JP2019059295A - Brake control device for vehicle - Google Patents

Abstract

To provide a brake control device whose dimension in a longitudinal direction is reduced in the brake control device for a vehicle.SOLUTION: A brake control device includes: "a pressure adjusting unit adjusting fluid pressure generated by an electric motor and generating adjusted fluid pressure"; "a master unit which is composed of a master cylinder and a master piston and has 'a master chamber connected to a wheel cylinder' and 'a servo chamber to which the adjusted fluid pressure is introduced and which imparts to the master piston a first advancing force Fa opposing a first backward moving force Fb added to the master piston by the master chamber'"; and "a bypass unit which is composed by a bypass cylinder and a bypass piston and has 'a bypass chamber connected to the wheel cylinder' and 'a pressure regulation chamber to which the adjusted fluid pressure is introduced and which imparts to the bypass piston a second advancing force Fc opposing a second backward moving force Fd added to the bypass piston by the bypass chamber'".SELECTED DRAWING: Figure 1

Description

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

  Patent Document 1 discloses that in a vehicle braking system to which a bi-wire brake system is applied, a failure such as an abnormality in a communication network is transmitted to the vehicle for the purpose of preventing a decrease in braking force at the time of backup. When it occurs in the braking system, open the first and second shutoff valves to connect the slave cylinder and the master cylinder, and maintain the current position of the first and second slave pistons by driving the motor. Thereafter, when the operation of the brake pedal is released, the operation of the motor is stopped.

  In the device described in Patent Document 1, a slave cylinder drives a ball screw shaft with the power of a motor serving as an electric actuator, and the brake fluid pressure is generated by the first and second slave pistons based on the driving of the ball screw shaft. Let The first and second slave pistons are biased in the reverse direction by coil springs, respectively. The ball screw shaft is driven in the forward direction by the power of the motor to move the first and second slave pistons in the forward direction against the biasing force of the coil spring, thereby generating the brake fluid pressure. That is, in this device, a tandem-type slave cylinder is adopted, a ball screw is provided on the central axis of the slave cylinder, and the rotational power of the electric motor is converted into linear power of the slave piston by the ball screw Is generated. Due to the construction, the longitudinal dimension of the cylinder is long, so shortening thereof is desired.

JP, 2016-165913, A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a brake control device for a vehicle, which has a reduced longitudinal dimension and high mountability to a vehicle.

  The braking control device for a vehicle according to the present invention comprises a fluid of a braking fluid (BF) in a wheel cylinder (CW) provided on a wheel (WH) of the vehicle according to an operation of a braking operation member (BP) of the vehicle Pressure adjustment unit (Yc) that adjusts the hydraulic pressure generated by the electric motor (MC, MZ, MD) to obtain adjusted hydraulic pressure (Pc), and A cylinder (CM) and a master piston (PM), and "a master chamber (Rm) connected to the wheel cylinder (CW)", and "the adjusted hydraulic pressure (Pc) are introduced, It has a servo chamber (Rs) that applies a first forward force (Fa) to the master piston (PM) opposite to a first reverse force (Fb) applied to the master piston (PM) by the master chamber (Rm) Master unit (YM And “a bypass chamber (Rb) configured with a bypass cylinder (CB) and a bypass piston (PB) and connected to the wheel cylinder (CW)”, ”and“ the adjusted hydraulic pressure (Pc) Pressure regulation chamber for applying a second forward force (Fc) to the bypass piston (PB) opposite to the second backward force (Fd) applied to the bypass piston (PB) by the bypass chamber (Rb) (Rc) "and" bypass unit (YB) ".

  The volume of master cylinder CM is determined by the maximum braking force to be generated, and the inner diameter of master cylinder CM is determined by the operating force Fp at the time of manual braking. In order for the two conditions to be satisfied, the master cylinder CM is required to have a small diameter and an axial length. According to the above configuration, the braking fluid BF is supplied to the wheel cylinder CW by the bypass unit YB in addition to the master unit YM. Therefore, even when the small-diameter master cylinder CM is employed, the flow rate of the braking fluid BF can be secured, and the dimension in the longitudinal direction of the master cylinder CM can be shortened.

  The braking control device for a vehicle according to the present invention comprises a master elastic body (SM) for applying a first elastic force opposed to the first forward force (Fa) to the master piston (PM); And a bypass elastic body (SB) for applying a second elastic force facing the Fc) to the bypass piston (PB). And, when the adjusted hydraulic pressure (Pc) increases from zero, the bypass elastic body (SB) is moved so that the master piston (PM) is moved before the bypass piston (PB) is moved. The relationship between the characteristics and the characteristics of the master elastic body (SM) is set.

  According to the above configuration, first, the master piston PM is moved in the forward direction Ha, the communication between the reservoir RV and the master chamber Rm is shut off, and the fluid-tight state of the master cylinder chamber Rm is achieved. Thereafter, the bypass piston PB starts to move in the forward direction Hc. Therefore, the braking fluid BF from the bypass unit YB is efficiently supplied to the wheel cylinder CW without being moved to the reservoir RV.

FIG. 1 is an overall configuration diagram for describing a first embodiment of a brake control device SC of a vehicle according to the present invention. It is the schematic for demonstrating bypass unit YB. It is a control flowchart for demonstrating the process of pressure regulation control. It is the schematic for demonstrating the other structural example of bypass unit YB. It is a whole block diagram for describing a 2nd embodiment of brake control control equipment SC of a vehicle concerning the present invention. It is the schematic for demonstrating the other example of arrangement | positioning of bypass unit YB. It is the schematic for demonstrating the other structural example of pressure regulation unit YC. It is the schematic for demonstrating the other structural example of the regeneration cooperation unit YK.

<Symbol such as component members, and suffix at the end of the symbol>
In the following description, components having the same symbol, such as “ECU”, etc., arithmetic processing, signals, characteristics, and values have the same functions. The subscripts "i" to "l" added at the end of the various symbols are generic symbols indicating which wheel it relates to. Specifically, “i” indicates the front right wheel, “j” indicates the front left wheel, “k” indicates the rear right wheel, and “l” indicates the rear left wheel. For example, in each of the four wheel cylinders, they are described 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. Furthermore, the suffixes "i" to "l" at the end of the symbol may be omitted. When the subscripts "i" to "l" are omitted, each symbol represents a generic name for each of the four wheels. For example, "WH" represents each wheel, and "CW" represents each wheel cylinder.

  The subscripts “1” and “2” added at the end of various symbols are generic symbols indicating in which of two braking systems it relates. Specifically, "1" indicates the first system, and "2" indicates the second system. For example, in the master cylinder chamber, the first master cylinder chamber Rm1 and the second master cylinder chamber Rm2 are described. Furthermore, the suffixes "1" and "2" at the end of the symbol may be omitted. When the subscripts “1” and “2” are omitted, each symbol represents a generic name of the two braking systems. For example, "Rm" represents a master cylinder chamber in each braking system.

  In the case where front and rear types are adopted in the two braking systems, the subscripts “f” and “r” added to the end of various symbols relate to any of the front and rear wheels in the two braking systems. It is a generic symbol indicating whether there is any. Specifically, "f" indicates a front wheel system, and "r" indicates a rear wheel system. For example, in a wheel cylinder, it is described as a front wheel wheel cylinder CWf and a rear wheel wheel cylinder CWr. Furthermore, the suffixes "f", "r" at the end of the symbol may be omitted. When the subscripts "f" and "r" are omitted, each symbol represents a generic name of the two braking systems. For example, "CW" represents a wheel cylinder in the front and rear braking systems.

  The operation of the braking control device SC is in a proper state, and the braking performed by the braking control device SC is referred to as "controlled braking". When the operation of the braking control device SC is in a malfunctioning state, braking by only the driver's operating force is referred to as "manual braking". Therefore, in the manual braking, the braking control device SC is not used.

<First Embodiment of Braking Control Device of 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 a general vehicle, two fluid paths are employed to ensure redundancy. Here, the fluid path is a path for moving the braking fluid BF, which is a working fluid of the braking control device, and corresponds to a braking pipe, a flow path of a fluid unit, a hose or the like. The inside of the fluid path is filled with the damping fluid BF. In the fluid passage, the side closer to the reservoir RV (the side farther from the wheel cylinder CW) is referred to as “upstream” or “upper”, and the side closer to the wheel cylinder CW (the side farther from the reservoir RV) is It is called "downstream" or "lower."

  In the first embodiment, the front wheel system of the two fluid paths is connected to the front wheel cylinders CWi, CWj (also described as "CWf"). Further, the rear wheel system of the two fluid paths is connected to rear wheel wheel cylinders CWk, CWl (also described as "CWr"). That is, so-called front and rear types (also referred to as “H-type”) are adopted as the fluid paths of two systems.

  The vehicle is a hybrid vehicle or an electric vehicle equipped with an electric motor GN for driving. The driving electric motor GN also functions as a generator (energy generator) for energy regeneration. For example, the drive motor GN is provided on the front wheel WHf. In the braking control device SC, so-called regenerative coordination control (coordination between regenerative braking and friction braking) is performed. A vehicle provided with a braking control device SC is provided with a braking operation member BP, a wheel cylinder CW, a reservoir RV, and a wheel speed sensor VW.

  The braking operation member (for example, a brake pedal) BP is a member operated by the driver 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 wheel WH of the vehicle. And a brake caliper is arrange | positioned so that the rotation member KT may be pinched.

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

  The reservoir (atmospheric pressure reservoir) RV is a tank for working fluid, in which the damping fluid BF is stored. The inside of the atmospheric pressure reservoir RV is divided into two parts Ru and Rd by a partition plate SK. Master reservoir chamber Ru is connected to master cylinder chamber Rm. In addition, the pressure control reservoir chamber Rd is connected to the pressure control unit YC by the first reservoir fluid path HR. When the damping fluid BF is filled in the reservoir RV, the liquid surface of the damping fluid BF is above the height of the partition plate SK. Therefore, the damping fluid BF can freely move between the master reservoir chamber Ru and the pressure control reservoir chamber Rd beyond the partition plate SK. On the other hand, when the amount of damping fluid BF in the reservoir RV decreases and the fluid surface of the damping fluid BF becomes lower than the height of the partition plate SK, the master reservoir chamber Ru and the pressure control reservoir chamber Rd become independent of each other. It will be a liquid reservoir.

  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 in anti-skid control or the like for suppressing the lock tendency (excessive deceleration slip) of the wheel WH. Each wheel speed Vw detected by the wheel speed sensor VW is input to the lower controller ECL. In the controller ECL, a vehicle speed Vx is calculated based on the wheel speed Vw.

«Braking control device SC»
The braking control device SC is configured by an upper fluid unit YU closer to the master cylinder CM and a lower fluid unit YL closer to the wheel cylinder CW. The upper fluid unit YU is a fluid unit controlled by the upper controller ECU and included in the braking control device SC.

  The upper fluid unit YU is configured of an operation amount sensor BA, an operation switch ST, a master unit YM, a pressure adjustment unit YC, a regeneration coordination unit YK, and an upper controller ECU.

  The brake operation member BP is provided with an operation amount sensor BA. The operation amount sensor BA detects the operation amount Ba of the braking operation member (brake pedal) BP by the driver. As the operation amount sensor BA, an operation displacement sensor SP is provided to detect an operation displacement Sp of the braking operation member BP. In addition, an operation force sensor FP may be provided to detect the operation force Fp of the braking operation member BP. Further, as the operation amount sensor BA, a simulator hydraulic pressure sensor PS is provided so as to detect the hydraulic pressure (simulator hydraulic pressure) Ps in the stroke simulator SS. Therefore, at least one of the simulator hydraulic pressure Ps, the braking operation displacement Sp, and the braking operation force Fp is detected as the braking operation amount Ba. The braking operation amount Ba is a command signal for decelerating the vehicle, and is input to the upper controller ECU.

  The braking operation member BP is provided with an operation switch ST. The operation switch ST detects the presence or absence of the operation of the braking operation member BP by the driver. When the braking operation member BP is not operated (that is, when not braking), the braking operation switch ST outputs an off signal as the operation signal St. On the other hand, when the braking operation member BP is operated (ie, at the time of braking), an ON signal is output as the operation signal St. The braking operation signal St is input to the controller ECU.

[Master unit YM (single type)]
The fluid pressure (front wheel braking fluid pressure) Pwf in the front wheel wheel cylinder CWf is adjusted by the master unit YM via the master cylinder chamber Rm. The master unit YM is configured to include a master cylinder CM, a master piston PM, and a master elastic body SM.

  Master cylinder CM is a cylinder member having a bottom. The master piston PM is a piston member inserted inside the master cylinder CM, and is movable in conjunction with the operation of the braking operation member BP. The inside of the master cylinder CM is divided into three chambers (fluid pressure chambers) Rm, Rs and Ro by a master piston PM.

  A groove is formed in the first inner peripheral portion Mc of the master cylinder CM, and two seals SL are fitted in the groove. An outer peripheral portion (outer peripheral cylindrical surface) Mp of the master piston PM and a first inner peripheral portion (inner peripheral cylindrical surface) Mc of the master cylinder CM are sealed by the two seals SL. Master piston PM can move smoothly along central axis Jm of master cylinder CM.

  The master cylinder chamber (simply referred to as “master chamber”) Rm is defined by “the first inner peripheral portion Mc, the first bottom portion (bottom surface) Mu” of the master cylinder CM, and the first end Mv of the master piston PM. It is a divided hydraulic chamber. A master cylinder fluid passage HM is connected to the master chamber Rm, and is ultimately connected to the front wheel wheel cylinder CWf via the lower fluid unit YL. In the first embodiment, a master cylinder chamber is not provided in the master cylinder CM for the rear wheel wheel cylinder CWr. The master cylinder CM is called "single type".

  The master piston PM is provided with a flange portion Tm. The inside of the master cylinder CM is divided into a servo hydraulic pressure chamber (also simply referred to as a “servo chamber”) Rs and a rear hydraulic pressure chamber (also simply referred to as a “rear chamber”) Ro by the flange portion Tm. A seal SL is provided on the outer peripheral portion of the collar portion Tm, and the collar portion Tm and the second inner peripheral portion Md of the master cylinder CM are sealed (sealed). The servo chamber Rs is a hydraulic pressure chamber partitioned by "the second inner peripheral portion Md and the second bottom portion (bottom surface) Mt of the master cylinder CM" and the first surface Ms of the flange portion Tm of the master piston PM. . The master chamber Rm and the servo chamber Rs are disposed to face each other across the master piston PM. A front wheel pressure adjustment fluid passage HCf is connected to the servo chamber Rs, and an adjusted hydraulic pressure Pc is introduced (supplied) from the pressure adjustment unit YC.

  The rear chamber (rear hydraulic pressure chamber) Ro is a hydraulic pressure chamber defined by the second inner peripheral portion Md of the master cylinder CM, the stepped portion Mz, and the second surface Mo of the flange portion Tm of the master piston PM. It is. The rear hydraulic pressure chamber Ro is sandwiched between the master hydraulic pressure chamber Rm and the servo hydraulic pressure chamber Rs in the direction of the central axis Jm and is located between them. A simulator fluid passage HS is connected to the rear chamber Ro. The amount of damping fluid BF in the upper fluid unit YU is adjusted by the rear chamber Ro.

  The first end Mv of the master piston PM is provided with a recess Mx. A master elastic body (e.g., a compression spring) SM is provided between the recess Mx and the first bottom Mu of the master cylinder CM. Master elastic body SM presses master piston PM against second bottom Mt of master cylinder CM in the direction of central axis Jm of master cylinder CM. At the time of non-braking, the stepped portion My of the master piston PM abuts on the second bottom portion Mt of the master cylinder CM. The position of the master piston PM in this state is referred to as "the initial position of the master unit YM".

  Between the two seals SL (for example, a cup seal), the master cylinder CM is provided with a through hole Ac. The through hole Ac is connected to the master reservoir chamber Ru via the replenishment fluid passage HU. A through hole Ap is provided in the vicinity of the first end Mv of the master piston PM. When the master piston PM is in the initial position, the master chamber Rm is in communication with the reservoir RV (in particular, the master reservoir chamber Ru) via the through holes Ac and Ap and the replenishment fluid passage HU.

  The master chamber Rm has an urging force Fb in the reverse direction Hb along the central axis Jm (referred to as a "first reverse force") by its internal pressure ("master cylinder fluid pressure", also referred to as "master fluid pressure") Pm. Is applied to the master piston PM. The servo chamber (servo hydraulic pressure chamber) Rs has an urging force Fa (referred to as “first forward force”) opposed to the reverse force Fb as the master piston PM by its internal pressure (that is, the introduced adjusted hydraulic pressure Pc). Give. That is, in master piston PM, forward force Fa by fluid pressure Pv (= Pc) in servo chamber Rs and reverse force Fb by fluid pressure (master fluid pressure) Pm in master chamber Rm are central axes of master cylinder CM. They face each other in the direction of Jm and are statically balanced.

  For example, the pressure receiving area rs of the first surface Ms of the flange portion Tm (that is, the pressure receiving area of the servo chamber Rs) is the pressure receiving area of the first end Mv of the master piston PM (that is, the pressure receiving area of the master chamber Rm) rm It is set to be equal. In this case, the hydraulic pressure Pc introduced into the servo chamber Rs (as a result, the servo hydraulic pressure Pv) and the hydraulic pressure Pm in the master chamber Rm are the same in the steady state. At this time, the first forward force Fa (= Pc × rs) and the first reverse force Fb (= Pm × rm (+ elastic force of the master elastic body SM)) are balanced.

  When the brake operation member BP is operated, the adjusted hydraulic pressure Pc is increased by the pressure control unit YC. The adjusted hydraulic pressure Pc is supplied into the servo chamber Rs, and the hydraulic pressure (servo hydraulic pressure) Pv in the servo chamber Rs is increased. When the force (first forward force) Fa of the forward direction (left direction in the figure) Ha generated by the servo hydraulic pressure Pv becomes larger than the attachment load (set load) of the master elastic body SM, the master piston PM is It is moved along the axis Jm. When the through hole Ap passes the seal SL by the movement in the forward direction Ha, the master chamber Rm is shut off from the reservoir RV (in particular, the master reservoir chamber Ru), and the master chamber Rm is made liquid tight. Furthermore, when the adjusted hydraulic pressure Pc is increased, the volume of the master chamber Rm decreases, and the braking fluid BF is pumped from the master cylinder CM toward the front wheel cylinder CWf with the master hydraulic pressure Pm. A force (first retraction force) Fb in the reverse direction Hb is applied to the master piston PM by the master hydraulic pressure Pm (= Pwf). The servo chamber Rs generates a force (first forward force) Fa in the forward direction Ha by the servo hydraulic pressure Pv (= Pc) so as to oppose (face) the reverse force Fb. Therefore, the master hydraulic pressure Pm is increased or decreased according to the increase or decrease of the adjusted hydraulic pressure Pc.

  When the brake operating member BP is returned, the adjusted hydraulic pressure Pc is decreased by the pressure control unit YC. Then, the servo hydraulic pressure Pv becomes smaller than the master chamber hydraulic pressure Pm (= Pwf), and the master piston PM is moved in the reverse direction (right direction in the drawing) Hb. When the braking operation member BP is not operated, the position (initial position) where the master piston PM (particularly, the stepped portion My) contacts the second bottom Mt of the master cylinder CM by the elastic force of the compression spring SM. Will be returned to

[Pressure regulator unit YC (reflux type)]
The fluid pressure Pm in the master chamber Rm and the fluid pressure (rear wheel braking fluid pressure) Pwr in the rear wheel wheel cylinder CWr are adjusted by the pressure adjustment unit YC. The pressure control unit YC includes an electric pump DC, a pressure control fluid path HC, a check valve GC, a solenoid valve UC, and a control hydraulic pressure sensor PC. In the pressure control unit YC, the braking fluid BF discharged by the electric pump DC is adjusted to the adjusted hydraulic pressure Pc by the solenoid valve UC. The adjusted hydraulic pressure Pc is applied to the master unit YM (in particular, the servo chamber Rs) and the rear wheel wheel cylinder CWr.

  The return motor pump DC is constituted by a set of one return electric motor MC and one return fluid pump QC. In the return electric motor pump DC, the electric motor MC is configured so that the electric return motor MC (also simply referred to as “reflow motor”) MC and the fluid pump for return liquid QC (also simply referred to as “reflux pump”) rotate integrally. And the fluid pump QC are fixed. The return electric motor pump DC (in particular, the return motor MC) is a power source for adjusting the hydraulic pressure (braking hydraulic pressure) Pw of the wheel cylinder CW at the time of control braking. The upper 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 for detecting the rotor position (rotation angle) Ka. The switching elements of the bridge circuit are controlled based on the rotation angle (actual value) Ka, and the electric motor MC is driven. That is, the direction (that is, the excitation direction) of the energization amounts of the coils of each of the three phases (U phase, V phase and W phase) is sequentially switched, and the brushless motor MC is rotationally driven.

  The first reservoir fluid passage HR is connected to the suction port Qs of the reflux pump QC. Further, a pressure control fluid passage HC is connected to the discharge port Qt of the fluid pump QC. By driving the electric pump DC (in particular, the fluid pump QC), the braking fluid BF is sucked from the first reservoir fluid passage HR through the suction port Qs and discharged from the discharge port Qt to the pressure regulating fluid passage HC. For example, a gear pump is employed as the adjustment fluid pump QC.

  A check valve GC (also referred to as a "check valve") is interposed in the pressure control fluid passage HC. For example, a check valve GC is provided near the discharge portion Qt of the fluid pump QC. The check fluid GC can move the braking fluid BF from the first reservoir fluid passage HR to the pressure regulating fluid passage HC, but moves from the pressure regulating fluid passage HC to the first reservoir fluid passage HR. (Ie, backflow of the damping fluid BF) is blocked. That is, the electric pump DC is rotated only in one direction.

  The solenoid valve UC is connected to the pressure control fluid passage HC and the first reservoir fluid passage HR. The pressure regulating solenoid valve UC is a linear solenoid valve (a “proportional valve” or a “differential pressure valve”) in which the valve opening amount (lift amount) is continuously controlled based on an energized state (for example, supplied current). Say). The pressure adjustment solenoid valve UC is controlled by the upper controller ECU based on the drive signal Uc. A normally open solenoid valve is employed as the solenoid valve UC.

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

  When the electric pump DC is operating, the braking 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 fully open (normally open type, no current flow), the fluid pressure (adjusted fluid pressure) Pc in the pressure regulating fluid passage HC is low, substantially "0 (atmospheric pressure)" It is. When the energization amount to the pressure regulation solenoid valve UC is increased and the return path is narrowed by the solenoid valve UC, the adjusted fluid pressure Pc is increased. The pressure control system is called "reflux type". In the pressure regulation unit YC, a regulated hydraulic pressure sensor PC is provided in the pressure regulation fluid path HC (particularly, between the check valve GC and the pressure regulation valve UC) so as to detect the regulated hydraulic pressure Pc.

  In the pressure control unit YC, the return electric motor DC is rotationally driven based on the braking operation amount Ba and a preset characteristic (calculation map). Then, based on the detection result (adjusted hydraulic pressure Pc) of the adjusted hydraulic pressure sensor PC, the pressure adjusting electromagnetic valve UC is controlled to adjust the hydraulic pressure Pc in the pressure adjusting fluid passage HC. Specifically, the rotational speed Na of the reflux electric pump DC (particularly, the upper electric motor MC) is controlled so that the target fluid pressure Pt is achieved, and the braking fluid BF from the electric pump DC (particularly, the fluid pump QC) is controlled. Flow (flow rate) is generated. The pressure regulating solenoid valve UC throttles the flow of the braking fluid BF to finally achieve the target fluid pressure Pt. That is, the adjustment hydraulic pressure Pc is adjusted by the orifice effect of the pressure control solenoid valve UC.

  The pressure control fluid passage HC is branched (split) into the front wheel pressure control fluid passage HCf and the rear wheel pressure control fluid passage HCr at a portion Bn. The front wheel pressure adjustment fluid path HCf is connected to the servo room Rs, and the adjusted hydraulic pressure Pc is introduced into the servo room Rs. Further, the rear wheel pressure adjustment fluid path HCr is connected to the lower fluid unit YL, and finally to the rear wheel wheel cylinder CWr (CWk, CWl). Accordingly, the adjusted hydraulic pressure Pc is introduced into the rear wheel wheel cylinder CWr. The hydraulic pressure Pwr of the rear wheel wheel cylinder CWr is directly controlled by the pressure control unit YC without intervention of the master cylinder CM. Therefore, the dimension in the direction of central axis Jm of master cylinder CM can be shortened.

[Regenerative coordination unit YK]
The regenerative coordination unit YK achieves coordinated control of friction braking and regenerative braking. That is, although the braking operation member BP is operated by the regenerative cooperation unit YK, a state in which the braking fluid pressure Pw is not generated may be formed. The regeneration coordination unit YK is configured of an input cylinder CN, an input piston PN, an input elastic body SN, a first on-off valve VA, a second on-off valve VB, a stroke simulator SS, and a simulator hydraulic pressure sensor PS.

  The input cylinder CN is a cylinder member fixed to the master cylinder CM and having a bottom. The input piston PN is a piston member inserted inside the input cylinder CN. The input piston PN is mechanically connected to the braking operation member BP via a clevis (U-shaped link) so as to interlock with the braking operation member BP. The input piston PN is provided with a flange portion Tn. An input elastic body (e.g., a compression spring) SN is provided between a mounting surface of the input cylinder CN to the master cylinder CM and the flange portion Tn of the input piston PN. The input elastic body SN presses the flange Tn of the input piston PN against the bottom of the input cylinder CN in the direction of the central axis Jm.

  When not braking, the stepped portion My of the master piston PM abuts on the second bottom Mt of the master cylinder CM, and the flange Tn of the input piston PN abuts on the bottom of the input cylinder CN. At the time of non-braking, the gap Ks between the master piston PM (especially, the end face Mq) and the input piston PN (especially, the end face Rv) is made a predetermined distance ks (referred to as "initial gap") inside the input cylinder CN. There is. That is, when each piston PM, PN is at the position in the most backward direction Hb (referred to as the “initial position” of each piston) (ie, when not braking), the master piston PM and the input piston PN are only the predetermined distance ks is seperated. Here, the predetermined distance ks corresponds to the maximum value of the regeneration amount Rg. When the regenerative coordinated control is executed, the gap (also referred to as “displacement displacement”) Ks is controlled (adjusted) by the adjusted hydraulic pressure Pc.

  The diameter dm of the master piston PM (end Mq) in the input cylinder CN is set to be equal to the diameter dn of the input piston PN entering the input cylinder CN when the braking operation member BP is operated. Ru. That is, the cross-sectional area am by the diameter dm matches the cross-sectional area an by the diameter dn. As described later, the manual braking is realized by fluid lock of the inside of the input cylinder CN. When manual braking is performed, since “dm = dn (am = an)”, the intruding volume of the input piston PN into the input cylinder CN is matched to the exiting volume of the master piston PM out of the input cylinder CN. Thus, each piston PN, PM is moved in the forward direction Ha. That is, the displacement Hn of the input piston PN matches the displacement Hm of the master piston PM, and the force Fn applied to the input piston PN by the driver is taken as the force Fm acting on the master piston PM as it is (Ie, "Hn = Hm, Fn = Fm").

  The input cylinder CN is connected to the reservoir RV (in particular, the pressure control reservoir chamber Rd) via the second reservoir fluid path HT. The second reservoir fluid passage HT can share a portion with the first reservoir fluid passage HR. However, it is desirable that the first reservoir fluid passage HR and the second reservoir fluid passage HT be separately connected to the reservoir RV. Although the fluid pump QC sucks the damping fluid BF from the reservoir RV via the first reservoir fluid path HR, bubbles may be mixed in the first reservoir fluid path HR at this time. For this reason, the second reservoir fluid passage HT does not have a common part with the first reservoir fluid passage HR and is separate from the first reservoir fluid passage HR so as to prevent air bubbles from being mixed in the input cylinder CN and the like. To the reservoir RV.

  Two on-off valves VA and VB are provided in series in the second reservoir fluid path HT. The first and second on-off valves VA and VB are two-position solenoid valves (also referred to as "on / off valves") having an open position (communication state) and a closed position (cut state). The first and second on-off valves VA and VB are controlled by the upper controller ECU based on the drive signals Va and Vb. A normally closed solenoid valve is adopted as the first on-off valve VA, and a normally open solenoid valve is adopted as the second on-off valve VB.

  The second reservoir fluid passage HT is connected to the simulator fluid passage HS at a connection Bs between the first on-off valve VA and the second on-off valve VB. In other words, one end of the simulator fluid path HS is connected to the rear chamber Ro, and the other end is connected to the portion Bs. The simulator fluid path HS is provided with a stroke simulator (also simply referred to as “simulator”) SS. When the regenerative coordinated control is executed by the simulator SS and the first on-off valve VA is in the open position and the second on-off valve VB is in the closed position, the operating force Fp of the braking operation member BP is generated. Inside the simulator SS, a piston and an elastic body (for example, a compression spring) are provided. The braking fluid BF is moved from the input cylinder CN to the simulator SS, and the piston is pushed by the inflowing braking fluid BF. A force is applied to the piston by the elastic body in a direction to prevent the inflow of the braking fluid BF. The elastic body forms an operating force Fp when the brake operating member BP is operated.

  A simulator fluid pressure sensor PS is provided in the simulator fluid path HS so as to detect the fluid pressure (simulator fluid pressure) Ps in the simulator SS. The simulator hydraulic pressure sensor PS is one of the braking operation amount sensors BA described above. The detected simulator hydraulic pressure Ps is input to the controller ECU as the braking operation amount Ba.

  The cross-sectional area am of the end Mq of the master piston PM and the area ao of the second surface Mo of the flange Tm are set equal so that the volume change associated with the movement of the master piston PM is absorbed. When the regenerative coordinated control is executed, the first on-off valve VA is in the open position and the second on-off valve VB is in the closed position, so the input chamber Rn and the rear chamber Ro are the second reservoir fluid path HT, , Simulator fluid path HS is connected. When the master piston PM is moved in the forward direction Ha, the volume in the input chamber Rn is increased by the movement amount, but since “am = ao”, all the damping fluid BF in the volume increase is the rear chamber Move from Ro to the input room Rn. In other words, the balance of the fluid amount accompanying the movement of the master piston PM is neither excessive nor insufficient. Therefore, the amount (volume) of the damping fluid BF which flows into or out of the simulator SS depends only on the movement of the input piston PN.

[Bypass unit YB]
A bypass unit YB is provided in parallel with the master unit YM so as to bypass the master unit YM. The brake fluid BF is supplied to the wheel cylinder CW by two units YM and YB. The pressure control fluid passage HC is branched at the portion Bb and connected to the bypass unit YB. Further, a bypass fluid passage HB is connected to the bypass unit YB, and an end of the bypass fluid passage HB is connected to the master cylinder fluid passage HM at a portion Bm. Accordingly, the adjusted hydraulic pressure Pc is introduced (supplied) to the bypass unit YB, and the output thereof is introduced to the front wheel wheel cylinder CWf via the bypass fluid passage HB. The detailed configuration of the bypass unit YB will be described later. The braking fluid BF adjusted to the adjusted hydraulic pressure Pc is applied to the master unit YM (in particular, the servo chamber Rs). In addition, the adjusted hydraulic pressure Pc is also applied to the bypass unit YB and is output to the front wheel cylinder CWf. That is, the braking fluid BF from the pressure adjustment unit YC is moved to the front wheel wheel cylinder CWf through the master unit YM and the bypass unit YB. As a result, the amount (volume) of the damping fluid BF required for the master unit YM is reduced, so that miniaturization of the master unit YM can be achieved.

  In particular, in order to reduce the operating force Fp in manual braking, the inner diameter of the master cylinder CM needs to be reduced. However, since the master cylinder CM requires a certain amount of volume, the master cylinder CM is extended in the longitudinal direction (direction of the central axis Jm). Since the capacity required for the master cylinder CM is reduced by the bypass unit YB, the master cylinder CM can be shortened.

[Upper controller ECU]
The upper controller (also referred to as "electronic control unit") ECU is configured of an electric circuit board on which a microprocessor MP or the like is mounted, and a control algorithm programmed in the microprocessor MP. The electric motor MC and three different solenoid valves VA, VB, and UC are controlled by the upper controller ECU based on the braking operation amount Ba, the operation signal St, and the adjusted hydraulic pressure Pc. Specifically, drive signals Va, Vb and Uc for controlling the various solenoid valves VA, VB and 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. Then, based on the drive signals Va, Vb, Uc, Mc, the solenoid valves 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 a network via the in-vehicle communication bus BS. The regeneration amount Rg (target value) is transmitted from the upper controller ECU to the driving controller ECD through the communication bus BS so as to execute the regeneration coordination control. The “regeneration amount Rg” is a state amount (target value) that represents the magnitude of regenerative braking generated by the drive motor (also a regeneration generator) GN. The regenerative braking is generated by controlling the regeneration generator GN by the drive controller ECD based on the target value Rg of the amount of regeneration. Electric power is supplied to each controller ECU, ECL, and ECD from the on-board generator AL and the storage battery BT.

  The upper controller ECU is provided with a drive circuit DR to drive the solenoid valves 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-FETs and IGBTs) so as to drive the electric motor MC. The energization state of each switching element is controlled based on the motor drive signal Mc, and the output of the electric motor MC is controlled. Further, in the drive circuit DR, the energized state (that is, the excited state) is controlled based on the drive signals Va, Vb and Uc so as to drive the solenoid valves VA, VB and UC. The drive circuit DR is provided with an electric motor MC and an energization amount sensor for detecting the actual energization amount of the solenoid valves VA, VB, and UC. For example, a current sensor is provided as an energization amount sensor, and a current supplied to the electric motor MC and the solenoid valves VA, VB, and UC is detected.

  During non-braking (for example, when the operation of the braking operation member BP is not performed), the electric motor MC and the solenoid valves VA, VB, and UC are not energized. Therefore, the electric motor MC is stopped, the first on-off valve VA is in the closed position, the second on-off valve VB is in the open position, and the pressure regulating valve UC is in the open position.

  During control braking when the braking control device SC is in the proper operation state, the controller ECU first energizes the first and second on-off valves VA and VB so that the first on-off valve VA is in the open position. 2 The on-off valve VB is in the closed position. The input chamber Rn and the rear chamber Ro are fluidly connected and the simulator SS is connected to the input chamber Rn by the open position of the first on-off valve VA. Further, the connection between the simulator SS and the reservoir RV is cut off by the closed position of the second on-off valve VB. The input piston PN is moved in the forward direction Ha by the operation of the braking operation member BP, and the amount of fluid flowing out of the input chamber Rn flows into the simulator SS by the movement, and the operation force Fp of the braking operation member BP is formed.

  During controlled braking, the controller ECU controls the electric pump DC (particularly, the electric motor MC) and the solenoid valve UC based on the operation amount Ba. Specifically, the braking fluid BF is pumped up from the reservoir RV through the first reservoir fluid path HR by the electric pump DC, and is discharged to the pressure control fluid path HC. Then, the discharged braking fluid BF is throttled by the solenoid valve UC and adjusted to the adjusted hydraulic pressure Pc. The adjusted hydraulic pressure Pc is introduced (supplied) to the servo chamber Rs via the front wheel pressure control fluid passage HCf. The master piston PM is moved in the forward direction Ha by the adjusted hydraulic pressure Pc, and the braking fluid BF is pumped from the master chamber Rm toward the front wheel wheel cylinder CWf (CWi, CWj). When the pressure receiving area rs of the servo chamber Rs and the pressure receiving area rm of the master chamber Rm are equal to each other, the master hydraulic pressure Pm equal to the adjusted hydraulic pressure Pc is applied to the front wheel wheel cylinder CWf. Further, the adjusted hydraulic pressure Pc is introduced to the rear wheel wheel cylinder CWr (CWk, CWl) through the rear wheel pressure adjustment fluid path HCr.

  At the time of manual braking when the operation of the braking control device SC is in a malfunction state, the first and second on-off valves VA, VB are not energized. Accordingly, the first on-off valve VA is in the closed position, and the second on-off valve VB is in the open position. By the closed position of the first on-off valve VA, the input chamber Rn is brought into the fluid lock state (sealed state), and the input piston PN and the master piston PM can not be moved relative to each other. Further, the rear chamber Ro is fluidly connected to the reservoir RV through the second reservoir fluid path HT by the open position of the second on-off valve VB. For this reason, although the volume of the rear chamber Ro is reduced by the movement of the master piston PM in the forward direction Ha, the liquid volume accompanying the volume reduction is discharged toward the reservoir RV. In conjunction with the operation of the braking operation member BP, the input piston PN and the master piston PM are integrally moved, and the braking fluid BF is pressure-fed from the master chamber Rm.

[Lower fluid unit YL]
The lower fluid unit YL is controlled by the lower controller ECL. The wheel speed Vw, the yaw rate Yr, the steering angle Sa, the longitudinal acceleration Gx, the lateral acceleration Gy, and the like are input to the lower controller ECL. For example, in the lower fluid unit YL, anti-skid control is performed to suppress excessive deceleration slip (for example, wheel lock) of the wheel WH based on the wheel speed Vw. Further, based on the yaw rate Yr, vehicle stabilization control (so-called ESC) is performed to suppress excessive oversteer behavior and understeer behavior of the vehicle. That is, in the lower fluid unit YL, braking control independent of each wheel is performed based on the above-mentioned signal (Vw etc.). The upper controller ECU and the lower controller ECL are connected in a communicable state by a communication bus BS, and sensor signals and arithmetic values are shared. The upper fluid unit YU and the lower fluid unit YL are connected via a master cylinder fluid passage HM and a rear wheel pressure adjustment fluid passage HCr.

  For lower fluid unit YL, lower electric pump DL, "front wheel, rear wheel low pressure reservoir RLf, RLr", "front wheel, rear wheel charge over valve UPf, UPr", "front wheel, rear wheel input hydraulic pressure sensor PQf, PQr" , “Inlet valve VI”, and “outlet valve VO”.

  The lower electric pump DL is configured of one lower electric motor ML and two lower fluid pumps QLf and QLr. Lower electric motor ML is controlled by lower controller ECL based on drive signal Ml. The two lower fluid pumps QLf, QLr are integrally rotated and driven by the electric motor ML. Then, the braking fluid BF is pumped up from the upstream portions Bof and Bor of the front wheel and rear wheel charge over valves (also simply referred to as "charge valves") UPf and UPr by the front wheel and rear wheel fluid pumps QLf and QLr of the electric pump DL. The pressure is discharged to the downstream portions Bpf and Bpr of the front wheel and rear wheel charge valves UPf and UPr. On the suction side of the front wheel and rear wheel fluid pumps QLf and QLr, front wheel and rear wheel low pressure reservoirs RLf and RLr are provided.

  Similar to the linear pressure regulation valve UC, a normally open linear pressure regulation valve (a solenoid valve whose valve opening amount is continuously controlled by energization) is employed as the charge valve UP (a generic term for UPf and UPr). The linear pressure regulating valve UP is controlled by the lower controller ECL based on the drive signal Up (Upf, Upr).

  When the front wheel fluid pump QLf is driven, a reflux (a flow of the circulating braking fluid BF) of “Bof → RLf → QLf → Bpf → UPf → Bof” is formed. The fluid pressure (front wheel output fluid pressure) Ppf downstream of the front wheel charge valve UPf is adjusted by the front wheel charge valve UPf provided in the master cylinder fluid path HM. The brake fluid BF is moved from the upstream portion Bof of the front wheel charge valve UPf to the downstream portion Bpf by the fluid pump QLf, and the input hydraulic pressure Pqf of the upstream portion is shifted by the front wheel charge valve UPf (the valve opening portion). The differential pressure (Ppf> Pqf) between the downstream output hydraulic pressure Ppf is adjusted.

  Similarly, by driving the rear wheel fluid pump QLr, a return flow of “Bor → RLr → QLr → Bpr → UPr → Bor” is formed. The hydraulic pressure (rear wheel output hydraulic pressure) Ppr at the downstream portion of the rear wheel charge valve UPr is adjusted by the rear wheel charge valve UPr provided in the rear wheel pressure adjustment fluid path HCr. That is, the brake fluid BF is moved from the upper portion Bor to the lower portion Bpr of the rear wheel charge valve UPr by the fluid pump QLr, and the upper hydraulic pressure (input hydraulic pressure) Pqr and the lower hydraulic pressure (output hydraulic pressure) are generated by the rear wheel charge valve UPr. ) The differential pressure (Ppr> Pqr) between Ppr is adjusted.

  Input hydraulic pressure sensors PQf and PQr are provided to detect input hydraulic pressures Pqf and Pqr of the front and rear wheels. The detected hydraulic pressure signal Pq is input to the lower controller ECL. Note that at least one of the two input hydraulic pressure sensors PQf and PQr can be omitted.

  The master cylinder fluid passage HM is branched (branched) to the front wheel cylinder fluid passages HWi and HWj at a front wheel branch portion Bpf downstream of the front wheel charge valve UPf. Similarly, the rear wheel pressure adjustment fluid passage HCr is branched into the respective rear wheel wheel cylinder fluid passages HWk and HWl at a rear wheel branch portion Bpr downstream of the rear wheel charge valve UPr.

  An inlet valve VI and an outlet valve VO are provided in the wheel cylinder fluid passage HW. A normally open on / off solenoid valve is employed as the inlet valve VI. Also, a normally closed on / off solenoid valve is employed as the outlet valve VO. The solenoid valves VI, VO are controlled by the lower controller ECL based on the drive signals Vi, Vo. The braking fluid pressure Pw of each wheel can be controlled independently by the inlet valve VI and the outlet valve VO.

  The configurations relating to the respective wheels WH are the same in the inlet valve VI and the outlet valve VO, so the configuration relating to the right front wheel WHi will be described as an example. A normally open inlet valve VIi is interposed in the wheel cylinder fluid passage HWi for the right front wheel (a fluid passage connecting the part Bpf and the right front wheel wheel cylinder CWi). The wheel cylinder fluid passage HWi is fluidly connected to the low pressure reservoir RLf via a normally closed outlet valve VOi downstream of the inlet valve VIi. For example, in anti-skid control, in order to reduce the hydraulic pressure Pwi in the wheel cylinder CWi, the inlet valve VIi is brought into the closed position and the outlet valve VOi is brought into the open position. The braking fluid BF is prevented from flowing from the inlet valve VIi, the braking fluid BF in the wheel cylinder CWi flows out to the low pressure reservoir RLf, and the braking fluid pressure Pwi is reduced. Further, in order to increase the braking fluid pressure Pwi, the inlet valve VIi is brought into the open position, and the outlet valve VOi is brought into the closed position. The braking fluid BF is prevented from flowing out to the low pressure reservoir RLf, the output hydraulic pressure through the front wheel charge valve UPf is introduced to the wheel cylinder CWi, and the right front wheel braking hydraulic pressure Pwi is increased.

<Bypass unit YB (single type)>
The bypass unit YB will be described with reference to the schematic view of FIG. The bypass unit YB includes a bypass cylinder CB, a bypass piston PB, and a bypass elastic body SB.

  In FIG. 2, the state of the upper part of the central axis Jb shows the case where the bypass piston PB is at the position (referred to as the “initial position”) in the most backward direction Hd (rightward in the drawing). Further, the state below the center line Jb shows the case where the bypass piston PB is at a position (referred to as "limit position") in the most forward direction Hc (left direction in the figure). The bypass piston PB can be displaced in the master cylinder CM over the distance bs from the initial position to the limit position.

  The bypass cylinder CB is a cylinder member having a bottom. The bypass piston PB is a piston member inserted into the bypass cylinder CB. A groove is formed in the inner peripheral portion Bc of the bypass cylinder CB, and two seals SL are fitted in the groove. An outer peripheral portion (an outer peripheral cylindrical surface) Bp of the bypass piston PB and an inner peripheral portion (an inner peripheral cylindrical surface) Bc of the bypass cylinder CB are sealed by the two seals SL. The bypass piston PB can move smoothly along the central axis Jb of the bypass cylinder CB. A cup seal (also referred to as "U-shaped packing") is adopted as the seal SL.

  The inside of the bypass cylinder CB is separated into two chambers (fluid pressure chambers) Rb and Rc by a bypass piston PB. The bypass chamber Rb is a hydraulic pressure chamber partitioned by the inner peripheral portion Bc of the bypass cylinder CB, the first bottom portion (bottom surface) Bu, and the first end portion Br of the bypass piston PB. A bypass fluid passage HB is connected to the bypass chamber Rb. The bypass fluid passage HB is connected to the master cylinder fluid passage HM at a portion Bm and finally to the wheel cylinder CW. Therefore, the internal pressure Pb of the bypass chamber Rb matches the master fluid pressure Pm. Here, the pressure receiving area of the bypass chamber Rb (the cross-sectional area perpendicular to the central axis Jb of the first end Br) has a value “rb”.

  The pressure adjustment chamber Rc is a hydraulic pressure chamber partitioned by the inner peripheral portion Bc, the second bottom portion (bottom surface) Bt of the bypass cylinder CB, and the second end Bq of the bypass piston PB. The bypass chamber Rb and the pressure control chamber Rc are formed opposite to each other so as to sandwich the bypass piston PB. In other words, in the central axis Jb of the bypass cylinder CB, the pressure adjustment chamber Rc and the bypass chamber Rb are located on the opposite side to the bypass piston PB. Therefore, a force (referred to as a "second forward force") Fc in the forward direction Hc applied to the bypass piston PB by the pressure control chamber Rc and a force in the reverse direction Hd applied to the bypass piston PB by the bypass chamber Rb ("second reverse The forces “Fd” face and oppose each other in the direction of the central axis Jb of the bypass cylinder CB.

  A front wheel pressure control fluid passage HCf is connected to the pressure control chamber Rc. Therefore, the pressure (adjustment hydraulic pressure) Pc adjusted by the pressure adjustment unit YC is introduced into the pressure adjustment chamber Rc. Here, the pressure receiving area of the pressure adjustment chamber Rc (the cross-sectional area perpendicular to the central axis Jb of the second end Bq) is a value “rc”. For example, the pressure receiving area rb of the bypass chamber Rb and the pressure receiving area rc of the pressure adjusting chamber Rc may be set equal.

  A bypass elastic body (for example, a compression spring) SB is provided between the first bottom Bu of the bypass cylinder CB and the bypass piston PB. The bypass elastic body SB presses the bypass piston PB against the second bottom Bt of the bypass cylinder CB in the direction of the central axis Jb of the bypass cylinder CB. At the time of non-braking, the second end Bq and the second bottom Bt abut, and the bypass piston PB is in the initial position. In the bypass unit YB described above, the number of the bypass chamber Rb is one, so it is called a "single type".

The relationship between the specifications of the bypass unit YB and the specifications of the master unit YM will be described.
The relationship between the characteristics of the bypass elastic body SB and the characteristics of the master elastic body SM is set to “when the control braking is started, the master piston PM is moved before the bypass piston PB is moved”. Ru. The characteristics of the elastic bodies SM, SB are based on the mounting load (also referred to as "set load"). Specifically, “a value wb obtained by dividing the attachment load sb of the bypass elastic body SB by the pressure receiving area rc of the pressure adjustment chamber Rc (referred to as“ attachment pressure ”) wb” means “the attachment load sm of the master elastic body SM It is set to be larger than the value wm divided by the pressure receiving area rs of the servo chamber Rs. Here, the “mounting load” is a force (load) applied to the elastic bodies SM, SB when the elastic bodies SM, SB are assembled to a machine (for example, the master unit YM, bypass unit YB). is there. The attachment loads sm and sb are biasing forces of the elastic bodies (for example, compression coil springs) SM and SB at initial positions of the piston members PM and PB, and are also referred to as “initial loads”.

  When each elastic body SM, SB is in a no-load state, each has a free length (also referred to as "free height"). When these are assembled to each unit YM, YB, the free length (free height) is reduced to the mounting length (mounting height). Depending on the difference between the free length and the mounting length, the biasing force in the reverse direction Hb, Hd that the elastic bodies SM, SB apply to the respective pistons PM, PB is the mounting load (also referred to as "set load") sm, sb is there. When the elastic body is a compression coil spring, “height” is used as a term in place of “length” (see “JIS B 0103 spring term”).

  The “mounting pressure” is a value obtained by dividing the mounting load by the piston pressure receiving area (cross-sectional area). Therefore, when the pressure acting on the piston exceeds the mounting pressure, the movement of the piston is started. That is, when the adjusted hydraulic pressure Pc becomes larger than the mounting pressure wm, the master piston PM starts moving in the forward direction Ha. Similarly, when the adjusted hydraulic pressure Pc exceeds the mounting pressure wb, the bypass piston PB starts to move in the forward direction Hc.

  The mounting pressure wb (= sb / rc) of the bypass elastic body SB is set larger than the mounting pressure wm (= sm / rs) of the master elastic body SM. Therefore, when the adjusted hydraulic pressure Pc is increased from "0" while each of the master piston PM and the bypass piston PB is at rest in the initial position, the master piston PM is first moved in the forward direction After starting to move to Ha, the bypass piston PB is moved in the forward direction Hc. That is, at the start of the control braking, the master piston PM is moved, and after the communication between the master chamber Rm and the master reservoir chamber Ru is shut off, the bypass piston PB is moved.

  If the movement of the bypass piston PB is first started before the communication between the master chamber Rm and the master reservoir chamber Ru is shut off, the braking fluid BF from the bypass chamber Rb is transmitted to the master cylinder fluid passage HM, And it will be moved to the reservoir RV via the master chamber Rm. In order to avoid such a situation and efficiently pump the braking fluid BF from the bypass unit YB toward the wheel cylinder CW, the mounting pressure wb of the bypass elastic body SB is larger than the mounting pressure wm of the master elastic body SM. It is set.

  The ratio of the pressure receiving area rb of the bypass chamber Rb to the pressure receiving area rc of the pressure adjusting chamber Rc (referred to as “area ratio”) Ab (= rb / rc) so that the master piston PM and the bypass piston PB move simultaneously. It is set to be equal to the ratio Am (= rm / rs) of the pressure receiving area rm of the master chamber Rm to the pressure receiving area rs of the servo chamber Rs. For example, the area ratio Am of the master unit YM and the area ratio Ab of the bypass unit YB are both set to “1” (ie, “rm = rs” and “rb = rc”).

The relationship between the operation of the bypass unit YB and the operation of the master unit YM will be described.
At the time of non-braking, in the master unit YM, the master piston PM is pressed in the reverse direction Hb by the master elastic body SM and is in its initial position. Similarly, in the bypass unit YB, the bypass piston PB is pushed in the reverse direction Hd by the bypass elastic body SB and is in its initial position. Here, the attachment pressure wm of the master elastic body SM is set to a value lower than the attachment pressure wb of the bypass elastic body SB.

  When the brake operation member BP is operated, the adjusted hydraulic pressure Pc is increased from “0” by the pressure control unit YC. The adjusted hydraulic pressure Pc is increased to a hydraulic pressure (cutoff hydraulic pressure) p1 at which the connection between the master chamber Rm and the master reservoir chamber Ru is shut off. A force (first forward force) Fa in the forward direction Ha with a value “p1 × rs” acts on the master unit YM. Since this force Fa is larger than the attachment load sm, the master piston PM is moved in the forward direction Ha. As a result, the through holes Ap pass through the seal SL, and the master chamber Rm is shut off from the master reservoir chamber Ru. On the other hand, a force (second forward force) Fc in the forward direction Hc of a value “p1 × rc” acts on the bypass piston PB. Since “wb> wm” is set, the forward force Fc (= p1 × rc) is smaller than the mounting load sb. Therefore, the bypass piston PB is not moved and maintains the initial position.

  When the adjusted hydraulic pressure Pc is further increased and reaches the value p2 (> p1), the bypass piston PB is subjected to the forward force Fc of the value “p2 × rc”. As “Fc> sb”, the bypass piston PB starts to be moved in the forward direction Hc. Since the mounting pressure wb of the bypass elastic body SB is set to be larger than the mounting pressure wm of the master elastic body SM, the master piston PM at the start of the control braking (when the adjusted hydraulic pressure Pc rises from “0”). After the start of the movement of the bypass piston PB, the movement of the bypass piston PB is started. Since movement of the bypass piston PB is started after the communication between the master chamber Rm and the reservoir RV is shut off by forward movement of the master piston PM, the braking fluid BF via the bypass unit YB is efficiently applied to the wheel cylinder CW. Can be transmitted to

  The bypass piston PB receives a force (second reverse force) Fb in the reverse direction Hd from the bypass chamber Rb by the braking fluid pressure Pw. When the brake operating member BP is returned, the adjusted hydraulic pressure Pc is decreased by the pressure control unit YC. Then, when the adjusted hydraulic pressure Pc becomes smaller than the braking hydraulic pressure Pw, the pistons PM and PB are moved in the reverse direction Hb and Hd. When the braking operation member BP is in the non-operating state, the elastic force of the elastic bodies (compression coil springs) SM, SB causes the pistons PM, PB to return to their initial positions. At this time, the master chamber Rm and the reservoir RV are in communication with each other, and the fluid pressures Pm and Pb in the master chamber Rm and the bypass chamber Rb are returned to “0”.

  The volume of the master cylinder chamber Rm (that is, the inner diameter and the length of the master cylinder CM) is determined by the stiffness of the braking device (for example, the stiffness of the caliper, the stiffness of the friction material, and the stiffness of the braking pipe). In controlled braking, even when the coefficient of friction between the friction material and the rotating member KT decreases (e.g., when a fading phenomenon occurs), the capacity of the master chamber Rm is set so that the wheel WH can exhibit the maximum braking force. Is set. On the other hand, in manual braking, the master cylinder CM needs to have a relatively small diameter so that the operation force Fp of the braking operation member BP generated by the driver falls within the appropriate range. In order to achieve volume securing with a small diameter master cylinder CM, the master cylinder CM must be lengthened. As a result, the mountability of the device on the vehicle is reduced.

  In the present invention, in order to pump the brake fluid BF to the wheel cylinder CW, a bypass unit YB is provided in parallel with the master unit YM (in particular, the master cylinder CM). At the time of control braking, the braking fluid BF is moved to the wheel cylinder CW via the bypass unit YB in addition to the master unit YM. Thereby, the capacity of master cylinder CM is reduced, and the device is shortened in the longitudinal direction (direction of central axis Jm). In addition, since a small-diameter one can be adopted as the master cylinder CM, the operation force Fp in manual braking can be made appropriate. During manual braking, the bypass piston PB is pressed by the second bottom Bt by the master hydraulic pressure Pm to be in the initial position, and the bypass unit YB does not operate.

  The movable range of the master piston PM is limited. Similarly, the movable range of the bypass piston PB is limited to a predetermined distance bs (displacement from the initial position to the limit position). Therefore, the pressure control unit YC and the wheel cylinder CW are fluidly separated by the units YM and YB, and the braking fluid BF is not moved between the pressure control unit YC and the wheel cylinder CW. For example, if a fluid channel failure occurs around the wheel cylinder CW, the amount of damping fluid BF lost in the failure is limited.

<Processing of pressure regulation control including regenerative coordination control>
The process of pressure regulation control will be described with reference to the control flowchart of FIG. The "pressure control control" is drive control of the electric motor MC and the solenoid valve UC for adjusting the adjusted hydraulic pressure Pc. The control algorithm is programmed in the controller ECU.

  In step S110, the braking operation amount Ba, the operation signal St, the adjusted hydraulic pressure Pc, and the rotation angle Ka are read. The operation amount Ba is detected by an operation amount sensor BA (for example, a simulator liquid pressure sensor PS, an operation displacement sensor SP, an operation force sensor FP). The operation signal St is detected by an operation switch ST provided on the braking operation member BP. The adjusted hydraulic pressure Pc is detected by an adjusted hydraulic pressure sensor PC provided in the pressure control fluid passage HC. The motor rotation angle Ka is detected by a rotation angle sensor KA provided to the electric motor MC.

  In step S120, it is determined whether or not the braking operation is in progress based on at least one of the braking operation amount Ba and the braking operation signal St. For example, if the operation amount Ba is equal to or larger 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. If the operation signal St is on, the process proceeds to step S130. If the operation signal St is off, the process returns to step S110.

  In step S130, the normally closed first on-off valve VA is brought to the open position, and the normally open second on-off valve VB is brought to the closed position. Thereby, the input hydraulic pressure chamber Rn and the rear hydraulic pressure chamber Ro are connected. Also, the simulator SS is connected to the input chamber Rn and is shut off from the reservoir RV.

  In step S140, a target deceleration Gt is calculated based on the operation amount Ba. The target deceleration Gt is a target value of deceleration at deceleration of the vehicle. The target deceleration Gt is determined to be “0” in the range from “0” to the predetermined value bo according to the calculation map Zgt, and the manipulation amount Ba increases when the operation amount Ba is the predetermined value bo or more. Along with this, it is calculated so as to monotonically increase from "0".

  In step S150, a regeneration amount Rg (target value) is determined based on the target deceleration Gt. For example, when the target deceleration Gt is less than the predetermined regeneration amount rg, the regeneration amount Rg (a value corresponding to the vehicle deceleration) is determined to coincide with the target deceleration Gt. On the other hand, when the target deceleration Gt is equal to or greater than the predetermined regeneration amount rg, the regeneration amount Rg is determined to coincide with the predetermined regeneration amount rg. Here, the predetermined regeneration amount rg is preset as a constant. The predetermined regeneration amount rg may be set based on the state of the regeneration generator GN or the storage battery BT. The calculation result (“Rg = Gt” or “Rg = rg”) is transmitted from the upper controller ECU to the drive controller ECD via the communication bus BS. In the controller ECD, control of the generator GN is performed such that the target value Rg is achieved.

  In step S160, a target fluid pressure Pt (a target value of the adjusted fluid pressure Pc) is determined based on the target deceleration Gt and the regeneration amount Rg. For example, when the target deceleration Gt is less than the predetermined regeneration amount rg and “Rg = Gt”, the target hydraulic pressure Pt is calculated to “0”. That is, friction braking is not adopted for vehicle deceleration, and the target deceleration Gt is achieved only by regenerative braking. When the target deceleration Gt is equal to or greater than the predetermined regeneration amount rg, a value obtained by subtracting the predetermined regeneration amount rg from the target deceleration Gt is converted to a fluid pressure, and the target fluid pressure Pt is calculated. That is, of the target deceleration Gt, a portion corresponding to the predetermined regeneration amount rg is achieved by regenerative braking (braking force generated by the generator GN), and the remaining ("Gt-rg") is friction braking (rotation The target fluid pressure Pt is determined to be achieved by the braking force generated by the friction between the member KT and the friction material.

  At step 170, a target rotational speed Nt is calculated based on the target fluid pressure Pt. The target rotation speed Nt is a target value of the rotation speed of the electric motor MC. The target rotational speed Nt is calculated to monotonously increase as the target fluid pressure Pt increases in accordance with the operation map Znt. As described above, the adjusted hydraulic pressure Pc is generated by the orifice effect of the pressure control solenoid valve UC. Since a certain amount of flow rate is required to obtain the orifice effect, the target rotation speed Nt is provided with a predetermined lower limit rotation speed no. The lower limit rotational speed no is a minimum required value (preset constant) in hydraulic pressure generation. The target rotation 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 S180, servo control based on the number of rotations (control to make the actual value follow the target value quickly) is executed in the electric motor MC. For example, as the rotational speed servo control, rotational speed feedback control of the upper electric motor MC is performed based on the target rotational speed Nt and the actual rotational speed Na. In step S180, the rotation angle Ka is time-differentiated based on the motor rotation angle (detection value) Ka, and the motor rotation speed (actual rotation number per unit time) Na is calculated. Then, the number of rotations of the electric motor MC is used as a control variable, and the amount of energization (for example, supply current) to the electric motor MC 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) ) And the amount of energization of the electric motor MC is finely adjusted. In the case of "hN> nx", the amount of energization 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 amount of energization to the electric motor MC is decreased, and the electric motor MC is decelerated. Here, the predetermined value nx is a constant set in advance.

  In step S190, servo control based on fluid pressure is performed in the solenoid valve UC. For example, as fluid pressure servo control, fluid pressure feedback control of the pressure adjustment solenoid valve UC is executed based on the target fluid pressure Pt and the adjusted fluid pressure Pc (detection value). In the feedback control, the pressure Pc of the braking fluid BF in the pressure control fluid passage HC is used as a control variable to control the amount of current supplied to the normally open linear solenoid valve UC. Based on the deviation hP (= Pt−Pc) between the target fluid pressure Pt and the adjusted fluid pressure Pc, the fluid pressure deviation hP becomes “0” (that is, the adjusted fluid pressure Pc approaches the target fluid pressure Pt) The amount of energization of the solenoid valve UC is adjusted. When “hP> px”, the amount of energization of the solenoid valve UC is increased, and the amount of opening of the solenoid valve UC is decreased. On the other hand, in the case of "hP <-px", the amount of energization to the solenoid valve UC is decreased, and the valve opening amount of the solenoid valve UC is increased. Here, the predetermined value px is a constant set in advance.

<Another Configuration Example of Bypass Unit YB (Stepped Configuration)>
Another configuration example of the bypass unit YB will be described with reference to the schematic view of FIG. 4. In the bypass unit YB described with reference to FIG. 2, the cylindrical bypass piston PB is adopted, and the pressure receiving area rc and the pressure receiving area rb of the bypass chamber Rb are set identical in the pressure control chamber Rc. In another configuration example, the bypass piston PB has two different diameters, and the area rc is set larger than the area rb. The bypass piston PB is referred to as a "stepped piston". The adoption of the stepped piston (referred to as a “stepped configuration”) improves the pressure response of the braking fluid pressure Pw at the initial stage of braking.

  The bypass piston PB of the bypass unit YB has a large diameter outer peripheral portion Pd (diameter dd) and a small diameter outer peripheral portion Pe (diameter de). Two annular grooves are formed in the cylindrical surface Pd of the large diameter outer peripheral portion, and a seal SL (e.g., a cup seal) is inserted in each groove. An annular groove is formed on the cylindrical surface Pe of the small diameter outer peripheral portion, and the groove is provided with a seal SO. Here, a cup seal (referred to as “U-shaped packing”) is adopted as the seal SO. Thus, the seal SO is directional in the sealing state.

  The inner peripheral portion of the bypass cylinder CB has two different inner diameters so as to be in sliding contact with the bypass piston PB (specifically, the seals SL, SO). The large diameter inner circumference Bd of the bypass cylinder CB corresponds to the large diameter outer circumference Pd of the bypass piston PB, and the small diameter inner circumference of the bypass cylinder CB corresponds to the small diameter outer circumference Pe of the bypass piston PB It is Be.

  The inside of the bypass cylinder CB is divided into three chambers (fluid pressure chambers) Rc, Rb and Rh. The pressure control chamber Rc (pressure receiving area rc) is formed by the second end Bq (diameter dd) of the bypass piston PB, the large diameter inner circumferential portion Bd of the bypass cylinder CB, and the second bottom Bt of the bypass cylinder CB. Ru. The bypass chamber Rb (pressure receiving area rb) is formed by the first end Br (diameter de) of the bypass piston PB, the small diameter inner circumferential portion Be of the bypass cylinder CB, and the first bottom Bu of the bypass cylinder CB. The pressure adjustment chamber Rc applies a second forward force Fc to the bypass piston PB by the adjusted hydraulic pressure Pc. The bypass chamber Rb applies the second reverse force Fd to the bypass piston PB by the internal pressure Pb (= Pm). The second forward force Fc and the second reverse force Fd are opposed to each other.

  In the bypass cylinder CB, in addition to the fluid pressure chambers Rc and Rb, the small diameter outer peripheral portion Pe of the bypass piston PB, the stepped portion Pg of the bypass piston PB, the large diameter inner peripheral portion Bd of the bypass cylinder CB, and the bypass cylinder An auxiliary chamber Rh is formed surrounded by the stepped portion Bg of the CB. The auxiliary chamber Rh is connected to the relief chamber Rq via the first through hole Ad.

  When the internal pressure Po becomes a predetermined pressure (relief pressure) po, the relief chamber Rq releases the internal pressure Po and the valve unit YV prevents the negative pressure (less than atmospheric pressure) in the relief chamber Rq. Provided. Specifically, the valve unit YV functions as a relief valve with the sphere BL, the bearing surface Sb, and the compression spring BV. When the relief chamber hydraulic pressure Po is less than the predetermined pressure po, the compression spring BV presses the spherical body BL against the bearing surface Sb (conical surface) provided with the through hole Ax, and the relief chamber Rq and the reservoir RV Communication is blocked. When the hydraulic pressure Po becomes equal to or higher than the predetermined pressure po, the spherical body BL is pushed by the hydraulic pressure Po, and a gap is generated between the ball BL and the bearing surface Sb. Thereby, the braking fluid BF is moved from the relief chamber Rq to the reservoir RV, and the hydraulic pressure Po is provided with the upper limit value po.

  The valve unit YV is provided with a suction hole Au connected to the reservoir RV. A suction valve VC is provided at an end of the suction hole Au. The suction valve VC blocks the movement of the braking fluid BF from the relief chamber Rq to the reservoir RV, but allows the movement of the braking fluid BF from the reservoir RV to the relief chamber Rq (see blowout diagram). The damping fluid BF is supplied from the reservoir RV via the suction valve VC so that the pressure in the relief chamber Rq (that is, the auxiliary chamber Rh) does not become lower than the atmospheric pressure (negative pressure).

  At the time of non-braking (when “Pc = 0”), the bypass piston PB is pressed in the reverse direction Hd by the bypass elastic body SB, and the initial position (the second end Bq and the second bottom Bt are in contact) The position of the bypass piston PB is). In this state, the bypass cylinder CB is provided with a second through hole Aa such that the relief chamber Rq and the bypass chamber Rb communicate with each other. Therefore, when not braking, the internal pressure of the fluid pressure chambers Rb, Rq, and Rh is set to "0 (atmospheric pressure)".

  When the control braking is started and the adjusted hydraulic pressure Pc is increased from “0”, a forward force Fc is applied to the bypass piston PB by the pressure control chamber Rc. As a result, the bypass piston PB is advanced, and the second through hole Aa is closed by the seal SO. Furthermore, when the adjusted hydraulic pressure Pc is increased, the volume of the auxiliary chamber Rh is decreased, and the hydraulic pressure Ph in the auxiliary chamber Rh is increased. The seal SO is directional in the sealing direction. That is, the seal member SO seals in one direction but does not seal in the other direction. Specifically, the seal member SO holds the hydraulic pressure Pb (= Pm) from the bypass chamber Rb, but does not hold the hydraulic pressure Ph from the auxiliary chamber Rh. Therefore, when the state of "Ph> Pb" is established as the bypass piston PB advances, the braking fluid BF in the auxiliary chamber Rh passes between the outer peripheral lip portion of the seal SO and the small diameter inner peripheral portion Be. , Is moved to the bypass chamber Rb. That is, when the adjusted hydraulic pressure Pc is increased, the braking fluid BF is replenished from the auxiliary chamber Rh to the bypass chamber Rb. The replenishment of the damping fluid BF by the auxiliary chamber Rh is referred to as "fast fill". This fast fill allows the wheel cylinder CW to be rapidly supplied with a larger amount of the braking fluid BF, so that the responsiveness can be improved in the increase of the braking fluid pressure Pw.

  When the control braking is ended and the adjusted hydraulic pressure Pc is returned toward “0”, the bypass piston PB is moved in the reverse direction Hd, and the volume of the auxiliary chamber Rh is increased. In this case, the braking fluid BF is supplied from the reservoir RV to the auxiliary chamber Rh via the suction valve VC of the valve unit YV.

  In the stepped configuration of the bypass unit YB as well, the mounting pressure wb of the bypass elastic body SB (the value obtained by dividing the mounting load sb by the pressure receiving area rc of the pressure control chamber Rc) is the mounting pressure of the master elastic body SM. It is set larger than wm (the value obtained by dividing the mounting load sm by the pressure receiving area rs of the servo chamber Rs). For this reason, when control braking is started, before the bypass piston PB is moved, the master piston PM is moved, and the braking fluid BF can be efficiently moved from the bypass unit YB to the wheel cylinder CW.

  Area ratio Ab of bypass unit YB (ratio of pressure receiving area rb of bypass chamber Rb to pressure receiving area rc of pressure regulating chamber Rc) and area ratio Am of master unit YM (pressure received of master chamber Rm relative to pressure receiving area rs of servo chamber Rs) The ratio of the areas rm is set to match. Here, since the stepped configuration is adopted for the bypass unit YB, “rc> rb” and the area ratio Ab is less than “1”. Therefore, even in the master unit YM, “rs> rm” is set, and the area ratio Am is less than “1”. Since “Ab = Am” is set, the master piston PM and the bypass piston PB can be operated synchronously. That is, one of the pistons is first moved to its limit, and thereafter the movement of the other piston is not started.

Second Embodiment of Braking Control Device SC of Vehicle
A second embodiment of a vehicle braking control device SC according to the present invention will be described with reference to the overall configuration diagram of FIG. As described above, constituent members, arithmetic processing, signals, characteristics, and values having the same symbol are of the same function. In subscripts “i” to “l” at the end of various symbols, “i” indicates the front right wheel, “j” indicates the front left wheel, “k” indicates the rear right wheel, and “l” indicates the rear left wheel. The suffixes "i" to "l" at the end of the symbol may be omitted. In this case, each symbol represents a generic name for each of the four wheels. In addition, subscripts "1" and "2" at the end of various symbols indicate that in the two braking systems, "1" indicates the first system and "2" indicates the second system. The suffixes "1" and "2" at the end of the symbol may be omitted. In this case, each symbol represents a generic name of the two braking systems. When front and rear type fluid paths are adopted, suffixes “f” and “r” at the end of various symbols indicate “f” for the front wheel system and “r” for the rear wheel system. The suffixes "f" and "r" at the end of the symbol may be omitted. In this case, each symbol represents a generic name of the two braking systems. The braking performed by the braking control device SC is "control braking", and the braking only by the driver's operation force is "manual braking".

  In the first embodiment, a single type master cylinder CM, a reflux type pressure regulating unit YC, and a single type bypass unit YB are adopted. Furthermore, a front and rear type was used as a two-system fluid path. In the second embodiment, in place of these, a tandem-type master cylinder CM and a tandem-type bypass unit YB are adopted, and an accumulator is used as a pressure regulation unit YC (referred to as “accumulator type”). Also, so-called diagonal type (also referred to as X type) is adopted as the two-system fluid path. In addition, as a two-system fluid path, the thing of order order (it is also called H type) may be used.

  Hereinafter, differences from the first embodiment will be mainly described. The regenerative cooperation unit YK is the same as that of the first embodiment, and thus the description thereof is omitted.

[Master unit YM (tandem type)]
The master cylinder CM is a tandem type, and the inside is divided into first and second master cylinder chambers (first and second master chambers) Rm1 and Rm2 by the first and second master pistons PS1 and PS2. There is. The inside of the atmospheric pressure reservoir RV is divided into three parts Ru1, Ru2 and Rd 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. In addition, the pressure control reservoir chamber Rd is connected to the pressure control unit YC by the reservoir fluid passage HR.

  The pressure receiving areas of the first and second master chambers Rm1 and Rm2 are the same at the value "rm". That is, the diameters of the first and second master pistons PS1 and PS2 are equal. First and second master cylinder fluid passages HM1 and HM2 are connected to the first and second master chambers Rm1 and Rm2. The first master cylinder fluid passage HM1 is connected to the wheel cylinders CWi, CWl. The second master cylinder fluid passage HM2 is connected to the wheel cylinders CWj and CWk. That is, a diagonal type fluid passage is employed as the two-system fluid passage.

  In the first master chamber Rm1, a first master elastic body SM1 is provided which applies an urging force in the reverse direction Hb to the first master piston PM1. Further, in the second master chamber Rm2, a second master elastic body SM2 is provided which applies an urging force in the reverse direction Hb to the second master piston PM2. When the first and second master pistons PM1 and PM2 are at the position in the most backward direction Hb (that is, the initial position of the master piston PM), the master chambers Rm1 and Rm2 are the replenishment fluid passage HU and the through hole It is connected to the reservoir RV (in particular, the master reservoir chamber Ru) via Ac and Ap. When the control braking is started, the introduction of the adjusted hydraulic pressure Pc is started to the servo chamber Rs (pressure receiving area rs). When the forward force Fa by the servo chamber Rs becomes larger than the attachment loads sm1 and sm2 of the first and second master elastic bodies SM1 and SM2, the master piston PM starts to be moved in the forward direction Ha. Through the forward movement of the master piston PM, the through hole Ap intrudes into the master chamber Rm, and the communication between the master chamber Rm and the master reservoir chamber Ru is blocked. As a result, the master chamber Rm is made liquid tight.

  The servo chamber Rs applies an urging force (first forward force) Fa in the forward direction Ha to the first master piston PM1 by the adjusted hydraulic pressure Pc. The first master chamber Rm1 applies an urging force (first reverse force) Fb in the reverse direction Hb to the first master piston PM1 by the internal pressure (first master fluid pressure) Pm1. Here, the first forward force Fa and the first reverse force Fb are opposed to each other.

  The servo chamber Rs indirectly applies the first forward force Fa to the second master piston PM2 via the first master chamber Rm1 and the first master elastic body SM1 by the adjusted hydraulic pressure Pc. . The second master chamber Rm2 directly applies the first reverse force Fb to the second master piston PM2 by the second master hydraulic pressure Pm2. Here too, the first forward force Fa and the first reverse force Fb face each other in the direction of the central axis Jm of the master cylinder CM.

[Pressure regulator unit YC (accumulator type)]
The adjusted hydraulic pressure Pc is adjusted by the pressure control unit YC. The pressure regulation unit YC is configured of an electric pump DZ, an accumulator AZ, an accumulator fluid pressure sensor (also referred to as an “accumulated pressure sensor”) PZ, an increase pressure regulation valve UA, a decrease pressure regulation valve UB, and an adjusted hydraulic pressure sensor PC. The pressure regulation unit YC is an "accumulator type" in which an accumulator is used.

  The pressure regulating unit YC is provided with a pressure-accumulated electric pump DZ so that the pressurized braking fluid BF is stored in the accumulator AZ. The pressure accumulation electric pump DZ is configured by a set of one pressure accumulation electric motor MZ and one pressure accumulation fluid pump QZ. In the pressure accumulation electric pump DC, the electric motor MZ and the fluid pump QZ are fixed so that the electric motor MZ and the fluid pump QZ rotate integrally. The accumulator electric pump DZ (in particular, the accumulator electric motor MZ) is a power source for maintaining the hydraulic pressure (accumulator hydraulic pressure) Pz in the accumulator AZ at a high pressure. The accumulator electric motor MZ is rotationally driven by the controller ECU. For example, a motor with a brush is employed as the electric motor MZ.

  The braking fluid BF discharged from the pressure accumulation fluid pump QZ is stored in the accumulator AZ. An accumulator fluid path HZ is connected to the accumulator AZ, and the accumulator AZ and the increase pressure regulator valve UA are connected. An accumulator sensor PZ is provided in the accumulator fluid passage HZ so as to detect the hydraulic pressure (accumulator hydraulic pressure) Pz accumulated in the accumulator AZ. A check valve GZ is provided at the discharge portion of the pressure accumulation fluid pump QZ so that the braking fluid BF does not reversely flow from the accumulator AZ.

  The controller ECU controls the accumulator electric pump DZ (in particular, the accumulator electric motor MZ) so that the accumulator hydraulic pressure Pz is maintained within a predetermined range. Specifically, when the accumulator hydraulic pressure Pz is less than the lower limit value (predetermined value) pl, the electric motor MZ is driven at a predetermined rotation speed. Further, when the accumulator hydraulic pressure Pz is equal to or higher than the upper limit value (predetermined value) pu, the electric motor MZ is stopped. Here, the lower limit value pl and the upper limit value pu are predetermined constants set in advance, and have a relationship of “pl <pu”. Therefore, the hydraulic pressure Pz in the accumulator AZ is maintained in the range from the lower limit value pl to the upper limit value pu.

  The pressure regulation unit YC is provided with a normally closed increase pressure regulation valve UA and a normally open decrease pressure regulation valve UB. A pressure control fluid passage HC connects between the increase pressure control valve UA and the decrease pressure control valve UB. In addition, the decrease pressure control valve UB is connected to the reservoir fluid path HR. The increase and decrease pressure adjustment valves UA and UB are linear solenoid valves (proportional valves) whose valve opening amount is continuously controlled based on the amount of electric current (for example, supply current). The pressure regulating valves UA, UB are controlled by the controller ECU based on the drive signals Ua, Ub.

  When the adjusted hydraulic pressure Pc is adjusted, the increase pressure control valve UA is energized, and the braking fluid BF flows from the accumulator AZ into the pressure control fluid path HC via the accumulator fluid path HZ. Further, based on the adjusted hydraulic pressure Pc (actual value), the reduction pressure regulating valve UB is energized to adjust the adjusted hydraulic pressure Pc. As in the first embodiment, an adjusted hydraulic pressure sensor PC is provided to detect the adjusted hydraulic pressure Pc.

  The pressure control fluid passage HC is divided into two at the portion Bb, one connected to the master unit YM (particularly, the servo chamber Rs), and the other connected to the bypass unit YB (particularly, the pressure controlled chamber Rc). Ru. Therefore, the adjusted hydraulic pressure Pc is added to the servo chamber Rs and the pressure control chamber Rc.

[Bypass unit YB (tandem type)]
In the second embodiment, since the tandem-type master cylinder CM is adopted, a bypass unit YB having one pressure regulation chamber Rc and two bypass chambers Rb1 and Rb2 is adopted correspondingly. The bypass unit YB is configured of a bypass cylinder CB, "first and second bypass pistons PB1 and PB2", and "first and second bypass elastic bodies SB1 and SB2".

  Inside bypass cylinder CB, two bypass pistons PB1 and PB2 are arranged coaxially with central axis Jb of bypass cylinder CB. The inner peripheral portion of the bypass cylinder CB and the outer peripheral portions of the first and second bypass pistons PB1, PB2 are sealed by a seal SL. The bypass cylinder CB is divided into three chambers (fluid pressure chambers) Rc, Rb1 and Rb2 by the first and second bypass pistons PB1 and PB2. The fluid pressure chambers Rc, Rb1 and Rb2 are arranged in series on the central axis Jb. The bypass unit YB is called "tandem type".

  A second bypass chamber Rb2 is formed by the one side bottom portion of the bypass cylinder CB, the inner peripheral portion of the bypass cylinder CB, and the one side end portion of the second bypass piston PB2. The second bypass chamber Rb2 is connected to the second master cylinder fluid path HM2 via the second bypass fluid path HB2. A first bypass chamber Rb1 is formed by the other end of the second bypass piston PB2, the inner peripheral portion of the bypass cylinder CB, and the one end of the first bypass piston PB1. The first bypass chamber Rb1 is connected to the first master cylinder fluid passage HM1 via the first bypass fluid passage HB1. Further, a bypass chamber Rc is formed by the other end of the first bypass piston PB1, the inner peripheral portion of the bypass cylinder CB, and the other bottom of the bypass cylinder CB. A pressure control fluid passage HC is connected to the pressure control chamber Rc.

  The first and second bypass chambers Rb1 and Rb2 have the same pressure receiving area rb, and the pressure regulating chamber Rc has a pressure receiving area rc. For example, the area rb and the area rc may be set equal. The pressure adjustment chamber Rc applies a force Fc (= Pc × rc) in the forward direction Hc to the first and second bypass pistons PB1 and PB2. The first and second bypass chambers Rb1 and Rb2 apply a force Fd (= Pm × rb) in the reverse direction Hd to the first and second bypass pistons PB1 and PB2.

  Specifically, the pressure adjustment chamber Rc applies an urging force (second forward force) Fc in the forward direction Hc to the first bypass piston PB1 by the adjusted hydraulic pressure Pc. Further, the bypass chamber Rb1 applies an urging force (second reverse force) Fd in the reverse direction Hd to the first bypass piston PB1 by the internal pressure Pb1 (= Pm1). Here, the second forward force Fc and the second reverse force Fd are opposed to each other.

  The pressure adjustment chamber Rc indirectly applies the second forward force Fc to the second bypass piston PB2 via the first bypass chamber Rb1 and the first bypass elastic body SB1 by the adjusted hydraulic pressure Pc. The second bypass chamber Rm2 applies a second reverse force Fd to the second bypass piston PB2 by the internal pressure Pb2 (= Pm2). Here too, the second forward force Fc and the second reverse force Fd face each other in the direction of the central axis Jb of the bypass cylinder CB.

  As in the first embodiment, each elastic body (e.g., a compression coil spring) SM1, SM2, SB1, and so that movement of the master piston PM is started before movement of the bypass piston PB at the start of controlled braking. The relationship between the characteristics of the bypass elastic body SB and the characteristics of the master elastic body SM is set based on the attachment load of SB2. Specifically, "mounting pressure wb of bypass elastic body SB (value obtained by dividing mounting load sb by pressure receiving area rb)" is obtained by dividing mounting pressure wm of master elastic body SM (mounting load sm by pressure receiving area rs) Value) is set to be larger than

  Furthermore, the area ratio Am of the master unit YM (the ratio of the pressure receiving area rm of the master chamber Rm to the pressure receiving area rs of the servo chamber Rs) and the bypass so that the respective pistons PM1, PM2, PB1, PB2 are moved synchronously Each item of each unit YM, YB is determined so that area ratio Am of unit YB (ratio of pressure receiving area rb of bypass chamber Rb to pressure receiving area rc of pressure adjusting chamber Rc) becomes the same.

  Similar to the first embodiment, in the series-arranged bypass unit YB, the bypass unit YB is provided in parallel with the master unit YM, and the wheel cylinder CW is braked by the master unit YM and the bypass unit YB. Liquid BF is supplied. Thereby, shortening of master cylinder CM and operation force Fp of manual braking can be made compatible suitably.

<Another Arrangement Example of Bypass Unit YB (Single Type Parallel Arrangement)>
An arrangement example of the two single bypass units YB will be described with reference to the schematic view of FIG. In the bypass unit YB of the second embodiment, the first and second bypass pistons PB1, PB2 are arranged in series on the coaxial Jb. Instead, two single bypass units YB are arranged in parallel.

  Two bypass units YB1 and YB2 having the same configuration as the bypass unit YB described with reference to FIG. 2 are connected to the first and second master cylinder fluid paths HM1 via the first and second bypass fluid paths HB1 and HB2. , Connected to HM2. On the first and second central axes Jb1 and Jb2, the first and second bypass chambers Rb1 and Rb2, and the first and second pressure adjustment chambers Rc1 and Rc2, respectively, correspond to the first and second bypass pistons PB1 and PB2. It is arranged so as to face each other.

  The pressure control fluid passage HC is branched into first and second pressure control fluid passages HC1 and HC2 at the portion Bb. The first and second pressure control fluid passages HC1 and HC2 are connected to the first and second pressure control chambers Rc1 and Rc2 of the first and second bypass units YB1 and YB2, respectively. The hydraulic pressure Pc in the pressure control fluid passage HC is added to the first and second pressure control chambers Rc1 and Rc2 through the first and second pressure control fluid passages HC1 and HC2. Also in the single type bypass unit YB arranged in parallel, the same effect as described above is obtained.

<Another Example of Configuration of Pressure Control Unit YC (Electric Cylinder Type)>
Another configuration example of the pressure regulation unit YC will be described with reference to the schematic view of FIG. 7. The reflux type pressure regulating unit YC has been described with reference to FIG. 1, and the accumulator type pressure regulating unit YC has been described with reference to FIG. Instead of these, in the third configuration example of the pressure control unit YC, the pressure control piston PD provided in the pressure control cylinder CD is pressed by the pressure control electric motor MD. Thus, the adjustment of the adjusted hydraulic pressure Pc is performed. The pressure control system is called "electric cylinder type". In the electric cylinder type pressure regulating unit YC, the fluid pump and the pressure regulating valve are not used.

  The pressure regulation unit YC includes an electric motor MD for pressure regulation, a reduction gear GS, a rotation / linear motion conversion mechanism (screw mechanism) NJ, a pressing member PO, a pressure regulation cylinder CD, a pressure regulation piston PD, and a return elastic body SD. Is configured.

  The pressure-adjusting electric motor (pressure-adjusting motor) MD is a power source for the pressure-adjusting unit YC to adjust (increase or decrease) the braking fluid pressure Pw. The pressure adjustment motor MD is driven by the controller ECU based on the drive signal Md. For example, a brushless motor may be employed as the pressure adjustment motor MD.

  The reduction gear GS is configured of a small diameter gear SK and a large diameter gear DK. Here, the number of teeth of the large diameter gear DK is larger than the number of teeth of the small diameter gear SK. Therefore, the rotational power of the electric motor MD is decelerated by the reducer GS and transmitted to the screw mechanism NJ. Specifically, the small diameter gear SK is fixed to the output shaft of the electric motor MD. The large diameter gear DK is engaged with the small diameter gear SK, and the large diameter gear DK and the bolt member BT are fixed such that the rotation axis of the large diameter gear DK coincides with the rotation axis of the bolt member BT of the screw mechanism NJ. . That is, in the reduction gear GS, rotational power from the electric motor MD is input to the small diameter gear SK, decelerated, and output from the large diameter gear DK to the screw mechanism NJ.

  The rotational power of the reduction gear GS is converted into the linear power Fe of the pressing member PO by the screw mechanism NJ. The nut member NT is fixed to the pressing member PO. The bolt member BT of the screw mechanism NJ is coaxially fixed to the large diameter gear DK. Since the rotational movement of the nut member NT is restrained by the key member KY, the nut member NT (that is, the pressing member PO) screwed with the bolt member BT by the rotation of the large diameter gear DK Moved in the direction. That is, the rotational power of the pressure adjustment motor MD is converted into the linear power Fe of the pressing member PO by the screw mechanism NJ.

  The pressure control piston PD is moved by the pressing member PO. The pressure control piston PD is inserted into the inner hole of the pressure control cylinder CD, and a combination of the piston and the cylinder is formed. Specifically, a seal SL is provided on the outer periphery of the pressure control piston PD, and liquid tightness is secured between the seal SL and the inner hole (the inner cylindrical surface) of the pressure control cylinder CD. That is, a fluid pressure chamber (pressure control cylinder chamber) Ra partitioned by the pressure control cylinder CD and the pressure control piston PD is formed.

  A return elastic body (compression spring) SD is provided in the pressure control cylinder chamber Re of the pressure control unit YC. When the energization of the pressure adjustment motor MD is stopped by the return elastic body SD, the pressure adjustment piston PD is returned to the initial position (a position corresponding to zero of the braking fluid pressure). Specifically, the stopper portion Sp is provided inside the pressure adjustment cylinder CD, and when the output of the pressure adjustment motor MD is “0”, the pressure adjustment piston PD abuts against the stopper portion Sp by the return elastic body SD. It is pushed to the position (initial position).

  The pressure control cylinder chamber Re is connected to the pressure control fluid passage HC. By moving the pressure control piston PD in the central axis direction, the volume of the pressure control cylinder chamber Re changes. Thus, the adjusted hydraulic pressure Pc is adjusted. Specifically, when the pressure adjustment motor MD is rotationally driven in the forward direction, the pressure adjustment piston PD is moved in the forward direction (left direction in the drawing) He so that the volume of the pressure adjustment cylinder chamber Re decreases. The adjusted hydraulic pressure Pc is increased, and the braking fluid BF is discharged from the pressure control cylinder CD to the pressure control fluid passage HC. On the other hand, when the pressure adjusting motor MD is rotationally driven in the reverse direction, the pressure adjusting piston PD is moved in the reverse direction (right direction in the figure) Hg so that the volume of the pressure adjusting cylinder chamber Re increases, Pc is reduced, and the damping fluid BF is returned to the pressure control cylinder chamber Re via the pressure control fluid passage HC. The adjustment hydraulic pressure Pc is adjusted (increased or decreased) by driving the pressure adjustment motor MD in the forward or reverse direction. As described above, the pressure control fluid passage HC is provided with the control fluid pressure sensor PC so as to detect the control fluid pressure Pc.

  The pressure adjustment motor MD is controlled based on the target fluid pressure Pt and the adjusted fluid pressure Pc (detection value). First, based on the target fluid pressure Pt, as the target fluid pressure Pt increases from "0", the command energization amount Is is calculated so as to monotonously increase from "0". Then, the compensation energization amount Iu is calculated based on the deviation hP between the target fluid pressure Pt and the adjusted fluid pressure Pc. When “hP> py (predetermined value)”, the compensation energization amount Iu is increased as a positive sign value (corresponding to the forward rotation direction of the pressure adjustment motor MD) according to the increase of the hydraulic pressure deviation hP. In the case of “hP <−py (predetermined value)”, the compensated energization amount Iu is decreased as a negative sign value (corresponding to the reverse direction of the pressure adjustment motor MD) according to the decrease of the hydraulic pressure deviation hP. In the case of “−py ≦ hP ≦ py”, “Iu = 0” is calculated. Here, the predetermined value py is a preset constant.

  Finally, the target energization amount It is determined based on the command energization amount Is and the compensation energization amount Iu. In pressure adjustment control of the adjusted hydraulic pressure Pc, the instructed energization amount Is is a feed forward component, and the compensated energization amount Iu is a feedback component. For example, the command energization amount Is and the compensation energization amount Iu are added up to calculate the target energization amount It. The target energization amount It is a target value of the energization amount to the pressure adjustment motor MD, and the energization amount (current) feedback control is executed based on the target energization amount It and the actual energization amount Ia (detection value). . Here, the actual energization amount Ia is detected by an energization amount sensor (current sensor) IA provided in a drive circuit of the pressure adjustment motor MD.

<Another Configuration Example of Regenerative Cooperative Unit YK>
Another configuration example of the regeneration coordination unit YK will be described with reference to the schematic view of FIG. Another configuration example of the regenerative coordination unit YK will be described. In the regenerative coordination unit YK described with reference to FIGS. 1 and 5, the diameter dm of the master piston PM and the diameter dn of the input piston PN are set to be equal. Alternatively, the diameter dm of the master piston PM may be set to be larger than the diameter dn of the input piston PN.

  As described above, the input cylinder CN is fixed to the master cylinder CM at the mounting surface Rx. An input piston PN is inserted into the input cylinder CN so as to be in sliding contact therewith. The input piston PN is mechanically connected to the braking operation member BP by a clevis or the like and interlocked with the braking operation member BP. A flange portion Tn is formed on the input piston PN, and a compression spring (input elastic body) SN is provided between the flange portion Tn and a mounting surface Rx of the input cylinder CN. The collar Tn is pressed in the reverse direction Hb along the central axis Jm by the input elastic body SN. When not braking, the flange Tn abuts on the bottom Rt of the input cylinder CN. The state is a position where the input piston PN is in the most backward direction Hb (initial position of the input piston PN).

  Further, at the time of non-braking, the stepped portion My of the master piston PM is in contact with the second bottom portion Mt of the master cylinder CM. At this time, the end Mq of the master piston PM enters the inside of the input cylinder CN. The state is a position where the master piston PM is in the most backward direction Hb (initial position of the master piston PM). At the time of non-braking (that is, when each piston PN and PM are both in the initial position), the gap Ks between the end Mq of the master piston PM and the end Rv of the input piston PN is an initial gap ks (predetermined value ).

  The diameter of the master piston PM in the input cylinder CN is a diameter dm, and the cross-sectional area is a predetermined value am. The diameter of the input piston PN entering the input cylinder CN when the braking operation member BP is operated is a predetermined value dn, and the cross-sectional area is a predetermined value an. Here, the diameter dm (that is, the area am) can be set to be larger than the diameter dn (that is, the area an) (dm> dn, am> an).

  The manual braking is realized by the first on-off valve VA being in the closed position and the input cylinder CN being fluid locked (that is, the braking fluid BF is contained). By the fluid lock, the amount of damping fluid BF in the input chamber Rn of the input cylinder CN is maintained constant. When a force Fn acts on the input piston PN and is moved in the forward direction Ha, the hydraulic pressure in the input cylinder CN (input chamber Rn) is increased. In the pressure receiving area of each piston, since the area am is larger than the area an, the force Fm acting on the master piston PM is larger than the force Fn of the input piston PN. Specifically, the ratio of the output area am to the input area an (area ratio “am / an”) multiplied by the force Fn is output as the force Fm (Fm = Fn × (am / an)) . Further, since the volume of the braking fluid BF in the input cylinder CN is constant, the movement amount (displacement) Hm of the master piston PM is smaller than the movement amount (displacement) Hn of the input piston PN. That is, by containing the input cylinder CN, the input piston PN and the master piston PM operate as a lever.

  As described above, the volume required for the master cylinder chamber Rm (i.e., the inner diameter and the length of the master cylinder CM) is the rigidity of the braking device (for example, the rigidity of the caliper, the rigidity of the friction material, the rigidity of the braking piping) based on. In controlled braking, the volume of the master chamber Rm is set so that the wheel WH can exert the maximum braking force even when the coefficient of friction of the friction material decreases. On the other hand, in order to secure an appropriate operating force Fp for manual braking, it is necessary to reduce the diameter of the master cylinder CM.

  As described above, by setting “am> an”, the force (input piston thrust) Fn generated by the operating force Fp in the direction of the central axis Jm is the force (master piston thrust) Fm (= Fn). It is amplified to × (am / an). Therefore, under the condition that the operating force Fp is constant, the diameter of the master cylinder CM can be made larger than in the case of “am = an”. As a result, the dimension in the longitudinal direction of the master cylinder CM can be reduced under the condition that the capacity is constant.

<Operation and effect>
The braking control device SC according to the present invention adjusts the hydraulic pressure Pw of the braking fluid BF in the wheel cylinder CW provided on the wheel WH of the vehicle according to the operation of the braking operation member BP of the vehicle. The braking control device SC includes a pressure adjustment unit YC, a master unit YM, and a bypass unit YB. The fluid pressure generated by the electric motors MC, MZ, and MD is adjusted to the adjusted fluid pressure Pc by the pressure adjustment unit YC.

  The master unit YM is configured of a master cylinder CM, a master piston PM, and a master elastic body SM. The master piston PM is movable in conjunction with the operation of the braking operation member BP. Inside the master cylinder CM, a master chamber Rm and a servo chamber Rs are provided. Master room Rm is connected to wheel cylinder CW. Further, the adjusted hydraulic pressure Pc is introduced (supplied) to the servo chamber Rs. The servo chamber Rs applies, to the master piston PM, a first forward force Fa that opposes (opposes) the first reverse force Fb applied to the master piston PM in the master chamber Rm.

  The bypass unit YB includes a bypass cylinder CB, a bypass piston PB, and a bypass elastic body SB. A bypass chamber Rb and a pressure control chamber Rc are provided inside the bypass cylinder CB. The bypass chamber Rb is connected to the wheel cylinder CW similarly to the master chamber Rm. Further, in the pressure adjustment chamber Rc, the adjusted hydraulic pressure Pc is introduced (applied) as in the servo chamber Rs. A second forward force Fc is applied to the bypass piston PB by the pressure control chamber Rc, which opposes the second reverse force Fd applied to the bypass piston PB in the bypass chamber Rb.

  The volume of master cylinder CM is determined by the maximum braking force to be generated, and the inner diameter of master cylinder CM is determined by operation force Fp at the time of manual braking. In order for the condition to be satisfied, the master cylinder CM is required to have a small diameter and an axial length. However, the braking fluid BF is moved to the wheel cylinder CW by the bypass unit YB provided parallel to the master unit YM in addition to the master unit YM. Therefore, even when the small-diameter master cylinder CM is employed, the flow rate of the braking fluid BF can be secured, and the length in the longitudinal direction (axial direction) of the master cylinder CM can be shortened. As a result, the braking control device SC can be miniaturized, and the mountability to a vehicle can be improved.

  The master elastic body SM applies a first elastic force opposite to the first forward force Fa to the master piston PM. Further, the bypass elastic body SB applies a second elastic force opposed to the second forward force Fc to the bypass piston PB. Then, when the adjusted hydraulic pressure Pc increases from “0 (zero)”, the characteristics of the bypass elastic body SB and the characteristics of the master elastic body SM are moved so that the master piston PM is moved before the bypass piston PB is moved. The relationship with the characteristic is set.

  The above characteristics are based on the attachment load sm of the master elastic body SM and the attachment load sb of the bypass elastic body SB. Specifically, the “mounting pressure wb obtained by dividing the mounting load sb of the bypass elastic body SB by the pressure receiving area rc of the pressure adjustment chamber Rc” corresponds to the “mounting load sm of the master elastic body SM” and the pressure receiving area of the servo chamber Rs. The setting pressure is set to be larger than the mounting pressure wm divided by rs, whereby the master piston PM is first moved in the forward direction Ha before the bypass piston PB starts to move in the forward direction Hc. As a result, the brake fluid BF can be efficiently supplied to the wheel cylinder CW from the bypass unit YB.

  “Area ratio Am (= rm / rs) of pressure receiving area rs of servo chamber Rs to pressure receiving area rm of master chamber Rm”, “area of pressure receiving area rc of pressure regulating chamber Rc and pressure receiving area rb of bypass chamber Rb” The ratio Ab (= rb / rc) is set to the same value. Therefore, the master piston PM and the bypass piston PB can be moved in synchronization with each other by the adjusted hydraulic pressure Pc.

  The bypass piston PB has a large diameter outer peripheral portion Pd and a small diameter outer peripheral portion Pe. Similarly, the bypass cylinder CB has a large diameter inner circumferential portion Bd and a small diameter inner circumferential portion Be. Then, in the bypass cylinder CB, in addition to the two fluid pressure chambers Rc and Rb, an auxiliary chamber Rh is formed by the small diameter outer peripheral portion Pe and the large diameter inner peripheral portion Bd. When the adjusted hydraulic pressure Pc is increased from “0 (zero)”, the braking fluid BF is moved from the auxiliary chamber Rh to the bypass chamber Rb via the seal member SO which can be sealed only in one direction. . At the time of pressure increase, the braking fluid BF is replenished to the bypass chamber Rb by the auxiliary chamber Rh, so pressure increase responsiveness of the brake hydraulic pressure Pw can be improved.

  The regeneration coordination unit YK is configured of an input piston PN interlocked with the braking operation member BP, and an input cylinder CN fixed to a master cylinder CM. In the input cylinder CN of the regenerative cooperation unit YK, the master piston PM and the input piston PN are separated by a gap (displacement displacement) Ks at the central axis Jm. In control braking (braking by the braking control device SC), although the braking operation member BP is operated by the clearance Ks, there is a situation where the friction braking force is not generated while the hydraulic pressure Pw of the wheel cylinder CW remains "0". It can be formed. The clearance Ks is controlled by the adjusted hydraulic pressure Pc, and the regenerative coordinated control is achieved by adjusting the adjusted hydraulic pressure Pc.

  The diameter dm of the master piston PM (part included in the input cylinder CN) is set larger than the diameter dn of the input piston PN (part moved into the input cylinder CN when the braking operation member BP is operated) Ru. Therefore, in the input cylinder CN, the cross-sectional area am of the master piston PM is larger than the cross-sectional area an of the input piston PN.

  In the regenerative cooperation unit YK, since “am> an, dm> dn”, the force (input piston thrust) Fn acting on the input piston PN is increased in the manual braking, and is set as a master piston thrust Fm, It is transmitted to the master piston PM. Therefore, even if the inner diameter of master cylinder CM (particularly, master chamber Rm) is set large, the operating force Fp at the time of manual braking can be made appropriate. Therefore, shortening of master cylinder CM can be achieved.

Other Embodiments
Hereinafter, other embodiments will be described. Also in the other embodiments, the same effects as above (coexistence of securing of capacity and reduction in diameter in the master cylinder CM, efficient movement of the braking fluid BF by the bypass unit YB, improvement of responsiveness of the braking fluid pressure Pw, etc.) Play.

  In the first embodiment described above, the configuration (see FIG. 1) of “single-type master cylinder CM + single-type bypass unit YB + recirculation-type pressure adjustment unit YC” has been exemplified. In the second embodiment, the configuration (see FIG. 5) of “tandem type master cylinder CM + tandem type bypass unit YB + accumulator type pressure regulating unit YC” has been exemplified. As an example of the pressure regulation unit YC, the configuration of the “electric cylinder type pressure regulation unit YC” (see FIG. 7) is exemplified. As an example of the bypass unit YB, a single-type configuration (see FIG. 6) arranged in parallel is shown. These elements are combinational. Therefore, one of nine sets shown in the list of Table 1 is adopted as the configuration of the braking control device SC. In the case where the single type master unit YM is adopted, the front and rear type fluid passages are adopted. On the other hand, in the case of the tandem-type master unit YM, the two-system fluid path is one of a diagonal type and an anteroposterior type.

  In any of the above configuration examples, a stepped type (see FIG. 4) can be adopted as the bypass unit YB. Further, in any of the above configuration examples, the regenerative cooperation unit YK shown in FIG. 8 can be used.

  In the above embodiment, the vehicle is an electric vehicle or a hybrid vehicle having a drive motor. Alternatively, the braking control device SC may be applied to a vehicle having a general internal combustion engine (gasoline engine, diesel engine) having no drive motor. The braking control device SC is suitable for, for example, a vehicle requiring a high response collision damage reducing brake (so-called AEB) because the responsiveness of the braking fluid pressure Pw is high. In a vehicle that does not have the generator GN, regenerative braking is not generated. Therefore, in the braking control device SC, regenerative coordinated control is unnecessary and is not performed. That is, the vehicle is decelerated only by friction braking by the braking control device SC. In pressure adjustment control, control is executed as "Gt = Rg = 0".

  In the above embodiment, for the linear solenoid valves UC, UA, UB, ones in which the valve opening amount is adjusted in accordance with the energization amount are adopted. For example, although the solenoid valves UC, UA, and UB are on / off valves, opening and closing of the valves may be controlled by a duty ratio, and hydraulic pressure may be controlled linearly.

  In the above embodiment, the configuration of the disk brake device (disk brake) has been exemplified. In this case, the friction member is a brake pad and the rotating member is a brake disc. Instead of the disc brake, a 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, the upper fluid unit YU and the lower fluid unit YL are configured separately. The upper fluid unit YU and the lower fluid unit YL may be configured integrally. In this case, the lower controller ECL is included in the upper controller ECU.

BP: braking operation member, CW: wheel cylinder, YC: pressure regulating unit, DC: electric pump (QC + MC), UC: pressure regulating solenoid valve (normally open linear type), YM: master unit, CM: master cylinder, PM ... Master piston, SM ... Master elastic body, Rm ... Master chamber, Rs ... Servo chamber, YB ... Bypass unit, CB ... Bypass cylinder, PB ... Bypass piston, SB ... Bypass elastic body, Rc ... Pressure regulation chamber, Rb ... Bypass Chamber, YK: Regeneration coordination unit, CN: Input cylinder, PN: Input piston, ECU: Controller, BA: Operation amount sensor, PC: Adjustment hydraulic pressure sensor.

Claims (2)

A braking control device for a vehicle, which adjusts the hydraulic pressure of a braking fluid in a wheel cylinder provided on a wheel of the vehicle according to an operation of a braking operation member of the vehicle.
A pressure control unit for adjusting the fluid pressure generated by the electric motor to obtain an adjusted fluid pressure;
It consists of a master cylinder and a master piston,
“Master chamber connected to the wheel cylinder”, and “The adjusted hydraulic pressure is introduced, and the master chamber applies a first forward force to the master piston, which is opposed to the first reverse force applied to the master piston by the master chamber A master unit having a servo room
It consists of a bypass cylinder and a bypass piston,
“Bypass chamber connected to the wheel cylinder”, and “The adjusted hydraulic pressure is introduced, and the bypass piston applies a second forward force to the bypass piston, which opposes the second reverse force applied to the bypass piston. A bypass unit having a pressure control chamber
And a braking control device for a vehicle. The vehicle braking control device according to claim 1, wherein
A master elastic body that applies a first elastic force opposite to the first forward force to the master piston;
A bypass elastic body that applies a second elastic force opposite to the second forward force to the bypass piston;
Equipped with
When the adjusted hydraulic pressure increases from zero,
The vehicle braking control device, wherein the relationship between the characteristics of the bypass elastic body and the characteristics of the master elastic body is set such that the master piston is moved before the bypass piston is moved.