JP6935711B2 - Vehicle braking control device - Google Patents

Description

The present invention relates to a vehicle braking control device.

In Patent Document 1, for the purpose of "preventing a decrease in braking force at the time of backup in a vehicle braking system to which a by-wire braking system is applied", "a vehicle has a failure such as an abnormality in a communication network". When it occurs in the braking system, the first and second shutoff valves are opened to communicate the slave cylinder and the master cylinder. In addition, the first and second slave pistons are maintained in their current positions by driving the motor. After that, when the operation of the brake pedal is released, the operation of the motor is stopped. "

In the device described in Patent Document 1, the slave cylinder drives the ball screw shaft by the power of a motor serving as an electric actuator, and the brake hydraulic pressure is generated by the first and second slave pistons based on the drive of the ball screw shaft. Let me. The first and second slave pistons are urged in the backward direction by coil springs, respectively. The ball screw shaft is driven in the forward direction by the power of the motor, and moves the first and second slave pistons in the forward direction against the urging force of the coil spring, thereby generating brake fluid pressure. That is, in the device, a tandem type slave cylinder is adopted, a ball screw is provided on the central axis of the slave cylinder, and the ball screw converts the rotational power of the electric motor into the linear power of the slave piston, thereby braking hydraulic pressure. Is generated. Due to the structure, the length of the cylinder in the longitudinal direction becomes long, and its shortening is desired.

Japanese Unexamined Patent Publication No. 2016-165913

An object of the present invention is to provide a vehicle braking control device having a shortened longitudinal dimension and high mountability in a vehicle.

The vehicle braking control device according to the present invention is a liquid of a braking liquid (BF) in a wheel cylinder (CW) provided on a wheel (WH) of the vehicle in response to an operation of a vehicle braking operation member (BP). The pressure (Pw) is adjusted, and the "pressure adjusting unit (YC) that adjusts the hydraulic pressure generated by the electric motor (MC, MZ, MD) to obtain the adjusting hydraulic pressure (Pc)" and "master" It is composed of a cylinder (CM) and a master piston (PM), and "a master chamber (Rm) connected to the wheel cylinder (CW)" and "the adjusting hydraulic pressure (Pc) are introduced, and the above It has a servo chamber (Rs) that applies a first forward force (Fa) facing the first retracting force (Fb) applied to the master piston (PM) by the master chamber (Rm) to the master piston (PM). "Master unit (YM)", "Bypass cylinder (CB), and bypass piston (PB)," Bypass chamber (Rb) connected to the wheel cylinder (CW) ", and" The adjustment A hydraulic pressure (Pc) is introduced, and a second forward force (Fc) facing the second retracting force (Fd) applied to the bypass piston (PB) by the bypass chamber (Rb) is applied to the bypass piston (PB). A bypass unit (YB) having a pressure adjusting chamber (Rc) to be applied, and a bypass unit (YB).

The volume of the master cylinder CM is determined by the maximum braking force to be generated, and the inner diameter of the master cylinder CM is determined by the operating force Fp during manual braking. In order to satisfy the two conditions, the master cylinder CM needs to have a small diameter and a long axial direction. According to the above configuration, the brake fluid BF is supplied to the wheel cylinder CW by the bypass unit YB in addition to the master unit YM. Therefore, even when a master cylinder CM having a small diameter is adopted, the flow rate of the braking liquid BF can be secured, and the dimension of the master cylinder CM in the longitudinal direction can be shortened.

The vehicle braking control device according to the present invention includes a master elastic body (SM) that applies a first elastic force facing the first forward force (Fa) to the master piston (PM), and the second forward force (the second forward force). A bypass elastic body (SB) that applies a second elastic force facing the Fc) to the bypass piston (PB) is provided. Then, when the adjusting 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 cut off, and the liquidtight state of the master cylinder chamber Rm is achieved. After that, the bypass piston PB starts to move in the forward direction Hc. Therefore, the brake fluid BF from the bypass unit YB is efficiently supplied to the wheel cylinder CW without being moved to the reservoir RV.

It is an overall block diagram for demonstrating the 1st Embodiment of the brake control device SC of the vehicle which concerns on this invention. It is the schematic for demonstrating the bypass unit YB. It is a control flow diagram for demonstrating the process of pressure adjustment control. It is the schematic for demonstrating another configuration example of a bypass unit YB. It is an overall block diagram for demonstrating the 2nd Embodiment of the brake control device SC of the vehicle which concerns on this invention. It is the schematic for demonstrating another arrangement example of a bypass unit YB. It is the schematic for demonstrating another configuration example of a pressure control unit YC. It is the schematic for demonstrating another configuration example of a regenerative cooperation unit YK.

<Symbols of components, etc. and subscripts at the end of the symbols>
In the following description, components, arithmetic processing, signals, characteristics, and values having the same symbols, such as "ECU", have the same function. The subscripts "i" to "l" added to the end of each symbol are comprehensive symbols indicating which wheel they are related to. Specifically, "i" indicates the right front wheel, "j" indicates the left front wheel, "k" indicates the right rear wheel, and "l" indicates the left rear wheel. For example, in each of the four wheel cylinders, it is described as a right front wheel cylinder CWi, a left front wheel cylinder CWj, a right rear wheel cylinder CWk, and a left rear wheel wheel cylinder CWl. Further, the subscripts "i" to "l" at the end of the symbol may be omitted. When the subscripts "i" to "l" are omitted, each symbol represents a general term for each of the four wheels. For example, "WH" represents each wheel and "CW" represents each wheel cylinder.

The subscripts "1" and "2" added to the end of each symbol are comprehensive symbols indicating which system the two braking systems are related to. Specifically, "1" indicates the first system, and "2" indicates the second system. For example, in the master cylinder chamber, it is described as the first master cylinder chamber Rm1 and the second master cylinder chamber Rm2. Further, the subscripts "1" and "2" at the end of the symbol may be omitted. When the subscripts "1" and "2" are omitted, each symbol represents a general term for each of the two braking systems. For example, "Rm" represents a master cylinder chamber in each braking system.

When the front and rear type is adopted in the two braking systems, the subscripts "f" and "r" added to the end of each symbol are related to any of the front and rear wheel systems in the two braking systems. It is a comprehensive symbol indicating the existence. 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 cylinder CWf and a rear wheel wheel cylinder CWr. Further, the subscripts "f" and "r" at the end of the symbol may be omitted. When the subscripts "f" and "r" are omitted, each symbol represents a general term for each 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 called "control braking". When the operation of the braking control device SC is in a malfunctioning state, braking by only the operating force of the driver is called "manual braking". Therefore, in manual braking, the braking control device SC is not used.

<First Embodiment of the vehicle braking control device according to the present invention>
A first embodiment of the 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 adopted to ensure redundancy. Here, the fluid path is a path for moving the braking liquid BF, which is the working liquid of the braking control device, and corresponds to the braking pipe, the flow path of the fluid unit, the hose, and the like. The inside of the fluid path is filled with the braking fluid BF. In the fluid path, the side closer to the reservoir RV (the side far from the wheel cylinder CW) is called the "upstream side" or "upper part", and the side closer to the wheel cylinder CW (the side far from the reservoir RV) is called. 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 and CWj (also referred to as "CWf"). The rear wheel system of the two fluid paths is connected to the rear wheel cylinders CWk and CWl (also referred to as "CWr"). That is, as the two fluid paths, a so-called front-rear type (also referred to as "H type") is adopted.

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 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 cooperative control (coordination between regenerative braking and friction braking) is executed. The vehicle equipped with the 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, the 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. Then, the brake caliper is arranged so as to sandwich the rotating member KT.

The brake caliper is provided with a wheel cylinder CW. By increasing the pressure (braking fluid pressure) Pw of the braking fluid BF in the wheel cylinder CW, 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 so as to rotate integrally, a braking torque (friction braking force) is generated on the wheel WH by the frictional force generated at this time.

The reservoir (atmospheric pressure reservoir) RV is a tank for the working liquid, and the braking liquid BF is stored in the tank. The inside of the atmospheric pressure reservoir RV is divided into two parts Ru and Rd by a partition plate SK. The master reservoir chamber Ru is connected to the master cylinder chamber Rm. Further, the pressure adjusting reservoir chamber Rd is connected to the pressure adjusting unit YC by the first reservoir fluid passage HR. When the reservoir RV is filled with the braking fluid BF, the liquid level of the braking fluid BF is above the height of the partition plate SK. Therefore, the brake fluid BF can freely move between the master reservoir chamber Ru and the pressure adjusting reservoir chamber Rd beyond the partition plate SK. On the other hand, when the amount of the braking liquid BF in the reservoir RV decreases and the liquid level of the braking liquid BF becomes lower than the height of the partition plate SK, the master reservoir chamber Ru and the pressure adjusting reservoir chamber Rd become independent, respectively. It becomes a liquid pool.

Each wheel WH is provided with a wheel speed sensor VW to detect the wheel speed Vw. The wheel speed Vw signal is used for anti-skid control or the like that suppresses the locking 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, the vehicle body speed Vx is calculated based on the wheel speed Vw.

≪Brake control device SC≫
The braking control device SC is composed of an upper fluid unit YU on the side close to the master cylinder CM and a lower fluid unit YL on the side close 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 composed of an operation amount sensor BA, an operation switch ST, a master unit YM, a pressure adjusting unit YC, a regenerative coordination unit YK, and an upper controller ECU.

The braking 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 so as to detect the operation displacement Sp of the braking operation member BP. Further, an operating force sensor FP that detects the operating force Fp of the braking operating member BP may be provided. Further, as the manipulated variable 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 an instruction 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 whether or not the driver operates the braking operation member BP. 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 (that is, during braking), an on signal is output as an operation signal St. The braking operation signal St is input to the controller ECU.

[Master unit YM (single type)]
The master unit YM adjusts the hydraulic pressure (front wheel braking hydraulic pressure) Pwf in the front wheel cylinder CWf via the master cylinder chamber Rm. The master unit YM includes a master cylinder CM, a master piston PM, and a master elastic body SM.

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

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

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

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

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

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

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

The master chamber Rm has an urging force Fb (referred to as "first retreat force") in the retreat direction Hb along the central axis Jm due to its internal pressure ("master cylinder hydraulic pressure", also referred to as "master hydraulic pressure") Pm. Is given to the master piston PM. The servo chamber (servo hydraulic chamber) Rs applies an urging force Fa (referred to as "first forward force") facing the retreating force Fb to the master piston PM by its internal pressure (that is, the introduced adjusting hydraulic pressure Pc). Give. That is, in the master piston PM, the forward force Fa due to the hydraulic pressure Pv (= Pc) in the servo chamber Rs and the backward force Fb due to the hydraulic pressure (master hydraulic pressure) Pm in the master chamber Rm are the central axis of the master cylinder CM. They oppose each other (face each other) in the direction of Jm and are statically balanced.

For example, the pressure receiving area of the first surface Ms of the brim portion Tm (that is, the pressure receiving area of the servo chamber Rs) rs is the pressure receiving area of the first end portion 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 (resulting in the servo hydraulic pressure Pv) introduced into the servo chamber Rs 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 backward force Fb (= Pm × rm (+ elastic force of the master elastic body SM)) are in equilibrium.

When the braking operation member BP is operated, the adjusting hydraulic pressure Pc is increased by the pressure adjusting unit YC. The adjusting 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 forward force (first forward force) Fa generated by the servo hydraulic pressure Pv in the forward direction (left direction in the figure) becomes larger than the mounting load (set load) of the master elastic body SM, the master piston PM is centered. It is moved along the axis Jm. When the through hole Ap passes through the seal SL by this movement in the forward direction Ha, the master chamber Rm is shut off from the reservoir RV (particularly, the master reservoir chamber Ru), and the master chamber Rm is made liquid-tight. Further, when the adjusting hydraulic pressure Pc is increased, the volume of the master chamber Rm is reduced, and the braking liquid BF is pressure-fed from the master cylinder CM toward the front wheel cylinder CWf at the master hydraulic pressure Pm. A force (first retreating force) Fb in the retreating direction Hb acts on 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 (oppose) the backward 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 braking operation member BP is returned, the adjusting hydraulic pressure Pc is reduced by the pressure adjusting 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 backward direction (right direction in the figure) Hb. When the braking operation member BP is put into a non-operation state, the position (initial position) where the master piston PM (particularly, the stepped portion My) comes into contact with the second bottom Mt of the master cylinder CM due to the elastic force of the compression spring SM. Is returned to.

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

The reflux electric pump DC is composed of a set of one reflux electric motor MC and one reflux fluid pump QC. In the recirculation electric pump DC, the electric motor MC so that the recirculation electric motor (simply also referred to as “recirculation motor”) MC and the recirculation fluid pump (simply also referred to as “recirculation pump”) QC rotate together. And the fluid pump QC are fixed. The recirculation electric pump DC (particularly, the recirculation motor MC) is a power source for adjusting the hydraulic pressure (braking fluid pressure) Pw of the wheel cylinder CW during 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 adopted as the electric motor MC. The brushless motor MC is provided with a rotation angle sensor KA that detects the rotor position (rotation angle) Ka. The switching element of the bridge circuit is controlled based on the rotation angle (actual value) Ka, and the electric motor MC is driven. That is, the direction of the energization amount (that is, the excitation direction) of the coils of each of the three phases (U phase, V phase, 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 recirculation pump QC. Further, a pressure regulating fluid passage HC is connected to the discharge port Qt of the fluid pump QC. By driving the electric pump DC (particularly, the fluid pump QC), the braking liquid 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 adopted as the adjusting fluid pump QC.

A check valve GC (also referred to as a "check valve") is interposed in the pressure regulating fluid path HC. For example, a check valve GC is provided near the discharge portion Qt of the fluid pump QC. The check valve GC allows the brake fluid BF to move from the first reservoir fluid path HR toward the pressure regulating fluid path HC, but moves from the pressure regulating fluid path HC toward the first reservoir fluid path HR. (That is, the backflow of the braking 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 regulating fluid path HC and the first reservoir fluid path HR. The pressure regulating solenoid valve UC is also called a linear solenoid valve (“proportional valve” or “differential pressure valve”” in which the valve opening amount (lift amount) is continuously controlled based on the energized state (for example, supply current). ). The pressure regulating solenoid valve UC is controlled by the upper controller ECU based on the drive signal Uc. As the solenoid valve UC, a normally open type solenoid valve is adopted.

The brake fluid BF is pumped from the first reservoir fluid passage HR through the suction port Qs of the fluid pump QC and discharged from the discharge port Qt. Then, the brake 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 adjusting fluid passage HC form a recirculation path (a fluid path in which the flow of the braking fluid BF returns to the original flow), and the check regurgitation is performed in this recirculation path. A valve GC and a solenoid valve UC are interposed.

When the electric pump DC is operating, the brake fluid BF recirculates in the order of "HR-> QC (Qs-> Qt)-> GC-> UC-> HR" as shown by the broken line arrow (A). .. When the pressure regulating solenoid valve UC is in the fully open state (because it is a normally open type, it is not energized), the hydraulic pressure (adjusting hydraulic pressure) Pc in the pressure regulating fluid passage HC is low, and is approximately "0 (atmospheric pressure)". Is. When the amount of electricity supplied to the pressure regulating solenoid valve UC is increased and the return path is narrowed by the solenoid valve UC, the adjusting hydraulic pressure Pc is increased. The pressure regulation method is called "recirculation type". In the pressure adjusting unit YC, an adjusting hydraulic pressure sensor PC is provided in the pressure adjusting fluid passage HC (particularly between the check valve GC and the pressure adjusting valve UC) so as to detect the adjusting hydraulic pressure Pc.

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

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

[Regenerative cooperation unit YK]
The regenerative braking unit YK achieves coordinated control of friction braking and regenerative braking. That is, a state in which the braking operation member BP is operated by the regenerative cooperation unit YK but the braking hydraulic pressure Pw is not generated can be formed. The regeneration cooperation unit YK is composed 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 having a bottom portion fixed to the master cylinder CM. 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 be interlocked with the braking operation member BP. The input piston PN is provided with a flange portion Tn. An input elastic body (for example, a compression spring) SN is provided between the mounting surface of the input cylinder CN to the master cylinder CM and the brim Tn of the input piston PN. The input elastic body SN presses the brim portion Tn of the input piston PN against the bottom portion of the input cylinder CN in the direction of the central axis Jm.

During non-braking, the stepped portion My of the master piston PM is in contact with the second bottom Mt of the master cylinder CM, and the brim Tn of the input piston PN is in contact with the bottom of the input cylinder CN. During non-braking, the gap Ks between the master piston PM (particularly the end face Mq) and the input piston PN (particularly the end face Rv) is set to a predetermined distance ks (referred to as "initial gap") inside the input cylinder CN. There is. That is, when each piston PM and PN are in the position of the most retracting direction Hb (referred to as the "initial position" of each piston) (that is, when not braking), the master piston PM and the input piston PN are separated by a predetermined distance ks. is seperated. Here, the predetermined distance ks corresponds to the maximum value of the regenerative amount Rg. When the regenerative cooperative control is executed, the gap (also referred to as “separation displacement”) Ks is controlled (adjusted) by the adjusting 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 that invades the input cylinder CN when the braking operation member BP is operated. NS. That is, the cross-sectional area am due to the diameter dm and the cross-sectional area an according to the diameter dn are the same. As will be described later, manual braking is realized by fluid-locking the inside of the input cylinder CN. When manual braking is performed, since "dm = dn (am = an)", the intrusion volume of the input piston PN into the input cylinder CN matches the exit volume of the master piston PM outside the input cylinder CN. Then, the pistons PN and PM are moved in the forward direction Ha. That is, the displacement Hn of the input piston PN and the displacement Hm of the master piston PM coincide with each other, and the force Fn applied to the input piston PN by the driver is regarded as the force Fm acting on the master piston PM as it is. (That is, "Hn = Hm, Fn = Fm").

The input cylinder CN is connected to the reservoir RV (particularly, the pressure adjusting reservoir chamber Rd) via the second reservoir fluid passage HT. A part of the second reservoir fluid passage HT can be shared with the first reservoir fluid passage HR. However, it is desirable that the first reservoir fluid path HR and the second reservoir fluid path HT are separately connected to the reservoir RV. The fluid pump QC sucks the brake fluid BF from the reservoir RV via the first reservoir fluid passage HR, but at this time, air bubbles may be mixed in the first reservoir fluid passage HR. Therefore, the second reservoir fluid passage HT does not have an intersection 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 into the input cylinder CN and the like. Is connected to the reservoir RV.

Two on-off valves VA and VB are provided in series in the second reservoir fluid passage 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 (blocking 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 opened solenoid valve is adopted as the second on-off valve VB.

The second reservoir fluid path HT is connected to the simulator fluid path HS at the connection portion 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 site Bs. The simulator fluid path HS is provided with a stroke simulator (simply also referred to as “simulator”) SS. When the regenerative cooperative 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. A piston and an elastic body (for example, a compression spring) are provided inside the simulator SS. 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 in a direction that prevents the inflow of the braking fluid BF by the elastic body. The elastic body forms an operating force Fp when the braking operating member BP is operated.

A simulator hydraulic pressure sensor PS is provided in the simulator fluid path HS so as to detect the hydraulic pressure (simulator hydraulic pressure) Ps in the simulator SS. The simulator hydraulic pressure sensor PS is one of the above-mentioned braking operation amount sensors BA. 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 portion Mq of the master piston PM and the area ao of the second surface Mo of the brim portion Tm are set to be equal so that the volume change accompanying the movement of the master piston PM is absorbed. When the regenerative cooperative 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. Therefore, the input chamber Rn and the rear chamber Ro are the second reservoir fluid passage HT and the rear chamber Ro. , Connected by the simulator fluid path HS. When the master piston PM is moved in the forward direction Ha, the volume in the input chamber Rn is increased by the movement, but since "am = ao", the brake fluid BF for the increased volume is all in the rear chamber. It is moved from Ro to the input room Rn. In other words, there is no excess or deficiency in the balance of the amount of liquid due to the movement of the master piston PM. Therefore, the amount (volume) of the braking fluid BF that 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 regulating fluid path HC is branched at the portion Bb and connected to the bypass unit YB. Further, the bypass fluid path HB is connected to the bypass unit YB, and the end portion of the bypass fluid path HB is connected to the master cylinder fluid path HM at the portion Bm. Therefore, the adjusting hydraulic pressure Pc is introduced (supplied) into the bypass unit YB, and its output is introduced into the front wheel cylinder CWf via the bypass fluid path HB. The detailed configuration of the bypass unit YB will be described later. The braking liquid BF adjusted to the adjusting hydraulic pressure Pc is applied to the master unit YM (particularly, the servo chamber Rs). In addition, the adjusting hydraulic pressure Pc is also applied to the bypass unit YB and output to the front wheel cylinder CWf. That is, the braking fluid BF from the pressure adjusting unit YC is moved to the front wheel cylinder CWf through the master unit YM and the bypass unit YB. As a result, the amount (volume) of the braking fluid BF required for the master unit YM is reduced, so that the master unit YM can be miniaturized.

In particular, in order to reduce the operating force Fp in manual braking, it is necessary to reduce the inner diameter of the master cylinder CM. However, since the master cylinder CM requires a certain 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 composed 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 upper controller ECU controls the electric motor MC and three different types of solenoid valves VA, VB, and UC based on the braking operation amount Ba, the operation signal St, and the adjusting hydraulic pressure Pc. Specifically, the drive signals Va, Vb, and Uc for controlling various solenoid valves VA, VB, and UC are calculated based on the control algorithm in the microprocessor MP. Similarly, the drive signal Mc for controlling the electric motor MC is calculated. Then, the solenoid valves VA, VB, UC, and the electric motor MC are driven based on the drive signals Va, Vb, Uc, and Mc.

The upper controller ECU is network-connected to the lower controller ECL and the controller (electronic control unit) of another system via the vehicle-mounted communication bus BS. The regenerative amount Rg (target value) is transmitted from the upper controller ECU to the drive controller ECD through the communication bus BS so as to execute the regenerative cooperative control. The "regenerative amount Rg" is a state amount (target value) representing the magnitude of regenerative braking generated by the drive motor (which is also a regenerative generator) GN. Regenerative braking is generated by controlling the regenerative generator GN by the drive controller ECD based on the target value Rg of the regenerative amount. Electric power is supplied to each controller ECU, ECL, and ECD from the in-vehicle generator AL and the storage battery BT.

The upper controller ECU is provided with a drive circuit DR so as 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. Based on the motor drive signal Mc, the energized state of each switching element is controlled, and the output of the electric motor MC is controlled. Further, in the drive circuit DR, the energization state (that is, the excitation state) of the solenoid valves VA, VB, and UC is controlled based on the drive signals Va, Vb, and Uc so as to drive them. 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 the supply currents to the electric motor MC and the solenoid valves VA, VB, and UC are detected.

During non-braking (for example, when the braking operation member BP is not operated), 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 a state of proper operation, the controller ECU first energizes the first and second on-off valves VA and VB, and the first on-off valve VA is in the open position. 2 The on-off valve VB is set to the closed position. Depending on the open position of the first on-off valve VA, the input chamber Rn and the rear chamber Ro are fluidly connected, and the simulator SS is connected to the input chamber Rn. 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 liquid flowing out from the input chamber Rn due to the movement flows into the simulator SS, and the operating force Fp of the braking operation member BP is formed.

At the time of control braking, the electric pump DC (particularly, the electric motor MC) and the solenoid valve UC are controlled by the controller ECU based on the operation amount Ba. Specifically, the electric pump DC pumps the braking fluid BF from the reservoir RV through the first reservoir fluid passage HR and discharges it to the pressure regulating fluid passage HC. Then, the discharged braking liquid BF is throttled by the solenoid valve UC and adjusted to the adjusting hydraulic pressure Pc. The adjusting hydraulic pressure Pc is introduced (supplied) to the servo chamber Rs via the front wheel pressure adjusting fluid path HCf. The adjusting hydraulic pressure Pc moves the master piston PM in the forward direction Ha, and the braking fluid BF is pumped from the master chamber Rm toward the front wheel cylinders 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, the master hydraulic pressure Pm equal to the adjusting hydraulic pressure Pc is applied to the front wheel cylinder CWf. Further, the adjusting hydraulic pressure Pc is introduced into the rear wheel cylinder CWr (CWk, CWl) through the rear wheel pressure adjusting fluid path HCr.

During manual braking when the operation of the braking control device SC is in a malfunctioning state, the first and second on-off valves VA and VB are not energized. Therefore, the first on-off valve VA is set to the closed position and the second on-off valve VB is set to the open position. The closed position of the first on-off valve VA puts the input chamber Rn in a fluid-locked state (sealed state) so that the input piston PN and the master piston PM cannot move relative to each other. Further, depending on the open position of the second on-off valve VB, the rear chamber Ro is fluidly connected to the reservoir RV through the second reservoir fluid passage HT. Therefore, the volume of the rear chamber Ro is reduced by the movement of the forward direction Ha of the master piston PM, but the amount of liquid accompanying the volume reduction is discharged toward the reservoir RV. The input piston PN and the master piston PM are integrally moved in conjunction with the operation of the braking operation member BP, and the braking liquid BF is pumped from the master chamber Rm.

[Lower fluid unit YL]
The lower fluid unit YL is controlled by the lower controller ECL. Wheel speed Vw, yaw rate Yr, steering angle Sa, front-rear acceleration Gx, 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 executed so as to suppress an 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) that suppresses excessive oversteering behavior and understeering behavior of the vehicle is performed. That is, in the lower fluid unit YL, braking control independent of each wheel is executed based on the above signal (Vw or the like). The upper controller ECU and the lower controller ECL are connected in a communicable state by the communication bus BS, and the sensor signal and the calculated value are shared. The upper fluid unit YU and the lower fluid unit YL are connected via the master cylinder fluid passage HM and the rear wheel pressure regulating fluid passage HCr.

The lower fluid unit YL includes a 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 composed of one lower electric motor ML and two lower fluid pumps QLf and QLr. The lower electric motor ML is controlled by the lower controller ECL based on the drive signal Ml. The two lower fluid pumps QLf and QLr are integrally rotated and driven by the electric motor ML. Then, the brake fluid BF is pumped from the front wheels and the rear wheel charge over valves (simply also referred to as "charge valves") UPf, and the upstream parts Bof and Bor of the UPr by the front wheels and the rear wheel fluid pumps QLf and QLr of the electric pump DL. , Front wheel, rear wheel charge valve UPf, discharge to downstream Bpf, Bpr of UPr. Front wheels and rear wheel low pressure reservoirs RLf and RLr are provided on the suction side of the front wheel and rear wheel fluid pumps QLf and QLr.

Similar to the linear pressure regulating valve UC, a normally open type linear pressure regulating valve (a solenoid valve whose valve opening amount is continuously controlled depending on the energized state) is adopted as a charge valve UP (general 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 (flow of the circulating braking fluid BF) of "Bof-> RLf-> QLf-> Bpf-> UPf-> Bof" is formed. The front wheel charge valve UPf provided in the master cylinder fluid passage HM adjusts the hydraulic pressure (front wheel output hydraulic pressure) Ppf in the downstream portion of the front wheel charge valve UPf. The fluid pump QLf moves the braking liquid BF from the upstream portion Bof of the front wheel charge valve UPf toward the downstream portion Bpf, and the front wheel charge valve UPf (squeezing of the valve opening portion) causes the input hydraulic pressure Pqf in the upstream portion. The differential pressure (Ppf> Pqf) with the output hydraulic pressure Ppf in the downstream portion is adjusted.

Similarly, by driving the rear wheel fluid pump QLr, a reflux of "Bor-> RLr-> QLr-> Bpr-> UPr-> Bor" is formed. The hydraulic pressure (rear wheel output hydraulic pressure) Ppr in 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 regulating fluid passage HCr. That is, the fluid pump QLr moves the braking liquid BF from the upper Bor of the rear wheel charge valve UPr to the lower Bpr, and the rear wheel charge valve UPr moves the upper hydraulic pressure (input hydraulic pressure) Pqr and the lower hydraulic pressure (output hydraulic pressure). ) The differential pressure with Ppr (Ppr> Pqr) is adjusted.

Input hydraulic pressure sensors PQf and PQr are provided so as to detect the 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. At least one of the two input hydraulic pressure sensors PQf and PQr can be omitted.

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

The wheel cylinder fluid passage HW is provided with an inlet valve VI and an outlet valve VO. As the inlet valve VI, a normally open type on / off solenoid valve is adopted. Further, as the outlet valve VO, a normally closed type on / off solenoid valve is adopted. The solenoid valves VI and VO are controlled by the lower controller ECL based on the drive signals Vi and Vo. The brake fluid pressure Pw of each wheel can be independently controlled by the inlet valve VI and the outlet valve VO.

Since the configuration of each wheel WH is the same in the inlet valve VI and the outlet valve VO, the configuration of the right front wheel WH will be described as an example. A normally open type inlet valve VIi is interposed in the wheel cylinder fluid passage HWi for the right front wheel (the fluid passage connecting the portion Bpf and the right front wheel cylinder CWi). The wheel cylinder fluid passage HWi is fluidly connected to the low pressure reservoir RLf at the downstream portion of the inlet valve VIi via the normally closed outlet valve VOi. For example, in anti-skid control, in order to reduce the hydraulic pressure Pwi in the wheel cylinder CWi, the inlet valve VIi is closed and the outlet valve VOi is opened. The inflow of the braking fluid BF from the inlet valve VIi is blocked, 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 opened and the outlet valve VOi is closed. The outflow of the braking fluid BF to the low pressure reservoir RLf is prevented, the output hydraulic pressure via the front wheel charge valve UPf is introduced into 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 diagram of FIG. The bypass unit YB is composed of 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 “initial position”) in the most backward direction Hd (right direction in the figure). Further, the state of the lower part of the center line Jb indicates a case where the bypass piston PB is at the 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 a distance bs between the initial position and the limit position.

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

The inside of the bypass cylinder CB is separated into two chambers (hydraulic chambers) Rb and Rc by the bypass piston PB. The bypass chamber Rb is a hydraulic chamber partitioned by an inner peripheral portion Bc of the bypass cylinder CB, a first bottom portion (bottom surface) Bu, and a first end portion Br of the bypass piston PB. A bypass fluid path HB is connected to the bypass chamber Rb. The bypass fluid path HB is connected to the master cylinder fluid path HM at the portion Bm and finally to the wheel cylinder CW. Therefore, the internal pressure Pb of the bypass chamber Rb corresponds to the master hydraulic 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 portion Br) is the value "rb".

The pressure regulating chamber Rc is a hydraulic chamber partitioned by an inner peripheral portion Bc of the bypass cylinder CB, a second bottom portion (bottom surface) Bt, and a second end portion Bq of the bypass piston PB. The bypass chamber Rb and the pressure adjusting chamber Rc are formed so as to sandwich the bypass piston PB. In other words, on the central axis Jb of the bypass cylinder CB, the pressure adjusting chamber Rc and the bypass chamber Rb are located on opposite sides of the bypass piston PB, respectively. Therefore, the force in the forward direction Hc (referred to as "second forward force") applied to the bypass piston PB by the pressure adjusting chamber Rc and the force in the backward direction Hd applied to the bypass piston PB by the bypass chamber Rb ("second backward force"). Fd (referred to as "force") faces and opposes each other in the direction of the central axis Jb of the bypass cylinder CB.

The front wheel pressure regulating fluid path HCf is connected to the pressure regulating chamber Rc. Therefore, the pressure (adjusted hydraulic pressure) Pc adjusted by the pressure adjusting unit YC is introduced into the pressure adjusting chamber Rc. Here, the pressure receiving area of the pressure adjusting chamber Rc (the cross-sectional area perpendicular to the central axis Jb of the second end portion 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 can be set equally.

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. When not braking, the second end Bq and the second bottom Bt are in contact with each other, and the bypass piston PB is in the initial position. The bypass unit YB described above is referred to as a "single type" because it has one bypass chamber Rb.

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 control braking is started, the master piston PM is moved before the bypass piston PB is moved". NS. The characteristics of the elastic bodies SM and SB are based on the mounting load (also referred to as "set load"). Specifically, "a value obtained by dividing the mounting load sb of the bypass elastic body SB by the pressure receiving area rc of the pressure adjusting chamber Rc (referred to as" mounting pressure ") wb" is the "mounting 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 and SB when the elastic bodies SM and SB are assembled to a machine (for example, master unit YM and bypass unit YB). be. The mounting loads sm and sb are urging forces of the elastic bodies (for example, compression coil springs) SM and SB at the initial positions of the piston members PM and PB, and are also referred to as "initial loads".

When each elastic body SM and SB is in a no-load state, each has a free length (also referred to as “free height”). When these are assembled to the units YM and 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 urging force of the retreating directions Hb and Hd applied to the respective pistons PM and PB by the elastic bodies SM and SB is the mounting load (also referred to as “set load”) sm and sb. be. When the elastic body is a compression coil spring, "height" is used instead of "length" as a term (see "JIS B0103 spring term").

Since the "mounting pressure" is a value obtained by dividing the mounting load by the piston pressure receiving area (cross-sectional area), the movement of the piston is started when the pressure acting on the piston exceeds the mounting pressure. That is, when the adjusting hydraulic pressure Pc becomes larger than the mounting pressure wm, the master piston PM starts moving in the forward direction Ha. Similarly, when the adjusting 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 to be larger than the mounting pressure wm (= sm / rs) of the master elastic body SM. Therefore, when the adjusting hydraulic pressure Pc is increased from "0" while the master piston PM and the bypass piston PB are stationary at the initial positions, the master piston PM first moves in the forward direction. It begins to move to Ha, after which 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, the communication between the master chamber Rm and the master reservoir chamber Ru is cut off, and then the bypass piston PB is moved.

If the movement of the bypass piston PB is started before the communication between the master chamber Rm and the master reservoir chamber Ru is cut off, the braking fluid BF from the bypass chamber Rb will be the master cylinder fluid path HM. Then, it is moved to the reservoir RV via the master chamber Rm. In order to avoid such a situation and efficiently pump the brake 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 at the same time. The ratio of the pressure receiving area rm of the master chamber Rm to the pressure receiving area rs of the servo chamber Rs is set to be equal to Am (= rm / 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" (that is, "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 by the master elastic body SM in the backward direction Hb and is in the initial position thereof. Similarly, in the bypass unit YB, the bypass piston PB is pushed in the backward direction Hd by the bypass elastic body SB and is in the initial position thereof. Here, the mounting pressure wm of the master elastic body SM is set to a value lower than the mounting pressure wb of the bypass elastic body SB.

When the braking operation member BP is operated, the adjusting hydraulic pressure Pc is increased from "0" by the pressure adjusting unit YC. The adjusting hydraulic pressure Pc is increased to the hydraulic pressure (blocking hydraulic pressure) p1 at which the connection between the master chamber Rm and the master reservoir chamber Ru is cut off. A force (first forward force) Fa in the forward direction Ha having a value “p1 × rs” acts on the master unit YM. Since this force Fa is larger than the mounting load sm, the master piston PM is moved in the forward direction Ha. As a result, the through hole Ap passes through the seal SL, and the master chamber Rm is blocked from the master reservoir chamber Ru. On the other hand, a force (second forward force) Fc in the forward direction Hc having a value of "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 adjusting hydraulic pressure Pc is further increased and reaches the value p2 (> p1), a forward force Fc having a value of “p2 × rc” acts on the bypass piston PB. “Fc> sb”, and the bypass piston PB starts to move 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 is set at the start of control braking (when the adjusting hydraulic pressure Pc rises from "0"). After the movement of the bypass piston PB is started, the movement of the bypass piston PB is started. Since the movement of the bypass piston PB is started after the communication between the master chamber Rm and the reservoir RV is cut off by the advancement of the master piston PM, the braking fluid BF via the bypass unit YB efficiently uses the wheel cylinder CW. Can be transmitted to.

The bypass piston PB receives a force (second retreat force) Fb in the retreat direction Hd from the bypass chamber Rb by the braking hydraulic pressure Pw. When the braking operation member BP is returned, the adjusting hydraulic pressure Pc is reduced by the pressure adjusting unit YC. Then, when the adjusting hydraulic pressure Pc becomes smaller than the braking hydraulic pressure Pw, the pistons PM and PB are moved in the backward directions Hb and Hd. When the braking operation member BP is in a non-operated state, it is returned to the initial position of each piston PM and PB by the elastic force of each elastic body (compression coil spring) SM and SB, respectively. At this time, the master chamber Rm and the reservoir RV are brought into a communicating state, and the hydraulic 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 length of the master cylinder CM) is determined by the rigidity of the braking device (for example, the rigidity of the caliper, the rigidity of the friction material, the rigidity of the braking pipe). In control braking, the capacity of the master chamber Rm so that the wheel WH can exert the maximum braking force even when the friction coefficient between the friction material and the rotating member KT decreases (for example, when fading occurs). Is set. On the other hand, in manual braking, the master cylinder CM needs to have a relatively small diameter so that the operating force Fp of the braking operation member BP generated by the driver falls within an appropriate range. In order to secure the volume in the master cylinder CM with a small diameter, 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 (particularly, 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. As a result, the capacity of the master cylinder CM is reduced, and the apparatus is shortened in the longitudinal direction (direction of the central axis Jm). Further, since a small-diameter master cylinder CM can be adopted, the operating force Fp in manual braking can be made appropriate. At the time of manual braking, the bypass piston PB is pressed by the second bottom Bt by the master hydraulic pressure Pm to set 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 adjusting unit YC and the wheel cylinder CW are fluidly separated by each of the units YM and YB, and the braking fluid BF is not moved between the pressure adjusting unit YC and the wheel cylinder CW. For example, when a fluid path is lost around the wheel cylinder CW, the amount of brake fluid BF lost due to the failure is limited.

<Processing of pressure regulation control including regenerative cooperative control>
The pressure adjustment control process will be described with reference to the control flow diagram of FIG. "Pressure adjustment control" is drive control of the electric motor MC and the solenoid valve UC for adjusting the adjusting 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 adjustment hydraulic pressure Pc, and the rotation angle Ka are read. The operation amount Ba is detected by the operation amount sensor BA (for example, the simulator hydraulic pressure sensor PS, the operation displacement sensor SP, the operation force sensor FP). The operation signal St is detected by the operation switch ST provided on the braking operation member BP. The adjusting hydraulic pressure Pc is detected by the adjusting hydraulic pressure sensor PC provided in the pressure adjusting fluid passage HC. The motor rotation angle Ka is detected by the rotation angle sensor KA provided in the electric motor MC.

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

In step S130, the normally closed type first on-off valve VA is set to the open position, and the normally open type second on-off valve VB is set to the closed position. As a result, the input hydraulic pressure chamber Rn and the rear hydraulic pressure chamber Ro are connected. Further, the simulator SS is connected to the input chamber Rn and is cut off from the reservoir RV.

In step S140, the target deceleration Gt is calculated based on the operation amount Ba. The target deceleration Gt is a target value for deceleration in deceleration of the vehicle. The target deceleration Gt is determined to be "0" when the manipulated variable Ba is in the range of "0" to the predetermined value bo according to the calculation map Zgt, and when the manipulated variable Ba is equal to or greater than the predetermined value bo, the manipulated variable Ba increases. Therefore, it is calculated so as to monotonically increase from "0".

In step S150, the regenerative amount Rg (target value) is determined based on the target deceleration Gt. For example, when the target deceleration Gt is less than the predetermined regenerative amount rg, the regenerative amount Rg (value corresponding to the vehicle deceleration) is determined to match 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 match the predetermined regeneration amount rg. Here, the predetermined regeneration amount rg is preset as a constant. Further, the predetermined regeneration amount rg can 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, the generator GN is controlled so that the target value Rg is achieved.

In step S160, the target hydraulic pressure Pt (target value of the adjusted hydraulic 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 as “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 deceleration amount rg, the value obtained by subtracting the predetermined regeneration amount rg from the target deceleration Gt is converted into the hydraulic pressure, and the target hydraulic pressure Pt is calculated. That is, of the target deceleration Gt, the portion corresponding to the predetermined regeneration amount rg is achieved by the regenerative braking (braking force generated by the generator GN), and the rest (“Gt-rg”) is friction braking (rotation). The target hydraulic pressure Pt is determined so as to be achieved by the braking force (braking force generated by the friction between the member KT and the friction material).

In step 170, the target rotation speed Nt is calculated based on the target hydraulic pressure Pt. The target rotation speed Nt is a target value of the rotation speed of the electric motor MC. The target rotation speed Nt is calculated so as to monotonically increase as the target hydraulic pressure Pt increases according to the calculation map Znt. As described above, the adjusting hydraulic pressure Pc is generated by the orifice effect of the pressure adjusting solenoid valve UC. Since a certain amount of flow rate is required to obtain the orifice effect, a predetermined lower limit rotation speed no is provided for the target rotation speed Nt. The lower limit rotation speed no is a minimum required value (a preset constant) for generating hydraulic pressure. The target rotation speed Nt may be calculated directly based on the braking operation amount Ba. In any case, the target rotation speed Nt is determined based on the braking operation amount Ba.

In step S180, the electric motor MC executes servo control (control to quickly follow the actual value to the target value) based on the rotation speed. For example, as the rotation speed servo control, the rotation speed feedback control of the upper electric motor MC is executed based on the target rotation speed Nt and the actual rotation 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 speed per unit time) Na is calculated. Then, the rotation speed of the electric motor MC is used as a control variable, and the amount of electricity supplied to the electric motor MC (for example, the supply current) is controlled. Specifically, the rotation speed deviation hN becomes "0" based on the deviation hN (= Nt-Na) between the target value Nt of the rotation speed and the actual value Na (that is, the actual value Na is the target value Nt). The amount of electricity supplied to the electric motor MC is finely adjusted. When "hN> nx", the amount of electricity supplied to the electric motor MC is increased, and the speed of the electric motor MC is increased. On the other hand, in the case of "hN <-nx", the amount of electricity supplied to the electric motor MC is reduced, and the electric motor MC is decelerated. Here, the predetermined value nx is a preset constant.

In step S190, servo control based on hydraulic pressure is executed in the solenoid valve UC. For example, as the hydraulic pressure servo control, the hydraulic pressure feedback control of the pressure adjusting solenoid valve UC is executed based on the target hydraulic pressure Pt and the adjusted hydraulic pressure Pc (detection value). In the feedback control, the pressure Pc of the braking fluid BF in the pressure adjusting fluid path HC is used as a control variable, and the amount of electricity supplied to the normally open / linear solenoid valve UC is controlled. Based on the deviation hP (= Pt-Pc) between the target hydraulic pressure Pt and the adjusted hydraulic pressure Pc, the hydraulic pressure deviation hP becomes "0" (that is, the adjusted hydraulic pressure Pc approaches the target hydraulic pressure Pt). , The amount of electricity supplied to the solenoid valve UC is adjusted. When "hP> px", the amount of electricity supplied to the solenoid valve UC is increased, and the amount of valve opening of the solenoid valve UC is decreased. On the other hand, in the case of "hP <-px", the amount of electricity supplied to the solenoid valve UC is reduced, and the amount of valve opening of the solenoid valve UC is increased. Here, the predetermined value px is a preset constant.

<Other configuration examples of bypass unit YB (stepped configuration)>
Another configuration example of the bypass unit YB will be described with reference to the schematic diagram of FIG. In the bypass unit YB described with reference to FIG. 2, a 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 to be the same in the pressure adjusting chamber Rc. In another configuration example, the bypass piston PB has two different diameters and the area rc is set to be larger than the area rb. The bypass piston PB is referred to as a "stepped piston". By adopting a stepped piston (referred to as a "stepped configuration"), the pressurizing responsiveness of the braking hydraulic pressure Pw is improved 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 on the cylindrical surface Pd on the outer peripheral portion of the large diameter, and a seal SL (for example, a cup seal) is fitted in each groove. One annular groove is formed on the cylindrical surface Pe on the outer peripheral portion of the small diameter, and a seal SO is provided in the groove. Here, a cup seal (referred to as "U-shaped packing") is adopted as the seal SO. Therefore, the seal SO has directionality in the sealed 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 seal SL, SO). The large-diameter inner peripheral portion Bd of the bypass cylinder CB corresponds to the large-diameter outer peripheral portion Pd of the bypass piston PB, and the small-diameter inner peripheral portion of the bypass cylinder CB corresponds to the small-diameter inner peripheral portion Pe of the bypass piston PB. Be.

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

In the bypass cylinder CB, in addition to the hydraulic 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 of the relief chamber Rq becomes a predetermined pressure (relief pressure) po, the valve unit YV releases the internal pressure Po and prevents the inside of the relief chamber Rq from becoming a negative pressure (less than atmospheric pressure). It will be provided. Specifically, the valve unit YV functions as a relief valve in the spherical BL, the seat surface Sb, and the compression spring BV. When the relief chamber hydraulic pressure Po is less than the predetermined pressure po, the sphere BL is pressed against the seat surface Sb (conical surface) provided with the through hole Ax by the compression spring BV, and the relief chamber Rq and the reservoir RV Communication is cut off. When the hydraulic pressure Po becomes equal to or higher than the predetermined pressure po, the sphere BL is pushed by the hydraulic pressure Po, and a gap is created between the sphere BL and the seat surface Sb. As a result, the braking liquid BF is moved from the relief chamber Rq to the reservoir RV, and an upper limit value po is provided at the hydraulic pressure Po.

The valve unit YV is provided with a suction hole Au connected to the reservoir RV. A suction valve VC is provided at the end of the suction hole Au. The suction valve VC blocks the movement of the brake fluid BF from the relief chamber Rq to the reservoir RV, but allows the movement of the brake fluid BF from the reservoir RV to the relief chamber Rq (see the blowout diagram). The brake 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 less than atmospheric pressure (negative pressure).

When not braking (when "Pc = 0"), the bypass piston PB is pressed in the backward direction Hd by the bypass elastic body SB, and the initial position (the second end Bq and the second bottom Bt come into contact with each other). The position of the bypass piston PB). In this state, the bypass cylinder CB is provided with the second through hole Aa so that the relief chamber Rq and the bypass chamber Rb communicate with each other. Therefore, when not braking, the internal pressures of the hydraulic chambers Rb, Rq, and Rh are set to "0 (atmospheric pressure)".

When the control braking is started and the adjusting hydraulic pressure Pc is increased from "0", the pressure adjusting chamber Rc applies a forward force Fc to the bypass piston PB. As a result, the bypass piston PB advances, and the second through hole Aa is closed by the seal SO. Further, when the adjusting 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 has directionality in the sealing direction. That is, the seal member SO is sealed in one direction but not in the other direction. Specifically, the seal member SO retains the hydraulic pressure Pb (= Pm) from the bypass chamber Rb, but does not retain the hydraulic pressure Ph from the auxiliary chamber Rh. Therefore, when the state of “Ph> Pb” is reached 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. , Moved to the bypass chamber Rb. That is, when the adjusting hydraulic pressure Pc is increased, the braking liquid BF is replenished from the auxiliary chamber Rh to the bypass chamber Rb. The replenishment of the braking fluid BF by the auxiliary chamber Rh is called "fast fill". Due to this fast fill, a larger amount of the braking fluid BF is rapidly supplied to the wheel cylinder CW, so that the responsiveness to the increase in the braking fluid pressure Pw can be improved.

When the control braking is completed and the adjusting hydraulic pressure Pc is returned toward "0", the bypass piston PB is moved in the backward direction Hd, and the volume of the auxiliary chamber Rh is increased. In this case, the brake 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, 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 adjusting chamber Rc) is the mounting pressure of the master elastic body SM as described above. It is set to be larger than wm (a value obtained by dividing the mounting load sm by the pressure receiving area rs of the servo chamber Rs). Therefore, when the control braking is started, the master piston PM is moved before the bypass piston PB 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 receiving of master chamber Rm to pressure receiving area rs of servo chamber Rs) The ratio of the area rm) is set to match. Here, since the bypass unit YB adopts a stepped configuration, “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 set to 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 not moved to the limit first, and then the other piston is not started to move.

<Second Embodiment of Vehicle Braking Control Device SC>
A second embodiment of the 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, the components, arithmetic processing, signals, characteristics, and values with the same symbols have the same function. In the subscripts "i" to "l" at the end of each symbol, "i" indicates the right front wheel, "j" indicates the left front wheel, "k" indicates the right rear wheel, and "l" indicates the left rear wheel. The subscripts "i" to "l" at the end of the symbol may be omitted. In this case, each symbol represents a generic term for each of the four wheels. In addition, the subscripts "1" and "2" at the end of each symbol indicate, in the two braking systems, "1" indicates the first system and "2" indicates the second system. The subscripts "1" and "2" at the end of the symbol may be omitted. In this case, each symbol represents a generic term for each of the two braking systems. When a front-rear fluid path is adopted, the subscripts "f" and "r" at the end of various symbols indicate that "f" indicates a front wheel system and "r" indicates a rear wheel system. The subscripts "f" and "r" at the end of the symbol may be omitted. In this case, each symbol represents a generic term for each of the two braking systems. The braking performed by the braking control device SC is "control braking", and the braking performed only by the driver's operating force is "manual braking".

In the first embodiment, a single type master cylinder CM, a reflux type pressure adjusting unit YC, and a single type bypass unit YB are adopted. Further, the front-rear type was used as the two-system fluid path. In the second embodiment, instead of these, a tandem type master cylinder CM and a tandem type bypass unit YB are adopted, and an accumulator is used as the pressure adjusting unit YC (referred to as “accumulator type”). Further, as the two-system fluid path, a so-called diagonal type (also referred to as an X type) is adopted. The two-system fluid path may be a front-rear type (also referred to as an H-type).

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

[Master unit YM (tandem type)]
The master cylinder CM is a tandem type, and the inside thereof 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, respectively. Further, the pressure adjusting reservoir chamber Rd is connected to the pressure adjusting 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 with the value "rm". That is, the diameters of the first and second master pistons PS1 and PS2 are equal. The 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 and CWl. Further, the second master cylinder fluid path HM2 is connected to the wheel cylinders CWj and CWk. That is, a diagonal type fluid path is adopted as the two-system fluid path.

In the first master chamber Rm1, a first master elastic body SM1 that applies an urging force in the backward direction Hb to the first master piston PM1 is provided. Further, in the second master chamber Rm2, a second master elastic body SM2 that applies an urging force in the backward direction Hb to the second master piston PM2 is provided. When the first and second master pistons PM1 and PM2 are at the position of the most retracting 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 (particularly, the master reservoir chamber Ru) via Ac and Ap. When the control braking is started, the introduction of the adjusting hydraulic pressure Pc into the servo chamber Rs (pressure receiving area rs) is started. When the forward force Fa by the servo chamber Rs becomes larger than the mounting loads sm1 and sm2 of the first and second master elastic bodies SM1 and SM2, the master piston PM starts to move in the forward direction Ha. Due to the forward movement of the master piston PM, the through hole Ap penetrates into the master chamber Rm, and the communication between the master chamber Rm and the master reservoir chamber Ru is cut off. As a result, the master chamber Rm is brought into a liquid-tight state.

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 adjusting hydraulic pressure Pc. Further, the first master chamber Rm1 applies an urging force (first retreating force) Fb in the retreating direction Hb to the first master piston PM1 by its internal pressure (first master hydraulic pressure) Pm1. Here, the first forward force Fa and the first backward 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 adjusting hydraulic pressure Pc. .. The second master chamber Rm2 directly applies the first retreat 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 backward force Fb face each other in the direction of the central axis Jm of the master cylinder CM.

[Pressure control unit YC (accumulator type)]
The adjusting hydraulic pressure Pc is adjusted by the pressure adjusting unit YC. The pressure regulating unit YC is composed of an electric pump DZ, an accumulator AZ, an accumulator hydraulic pressure sensor (also referred to as “accumulation sensor”) PZ, an increasing pressure regulating valve UA, a decreasing pressure regulating valve UB, and a regulating hydraulic pressure sensor PC. The pressure adjusting unit YC is an "accumulator type" in which an accumulator is used.

The pressure adjusting unit YC is provided with a pressure accumulator dynamic pump DZ so that the pressurized braking fluid BF is stored in the accumulator AZ. The accumulator and piezoelectric dynamic pump DZ is composed of a set of one accumulator electric motor MZ and one accumulator fluid pump QZ. In the storage piezoelectric dynamic 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 dynamic pump DZ (particularly, 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, as the electric motor MZ, a motor with a brush is adopted.

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

The accumulator hydraulic pump DZ (particularly, the accumulator electric motor MZ) is controlled by the controller ECU 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 regulating unit YC is provided with a normally closed type increasing pressure regulating valve UA and a normally open type decreasing pressure regulating valve UB. The increasing pressure regulating valve UA and the decreasing pressure regulating valve UB are connected by a pressure regulating fluid path HC. Further, the pressure reducing valve UB is connected to the reservoir fluid path HR. The increasing / decreasing pressure regulating valves UA and UB are linear solenoid valves (proportional valves) in which the valve opening amount is continuously controlled based on the energized amount (for example, supply current). The pressure regulating valves UA and UB are controlled by the controller ECU based on the drive signals Ua and Ub.

When the adjusting hydraulic pressure Pc is adjusted, the increasing pressure adjusting valve UA is energized, and the braking fluid BF flows from the accumulator AZ into the pressure adjusting fluid path HC via the accumulator fluid path HZ. Further, the reducing pressure regulating valve UB is energized based on the adjusting hydraulic pressure Pc (actual value), and the adjusting hydraulic pressure Pc is adjusted. Similar to the first embodiment, the adjusting hydraulic pressure sensor PC is provided so as to detect the adjusting hydraulic pressure Pc.

The pressure regulating fluid path HC is divided into two at the site Bb, one is connected to the master unit YM (particularly the servo chamber Rs) and the other is connected to the bypass unit YB (particularly the pressure regulating chamber Rc). NS. Therefore, the adjusting hydraulic pressure Pc is applied to the servo chamber Rs and the pressure adjusting chamber Rc.

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

Inside the bypass cylinder CB, two bypass pistons PB1 and PB2 are arranged coaxially with the central axis Jb of the 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 and PB2 are sealed by the seal SL. The bypass cylinder CB is divided into three chambers (hydraulic chambers) Rc, Rb1 and Rb2 by the first and second bypass pistons PB1 and PB2. The hydraulic chambers Rc, Rb1 and Rb2 are arranged in series on the central axis Jb. The bypass unit YB is referred to as a "tandem type".

The 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. The 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, the 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. The pressure regulating fluid path HC is connected to the pressure regulating chamber Rc.

The first and second bypass chambers Rb1 and Rb2 have the same pressure receiving area rb, and the pressure adjusting chamber Rc has a pressure receiving area rc. For example, the area rb and the area rc can be set equally. The pressure regulating 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 backward direction Hd to the first and second bypass pistons PB1 and PB2.

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

The pressure adjusting 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 adjusting hydraulic pressure Pc. The second bypass chamber Rm2 applies a second retreat force Fd to the second bypass piston PB2 by its internal pressure Pb2 (= Pm2). Again, the second forward force Fc and the second backward force Fd face each other in the direction of the central axis Jb of the bypass cylinder CB.

Similar to the first embodiment, at the start of control braking, the elastic bodies (for example, compression coil springs) SM1, SM2, SB1, so that the movement of the master piston PM is started before the movement of the bypass piston PB. 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 mounting load of the SB2. Specifically, the "mounting pressure wb of the bypass elastic body SB (value obtained by dividing the mounting load sb by the pressure receiving area rb)" is the "mounting pressure wm of the master elastic body SM (mounting load sm divided by the pressure receiving area rs)". Value) ”is set to be larger than.

Further, 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 pistons PM1, PM2, PB1 and PB2 are moved in synchronization with each other. The specifications of each unit YM and YB are determined so that the area ratio Am of the unit YB (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) is 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 master unit YM and the bypass unit YB brake the wheel cylinder CW. Liquid BF is supplied. As a result, the shortening of the master cylinder CM and the operating force Fp of manual braking can be suitably compatible with each other.

<Other arrangement examples of bypass unit YB (single type parallel arrangement)>
An arrangement example of the two single type bypass units YB will be described with reference to the schematic diagram of FIG. In the bypass unit YB of the second embodiment, the first and second bypass pistons PB1 and PB2 are arranged in series on the coaxial Jb. Instead, two single-type 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 regulating chambers Rc1 and Rc2 refer to the first and second bypass pistons PB1 and PB2. They are placed so that they face each other.

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

<Other configuration example of pressure regulating unit YC (electric cylinder type)>
Another configuration example of the pressure regulating unit YC will be described with reference to the schematic diagram of FIG. 7. The reflux type pressure adjusting unit YC was described with reference to FIG. 1, and the accumulator type pressure adjusting unit YC was described with reference to FIG. Instead of these, in the third configuration example of the pressure adjusting unit YC, the pressure adjusting piston PD provided in the pressure adjusting cylinder CD is pressed by the electric motor MD for pressure adjusting. As a result, the adjusting hydraulic pressure Pc is adjusted. The pressure adjustment method is called an "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 adjusting unit YC includes an electric motor MD for pressure adjusting, a speed reducer GS, a rotation / linear motion conversion mechanism (screw mechanism) NJ, a pressing member PO, a pressure adjusting cylinder CD, a pressure adjusting piston PD, and a return elastic body SD. It is composed of.

The pressure adjusting electric motor (pressure adjusting motor) MD is a power source for adjusting (increasing or decreasing) the braking fluid pressure Pw by the pressure adjusting unit YC. The pressure adjusting motor MD is driven by the controller ECU based on the drive signal Md. For example, a brushless motor may be adopted as the pressure adjusting motor MD.

The speed reducer GS is composed 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 speed reducer GS reduces the rotational power of the electric motor MD and transmits it 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 meshed with the small-diameter gear SK, and the large-diameter gear DK and the bolt member BT are fixed so 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 speed reducer GS, the rotational power from the electric motor MD is input to the small diameter gear SK, which is decelerated and output from the large diameter gear DK to the screw mechanism NJ.

The screw mechanism NJ converts the rotational power of the speed reducer GS into the linear power Fe of the pressing member PO. A nut member NT is fixed to the pressing member PO. The bolt member BT of the screw mechanism NJ is fixed coaxially with the large-diameter gear DK. Since the rotational movement of the nut member NT is constrained by the key member KY, the nut member NT (that is, the pressing member PO) screwed with the bolt member BT due to the rotation of the large-diameter gear DK is the rotating shaft of the large-diameter gear DK. Moved in the direction. That is, the screw mechanism NJ converts the rotational power of the pressure adjusting motor MD into the linear power Fe of the pressing member PO.

The pressure adjusting piston PD is moved by the pressing member PO. The pressure adjusting piston PD is inserted into the inner hole of the pressure adjusting cylinder CD to form a combination of the piston and the cylinder. Specifically, a seal SL is provided on the outer periphery of the pressure adjusting piston PD to ensure liquidtightness with the inner hole (internal cylindrical surface) of the pressure adjusting cylinder CD. That is, a hydraulic chamber (pressure adjusting cylinder chamber) Ra partitioned by the pressure adjusting cylinder CD and the pressure adjusting piston PD is formed.

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

The pressure adjusting cylinder chamber Re is connected to the pressure adjusting fluid path HC. By moving the pressure adjusting piston PD in the central axis direction, the volume of the pressure adjusting cylinder chamber Re changes. As a result, the adjusting hydraulic pressure Pc is adjusted. Specifically, when the pressure adjusting motor MD is rotationally driven in the forward rotation direction, the pressure adjusting piston PD is moved in the forward direction (left direction in the figure) He so as to reduce the volume of the pressure adjusting cylinder chamber Re. , The adjusting hydraulic pressure Pc is increased, and the braking fluid BF is discharged from the pressure adjusting cylinder CD to the pressure adjusting 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 backward direction (right direction in the figure) Hg so that the volume of the pressure adjusting cylinder chamber Re increases, and the adjusting fluid pressure is adjusted. Pc is reduced, and the braking fluid BF is returned to the pressure adjusting cylinder chamber Re via the pressure adjusting fluid passage HC. The adjusting hydraulic pressure Pc is adjusted (increased or decreased) by driving the pressure adjusting motor MD in the forward rotation or the reverse rotation direction. Similar to the above, the pressure adjusting fluid passage HC is provided with an adjusting hydraulic pressure sensor PC so as to detect the adjusting hydraulic pressure Pc.

The pressure adjusting motor MD is controlled based on the target hydraulic pressure Pt and the adjusting hydraulic pressure Pc (detected value). First, based on the target hydraulic pressure Pt, the indicated energization amount Is is calculated so as to monotonically increase from "0" as the target hydraulic pressure Pt increases from "0". Then, the compensation energization amount Iu is calculated based on the deviation hP between the target hydraulic pressure Pt and the adjusted hydraulic pressure Pc. In the case of "hP> py (predetermined value)", the compensation energization amount Iu is increased as a positive sign value (corresponding to the normal rotation direction of the pressure adjusting motor MD) according to the increase in the hydraulic pressure deviation hP. In the case of "hP <-py (predetermined value)", the compensation energization amount Iu is reduced as a negative sign value (corresponding to the reverse direction of the pressure adjusting motor MD) according to the decrease in the hydraulic pressure deviation hP. In the case of "−py ≦ hP ≦ py", it is calculated as “Iu = 0”. Here, the predetermined value py is a preset constant.

Finally, the target energization amount It is determined based on the indicated energization amount Is and the compensating energization amount Iu. In the pressure regulation control of the adjusting hydraulic pressure Pc, the indicated energizing amount Is is a feedforward component, and the compensating energizing amount Iu is a feedback component. For example, the indicated energization amount Is and the compensating energization amount Iu are added together to calculate the target energization amount It. The target energization amount It is a target value of the energization amount to the pressure regulating 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 the energization amount sensor (current sensor) IA provided in the drive circuit of the pressure regulating motor MD.

<Other configuration examples of regenerative cooperation unit YK>
Another configuration example of the regenerative cooperative unit YK will be described with reference to the schematic diagram of FIG. Another configuration example of the regenerative cooperation unit YK will be described. In the regenerative cooperation 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 to each other. Instead, the diameter dm of the master piston PM can 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 by the mounting surface Rx. An input piston PN is inserted into the input cylinder CN so as to be in sliding contact with the inside of the input cylinder CN. The input piston PN is mechanically connected to the braking operation member BP by a clevis or the like and interlocks with the braking operation member BP. A brim portion Tn is formed on the input piston PN, and a compression spring (input elastic body) SN is provided between the brim portion Tn and the mounting surface Rx of the input cylinder CN. The brim portion Tn is pressed by the input elastic body SN in the receding direction Hb along the central axis Jm. When not braking, the brim Tn is in contact with the bottom Rt of the input cylinder CN. This state is the position where the input piston PN is set to the most backward direction Hb (initial position of the input piston PN).

Further, when not 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 portion Mq of the master piston PM is inside the input cylinder CN. This state is the position where the master piston PM is set to the most backward direction Hb (initial position of the master piston PM). When non-braking (that is, when both pistons PN and PM are in the initial positions), the gap Ks between the end Mq of the master piston PM and the end Rv of the input piston PN is the initial gap ks (predetermined value). ).

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

Manual braking is realized by closing the first on-off valve VA and fluid-locking the input cylinder CN (that is, the braking fluid BF is contained). The fluid lock keeps the amount of brake fluid BF in the input chamber Rn of the input cylinder CN 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. Since the area am is larger than the area an in the pressure receiving area of each piston, 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, when the input cylinder CN is contained, the input piston PN and the master piston PM operate as "lever".

As described above, the volume required for the master cylinder chamber Rm (that is, the inner diameter and 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 pipe). based on. In the controlled braking, the capacity of the master chamber Rm is set so that the wheel WH can exert the maximum braking force even when the friction coefficient 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.

By setting "am> an" as described above, the force (input piston thrust) Fn generated by the operating force Fp in the direction of the central axis Jm becomes 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 increased as compared with the case of “am = an”. As a result, the dimension of the master cylinder CM in the longitudinal direction can be reduced under the condition that the capacity is constant.

<Action / 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 adjusting unit YC, a master unit YM, and a bypass unit YB. The pressure adjusting unit YC adjusts the hydraulic pressure generated by the electric motors MC, MZ, and MD to the adjusting hydraulic pressure Pc.

The master unit YM is composed of a master cylinder CM, a master piston PM, and a master elastic body SM. The master piston PM can move 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. The master chamber Rm is connected to the wheel cylinder CW. Further, the adjusting hydraulic pressure Pc is introduced (supplied) into the servo chamber Rs. The servo chamber Rs applies a first forward force Fa that opposes (opposes) the first backward force Fb applied to the master piston PM in the master chamber Rm to the master piston PM.

The bypass unit YB is composed of a bypass cylinder CB, a bypass piston PB, and a bypass elastic body SB. A bypass chamber Rb and a pressure adjusting chamber Rc are provided inside the bypass cylinder CB. The bypass chamber Rb is connected to the wheel cylinder CW in the same manner as the master chamber Rm. Further, in the pressure adjusting chamber Rc, the adjusting hydraulic pressure Pc is introduced (applied) in the same manner as in the servo chamber Rs. A second forward force Fc that opposes (opposes) the second backward force Fd applied to the bypass piston PB in the bypass chamber Rb is applied to the bypass piston PB by the pressure adjusting chamber Rc.

The volume of the master cylinder CM is determined by the maximum braking force to be generated, and the inner diameter of the master cylinder CM is determined by the operating force Fp during manual braking. In order to satisfy the above conditions, the master cylinder CM needs to have a small diameter and a long length in the axial direction. However, in addition to the master unit YM, the brake fluid BF is moved to the wheel cylinder CW by the bypass unit YB provided in parallel with the master unit YM. Therefore, even when a master cylinder CM having a small diameter is adopted, the flow rate of the braking fluid BF can be secured, and the length of the master cylinder CM in the longitudinal direction (axial direction) can be shortened. As a result, the braking control device SC can be miniaturized and the mountability on the vehicle can be improved.

The master elastic body SM applies a first elastic force facing the first forward force Fa to the master piston PM. Further, the bypass elastic body SB imparts a second elastic force facing the second forward force Fc to the bypass piston PB. Then, when the adjusting hydraulic pressure Pc increases from "0 (zero)", the characteristics of the bypass elastic body SB and 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 mounting load sm of the master elastic body SM and the mounting 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 adjusting chamber Rc" is "the mounting load sm of the master elastic body SM divided by the pressure receiving area rc of the servo chamber Rs". It is set to be larger than the mounting pressure wm divided by rs. As a result, the master piston PM is first moved to the forward direction Ha before the bypass piston PB starts to move in the forward direction Hc, and the reservoir RV and the reservoir RV The communication with the master chamber Rm is cut off and the liquid-tight state is established. As a result, the braking liquid BF can be efficiently supplied from the bypass unit YB to the wheel cylinder CW.

"Area ratio Am (= rm / rs) of the pressure receiving area rs of the servo chamber Rs and the pressure receiving area rm of the master chamber Rm" and "the area of the pressure receiving area rc of the pressure adjusting chamber Rc and the pressure receiving area rb of the 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 synchronously by the adjusting 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 peripheral portion Bd and a small-diameter inner peripheral portion Be. Then, in the bypass cylinder CB, in addition to the two hydraulic chambers Rc and Rb, an auxiliary chamber Rh is formed in the small diameter outer peripheral portion Pe and the large diameter inner peripheral portion Bd. When the adjusting 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 sealing member SO that can be sealed in only one direction. .. At the time of pressure increase, the brake fluid BF is replenished to the bypass chamber Rb by the auxiliary chamber Rh, so that the pressure increase response of the brake fluid pressure Pw can be improved.

The regenerative coordination unit YK is composed of an input piston PN interlocked with the braking operation member BP and an input cylinder CN fixed to the master cylinder CM. In the input cylinder CN of the regenerative coordination unit YK, the master piston PM and the input piston PN are separated by a gap (separation displacement) Ks at the central axis Jm. In control braking (braking by the braking control device SC), the braking operation member BP is operated by the gap Ks, but the hydraulic pressure Pw of the wheel cylinder CW remains "0" and no friction braking force is generated. Can be formed. The gap Ks is controlled by the adjusting hydraulic pressure Pc, and the regenerative cooperative control is achieved by adjusting the adjusting hydraulic pressure Pc.

The diameter dm of the master piston PM (the part included in the input cylinder CN) is set larger than the diameter dn of the input piston PN (the part moved into the input cylinder CN when the braking operation member BP is operated). NS. 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 coordination unit YK, since "am> an, dm> dn" is set, the force (input piston thrust) Fn acting on the input piston PN is increased in manual braking, and the master piston thrust Fm is used. It is transmitted to the master piston PM. Therefore, even if the inner diameter of the master cylinder CM (particularly, the master chamber Rm) is set large, the operating force Fp at the time of manual braking can be optimized. Therefore, the master cylinder CM can be shortened.

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

In the above-mentioned first embodiment, the configuration (see FIG. 1) of "single type master cylinder CM + single type bypass unit YB + reflux type pressure regulating unit YC" was exemplified. In the second embodiment, the configuration of "tandem type master cylinder CM + tandem type bypass unit YB + accumulator type pressure adjusting unit YC" (see FIG. 5) was exemplified. As an example of the pressure adjusting unit YC, the configuration of the "electric cylinder type pressure adjusting unit YC" (see FIG. 7) was exemplified. As an example of the bypass unit YB, a single type configuration (see FIG. 6) arranged in parallel is shown. These elements can be freely combined. Therefore, as the configuration of the braking control device SC, one of the nine sets shown in the table of Table 1 is adopted. When the single type master unit YM is adopted, the front-rear type fluid passage is adopted. On the other hand, in the case of the tandem type master unit YM, the two-system fluid path is either a diagonal type or a front-rear 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 having a drive motor or a hybrid vehicle. Alternatively, the braking control device SC may be applied to a vehicle having a general internal combustion engine (gasoline engine, diesel engine) that does not have a drive motor. Since the braking control device SC has high responsiveness to the braking hydraulic pressure Pw, it is also suitable for, for example, a vehicle that requires a highly responsive collision damage mitigation brake (so-called AEB). In a vehicle that does not have a generator GN, regenerative braking is not generated, so that regenerative cooperative control is unnecessary and is not executed in the braking control device SC. That is, the vehicle is decelerated only by frictional braking by the braking control device SC. In the pressure adjustment control, the control is executed with "Gt = Rg = 0".

In the above embodiment, as the linear solenoid valves UC, UA, and UB, those whose valve opening amount is adjusted according to the amount of energization are adopted. For example, the solenoid valves UC, UA, and UB are on / off valves, but the opening and closing of the valves may be controlled by the duty ratio, and the hydraulic pressure may be linearly controlled.

In the above embodiment, the configuration of the disc type braking device (disc brake) has been exemplified. In this case, the friction member is the brake pad and the rotating member is the brake disc. A drum type braking device (drum brake) may be adopted instead of the disc type braking device. In the case of drum brakes, brake drums are used instead of calipers. 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 as separate bodies. The upper fluid unit YU and the lower fluid unit YL can be configured as one. 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 electromagnetic 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 regulating chamber, Rb ... bypass Room, YK ... Regeneration cooperation unit, CN ... Input cylinder, PN ... Input piston, ECU ... Controller, BA ... Operation amount sensor, PC ... Adjusting hydraulic pressure sensor.

Claims (2)

A vehicle braking control device that adjusts the hydraulic pressure of the braking fluid in the wheel cylinders provided on the wheels of the vehicle in response to the operation of the vehicle braking operation member.
A pressure regulating unit that adjusts the hydraulic pressure generated by the electric motor to obtain the adjusted hydraulic pressure,
Consists of a master cylinder and a master piston
"A master chamber connected to the wheel cylinder" and "a first forward force opposed to a first retracting force applied to the master piston by the master chamber when the adjusting hydraulic pressure is introduced" is applied to the master piston. A master unit with a "servo chamber"
It consists of a bypass cylinder and a bypass piston.
"Bypass chamber connected to the wheel cylinder" and "A second forward force opposed to the second retreat force applied to the bypass piston by the bypass chamber when the adjusting hydraulic pressure is introduced is applied to the bypass piston." Bypass unit with "pressure control chamber" and
A vehicle braking control device equipped with. The vehicle braking control device according to claim 1.
A master elastic body that applies a first elastic force facing the first forward force to the master piston, and a master elastic body.
A bypass elastic body that applies a second elastic force opposed to the second forward force to the bypass piston, and a bypass elastic body.
With
When the adjusting hydraulic pressure increases from zero,
A vehicle braking control device in which the relationship between the characteristics of the bypass elastic body and the characteristics of the master elastic body is set so that the master piston is moved before the bypass piston is moved.

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