. In this case, the auxiliary control cannot be executed even in the secondary system that can operate properly. Alternatively, the normally-open solenoid-in valve 25a can be set to the closed position based on the identification of the above-mentioned failure portion. In this case, since the brake fluid BF is continuously supplied from the pump 7, the fluid pressure in the back pressure chamber R2 is rapidly increased. As a result, the braking operation member BP is returned, which may cause discomfort to the driver.

  In the apparatus of Patent Document 1, it is assumed that a normally open type is adopted as the stroke simulator in valve 23, and the stroke simulator out valve 24 is fixed in the open position. In this situation, it is difficult to ensure the wheel cylinder hydraulic pressure in the primary system during manual braking.

JP 2009-137376 A

  In view of the above points, an object of the present invention is to improve the reliability of the vehicle and to suppress a sense of discomfort to the driver in a vehicle braking control device in which a stroke simulator is used to improve boosting response. Is to provide what can be done.

  A vehicle braking control device according to the present invention adjusts the hydraulic pressure (Pw) of a wheel cylinder (CW) provided on a vehicle wheel (WH), and includes an “electric pump (DC) and an electromagnetic valve. (UC), and a pressure regulating unit (KC) for adjusting the hydraulic pressure (Pc) of the pressure regulating fluid path (HC) between the electric pump (DC) and the electromagnetic valve (UC) ”, “The simulator cylinder (CX) and the simulator piston (PX) are composed of“ the reaction force chamber (Rf) connected to the master cylinder (CM) of the vehicle ”” and “the simulator piston (PX). On the other hand, a simulator (SS) having an assisting chamber (Rh) positioned on the opposite side of the reaction force chamber (Rf) and applying an operating force (Fp) to the braking operation member (BP) of the vehicle; , “Separation cylinder (CB) and minute It is composed of a piston (PB) and is connected to the “pressure chamber (Ra) connected to the wheel cylinder (CW)” and “the pressure regulating fluid path (HC) and connected to the separation piston (PB)”. On the other hand, a separation unit (KB) having a separation chamber (Rb) located on the opposite side of the pressurizing chamber (Ra) ”, the assisting chamber (Rh), and the pressure regulating fluid path (HC) An assisting valve (VA) provided in an assisting fluid path (HA) to be connected, an opening fluid path between the assisting chamber (Rh) and the assisting valve (VA), and connecting the reservoir (RV) of the vehicle An opening valve (VB) provided in (HB), an operation amount sensor (BA) for detecting an operation amount (Ba) of the braking operation member (BP), the assist valve (VA), and the opening valve ( And a controller (ECU) for controlling VB).

  In the vehicle braking control apparatus according to the present invention, the controller (ECU) determines whether or not the operation of the braking operation member (BP) is a sudden operation based on the operation amount (Ba). When the sudden operation is affirmed, the assist valve (VA) is set to the open position, and the open valve (VB) is set to the closed position. When the sudden operation is denied, the assist valve is set. The valve (VA) is set to the closed position, and the release valve (VB) is set to the open position.

  A vehicle braking control device according to the present invention adjusts the hydraulic pressure (Pw) of a wheel cylinder (CW) provided on a vehicle wheel (WH), and includes an “electric pump (DC) and an electromagnetic valve. (UC), and a pressure regulating unit (KC) for adjusting the hydraulic pressure (Pc) of the pressure regulating fluid path (HC) between the electric pump (DC) and the electromagnetic valve (UC) ”, “The simulator cylinder (CX) and the simulator piston (PX) are composed of“ the reaction force chamber (Rf) connected to the master cylinder (CM) of the vehicle ”” and “the simulator piston (PX). On the other hand, a simulator (SS) having an assisting chamber (Rh) positioned on the opposite side of the reaction force chamber (Rf) and applying an operating force (Fp) to the braking operation member (BP) of the vehicle; , “Separation cylinder (CB) and minute It is composed of a piston (PB) and is connected to the “pressure chamber (Ra) connected to the wheel cylinder (CW)” and “the pressure regulating fluid path (HC) and connected to the separation piston (PB)”. On the other hand, a separation unit (KB) having a separation chamber (Rb) located on the opposite side of the pressurizing chamber (Ra) ”,“ the assisting chamber (Rh), and the pressure regulating fluid path (HC) ” Is provided in the assisting fluid passage (HA) for connecting the brake fluid (BF) from the assisting chamber (Rh) to the pressure regulating fluid passage (HC), but the pressure regulating fluid passage (HC) A check valve (GA) that prevents movement of the brake fluid (BF) from the support chamber (Rh) to the assist chamber (Rh), between the assist chamber (Rh) and the check valve (GA), and An open valve (VB) provided in an open fluid path (HB) for connecting a reservoir (RV) of the vehicle; Comprising operating amount of the brake operating member (BP) and (Ba) operation amount sensor for detecting (BA), and a controller for controlling the open valve (VB) (ECU), a.

  In the vehicle braking control apparatus according to the present invention, the controller (ECU) determines whether or not the operation of the braking operation member (BP) is a sudden operation based on the operation amount (Ba). When the sudden operation is affirmed, the release valve (VB) is set to the closed position, and when the sudden operation is denied, the release valve (VB) is set to the open position. .

  The separation unit KB fluidically separates the pressure regulating unit KC and the wheel cylinder CW so that the brake fluid BF is not moved between the pressure regulating unit KC and the wheel cylinder CW. According to the above configuration, even when the fluid path is damaged, the amount of the brake fluid BF that flows out of the device is limited to the maximum discharge amount mb or less, and the fail-safe property of the brake control device SC can be improved. .

  The maximum discharge amount mb of the separation unit KB is extremely large with respect to the amount required for the increase of the adjustment hydraulic pressure Pc in the discharge amount when the electric pump DC is started. The compensation control is terminated before the discharge amount of the electric pump DC reaches the maximum discharge amount mb. Therefore, even when the on / off type release valve VB is instantaneously switched from the closed position to the open position at the end of the compensation control, the influence on the operation characteristics of the braking operation member BP is small. The auxiliary control can ensure responsiveness and reduce discomfort to the driver.

1 is an overall configuration diagram for explaining a first embodiment of a vehicle braking control device SC according to the present invention. It is the schematic for demonstrating the structure of the separation unit KB. It is the schematic for demonstrating the structure of the stroke simulator SS. It is a control flowchart for demonstrating the arithmetic processing of pressure regulation control. FIG. 5 is a hydraulic circuit diagram for explaining a second embodiment of the vehicle braking control device SC according to the present invention.

<Symbols of components, subscripts at the end of symbols>
In the following description, components, arithmetic processing, signals, characteristics, and values having the same symbol, such as “ECU”, have the same function. The subscripts “i” to “l” attached to the end of various symbols are generic symbols indicating which wheel the wheel is associated with. Specifically, “i” indicates a right front wheel, “j” indicates a left front wheel, “k” indicates a right rear wheel, and “l” indicates a left rear wheel. For example, in each of the four wheel cylinders, they are expressed as a right front wheel wheel cylinder CWi, a left front wheel wheel cylinder CWj, a right rear wheel wheel cylinder CWk, and a left rear wheel wheel cylinder CWl. Further, the suffixes “i” to “l” at the end of the symbol can be omitted. When the subscripts “i” to “l” are omitted, each symbol represents a generic name of each of the four wheels. For example, “WH” represents each wheel, and “CW” represents each wheel cylinder.

  The subscripts “1” and “2” attached to the end of various symbols are comprehensive symbols indicating which system the two braking systems are related to. Specifically, “1” indicates the first system and “2” indicates the second system. For example, in two master cylinder fluid paths, they are denoted as a first master cylinder fluid path HM1 and a second master cylinder fluid path HM2. Further, the suffixes “1” and “2” at the end of the symbol can be omitted. When the subscripts “1” and “2” are omitted, each symbol represents a generic name of the two braking systems. For example, “VM” represents a master cylinder valve of each braking system.

<First Embodiment of Brake Control Device for Vehicle according to the Present Invention>
A first embodiment of a braking control device SC according to the present invention will be described with reference to the overall configuration diagram of FIG. In general vehicles, two fluid paths are employed to ensure redundancy. Here, the fluid path is a path for moving the brake fluid BF, which is the working fluid of the brake control device, and corresponds to a brake pipe, a fluid unit flow path, a hose, and the like. In the fluid path, the side close to the reservoir RV (the side far from the wheel cylinder CW) is called “upstream side” or “upper side”, and the side close to the wheel cylinder CW (the side far from the reservoir RV) It is called “downstream” or “lower”.

  Of the two fluid paths, the first system (system related to the first master cylinder chamber Rm1) is fluidly connected to the wheel cylinder CWi of the right front wheel WHi and the wheel cylinder CWl of the left rear wheel WHl. Of the two fluid paths, the second system (system related to the second master cylinder chamber Rm2) is fluidly connected to the wheel cylinder CWj of the left front wheel WHj and the wheel cylinder CWk of the right rear wheel WHk. That is, a so-called diagonal type (also referred to as “X type”) is adopted as the two fluid paths. The two-system fluid path may be a front-rear type (also referred to as “H type”). In this case, the front wheel cylinders CWi and CWj are connected to the first system, and the rear wheel cylinders CWk and CWl are connected to the second system.

  The vehicle is a hybrid vehicle provided with an electric motor for driving, or an electric vehicle. In the braking control device SC, so-called regenerative cooperative control (cooperation between the regenerative brake and the friction brake) is executed. A vehicle including the braking control device SC includes a braking operation member BP, a wheel cylinder CW, a reservoir RV, a master cylinder CM, and a wheel speed sensor VW.

  The braking operation member (for example, brake pedal) BP is a member that the driver operates to decelerate the vehicle. By operating the braking operation member BP, the braking torque of the wheel WH is adjusted, and a braking force is generated on the wheel WH. Specifically, a rotating member (for example, a brake disc) KT is fixed to the vehicle wheel WH. A brake caliper is arranged so as to sandwich the rotating member KT.

  The brake caliper is provided with a wheel cylinder CW. By increasing the pressure (braking fluid pressure) Pw of the brake fluid BF in the wheel cylinder CW, the friction member (for example, a brake pad) is pressed against the rotating member KT. Since the rotating member KT and the wheel WH are fixed to rotate integrally, a braking torque (friction braking force) is generated on the wheel WH by the frictional force generated at this time.

  The reservoir (atmospheric pressure reservoir) RV is a tank for working fluid, and the brake fluid BF is stored therein. The interior of the atmospheric pressure reservoir RV is partitioned into three parts by a partition plate SK. The first master reservoir chamber Ru1 is connected to the first master cylinder chamber Rm1, and the second master reservoir chamber Ru2 is connected to the second master cylinder chamber Rm2. The pressure regulating reservoir chamber Rd is fluidly connected to the pressure regulating unit KC by a reservoir fluid path HR. In a state where the brake fluid BF is filled in the reservoir RV, the liquid level of the brake fluid BF is higher than the height of the partition plate SK. For this reason, the brake fluid BF can freely move between the first and second master reservoir chambers Ru1 and Ru2 and the pressure regulating reservoir chamber Rd beyond the partition plate SK. On the other hand, when the amount of the brake fluid BF in the reservoir RV decreases and the level of the brake fluid BF becomes lower than the height of the partition plate SK, the first and second master reservoir chambers Ru1, Ru2, and the pressure regulating reservoir chamber Each of Rd becomes an independent liquid reservoir. The reservoir RV is provided with a liquid level sensor LV so as to detect the liquid level height Lv. The detected liquid level height Lv is input to the controller ECU.

  The master cylinder CM is mechanically connected to the braking operation member BP via a brake rod or the like. The master cylinder CM is a tandem type, and the interior thereof is divided into first and second master cylinder chambers Rm1 and Rm2 by first and second master pistons PS1 and PS2 interlocking with the braking operation member BP. When the braking operation member BP is not operated, the first and second master cylinder chambers Rm1, Rm2 of the master cylinder CM and the reservoir RV are in communication with each other. When the braking operation member BP is operated, the first and second pistons PS1 and PS2 in the master cylinder CM are pushed, and the first and second pistons PS1 and PS2 move forward. By this advance, the first and second master cylinder chambers Rm1 and Rm2 formed by the inner wall of the master cylinder CM and the first and second pistons PS1 and PS2 are stored in the reservoir RV (particularly, the first and second masters). Shut off from the reservoir chambers Ru1, Ru2). When the operation of the brake operation member BP is increased, the volumes of the master cylinder chambers Rm1 and Rm2 are reduced, and the brake fluid BF is pumped from the master cylinder CM toward the wheel cylinder CW. The case where the hydraulic pressure (braking hydraulic pressure) Pw of each wheel cylinder CW is adjusted (increased or decreased) by the master cylinder CM is referred to as “manual braking”.

  The wheel cylinder CW is pressurized by the braking control device SC instead of the master cylinder CM. The braking control device SC has a so-called brake-by-wire configuration. That is, the wheel cylinder CW is pressurized by any one of the master cylinder CM and the braking control device SC. The case where the hydraulic pressure Pw of each wheel cylinder CW is adjusted (increase / decrease) by the brake control device SC is referred to as “control braking”.

  Each wheel WH is provided with a wheel speed sensor VW so as to detect the wheel speed Vw. The signal of the wheel speed Vw is employed for anti-skid control or the like that suppresses the tendency of the wheel WH to lock. Each wheel speed Vw detected by the wheel speed sensor VW is input to the lower controller ECL. In the controller ECL, the vehicle body speed Vx is calculated based on the wheel speed Vw.

  Various fluid paths connecting the master cylinder CM, the wheel cylinder CW, the reservoir RV, and the braking control device SC will be described. The fluid path is a path (braking pipe, fluid unit flow path, hose, etc.) for moving the brake fluid BF.

  The first and second master cylinder fluid paths HM1 and HM2 are connected to the master cylinder CM (particularly, the first and second master cylinder chambers Rm1 and Rm2) and the first and second intermediate fluid paths HV1 and HV2. . The wheel cylinder fluid path HW is connected to the wheel cylinder CW. The reservoir fluid path HR is connected to the reservoir RV (particularly, the pressure regulation reservoir chamber Rd) and the pressure regulation unit KC (particularly, the fluid pump QC, the electromagnetic valve UC). The first and second intermediate fluid paths HV1 and HV2 are connected to the first and second separation units KB1 and KB2 and the four wheel cylinder fluid paths HW. Specifically, the first and second intermediate fluid paths HV1 and HV2 are branched to the respective wheel cylinder fluid paths HW at the first and second branch portions Bw1 and Bw2.

  The pressure regulation fluid path HC is connected to the pressure regulation unit KC. Further, the pressure regulating fluid path HC is branched into the first and second regulating fluid paths HC1 and HC2 at the first and second branch portions Bn1 and Bn2, and the first and second separation units KB1 and KB2 (particularly, , First and second separation chambers Rb1, Rb2). The reaction force fluid path HX is connected to the second master cylinder fluid path HM2 and the reaction force chamber Rf of the simulator SS. The assistance fluid passage HA is connected to the assistance chamber Rh of the simulator SS and the pressure regulation fluid passage HC (particularly between the electromagnetic valve UC and the check valve GC). The open fluid path HB is connected between the assist chamber Rh and the assist valve VA (or the check valve GA) of the simulator SS and to the reservoir RV (particularly, the pressure regulating reservoir chamber Rd). Note that the master cylinder CM, the wheel cylinder CW, the simulator SS, the separation unit KB, and the fluid paths HM, HW, HR, HV, HC, HX, HA, and HB are filled with the brake fluid BF (that is, The liquid-tight state of the brake fluid BF is achieved).

≪Brake control device SC≫
The braking control device SC includes an upper fluid unit HU on the side close to the master cylinder CM and a lower fluid unit HL on the side close to the wheel cylinder CW. The upper fluid unit HU is controlled by the upper controller ECU and is a fluid unit included in the braking control device SC.

  The lower fluid unit HL is controlled by the lower controller ECL. Wheel speed Vw, yaw rate Yr, steering angle Sa, longitudinal acceleration Gx, lateral acceleration Gy, and the like are input to the lower controller ECL. In the lower fluid unit HL, independent brake control such as anti-skid control and vehicle stabilization control is executed based on these signals. The upper controller ECU and the lower controller ECL are connected in a communicable state via the communication bus BS, and share sensor signals and calculation values.

  The braking control device SC (in particular, the upper fluid unit HU) includes an operation amount sensor BA, an operation switch ST, a master cylinder electromagnetic valve VM, an upper controller ECU, a pressure regulating unit KC (an electric pump DC, a linear electromagnetic valve UC, an adjustment fluid) Pressure sensor PC, etc.), separation unit KB, stroke simulator SS, assist valve VA, and release valve VB.

  An operation amount sensor BA is provided in the braking operation member BP. An operation amount Ba of the braking operation member (brake pedal) BP by the driver is detected by the operation amount sensor BA. As the operation amount sensor BA, first and second master cylinder hydraulic pressure sensors PM1 and PM2 are provided so as to detect the hydraulic pressures Pm1 and Pm2 of the first and second master cylinder chambers Rm1 and Rm2 of the master cylinder CM. Since “Pm1 = Pm2”, one of the first master cylinder hydraulic pressure sensor PM1 and the second master cylinder hydraulic pressure sensor PM2 can be omitted. Further, as the operation amount sensor BA, an operation displacement sensor SP that detects the operation displacement Sp of the braking operation member BP and an operation force sensor that detects the operation force Fp of the braking operation member BP are provided. That is, at least one of the first and second master cylinder hydraulic pressure sensors PM1, PM2, the operation displacement sensor SP, and the operation force sensor is employed as the braking operation amount sensor BA. Accordingly, at least one of the hydraulic pressure (master cylinder hydraulic pressure) Pm in the master cylinder CM, the operation displacement Sp of the brake operation member BP, and the operation force Fp of the brake operation member BP is detected as the brake operation amount Ba. The The braking operation amount Ba is an instruction signal for vehicle deceleration and is input to the upper controller ECU.

  The brake operation member BP is provided with an operation switch ST. The operation switch ST detects whether the driver has operated the braking operation member BP. When the brake operation member BP is not operated (that is, during non-braking), the brake operation switch ST outputs an off signal as the operation signal St. On the other hand, when the braking operation member BP is operated (that is, during braking), an ON signal is output as the operation signal St. The braking operation signal St is input to the controller ECU.

  First and second master cylinder fluid paths HM1 and HM2 are connected to the first and second master cylinder chambers Rm1 and Rm2. First and second master cylinder valves VM1 and VM2 are provided in the middle of the first and second master cylinder fluid passages HM1 and HM2. The master cylinder valve VM is a two-position electromagnetic valve (also referred to as “on / off valve”) having an open position (communication state) and a closed position (blocking state). The master cylinder valve VM is controlled by the upper controller ECU based on the drive signal Vm. At the time of non-braking or manual braking, the master cylinder valve VM is set to the open position, and the master cylinder CM and the wheel cylinder CW are brought into communication. In this case, the brake hydraulic pressure Pw is adjusted by the master cylinder CM. At the time of control braking, the master cylinder valve VM is closed, and the master cylinder CM and the wheel cylinder CW are not communicated. In this case, the brake fluid pressure Pw is controlled by the brake controller SC. As the master cylinder valve VM, a normally open electromagnetic valve is employed.

  The upper controller (also referred to as “electronic control unit”) ECU includes an electric circuit board on which a microprocessor MP and the like are mounted, and a control algorithm programmed in the microprocessor MP. The upper controller ECU controls the electric motor MC and the four different types of electromagnetic valves VM, VA, VB, and UC based on the braking operation amount Ba, the operation signal St, and the adjustment hydraulic pressure Pc. Specifically, drive signals Vm, Va, Vb, Uc for controlling the various solenoid valves VM, VA, VB, UC are calculated based on a control algorithm in the microprocessor MP. Similarly, a drive signal Mc for controlling the electric motor MC is calculated. Based on these drive signals Vm, Va, Vb, Uc, Mc, the electromagnetic valves VM, VA, VB, UC and the electric motor MC are driven.

  The upper controller ECU is connected to the lower controller ECL and a controller (electronic control unit) of another system via the in-vehicle communication bus BS. A regeneration amount Rg is transmitted from the driving controller to the upper controller ECU so as to execute the regeneration cooperative control. The “regeneration amount Rg” is a state amount that represents the size of the regenerative brake generated by the drive motor. Electric power is supplied to each controller ECU and ECL from the in-vehicle generator AL and the storage battery BT.

  In the upper controller ECU, pressure regulation control including auxiliary control is executed. The pressure regulation control is control for adjusting the brake fluid pressure Pw, and the electric motor MC and the electromagnetic valve UC are controlled. In the auxiliary control, the simulator SS compensates for the startup response of the electric motor MC and improves the increase response of the brake fluid pressure Pw. In the auxiliary control, the electromagnetic valves VA and VB are controlled.

  The upper controller ECU is provided with a drive circuit DR so as to drive the electromagnetic valves VM, VA, VB, UC and the electric motor MC. In the drive circuit DR, a bridge circuit is formed by switching elements (power semiconductor devices such as MOS-FET and IGBT) so as to drive the electric motor MC. Based on the motor drive signal Mc, the energization state of each switching element is controlled, and the output of the electric motor MC is controlled. In the drive circuit DR, the energization states (that is, the excitation states) are controlled based on the drive signals Vm, Va, Vb, Uc so as to drive the electromagnetic valves VM, VA, VB, UC.

  The pressure adjusting unit KC includes an electric pump DC, a pressure adjusting fluid path HC, a check valve GC, a solenoid valve UC, and an adjusting hydraulic pressure sensor PC.

  The pressure adjusting electric pump DC is constituted by a set of one pressure adjusting electric motor MC and one pressure adjusting fluid pump QC. In the electric pump DC, the electric motor MC and the fluid pump QC are fixed so that the electric motor MC and the fluid pump QC rotate together. The electric pump DC (in particular, the electric motor MC) is a power source for adjusting the hydraulic pressure (separation chamber hydraulic pressure) Pb in the separation chamber Rb of the separation unit KB during control braking. The electric motor MC is controlled by the upper controller ECU based on the drive signal Mc.

  For example, a three-phase brushless motor is employed as the electric motor MC. The brushless motor MC is provided with a rotation angle sensor KA that detects its rotor position (rotation angle) Ka. Based on the rotation angle (actual value) Ka, the switching element of the bridge circuit is controlled to drive the electric motor MC. That is, the direction of energization of the coils of each of the three phases (U phase, V phase, W phase) (that is, the excitation direction) is sequentially switched, and the brushless motor MC is rotationally driven. The drive circuit DR is provided with an energization amount sensor that detects an actual energization amount Ia (a generic name of each phase) of the electric motor MC. For example, a current sensor is provided as an energization amount sensor, and a supply current Ia to the electric motor MC is detected.

  A reservoir fluid path HR is connected to the suction port Qs of the pressure adjusting fluid pump QC. Further, a pressure regulating fluid path HC is connected to the discharge port Qt of the fluid pump QC. By driving the electric pump DC (particularly, the fluid pump QC), the brake fluid BF is sucked from the reservoir fluid path HR through the suction port Qs and discharged from the discharge port Qt to the pressure regulating fluid path HC. For example, a gear pump is employed as the adjustment fluid pump QC.

  A check valve GC (also referred to as “check valve”) is interposed in the pressure adjusting fluid path HC. For example, a check valve GC is provided near the discharge part Qt of the fluid pump QC. The check valve GC allows the brake fluid BF to move from the reservoir fluid path HR toward the pressure regulating fluid path HC, but moves from the pressure regulation fluid path HC toward the reservoir fluid path HR (ie, braking). The backflow of the liquid BF is prevented. That is, the electric pump DC is rotated only in one direction.

  The pressure regulating electromagnetic valve UC is connected to the pressure regulating fluid path HC and the reservoir fluid path HR. The pressure regulating solenoid valve UC is a linear solenoid valve (“proportional valve” or “differential pressure valve”) whose valve opening amount (lift amount) is continuously controlled based on an energized state (for example, supply current). Say). The pressure regulating electromagnetic valve UC is controlled by the upper controller ECU based on the drive signal Uc. As the electromagnetic valve UC, a normally open type electromagnetic valve is employed.

  The brake fluid BF is pumped from the reservoir fluid path HR through the suction port Qs of the fluid pump QC, and is discharged from the discharge port Qt. Then, the brake fluid BF passes through the check valve GC and the electromagnetic valve UC, and is returned to the reservoir fluid path HR. In other words, the reservoir fluid path HR and the pressure regulating fluid path HC form a reflux path (a fluid path in which the flow of the brake fluid BF circulates and returns to the original flow). A valve GC and a solenoid valve UC are interposed.

  When the electric pump DC is operating, the brake fluid BF is recirculated in the order of “HR → QC (Qs → Qt) → GC → UC → HR” as indicated by the broken arrow (A). . When the pressure regulating solenoid valve UC is in a fully open state (because it is a normally open type, when not energized), the hydraulic pressure (adjusted hydraulic pressure) Pc in the regulated fluid path HC is low and is substantially “0 (atmospheric pressure)”. It is. When the energization amount to the pressure regulating solenoid valve UC is increased and the return path is throttled by the solenoid valve UC, the adjustment hydraulic pressure Pc is increased. An adjustment hydraulic pressure sensor PC is provided in the pressure adjustment fluid path HC (particularly between the check valve GC and the electromagnetic valve UC) so as to detect the adjustment hydraulic pressure Pc.

  In the pressure adjusting unit KC, the electric pump DC is rotationally driven based on the operation amount Ba, the regeneration amount Rg, and preset characteristics (calculation map). Based on the detection result (adjusted hydraulic pressure Pc) of the adjusted hydraulic pressure sensor PC, the pressure regulating electromagnetic valve UC is controlled to adjust the hydraulic pressure Pc in the regulated fluid path HC. Specifically, the rotational speed Na of the electric pump DC (particularly, the electric motor MC) is controlled so that the target hydraulic pressure Pt is achieved, and the flow of the brake fluid BF from the electric pump DC (particularly, the fluid pump QC). (Flow rate) is generated. The flow of the brake fluid BF is throttled by the pressure regulating electromagnetic valve UC, and finally the target fluid pressure Pt is achieved. That is, the adjustment hydraulic pressure Pc is adjusted by the orifice effect of the pressure regulating electromagnetic valve UC.

  The adjustment hydraulic pressure Pc of the pressure adjustment unit KC is introduced into the separation unit KB via the pressure adjustment fluid path HC. Specifically, the pressure regulation fluid path HC is divided into first and second pressure regulation fluid paths HC1 and HC2 at the first and second branch portions Bn1 and Bn2. The first and second pressure regulating fluid paths HC1 and HC2 are connected to the first and second separation chambers Rb1 and Rb2 of the first and second separation units KB1 and KB2. Here, the adjustment fluid pressure Pc is equal to the first and second fluid pressures (separation fluid pressures) Pb1 and Pb2 in the first and second separation chambers Rb1 and Rb2 (Pc = Pb1 = Pb2). The two separation units KB1 and KB2 are provided in parallel to the pressure regulating fluid path HC (referred to as “parallel arrangement”).

[Separation unit KB]
The configuration of the separation unit KB will be described with reference to the schematic diagram of FIG.
A separation unit KB is provided between the pressure adjustment unit KC and the wheel cylinder CW. The separation unit KB fluidically separates the pressure regulating unit KC (particularly the pressure regulating fluid path HC) and the wheel cylinder CW (particularly the intermediate fluid path HV). Here, “fluid separation” refers to a state where pressure is transmitted but no movement of the brake fluid BF occurs.

  The separation unit KB includes a separation cylinder CB, a separation piston PB, and a separation elastic body SB. The first separation unit KB1 and the second separation unit KB2 arranged in parallel have the same structure.

  The separation cylinder CB is a cylinder member having a bottom. The separation piston PB is a piston member inserted into the separation cylinder CB. A groove is formed in the inner peripheral portion Bc of the separation cylinder CB, and two seals SL are fitted in the groove. The outer periphery (outer cylindrical surface) Bp of the separation piston PB and the inner peripheral portion (inner cylindrical surface) Bc of the separation cylinder CB are sealed by the two seals SL. The separation piston PB can move smoothly along the central axis Jb of the separation cylinder CB. For example, a cup seal can be adopted as the seal SL.

  The inside of the separation cylinder CB is separated into two chambers (hydraulic pressure chambers) Ra and Rb by the separation piston PB. In the central axis Jb, the pressurizing chamber Ra and the separating chamber Rb are respectively provided at opposite positions with respect to the separating piston PB. The pressurizing chamber Ra is a hydraulic chamber defined by the inner peripheral portion Bc of the separation cylinder CB, the first bottom portion (bottom surface) Bu, and the first end portion Br of the separation piston PB.

  The separation chamber Rb is a hydraulic chamber defined by the inner peripheral portion Bc, the second bottom portion (bottom surface) Bt of the separation cylinder CB, and the second end portion Bq of the separation piston PB. The pressurizing chamber Ra and the separation chamber Rb are formed to face each other with the separation piston PB interposed therebetween. In other words, in the central axis Jb of the separation cylinder CB, the separation chamber Rb is located on the opposite side of the pressurizing chamber Ra with respect to the separation piston PB. The fluid separation state is achieved in the pressurizing chamber Ra and the separation chamber Rb by the separation piston PB.

  A separation elastic body (for example, a compression spring) SB is provided between the first bottom Bu of the separation cylinder CB and the separation piston PB. The separation elastic body SB presses the separation piston PB against the second bottom Bt of the separation cylinder CB along the central axis Jb of the separation cylinder CB. That is, the separation elastic body SB applies an elastic force (spring force) in the backward direction Dq to the separation piston PB. During non-braking, the second end Bq and the second bottom Bt are in contact with each other, and the volume of the separation chamber Rb is in a minimum state. The position of the separation piston PB in this state is referred to as “the initial position of the separation unit KB”.

  The movement (displacement) of the separation piston PB along the central axis Jb is limited. Specifically, the movable range of the separation piston PB is a predetermined distance db from the initial position of the separation unit KB until the first end Br of the separation piston PB contacts the first bottom Bu of the separation cylinder CB. Is limited to. The predetermined distance db is geometrically determined due to the structure of the separation unit KB. Therefore, the amount (volume) of the brake fluid BF that can be discharged from the separation cylinder CB toward the wheel cylinder CW is limited to a volume (referred to as “maximum discharge amount mb”) corresponding to the predetermined distance db. The maximum discharge amount mb is a volume (which will be described later) in which the wheel cylinder CW connected to the separation unit KB can generate the required maximum braking hydraulic pressure (hydraulic pressure that can achieve the locked state of the wheel WH) in one braking. (Consumed liquid amount) to be set. For example, the first separation unit KB1 is configured to be able to discharge an amount by which the two wheel cylinders CWi and CWl can reach the maximum brake fluid pressure. The maximum discharge amount mb of the separation unit KB is determined by “(diameter φcb of the inner peripheral cylindrical surface of the separation cylinder CB) × (predetermined distance db)”.

  A return fluid path may be provided between the two seals SL (eg, cup seal) and connecting the reservoir RV (particularly the master reservoir chamber Ru). When the separation piston PB is in the initial position via the return fluid path, the reservoir RV is brought into communication between the two seals SL. The fluid pressure between the seals SL is set to “0 (atmospheric pressure)” (that is, no back pressure is generated) by the return fluid path. The return fluid path may not be provided.

  An intermediate fluid path HV is connected to the pressurizing chamber Ra, and is finally fluidly connected to the wheel cylinder CW. A master cylinder fluid passage HM is connected to the intermediate fluid passage HV at a connection portion Bm. A pressure regulating fluid path HC is connected to the separation chamber Rb. Therefore, the adjustment hydraulic pressure Pc is introduced into the separation chamber Rb. The adjustment hydraulic pressure Pc in the separation chamber Rb generates a force that presses the separation piston PB in the forward direction Dp. On the other hand, the brake fluid pressure Pw in the pressurizing chamber Ra acts as a force for pressing the separation piston PB in the backward direction Dq.

  When the braking operation member BP is operated, the adjustment hydraulic pressure Pc is generated by the pressure adjustment unit KC. Accordingly, the hydraulic pressure Pb (= Pc) in the separation chamber Rb is increased. By the hydraulic pressure Pb, the separation piston PB is moved along the central axis Jb in the forward direction (left direction in the figure, increasing direction of the braking hydraulic pressure Pw) Dp, and the volume (volume) of the separation chamber Rb is increased. The By the movement of the separation piston PB in the forward direction Dp, the volume of the pressurizing chamber Ra is reduced, and the brake fluid BF in the pressurizing chamber Ra is pumped to the intermediate fluid path HV. At this time, since the master cylinder valve VM is in the closed position, the brake fluid BF is moved toward the wheel cylinder CW via the fluid passages HV and HW, and the brake fluid pressure Pw is increased.

Conversely, when the braking operation member BP is returned, the adjustment hydraulic pressure Pc is reduced by the pressure adjustment unit KC. Since the separation chamber hydraulic pressure Pb is smaller than the pressurization chamber hydraulic pressure Pa (= Pw), the separation piston PB moves in the backward direction (the right direction in the figure, the decreasing direction of the braking hydraulic pressure Pw) Dq. Moved. When the braking operation member BP is brought into a non-operation state, the separation piston PB is returned to the position where it contacts the second bottom Bt of the separation cylinder CB (the initial position of the separation unit KB) by the elastic force of the compression spring SB. . As a result, the hydraulic pressure Pa in the pressurizing chamber Ra is returned to “0”.
The separation unit KB has been described above.

[Stroke simulator SS]
The configuration of the stroke simulator SS will be described with reference to the schematic diagram of FIG.
A stroke simulator (simply referred to as “simulator”) SS generates an operation force Fp of the brake operation member BP when the first and second master cylinder valves VM1 and VM2 are closed (during control braking). Provided. For example, the simulator SS is provided between the second master cylinder chamber Rm2 and the second master cylinder valve VM2 at the outlet of the second master cylinder chamber Rm2.

  The simulator SS forms operation characteristics (relationship of the operation force Fp with respect to the operation displacement Sp) of the braking operation member BP during control braking. In addition, when the braking operation member BP is suddenly operated, the starting characteristic of the electric pump DC (particularly, the electric motor MC) is compensated, and the boosting response of the braking hydraulic pressure Pw is improved. The simulator SS includes a simulator cylinder CX, a simulator piston PX, and a simulator elastic body SX.

  The simulator cylinder CX is a cylinder member having a bottom. The simulator piston PX is a piston member inserted into the simulator cylinder CX. A groove portion is formed in the outer peripheral portion Xp of the simulator piston PX, and the seal SM is fitted in the groove portion. The seal SM seals the outer peripheral portion (outer peripheral cylindrical surface) Xp of the simulator piston PX and the inner peripheral portion (inner peripheral cylindrical surface) Xc of the simulator cylinder CX. The simulator piston PX can move smoothly along the central axis Jx of the simulator cylinder CX. Here, a cup seal is employed as the seal SM so that the hydraulic pressure in the assisting fluid passage HA does not become excessive.

  The interior of the simulator cylinder CX is separated into two chambers (hydraulic pressure chambers) Rf and Rh by the simulator piston PX. In the central axis Jx, the reaction force chamber Rf and the assisting chamber Rh are provided on the opposite sides with respect to the simulator piston PX. The reaction force chamber Rf is a hydraulic chamber defined by “the inner peripheral portion Xc of the simulator cylinder CX, the first bottom portion (bottom surface) Xt” and the “first end portion Xq of the simulator piston PX”. The reaction force fluid path HX is connected to the reaction force chamber Rf, and the second master cylinder hydraulic pressure Pm2 is introduced.

  The assisting chamber Rh is a hydraulic chamber partitioned by the “inner peripheral portion Xc of the simulator cylinder CX, the second bottom portion (bottom surface) Xu” and the “second end portion Xr of the simulator piston PX”. The reaction force chamber Rf and the assisting chamber Rh are formed to face each other with the simulator piston PX interposed therebetween. That is, in the central axis Jx of the simulator cylinder CX, the assisting chamber Rh is located on the side opposite to the reaction force chamber Rf with respect to the simulator piston PX. The assisting fluid path HA is connected to the assisting chamber Rh.

  A simulator elastic body (for example, a compression spring) SX is provided between the second bottom portion (bottom surface forming the assisting chamber Rh) Xu of the simulator cylinder CX and the simulator piston PX. The simulator elastic body SX includes the simulator piston PX in the backward direction Ds (the left direction in the drawing and the direction opposite to the forward direction Dr) along the central axis Jx of the simulator cylinder CX. It is pressed against the bottom (bottom surface forming the reaction force chamber Rf) Xt. During non-braking, the first end portion Xq of the simulator piston PX and the first bottom portion Xt of the CX are in contact with each other, and the volume of the reaction force chamber Rf is in a minimum state. The position of the simulator piston PX in this state is referred to as “the initial position of the simulator SS”.

  The movement (displacement) of the simulator piston PX along the central axis Jx is limited. Specifically, the movable range of the simulator piston PX is a predetermined distance dx from the initial position of the simulator SS until the second end Xr of the simulator piston PX contacts the second bottom Xu of the simulator cylinder CX. Is limited to. The predetermined distance dx is geometrically determined due to the structure of the simulator SS.

  During control braking, when the braking operation member BP is operated, the braking fluid BF is pumped from the master cylinder chamber Rm2. The brake fluid BF is moved to the simulator SS (particularly the reaction force chamber Rf) via the fluid paths HM2 and HX, and the simulator piston PX is moved in the forward direction Dr by the brake fluid BF that flows in. That is, the master cylinder hydraulic pressure Pm2 in the reaction force chamber Rf generates a force that presses the piston PX in the forward direction Dr. A force (elastic force against the pressing force in the forward direction Dr) is applied to the simulator piston PX by a simulator elastic body (compression spring) SX in a direction (reverse direction) Ds that prevents the inflow of the brake fluid BF. . The elastic body SX forms an operation force Fp when the braking operation member BP is operated. Further, when the simulator piston PX is moved in the forward direction Dr, the volume (volume) of the reaction force chamber Rf is increased and the volume of the assisting chamber Rh is decreased. Therefore, the brake fluid BF is discharged from the assist chamber Rh to the assist fluid passage HA.

  When the brake operation member BP is returned, the volume of the second master cylinder chamber Rm2 is increased, and the brake fluid BF is returned from the reaction force chamber Rf toward the master cylinder chamber Rm2. At this time, the volume of the assisting chamber Rh increases, but the brake fluid BF flows into the assisting chamber Rh via the fluid paths HA and HB.

During non-braking or manual braking (when the braking control device SC is malfunctioning), the assisting chamber Rh of the simulator SS is brought into a fluid locked state. For this reason, the brake fluid BF from the master cylinder CM does not flow into the simulator SS.
The configuration of the simulator SS has been described above.

Returning to FIG. 1, the description of the first embodiment will be continued.
The other end of the reaction force fluid path HX connected to the reaction force chamber Rf is connected to the second master cylinder fluid path at the connection Bx (between the second master cylinder chamber Rm2 and the second master cylinder valve VM2). Connected to HM2. The reaction force fluid path HX is a fluid path that connects the master cylinder chamber Rm2 and the reaction force chamber Rf. The other end of the assisting fluid passage HA connected to the reaction force chamber Rf is connected to the pressure regulating fluid passage HC at a connection portion Bz (between the check valve GC and the electromagnetic valve UC). The assisting fluid path HA is a fluid path connecting the pressure regulating fluid path HC and the assisting chamber Rh. An assist valve VA is provided in the assist fluid passage HA. The assist valve VA is a two-position electromagnetic valve (on / off valve) having an open position (communication state) and a closed position (blocking state). A normally closed valve is used as the assist valve VA. The assist valve VA is controlled by the upper controller ECU based on the drive signal Va.

  An open fluid path HB is provided between the assist chamber Rh of the assist fluid path HA and the assist valve VA (connection portion Bb) and to connect the reservoir RV (particularly the pressure regulating reservoir chamber Rd) (in the drawing, The reservoir fluid path HR and the open fluid path HB partially overlap each other). An open valve VB is provided in the open fluid path HB. Similar to the assist valve VA, the open valve VB is a two-position normally closed on / off solenoid valve. The release valve VB is controlled by the upper controller ECU based on the drive signal Vb.

  The operation of the simulator SS during normal control braking (not during sudden braking operation) will be described. During normal control braking, when the braking operation member BP is operated, the second master cylinder valve VM2 is closed. Further, the assist valve VA is set to the closed position, and the release valve VB is set to the open position. When the operation of the brake operation member BP is increased, the volume of the master cylinder chamber Rm2 is decreased, and the brake fluid BF is discharged from the master cylinder chamber Rm2. The brake fluid BF flows into the simulator SS (particularly the reaction force chamber Rf) via the fluid passages HM2 and HX. An elastic force of the elastic body SX is generated so as to prevent the inflow of the brake fluid BF, and an operation force Fp of the brake operation member BP is generated.

  When the simulator piston PX is moved in the forward direction Dr, the brake fluid BF is discharged from the assist chamber Rh to the assist fluid passage HA. Depending on the closed position of the assist valve VA and the open position of the open valve VB, the brake fluid BF is moved toward the reservoir RV through the open fluid path HB without being moved to the pressure regulating fluid path HC. When the brake operation member BP is returned, the volume of the master cylinder chamber Rm2 is increased, and the brake fluid BF is moved from the reaction force chamber Rf toward the master cylinder chamber Rm2. At the same time, the volume of the assisting chamber Rh increases, but since the release valve VB is in the open position, the brake fluid BF is moved from the reservoir RV side into the reaction force chamber Rf via the open fluid path HB. The

  In the control braking, the operation of the simulator SS when the braking operation is sudden (during sudden operation) will be described. As in normal braking, the operating force Fp of the braking operation member BP is generated by a simulator elastic body (for example, a compression spring) SX during a sudden operation. When the controller ECU determines that the sudden operation is performed, the second master cylinder valve VM2 is set to the closed position, the assist valve VA is set to the open position, and the release valve VB is set to the closed position. Since the assist valve VA is in the communication state and the release valve VB is in the shut-off state, the braking fluid BF discharged from the reaction force chamber Rf is moved into the pressure regulating fluid path HC. As a result, auxiliary control is performed to assist the increase in the adjustment hydraulic pressure Pc from “0”.

  At the time of non-braking or manual braking (when the braking control device SC malfunctions), the assist valve VA and the release valve VB are left in the closed position (non-energized), and the master cylinder valve VM is opened. It is left (non-energized). The assisting chamber Rh of the simulator SS is brought into a fluid lock (containment) state by the closed positions of the two solenoid valves VA and VB. Therefore, at the time of manual braking, the brake fluid BF from the master cylinder CM is not consumed by the simulator SS, but all is moved toward the wheel cylinder CW.

  The upper fluid unit HU and the lower fluid unit HL are connected via first and second intermediate fluid paths HV1 and HV2. The lower fluid unit HL is provided with first and second fluid pumps QL1 and QL2 that are driven by the electric motor ML and pump up the brake fluid BF from the first and second low-pressure reservoirs RL1 and RL2. The first and second intermediate fluid passages HV1 and HV2 are provided with normally open first and second charge over valves VN1 and VN2. First and second input hydraulic pressure sensors PN1 and PN2 are provided to detect the first and second input hydraulic pressures Pn1 and Pn2 to the first and second charge over valves VN1 and VN2. Note that one of the two input hydraulic pressure sensors PN1 and PN2 can be omitted.

  The hydraulic pressures generated by the first and second fluid pumps QL1 and QL2 are adjusted by the first and second charge over valves VN1 and VN2, and downstream of the first and second charge over valves VN1 and VN2 (wheel cylinders). The hydraulic pressure on the side close to CW is increased. At the first and second branch portions Bw1 and Bw2 between the first and second chargeover valves VN1 and VN2 and each wheel cylinder CW, the intermediate fluid paths HV1 and HV2 are respectively connected to the wheel cylinder fluid paths HWi to HWl. Branch off.

  The wheel cylinder fluid path HW is provided with an inlet valve VI and an outlet valve VO. Since the configuration related to each wheel WH is the same, the configuration related to the right front wheel WHi will be described as an example. A normally-open inlet valve VIi is interposed in the intermediate fluid passage HVi for the right front wheel (the fluid passage connecting the first branch portion Bw1 and the right front wheel wheel cylinder CWi). The intermediate fluid path HVi is fluidly connected to the low pressure reservoir RL1 via a normally closed outlet valve VOi. For example, in the anti-skid control, in order to reduce the hydraulic pressure Pwi in the wheel cylinder CWi, the inlet valve VIi is closed and the outlet valve VOi is opened. The brake fluid BF in the wheel cylinder CWi flows out to the low pressure reservoir RL1, and the brake fluid pressure Pwi is decreased. Further, in order to increase the brake fluid pressure Pwi, the inlet valve VIi is set to the open position, and the outlet valve VOi is closed. The hydraulic pressure via the first charge over valve VN1 is introduced into the wheel cylinder CWi, and the right front wheel braking hydraulic pressure Pwi is increased.

  In the case of manual braking, the wheel cylinder CW is directly fluidly connected to the master cylinder CM, and the brake fluid BF is moved from the master cylinder CM to the wheel cylinder CW, and the brake fluid pressure Pw is increased.

  In the case of controlled braking (regulation of the braking fluid pressure Pw by the pressure regulating fluid path HC), the pressure regulating fluid path HC is pressurized by the pressure regulating unit KC (that is, the electric pump DC and the electromagnetic valve UC). Then, the hydraulic pressure Pb (= Pc) in the separation chamber Rb is increased. Then, the hydraulic pressure Pa in the pressurizing chamber Ra is increased by the separation hydraulic pressure Pb, and finally the braking hydraulic pressure Pw is increased. The hydraulic pressure generated by the pressure adjusting unit KC is transmitted in the order of “Pc → Pb → Pa → Pw”. On the other hand, when the adjustment hydraulic pressure Pc is decreased, the braking hydraulic pressure Pw is decreased contrary to the pressurization.

  Here, the fluid pressure transmission path (between the pressurizing chamber fluid pressure Pa and the separation chamber fluid pressure Pb) is separated by the separation piston PB in the actual flow of the brake fluid BF. The separation piston PB is sandwiched between the pressurizing chamber Ra and the separation chamber Rb. The separation piston PB is a so-called free piston, which transmits pressure but prevents movement of the brake fluid BF. In the separation unit KB, the range in which the separation piston PB can move in the separation cylinder CB (maximum displacement db) is “a position where the second end Bq of the separation piston PB contacts the second bottom Bt of the separation cylinder CB ( From the “initial position” to “a position where the first end Br of the separation piston PB contacts the first bottom Bu of the separation cylinder CB”, the amount (volume) of the brake fluid BF that can flow out from the separation unit KB is The volume is limited to the predetermined distance db (maximum discharge amount mb). The amount (volume) of the brake fluid BF that can flow out from the separation unit KB is set to be larger than the amount that the wheel cylinder CW connected to the separation unit KB generates the maximum hydraulic pressure required for the wheel cylinder CW. Has been.

  For example, when a fluid path failure occurs around the wheel cylinder CW, the hydraulic pressure Pa in the pressurizing chamber Ra does not increase and remains “0” even if the separation piston PB moves forward. If the pressurizing chamber hydraulic pressure Pa does not increase, the separation piston PB continues to move forward, and finally is moved until the first end Br of the separation piston PB contacts the first bottom Bu of the separation cylinder CB. . The movable range of the separation piston PB is geometrically limited to a predetermined distance db (displacement from the initial position to the corresponding contact position). Therefore, the amount of the brake fluid BF that is lost outside the apparatus due to the above-described failure is limited to the maximum discharge amount mb or less by the separation unit KB. As a result, the reliability of the braking control device SC is improved.

  A failure (breakage) in the fluid path from the reservoir RV to the wheel cylinder CW is identified based on the liquid level height Lv. Specifically, based on the change in the liquid level height Lv with respect to the braking operation, it is determined that the above-described failure has occurred when the decrease (decrease) in the liquid level height Lv is large. Further, based on the comparison result between the target hydraulic pressure Pt (described later) and the adjusted hydraulic pressure (detected value) Pc, it can be determined whether or not the fluid path is broken. When the difference hP between the target value Pt and the actual value Pc of the hydraulic pressure is continued for a predetermined time tp, it is determined that a failure state has occurred.

  When the braking operation member BP is suddenly operated, auxiliary control by the simulator SS is executed. Specifically, the responsiveness of the rising of the brake fluid pressure Pw is improved by introducing the brake fluid BF from the assisting chamber Rh of the simulator SS into the pressure regulating fluid path HC.

  The brake fluid pressure Pw is increased depending on the amount of the brake fluid BF flowing into the wheel cylinder CW. The relationship between the inflow amount (volume) of the brake fluid BF and the increase amount of the brake fluid pressure Pw depends on the rigidity of members (brake calipers, fluid passages (hydraulic piping, hoses), friction materials, etc.) arranged around the wheels. And based on the gap between the members. The amount of braking fluid BF consumed by these members is referred to as “consumed fluid amount”. In order to increase the brake fluid pressure Pw from “0”, first, the flow rate (volume) of the brake fluid BF is required to fill the gap between the rotating member KT and the friction member. Further, the friction member is slightly inclined with respect to the surface of the rotating member KT, and fine irregularities exist on the surface of the friction member. Therefore, in order to increase the brake fluid pressure Pw, a flow rate of the brake fluid BF is also required to press the friction member properly against the surface of the rotating member KT. The amount of liquid consumed to close the gap and bring the friction member into close contact with the surface of the rotating member KT is referred to as “initial liquid consumption”.

  In the auxiliary control, the initial consumption liquid amount is supplied in a period in which the rotation speed of the electric motor MC is insufficient. As a result, it is possible to achieve a reduction in size and weight of the entire apparatus while ensuring responsiveness. In the state where the initial consumption liquid amount is filled, the brake fluid pressure Pw is only slightly increased (or the brake fluid pressure Pw is not increased). Therefore, even when the on / off type release valve VB is instantaneously switched from the closed position to the open position at the end of the compensation control, the influence of the compensation control on the operation characteristics of the braking operation member BP is slight.

  For example, if a fluid path failure occurs around the right front wheel wheel cylinder CWi during the execution of the auxiliary control, the pressure adjusting fluid path HC and the brake fluid BF supplied from the stroke simulator SS are , And flows out of the device from the failed portion. At this time, the first separation piston PB1 of the first separation unit KB1 is displaced by a predetermined distance db, and the outflow of the brake fluid BF exceeding the maximum discharge amount mb is avoided. The maximum discharge amount mb is extremely larger than the amount necessary for generating the adjustment hydraulic pressure Pc in the discharge amount of the electric pump DC. Therefore, before the electric pump DC discharges the maximum discharge amount mb, the adjustment hydraulic pressure Pc is increased and the auxiliary control is ended. For this reason, a sudden change in operation characteristics due to a sudden increase in the adjustment hydraulic pressure Pc can be avoided.

  At the time of the failure, the brake fluid BF can be moved from the assisting chamber Rh of the simulator SS to the separation unit KB2 through the route “Rh → VA → Bz → Bn2 → Rb2.” For this reason, auxiliary control can be executed in the second system of wheel cylinders CWj and CWk in an appropriate state.

<Calculation processing of pressure regulation control>
With reference to the control flowchart of FIG. 4, calculation processing of pressure regulation control including auxiliary control will be described. “Pressure adjustment control” is drive control of the electric motor MC and the electromagnetic valve UC for adjusting the adjustment hydraulic pressure Pc. The “auxiliary control” is control for improving the response of the brake fluid pressure Pw in the initial stage of braking (referred to as “initial response”). The control algorithm is programmed in the controller ECU.

  In step S110, the braking operation amount Ba, the operation signal St, the adjustment hydraulic pressure Pc, the rotation angle Ka, and the regeneration amount Rg are read. The operation amount Ba is detected by an operation amount sensor BA (for example, master cylinder hydraulic pressure sensor PM, operation displacement sensor SP). The operation signal St is detected by an operation switch ST provided on the braking operation member BP. The adjustment hydraulic pressure Pc is detected by an adjustment hydraulic pressure sensor PC provided in the pressure adjustment fluid path HC. The rotation angle Ka is detected by a rotation angle sensor KA provided in the electric motor MC. The regeneration amount Rg is transmitted from the drive controller via the communication bus BS.

  In step S120, based on at least one of the braking operation amount Ba and the braking operation signal St, it is determined whether or not the braking operation is being performed. For example, when the operation amount Ba is equal to or greater than the predetermined value bo, step S120 is affirmed and the process proceeds to step S130. On the other hand, if “Ba <bo”, step S120 is denied and the process returns to step S110. Here, the predetermined value bo is a preset constant corresponding to the play of the braking operation member BP. When the operation signal St is on, the process proceeds to step S130, and when the operation signal St is off, the process returns to step S110.

  In step S130, it is determined whether “auxiliary control is in progress” or not. If the auxiliary control is being performed, step S130 is affirmed and the process proceeds to step S150. On the other hand, when the auxiliary control is not executed, Step S130 is denied and the process proceeds to Step S140.

  In step S140, based on the braking operation amount Ba, it is determined whether or not the auxiliary control start condition is satisfied. Specifically, the operation displacement Sp is adopted in the operation amount Ba. Then, the operation displacement Sp is time-differentiated to calculate the operation speed dS. The operation speed (actual value) dS is compared with the predetermined speed ds, and the above determination is executed (condition 1). Here, the predetermined speed ds is a threshold value for determination, and is a preset constant. When the operation speed dS is less than the predetermined speed ds, the above determination is denied and the process proceeds to step S160. If the operation speed dS is equal to or higher than the predetermined speed ds, the start condition is satisfied, and the process proceeds to step S170. In a series of braking operations (from the start of braking to the end of braking), the auxiliary control duration Tk is counted (integrated) from the time point (calculation cycle) when step S140 is satisfied for the first time.

Here, in order to improve the robustness of the start determination of the auxiliary control, the following start condition can be added in addition to the condition based on the operation speed dS.
(Condition 2) Whether or not the operation signal St is in an on state.
(Condition 3) Whether or not the operation displacement Sp is greater than or equal to a predetermined displacement sp. Here, the predetermined displacement sp is a threshold for determination, and is a preset constant.
The start condition is satisfied when all of the conditions “dS ≧ ds”, “St is on”, and “Sp ≧ sp” are satisfied. On the other hand, if at least one of “dS ≧ ds”, “St is on”, and “Sp ≧ sp” is denied, the start condition is not satisfied. One of the condition 2 and the condition 3 can be omitted.

  In step S150, based on the duration time Tk, it is determined whether or not the auxiliary control end condition is satisfied. The determination is performed by comparing the duration time Tk with the predetermined time tk (condition 4). Here, the predetermined time tk is a threshold value for determination, and is a preset constant. If the duration time Tk is less than the predetermined time tk, the above determination is denied, and the process proceeds to step S170. If the duration time Tk is equal to or longer than the predetermined time tk, the end condition is satisfied, and the process proceeds to step S160.

  For example, the predetermined time tk is set based on the discharge performance of the electric pump DC (MC + QC). The output characteristics of the electric motor MC and the discharge characteristics of the fluid pump QC are known. “The discharge amount (volume) of the electric pump DC when the electric pump DC is driven at its maximum output for a predetermined time tk from the stopped state” is “the maximum displacement in one separation unit KB”. The predetermined time tk is determined to be smaller than the volume (maximum discharge amount) mb ”corresponding to db (that is, the maximum amount by which the separation piston PB can be displaced). Since the predetermined time tk is set based on the discharge performance of the electric pump DC and the maximum discharge amount mb of the separation unit KB, the separation is performed when the auxiliary control is executed in a state where a failure has occurred. The auxiliary control is ended before the first end Br of the piston PB comes into contact with the first bottom Bu of the separation cylinder CB. As a result, sudden changes in operating characteristics can be avoided.

In order to improve the robustness of the auxiliary control end determination, the following start condition may be added in addition to the condition based on the duration Tk.
(Condition 5) Whether the rotational speed (actual value) Na is equal to or greater than the predetermined rotational speed na. For example, the rotation speed Na is calculated by time-differentiating the rotation angle Ka based on the rotation angle (detection value) Ka. The predetermined rotation number na is a threshold value for determination, and is a preset constant.
(Condition 6) Whether or not the adjusted hydraulic pressure (actual value) Pc is equal to or higher than a predetermined hydraulic pressure pc. The predetermined hydraulic pressure pc is a threshold value for determination, and is a preset constant.
The termination condition is satisfied when at least one of “Tk ≧ tk”, “Na ≧ na”, and “Pc ≧ pc” is satisfied. The adjusted hydraulic pressure Pc is generated by the orifice effect in the reflux path. Therefore, the adjustment hydraulic pressure Pc cannot be generated when the actual rotation speed Na is small, but the adjustment hydraulic pressure Pc can be generated if the rotation speed Na is sufficiently increased. Based on the rotational speed (actual value) Na, it is identified that the adjustment hydraulic pressure Pc is approaching that it can be generated. The predetermined rotational speed na is set to a value smaller than the rotational speed of the electric motor MC at which the orifice effect of the electromagnetic valve UC is sufficiently generated (that is, before the orifice effect is exhibited, auxiliary control is performed). Is terminated).

  Further, if the adjustment hydraulic pressure (detected value) Pc has already been increased to a predetermined hydraulic pressure pc or higher, it is not necessary to perform auxiliary control. Therefore, when the three conditions “Tk ≧ tk”, “Na ≧ na”, and “Pc ≧ pc” are denied, the termination condition is not satisfied. On the other hand, the auxiliary control is terminated at a time point (calculation cycle) when at least one of the three conditions is satisfied.

  In step S160, normal control of control braking (pressure regulation control not including auxiliary control) is executed. Specifically, the assist valve VA is set to the closed position, and the release valve VB is set to the open position. As a result, the brake fluid BF from the assisting chamber Rh of the simulator SS can move toward the reservoir RV.

  In step S170, pressure regulation control including auxiliary control for control braking is executed. Specifically, the assist valve VA is set to the open position, and the release valve VB is set to the close position. As a result, the brake fluid BF from the assisting chamber Rh of the simulator SS can move toward the pressure regulating fluid path HC.

  In step S180, the normally open master cylinder valve VM is set to the closed position. Thus, the first and second master cylinder chambers Rm1 and Rm2 are fluidly separated from the wheel cylinders CWi to CWl. Further, the brake fluid BF can be moved from the second master cylinder chamber Rm2 to the reaction force chamber Rf of the simulator SS.

  In step S190, the required hydraulic pressure Pr is calculated based on the operation amount Ba. The required hydraulic pressure Pr is a target value of the adjusted hydraulic pressure Pc, and is a value corresponding to vehicle deceleration. The required hydraulic pressure Pr is determined to be “0” when the operation amount Ba is in the range of “0” to the predetermined value bo according to the calculation map Zpr. When the operation amount Ba is equal to or greater than the predetermined value bo, the operation amount Ba increases. Accordingly, calculation is performed so as to monotonically increase from “0”.

  In step S200, the target hydraulic pressure Pt is calculated based on the required hydraulic pressure Pr and the regeneration amount Rg. The “regenerative amount Rg” is the regenerative brake amount generated by the drive motor. The regenerative amount Rg is converted into a hydraulic pressure dimension, and the regenerative fluid pressure Pg is calculated. The required hydraulic pressure Pr corresponds to vehicle deceleration, and vehicle deceleration is achieved by a regenerative brake and a friction brake. For this reason, the regenerative fluid pressure Pg is subtracted from the required fluid pressure Pr to determine the final fluid pressure target value (target fluid pressure) Pt (Pt = Pr−Pg). The target hydraulic pressure Pt is a target value of the hydraulic pressure that should be achieved by the friction brake.

  In step S210, the target rotational speed Nt is calculated based on the target hydraulic pressure Pt. The target rotational speed Nt is a target value for the rotational speed of the electric motor MC. The target rotational speed Nt is determined to be the predetermined rotational speed no when the target hydraulic pressure Pt is in the range from “0” to the predetermined value po according to the calculation map Znt. When the target hydraulic pressure Pt is equal to or higher than the predetermined value po, the target hydraulic pressure Pt Is calculated so as to monotonically increase from the predetermined rotational speed no. As described above, the adjustment hydraulic pressure Pc is generated by the orifice effect of the electromagnetic valve UC. In order to obtain the orifice effect, a certain amount of flow is required. Therefore, when the target hydraulic pressure Pt is in the range of “0” to the predetermined value po, the target rotational speed Nt is the minimum required for generating the hydraulic pressure. The value (preset constant) no is determined. The target rotational speed Nt may be directly calculated based on the braking operation amount Ba. In any case, the target rotational speed Nt is determined based on the braking operation amount Ba.

  In step S220, the rotational speed feedback control of the electric motor MC is executed based on the target rotational speed Nt and the actual rotational speed Na. In this feedback control, the rotational speed of the electric motor MC is used as a control variable, and the amount of current supplied to the electric motor MC (for example, supply current) is controlled. Specifically, based on the deviation hN (= Nt−Na) between the target value Nt of the rotational speed and the actual value Na, the rotational speed deviation hN becomes “0” (that is, the actual value Na is the target value Nt). The amount of current supplied to the electric motor MC is finely adjusted. In the case of “hN> nx”, the energization amount to the electric motor MC is increased, and the electric motor MC is accelerated. On the other hand, in the case of “hN <−nx”, the energization amount to the electric motor MC is decreased and the electric motor MC is decelerated. Here, the predetermined value nx is a preset constant. The rotation speed (number of rotations per unit time) Na is calculated based on the rotation angle (detection value) Ka.

  In step S230, hydraulic pressure feedback control of the electromagnetic valve UC is executed based on the target hydraulic pressure Pt and the adjusted hydraulic pressure Pc. In this feedback control, the pressure of the brake fluid BF in the pressure regulating fluid passage HC is used as a control variable, and the energization amount to the normally open / linear electromagnetic valve UC is controlled. Specifically, based on the deviation hP (= Pt−Pc) between the target hydraulic pressure Pt and the adjusted hydraulic pressure Pc, the hydraulic pressure deviation hP becomes “0” (that is, the adjusted hydraulic pressure Pc is equal to the target hydraulic pressure Pc). The amount of current supplied to the solenoid valve UC is finely adjusted so as to approach Pt. In the case of “hP> px”, the energization amount to the electromagnetic valve UC is increased, and the opening amount of the electromagnetic valve UC is decreased. On the other hand, in the case of “hP <−px”, the energization amount to the electromagnetic valve UC is decreased, and the opening amount of the electromagnetic valve UC is increased. Here, the predetermined value px is a preset constant.

  As described above, the auxiliary control is ended when the duration Tk from the start of the auxiliary control becomes equal to or longer than the predetermined time tk. For example, the predetermined time tk is the maximum output of the electric pump DC, and the discharge volume of the electric pump DC when the electric pump DC is driven from a stopped state is the maximum displacement of the separation piston PB in the separation cylinder CB. In this case, the volume is set to be smaller than the volume (maximum discharge amount) mb discharged from the separation cylinder CB. For this reason, since the auxiliary control is terminated in advance before the discharge amount from the electric pump DC reaches the maximum discharge amount mb, a sudden change in operation characteristics can be avoided.

  Further, when the auxiliary control is terminated, the open valve VB can be changed from the closed position to the open position before the assist valve VA is changed from the open position to the closed position. The auxiliary control is ended while the operation of the braking operation member BP is increasing and changing (that is, the operation speed dB is generated when the end condition is satisfied). For example, the fluid lock (containment of the brake fluid BF) of the assist chamber Rh may occur instantaneously due to an error in the switching timing of the assist valve VA and the opening valve VB. Should this situation occur, the operating force Fp is instantaneously increased, and the driver may feel it strange. In order to suppress this situation, at the end of the auxiliary control, first, the open valve VB is switched to the open position, and thereafter (after a predetermined short time ts has elapsed), the assist valve VA is switched to the closed position. By adjusting the drive timing of the two solenoid valves VA and VB, the operational feeling of the braking operation member BP can be suitably maintained.

<Second Embodiment of Braking Control Device SC>
A second embodiment of the braking control device SC will be described with reference to the hydraulic circuit diagram of FIG. In the first embodiment, the assist valve VA is provided in the assist fluid passage HA. In the second embodiment, instead of this, a check valve GA is provided in the assisting fluid passage HA. The check valve GA allows the movement of the braking fluid BF from the assisting chamber Rh toward the pressure regulating fluid path HC, but the movement (reverse flow) of the braking fluid BF from the reverse regulating fluid path HC toward the assisting chamber Rh. ) Is blocked. In the first embodiment, the first separation unit KB1 is provided in the first system, and the second separation unit KB2 is provided in parallel in the second system. In the second embodiment, instead of this, one tandem separation unit KB is provided. That is, in the separation unit KB, the first and second pressurizing chambers Ra1 and Ra2 are arranged in series with respect to the pressure regulating fluid path HC (referred to as “series arrangement”).

  As described above, components, operations, signals, characteristics, and values that have the same symbols are of the same function. In the suffixes “i” to “l” at the end of various symbols, “i” represents the right front wheel, “j” represents the left front wheel, “k” represents the right rear wheel, and “l” represents the left rear wheel. Further, the suffixes “i” to “l” at the end of the symbol can be omitted. In this case, each symbol represents a generic name for each of the four wheels. In addition, suffixes “1” and “2” at the end of various symbols indicate that in two braking systems, “1” indicates the first system and “2” indicates the second system. Also, the suffixes “1” and “2” at the end of the symbol can be omitted. In this case, each symbol represents a generic name of the two braking systems.

  As the separation unit KB, a series arrangement type is adopted. Inside the separation cylinder CB, two separation pistons PB1 and PB2 are arranged coaxially with the central axis Jb of the separation cylinder CB. The outer peripheral portion of the second separation piston PB2 and the inner peripheral portion of the separation cylinder CB are sealed by a seal SL, and one side bottom portion of the separation cylinder CB, the inner peripheral portion of the separation cylinder CB, and the second separation piston PB2. A second pressurizing chamber Ra2 is formed by the one end portion. Similarly, the outer periphery of the first separation piston PB1 and the inner periphery of the separation cylinder CB are sealed by a seal SL, and the other end of the second separation piston PB2, the inner periphery of the separation cylinder CB, and The first pressurizing chamber Ra1 is formed by one end portion of the first separation piston PB1. A separation chamber Rb is formed by the other end portion of the first separation piston PB1, the inner peripheral portion of the separation cylinder CB, and the other bottom portion of the separation cylinder CB. In the central axis Jb, the separation chamber Rb is located on the opposite side of the first and second pressurization chambers Ra1 and Ra2 with respect to the first and second separation pistons PB1 and PB2.

  During non-braking when the braking operation member BP is not operated, the first and second separation pistons PB1, PB2 are moved to their initial positions (shown in the right direction in the figure) by the first and second separation elastic bodies (compression springs) SB1, SB2. (The position in the most backward direction Dq). The first and second sets of seals are in communication with the first and second master reservoir chambers Ru1 and Ru2 of the reservoir RV via first and second return fluid paths (not shown), respectively. May be. However, the first and second return fluid paths can be omitted.

  Similar to the first embodiment, the simulator SS includes a cylinder member CX, a piston member PX, and an elastic body SX. The interior of the simulator cylinder CX is partitioned into two hydraulic chambers Rf and Rh by the simulator piston PX. The reaction force chamber Rf and the assisting chamber Rh are formed with the simulator piston PX interposed therebetween. That is, the reaction force chamber Rf and the assisting chamber Rh are located on the opposite sides with respect to the simulator piston PX on the central axis Jx.

  The simulator elastic body (for example, compression spring) SX is placed in the assisting chamber Rh (between the second bottom portion Xu in the cylinder CX and the piston PX) so that the operation force Fp of the braking operation member BP is generated during the control braking. Provided. The elastic body SX presses the piston PX in the backward direction Ds (left direction in the figure) against the cylinder CX. During the control braking, the brake fluid BF flows into the reaction force chamber Rf of the simulator SS. The elastic body SX increases the elastic force so as to oppose the movement of the brake fluid BF into the reaction force chamber Rf. Thereby, the operation force Fp is formed.

  In the second master cylinder fluid passage HM2, the reaction force fluid passage HX is connected to a connection portion Bx between the second master cylinder chamber Rm2 and the second master cylinder valve VM2. Further, the reaction force fluid path HX is set as a reaction force chamber Rf of the simulator SS. The assisting fluid passage HA is connected to the assisting chamber Rh located on the opposite side of the reaction force chamber Rf with respect to the simulator piston PX. The assisting fluid passage HA is connected to the pressure regulating fluid passage HC at the connection portion Bz. That is, the assisting fluid path HA is a fluid path that connects the pressure regulating fluid path HC and the assisting chamber Rh. A check valve GA is provided in the assisting fluid passage HA. The check valve GA allows the brake fluid BF to move from the assisting chamber Rh toward the pressure regulating fluid path HC, but cannot flow backward from the pressure regulating fluid path HC to the assisting chamber Rh.

  An open fluid path HB is connected at the connection portion Bb of the assist fluid path HA between the assist chamber Rh and the check valve GA so as to connect the assist chamber Rh and the reservoir RV (particularly the pressure regulating reservoir chamber Rd). Is done. An open valve VB is provided in the open fluid path HB. The release valve VB is a normally closed on / off solenoid valve. The release valve VB is controlled by the upper controller ECU based on the drive signal Vb.

  Also in the second embodiment, the same auxiliary control as in the first embodiment is executed. At the time of control braking in which the braking operation is sudden (that is, when the controller ECU determines that the sudden operation is performed), the release valve VB is set to the closed position. Since the adjustment hydraulic pressure Pc has not yet been generated at the initial stage of the braking start, the reaction force chamber Rf passes through the check valve GA to the pressure regulating fluid path HC (finally the separation chamber Rb). The brake fluid BF is moved. As a result, auxiliary control that assists the increase in the adjustment hydraulic pressure Pc from “0” is executed.

  When the electric pump DC is activated and a predetermined time elapses, the adjustment hydraulic pressure Pc is increased. When the adjusted hydraulic pressure Pc becomes larger than the hydraulic pressure Ph in the assisting chamber Rh, the check valve GA prevents the braking fluid BF from moving between the assisting chamber Rh and the pressure regulating fluid path HC. Further, when the duration time Tk becomes equal to or longer than the predetermined time tk, the auxiliary control is ended and the release valve VB is switched from the closed position to the open position. In this case, even if the adjustment hydraulic pressure Pc is smaller than the hydraulic pressure Ph in the assisting chamber Rh, the brake fluid BF is moved to the reservoir RV. As in the first embodiment, the auxiliary control compensates for the startup response of the electric pump DC and improves the boosting characteristic of the brake fluid pressure Pw. Further, since the auxiliary control is terminated at an appropriate timing, the operation characteristics of the braking operation member BP can be suitably maintained.

  In the second embodiment, during manual braking, the brake fluid BF can move from the reaction force chamber Rf to the pressure regulating fluid path HC via the check valve GA. However, the movement distance of the simulator piston PX of the simulator SS is geometrically limited to the predetermined displacement dx. For this reason, the amount of the brake fluid BF consumed in the simulator SS is limited.

<Other embodiments>
First, actions and effects of the braking control device SC will be summarized. As described above, the pressure adjusting unit KC and the wheel cylinder CW are fluidly separated by the separation unit KB so that the brake fluid BF is not moved between the pressure adjusting unit KC and the wheel cylinder CW. As a result, even when the fluid path is damaged, the amount of the brake fluid BF flowing out of the device is limited to the maximum discharge amount mb or less, and the fail-safe property of the brake control device SC can be improved.

  When the electric pump DC is started from a stop state, the initial consumption liquid amount is supplied by the auxiliary control in a period in which the rotation of the electric pump DC is insufficient. In the filling period of the initial consumption liquid amount, the brake fluid pressure Pw is slightly increased (or the brake fluid pressure Pw is not increased). Further, the maximum discharge amount mb of the separation unit KB is extremely large with respect to the amount necessary for the increase of the adjustment hydraulic pressure Pc in the discharge amount at the time of starting the electric pump DC. For this reason, before the discharge amount of the electric pump DC reaches the maximum discharge amount mb, any one condition of “Tk ≧ tk”, “Na ≧ na”, and “Pc ≧ pc” is satisfied. The compensation control is terminated. Therefore, even when the on / off type release valve VB is instantaneously switched from the closed position to the open position at the end of the compensation control, the influence on the operation characteristics of the braking operation member BP is small. The auxiliary control can ensure responsiveness and reduce discomfort to the driver.

  Specifically, the auxiliary control is ended when the auxiliary control execution duration Tk is equal to or longer than a predetermined time tk. The predetermined time tk is the maximum output of the electric pump DC, and the discharge volume of the electric pump DC when the electric pump DC is driven from a stopped state is the maximum displacement of the separation piston PB in the separation cylinder CB. It may be set to be smaller than the volume (maximum discharge amount) mb discharged from the separation cylinder CB. When the electric pump DC discharges by the maximum discharge amount mb at the time of failure of the fluid path, the separation piston PB hits the first bottom portion Bu of the separation cylinder CB, and the adjustment hydraulic pressure Pc is rapidly increased. Since the auxiliary control is reliably terminated before the discharge amount from the electric pump DC reaches the maximum discharge amount mb, a sudden change in operation characteristics can be avoided.

  Hereinafter, other embodiments will be described. In other embodiments, the same effects as described above are obtained.

  The configuration shown in the first embodiment (parallel arrangement type separation unit KB + assisting valve VA) is combined with the configuration shown in the second embodiment (series arrangement type separation unit KB + check valve GA). Be free. That is, “parallel arrangement type separation unit KB + assisting valve VA”, “parallel arrangement type separation unit KB + check valve GA”, “series arrangement type separation unit KB + assistance valve VA”, and “series arrangement type separation unit” Any one configuration of “unit KB + check valve GA” may be employed. In any configuration, the same effect can be obtained.

  In the above embodiment, the vehicle is an electric vehicle having a drive motor or a hybrid vehicle. Instead, the braking control device SC can be applied to a vehicle having a general internal combustion engine that does not have a drive motor. In this case, regenerative braking by the drive motor is not generated, and therefore, regenerative cooperative control is not executed in the braking control device SC. That is, the vehicle is decelerated only by the friction brake by the braking control device SC. In the pressure regulation control, the control is executed as “Pt = Pr (that is, Rg = 0)”.

  In the above-described embodiment, the linear solenoid valve UC whose valve opening amount is adjusted according to the energization amount is employed. For example, although the electromagnetic valve UC is an on / off valve, the opening / closing of the valve may be controlled by a duty ratio, and the hydraulic pressure may be linearly controlled.

  In the above embodiment, even if there is a failure state on one side of the two braking systems, auxiliary control is executed on the other system. Alternatively, when the fluid path failure state is determined, the execution of the auxiliary control may be prohibited. Here, the fluid path failure state is at least one of the detection value (liquid level height) Lv of the liquid level sensor LV and the deviation hP between the target value Pt of the adjusted hydraulic pressure and the actual value Pc. Judgment based on.

  In the above embodiment, the configuration of the disc type braking device (disc brake) is exemplified. In this case, the friction member is a brake pad, and the rotating member is a brake disk. Instead of the disc type braking device, a drum type braking device (drum brake) may be employed. In the case of a drum brake, a brake drum is employed instead of the caliper. The friction member is a brake shoe, and the rotating member is a brake drum.

  In the above embodiment, a brushless motor is employed as a drive source of the fluid pump QC. As the electric motor MC, a brush motor (simply referred to as a brush motor) may be employed instead of the brushless motor. In this case, an H bridge circuit formed by four switching elements (power transistors) is used as the bridge circuit. As in the case of the brushless motor, the electric motor MC is provided with a rotation angle sensor KA, and the drive circuit DR is provided with an energization amount sensor.

  In the above embodiment, a diagonal fluid path is exemplified as the two-system fluid path. Instead, a front-rear type (also referred to as “H type”) configuration may be employed. In the front-rear fluid path, the front wheel cylinders CWi and CWj are fluidly connected to the first master cylinder fluid path HM1 (that is, the first system). The second master cylinder fluid passage HM2 (that is, the second system) is fluidly connected to the rear wheel cylinders CWk and CWl.

  In the above embodiment, the stroke simulator SS is connected to the second master cylinder fluid path HM2. Alternatively, the simulator SS can be connected to the first master cylinder fluid passage HM1 (particularly between the first master cylinder chamber Rm1 and the first master cylinder valve VM1).

BP ... braking operation member, CM ... master cylinder, CW ... wheel cylinder, KB ... separation unit, PB ... separation piston, CB ... separation cylinder, KC ... pressure adjusting unit, DC ... electric pump, MC ... electric motor, QC ... fluid Pump, UC ... solenoid valve, SS ... stroke simulator, CX ... simulator cylinder, PX ... simulator piston, VA ... assistance valve, VB ... release valve, GA ... check valve, ECU ... controller, BA ... manipulated variable sensor, PC ... Adjustment fluid pressure sensor.

Claims (2)

A braking control device for a vehicle that adjusts a hydraulic pressure of a wheel cylinder provided on a wheel of the vehicle,
An electric pump and a solenoid valve, and a pressure regulating unit that adjusts a fluid pressure in a pressure regulating fluid path between the electric pump and the solenoid valve;
It is composed of a simulator cylinder and a simulator piston, and “a reaction force chamber connected to the master cylinder of the vehicle” and “an assisting chamber located on the opposite side of the reaction force chamber with respect to the simulator piston” A simulator for applying an operating force to the braking operation member of the vehicle,
It is composed of a separation cylinder and a separation piston, and “a pressurization chamber connected to the wheel cylinder” and “a pressure chamber connected to the pressure regulating fluid path, opposite to the pressurization chamber” A separation unit having a separation chamber located on the side;
An assist valve provided in the assist fluid path connecting the assist chamber and the pressure regulating fluid path;
An opening valve provided between the assisting chamber and the assisting valve and in an open fluid path connecting the reservoir of the vehicle;
An operation amount sensor for detecting an operation amount of the braking operation member;
A controller for controlling the assist valve and the release valve;
With
The controller is
Based on the operation amount, it is determined whether or not the operation of the braking operation member is a sudden operation,
When the sudden operation is affirmed, the assist valve is set to the open position, the open valve is set to the closed position,
A braking control device for a vehicle configured to place the assist valve in a closed position and open the release valve when the sudden operation is denied. A braking control device for a vehicle that adjusts a hydraulic pressure of a wheel cylinder provided on a wheel of the vehicle,
An electric pump and a solenoid valve, and a pressure regulating unit that adjusts a fluid pressure in a pressure regulating fluid path between the electric pump and the solenoid valve;
It is composed of a simulator cylinder and a simulator piston, and “a reaction force chamber connected to the master cylinder of the vehicle” and “an assisting chamber located on the opposite side of the reaction force chamber with respect to the simulator piston” A simulator for applying an operating force to the braking operation member of the vehicle,
It is composed of a separation cylinder and a separation piston, and “a pressurization chamber connected to the wheel cylinder” and “a pressure chamber connected to the pressure regulating fluid path, opposite to the pressurization chamber” A separation unit having a separation chamber located on the side;
Provided in the assisting chamber and the assisting fluid path connecting the pressure regulating fluid path, the brake fluid is allowed to move from the assisting chamber to the pressure regulating fluid path, but from the pressure regulating fluid path to the assisting chamber. A check valve for preventing movement of the brake fluid to
An opening valve provided between the assisting chamber and the check valve and in an opening fluid path connecting the reservoir of the vehicle;
An operation amount sensor for detecting an operation amount of the braking operation member;
A controller for controlling the open valve;
With
The controller is
Based on the operation amount, it is determined whether or not the operation of the braking operation member is a sudden operation,
When the sudden operation is affirmed, the release valve is closed,
A braking control device for a vehicle configured to open the release valve when the sudden operation is denied.