JP2023110713A - Vehicle brake control device - Google Patents

Abstract

To reduce power consumed by an electric motor when abnormality occurs in a main power supply and it is driven by an auxiliary power supply, in a brake control device.SOLUTION: A brake control device comprises: a pressurizing portion that increases wheel pressure; a control portion that drives the pressurizing portion; a main power supply that feeds power to the control portion; and an auxiliary power supply that feeds power to the control portion when the main power supply is in an abnormal condition. The pressurizing portion comprises: a fluid pump that is driven by an electric motor; a reflux path that connects a discharge portion and a suction portion of the fluid pump; a pressure-adjusting valve that is provided in the reflux path; and a hydraulic chamber that is connected to the reflux path. The control portion increases control pressure of the hydraulic chamber to increase the wheel pressure. When power is fed from the main power supply, the control portion drives the electric motor to generate a circulation flow of a brake liquid in the reflux path, and throttles it by the pressure-adjusting valve to increase the control pressure. However, when power is fed from the auxiliary power supply, the control portion closes the pressure-adjusting valve and drives the electric motor to move the brake liquid to the hydraulic chamber, thereby increasing the control pressure.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a vehicle braking control device.

The applicant has developed a braking control device for a vehicle using an electric motor as a power source, as described in Patent Document 1. Specifically, the device disclosed in Patent Document 1 is "consisting of an electric pump DC and a solenoid valve UC, and the brake fluid discharged by the electric pump is adjusted to the regulated hydraulic pressure Pc by the solenoid valve UC, A pressure regulating unit YC that introduces the pressure Pc to the rear wheel cylinder, and a master chamber Rm composed of a master cylinder CM and a master piston PM, and connected to the front wheel cylinder. It comprises a master unit YM'' having a servo chamber Rs'' into which hydraulic pressure Pc is introduced and which imparts a forward force Fa to the master piston PM opposing the backward force Fb exerted on the master piston PM by the master chamber Rm.

In patent document 2, in a hydraulic brake system having a main power supply and an auxiliary power supply as on-vehicle power supplies, in order to prevent the voltage of the auxiliary power supply from becoming lower than the minimum operating voltage of the hydraulic brake system when the main power supply malfunctions, , the following devices are disclosed. The device is a hydraulic pressure generating device including a pump and a pump motor for driving the pump. When the main power supply is normal, the main power supply starts the pump motor in response to a braking request. However, if the main power source is unable to supply power to the hydraulic pressure generator, the auxiliary power source will continue to operate the pump motor regardless of whether there is a demand for braking. When the main power supply is abnormal, chances of inrush current flow are reduced. As a result, it is possible to prevent the voltage of the auxiliary power supply from becoming lower than the minimum operating voltage.

However, in the device of Patent Document 2, the auxiliary power supply continues to drive the pump motor (also referred to as an "electric motor") even when there is no braking request. Therefore, the voltage drop due to the rush current is suppressed, but the power consumption is not reduced.

JP 2019-059294 A JP 2020-147185 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a braking control device capable of reducing the power consumed by an electric motor when the main power supply fails and the electric motor is driven by the auxiliary power supply.

A braking control device (SC) for a vehicle according to the present invention includes pressurizing units (CA, CB) for increasing a wheel pressure (Pw) of a wheel cylinder (CW) of a vehicle, and the pressurizing units (CA, CB). Control units (EA, EB) to be driven, a main power supply (BT) for supplying power to the control units (EA, EB), and when the main power supply (BT) is abnormal, instead of the main power supply (BT) and an auxiliary power supply (BU) for supplying power to the control units (EA, EB). Here, the pressurizing units (CA, CB) include fluid pumps (QA, QB) driven by electric motors (MA, MB) and discharge units (Qo, Qp) of the fluid pumps (QA, QB). return paths (HN, HL) connecting suction portions (Qi, Qj) of the fluid pumps (QA, QB); pressure regulating valves (UA, UB) provided in the return paths (HN, HL); Hydraulic pressure chambers (Ru, Rw) connected to the return paths (HN, HL) are provided between the discharge portions (Qo, Qp) and the pressure regulating valves (UA, UB).

In the vehicle braking control system (SC) according to the present invention, the control units (EA, EB) increase the control pressures (Pu, Pw) of the hydraulic pressure chambers (Ru, Rw) to increase the wheel pressures ( Pw). In the first state in which power is supplied from the main power supply (BT), the control units (EA, EB) drive the electric motors (MA, MB) to operate the return paths (HK, HL). Circulation flow (KN, KL) of braking fluid (BF) is generated in the pressure control valve (UA, UB) to increase the control pressure (Pu, Pw) . On the other hand, in the second state in which power is supplied from the auxiliary power supply (BU), the control units (EA, EB) close the pressure regulating valves (UA, UB) and control the electric motors (MA, MB). ) to move the brake fluid (BF) to the hydraulic pressure chambers (Ru, Rw), thereby increasing the control pressures (Pu, Pw).

According to the above configuration, in the first state, the circulating flows KN and KL must continue to be generated, so the fluid pumps QA and QB continue to be driven. On the other hand, in the second state, the control pressures Pu and Pw are increased by movement of the brake fluid BF, so the fluid pumps QA and QB need only be driven when necessary. Therefore, in the second state, the power consumption of the electric motors MA, MB is reduced as the control pressures Pu, Pw increase.

A braking control device (SC) for a vehicle according to the present invention is a check valve ( GC). In the case of the second state, the control unit (EA, EB) controls the servo pressure (Pu, Pw) to be a target pressure (Pt) calculated according to the braking demand amount (Bs) of the vehicle. , the electric motors (MA, MB) are de-energized.

According to the above configuration, the hydraulic pressure chambers Ru and Rw are sealed by the check valve GC and the pressure regulating valves UA and UB, so the control pressures Pu and Pw are not reduced. Therefore, even if the power supply to the electric motors MA, MB is completely stopped when the control pressures Pu, Pw reach the target pressure Pt, the control pressures Pu, Pw are maintained. Power saving is achieved.

1 is a schematic diagram for explaining a first embodiment of a braking control device SC; FIG. FIG. 5 is a flow diagram for explaining an example of pressure regulation control processing; FIG. 5 is a schematic diagram for explaining a second embodiment of the braking control device SC;

<Symbols of components, etc., and subscripts at the end of the symbols>
In the following description, constituent members, arithmetic processing, signals, characteristics, and values denoted with the same symbols such as "CW" have the same function. The suffixes "f" and "r" attached to the end of the symbol for each wheel are generic symbols indicating which system of the front and rear wheels it relates to. For example, the wheel cylinders CW provided for each wheel are denoted as "front wheel cylinder CWf" and "rear wheel cylinder CWr". Furthermore, the subscripts "f" and "r" at the end of the symbols can be omitted. If the subscripts "f" and "r" are omitted, each symbol represents a generic term. For example, "CW" is a general term for wheel cylinders provided on the front and rear wheels of a vehicle.

In the fluid path from the master cylinder CM to the wheel cylinder CW, the side closer to the master cylinder CM (the side farther from the wheel cylinder CW) is referred to as the "upper", and the side closer to the wheel cylinder CW (the side farther from the master cylinder CM) ) is referred to as "bottom". In addition, in the circulating flows KN and KL of the braking fluid BF, the side near the discharge portions Qo and Qp of the fluid pumps QA and QB (the side away from the suction portions Qi and Qj) is referred to as the "upstream side". , QB close to the suction portions Qi and Qj (the side away from the discharge portions Qo and Qp) is referred to as the "downstream side".

The master cylinder CM, pressurizing units CA and CB, and wheel cylinder CW are connected by a fluid path (communication path HS). Furthermore, in the pressurizing units CA and CB, various components (UA, etc.) are connected by fluid paths. Here, the "fluid path" is a path for moving the damping fluid BF, and corresponds to a pipe, a flow path in the actuator, a hose, and the like. In the following description, the communication path HS, return paths HK and HL, return path HT, reservoir path HR, servo path HV, pressure reduction path HG, etc. are fluid paths.

<First Embodiment of Braking Control Device SC>
A first embodiment of a braking control device SC according to the present invention will be described with reference to the schematic diagram of FIG. The braking control device SC according to the first embodiment is a brake-by-wire type device. That is, the braking control device SC can generate the wheel pressure Pw independently of the braking operation of the driver. FIG. 1 is a schematic diagram of the configuration (in particular, the upper fluid unit YU) described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2019-059294). Specifically, the figure shows the master cylinder CM described in the publication to the front and rear wheel cylinders CWf and CWr for one wheel (for example, the wheel cylinders CWi and CWk of Patent Document 1). .

The vehicle is provided with a brake operating member BP. A braking operation member (for example, a brake pedal) BP is a member operated by the driver to decelerate the vehicle. The vehicle is also provided with front wheel and rear wheel braking devices SXf and SXr (=SX). The braking device SX is composed of a brake caliper CP (=CPf, CPr), a friction member MS (for example, brake pad), and a rotating member KT (=KTf, KTr, for example brake disc). The brake caliper CP is provided with a wheel cylinder CW (=CWf, CWr). A wheel piston NW (=NWf, NWr) is inserted into the wheel cylinder CW. Inside the wheel cylinder CW, a hydraulic pressure chamber Rw (=Rwf, Rwr) is formed by the wheel piston NW. A wheel pressure Pw (=Pwf, Pwr) is supplied from the braking control device SC to the fluid pressure chamber Rw (referred to as “wheel chamber”), so that the friction member MS is pressed against the rotating member KT fixed to the wheel WH. be done. As a result, a frictional braking force Fm is generated on the wheels WH. The "frictional braking force Fm" is the braking force generated by the wheel pressure Pw.

The vehicle is provided with two power supplies BT and BU as power supply sources for the braking control device SC (in particular, the controller EA, pressurizing unit CA, etc.). The power supply BT is called a "main power supply" and is used for normal power supply. The power supply BU is called an "auxiliary power supply" and is used as an alternative power supply when the main power supply BT is abnormal. Here, the case where an abnormality occurs in the main power supply BT is also referred to as "at the time of power supply abnormality".

The braking control device SC employs a so-called front-rear type (also referred to as "type II") as two braking systems. The braking control device SC includes a braking operation amount sensor BA, a stroke simulator SS, a master cylinder CM, a first pressurizing unit CA (also referred to simply as a "pressurizing unit"), and a first controller EA (simply referred to as a "controller"). Also called).

An operation amount Ba (braking operation amount) of the braking operation member BP is detected by the braking operation amount sensor BA. For example, an operation displacement sensor SP that detects an operation displacement Sp of the braking operation member BP is employed as the braking operation amount sensor BA. A simulator pressure sensor PZ for detecting the hydraulic pressure Pz of the stroke simulator SS (referred to as "simulator pressure") is used as the braking operation amount sensor BA. That is, the braking operation amount Ba is a general term for signals representing the driver's intention to brake, and the braking operation amount sensor BA is a general term for sensors that detect the braking operation amount Ba. The braking operation amount Ba is input to the first controller EA.

A stroke simulator SS (also referred to simply as a "simulator") generates an operating force Fp for the brake operating member BP. Since the braking control device SC is of the brake-by-wire type, the operating characteristics of the braking operating member BP (the relationship between the operating displacement Sp and the operating force Fp) are generated by the simulator SS. A simulator pressure sensor PZ is provided to detect the simulator pressure Pz. The simulator pressure Pz is a state quantity representing the operating force Fp of the brake operating member BP.

A master pressure Pm is supplied as a front wheel pressure Pwf to the front wheel cylinder CWf (in particular, the front wheel chamber Rwf) by the single-type master cylinder CM. A master piston NM is inserted into the master cylinder CM. The interior of the master cylinder CM is partitioned into a master chamber Rm and a servo chamber Ru by a master piston NM. The master chamber Rm is connected to the hydraulic pressure chamber Rwf (front wheel chamber) of the front wheel cylinder CWf via a front wheel connecting passage HSf. The servo chamber Ru is connected to the pressurizing part CA via a servo path HV (fluid path). The pressure receiving area rm (referred to as "master area") of the master chamber Rm and the pressure receiving area ru (referred to as "servo area") of the servo chamber Ru are made equal (that is, "rm=ru").

During non-braking, the master piston NM is at the most retracted position (that is, the position where the volume of the master chamber Rm is maximized). In this state, the master chamber Rm communicates with the master reservoir RV (atmospheric pressure reservoir). When the brake operation member BP is operated, the servo pressure Pu in the servo chamber Ru is increased, and the master piston NM moves forward (the direction in which the volume of the master chamber Rm decreases and the volume of the servo chamber Ru increases). be done. This movement cuts off communication between the master chamber Rm and the master reservoir RV. Further, when the master piston NM is moved forward, the hydraulic pressure Pm (master pressure) in the master chamber Rm is increased from "0 (atmospheric pressure)", and the brake fluid BF is pressure-fed from the master chamber Rm. Here, since “rm=ru”, “Pm=Pu”.

[First pressure part CA]
A servo pressure Pu is generated by the first pressurizing part CA (corresponding to the "pressurizing part"). The servo pressure Pu (corresponding to the "control pressure") is applied to the servo chamber Ru (corresponding to the "hydraulic pressure chamber") of the master cylinder CM and the rear wheel chamber Rwr (corresponding to the "hydraulic pressure chamber") of the rear wheel cylinder CWr. equivalent). The first pressurizing section CA (simply referred to as "pressurizing section") is composed of a first electric motor MA, a first fluid pump QA, a first pressure regulating valve UA, and a master pressure sensor PM.

A first electric motor MA (also simply referred to as "electric motor") drives a first fluid pump QA (also simply referred to as "fluid pump"). The electric motor MA includes a first rotation angle sensor KA (simply referred to as a "rotation angle sensor") to detect a first rotation angle Ka (simply referred to as a "rotation angle") of the rotor. be provided. The first rotation angle Ka (actual value) is input to the controller EA.

In the first fluid pump QA, the first intake portion Qi and the first discharge portion Qo are connected by a first return path HK (fluid path, also simply referred to as "return path"). Further, the first suction portion Qi of the fluid pump QA (simply referred to as "suction portion") is also connected to the master reservoir RV via the reservoir passage HR. A check valve GC is provided in the vicinity of the first discharge portion Qo (simply referred to as “discharge portion”) of the fluid pump QA. Specifically, in the return passage HK, a check valve GC is arranged between the discharge portion Qo and the pressure regulating valve UA. Further, the return path HK is provided with a normally open first pressure regulating valve UA. The first pressure regulating valve UA (simply referred to as “pressure regulating valve”) is a linear electromagnetic valve whose valve opening amount is continuously controlled based on the energized state (for example, supply current Ia).

In the pressurizing unit CA, the electric motor MA and the pressure regulating valve UA are driven by the controller EA to generate the servo pressure Pu. The "servo pressure Pu" is the hydraulic pressure between the discharge port Qo of the fluid pump QA and the pressure regulating valve UA. In the braking control device SC, the front and rear wheel pressures Pwf and Pwr are increased by the servo pressure Pu. However, pressure transmission paths from the servo pressure Pu to the front and rear wheel pressures Pwf and Pwr differ between the braking system for the front wheels WHf and the braking system for the rear wheels WHr.

In the braking system for the front wheels WHf, the return passage HK is connected to the servo chamber Ru via the servo passage HV at a portion Bv between the discharge portion Qo of the fluid pump QA and the pressure regulating valve UA. Therefore, the servo pressure Pu is supplied to the servo chamber Ru. The increase in the servo pressure Pu pushes the master piston NM in the forward direction (the direction in which the volume of the master chamber Rm decreases), increasing the hydraulic pressure Pm (master pressure) in the master chamber Rm. A master pressure sensor PM is provided in the pressurizing portion CA so as to detect the master pressure Pm.

The master chamber Rm is connected to the front wheel chamber Rwf of the front wheel cylinder CWf by the front wheel communication passage HSf via the hydraulic modulator MJ. Therefore, the master pressure Pm is supplied from the master chamber Rm of the master cylinder CM to the front wheel chamber Rwf of the front wheel cylinder CWf as the front wheel pressure Pwf. Here, the hydraulic pressure modulator MJ is a general-purpose unit for executing antilock brake control and the like. When antilock brake control or the like is not executed by the hydraulic pressure modulator MJ, the servo pressure Pu, the master pressure Pm, and the front wheel pressure Pwf are equal (that is, "Pu=Pm=Pwf").

In the braking system for the rear wheels WHr, the return passage HK is connected to the rear wheel communication passage HSr at a portion Bv between the discharge portion Qo of the fluid pump QA and the pressure regulating valve UA. The rear wheel communication path HSr is connected to the rear wheel chamber Rwr of the rear wheel cylinder CWr via the hydraulic pressure modulator MJ. Therefore, in the braking system for the rear wheel WHr, the servo pressure Pu is directly supplied to the rear wheel chamber Rwr of the rear wheel cylinder CWr. Similarly to the above, the servo pressure Pu and the rear wheel pressure Pwr are equal (that is, "Pu=Pwr") when the antilock brake control or the like is not executed by the hydraulic pressure modulator MJ.

Electric power is supplied from the controller EA to drive the pressurizing part CA (in particular, the electric motor MA and the pressure regulating valve UA) to generate the servo pressure Pu. The controller EA receives power from either the main power supply BT or the auxiliary power supply BU. However, the pressurizing method in the pressurizing part CA differs depending on which one of them is selected. A state in which power is supplied from the main power supply BT to the controller EA is referred to as a "first state", and a state in which power is supplied to the controller EA from the auxiliary power supply BU is referred to as a "second state". In the braking control device SC, the first state is normally selected, but the second state is selected when there is a power failure.

<<Pressurization method when power is supplied from the main power supply BT>>
A pressurization method when power is supplied to the braking control device SC (particularly, the pressurization unit CA) by the main power supply BT (that is, the first state) will be described. In the first state, the circulating flow KN of the braking fluid BF discharged by the fluid pump QA driven by the electric motor MA is throttled by the pressure regulating valve UA, thereby increasing the servo pressure Pu. This pressurization method is called a "dynamic pressure system or dynamic pressurization". “Dynamic pressure” is the pressure generated when the flow of a fluid (for example, damping fluid BF) is blocked. Dynamic pressurization (pressurization by dynamic pressure) will be described in detail below.

Fluid pump QA is driven by electric motor MA. When the brake fluid BF is discharged from the fluid pump QA, a circulating flow KN (indicated by a dashed arrow) of the brake fluid BF is generated in the return path HK. When the pressure regulating valve UA is in a fully open state (when the pressure regulating valve UA is of a normally open type and therefore is not energized), the fluid pressure between the discharge portion Qo of the fluid pump QA and the pressure regulating valve UA in the return path HK is Pu (servo pressure) is "0 (atmospheric pressure)". When the energization amount Ia (supplied current) to the pressure regulating valve UA is increased, the circulating flow KN (the flow of the brake fluid BF circulating in the return path HK) is throttled by the pressure regulating valve UA, and the flow of the circulating flow KN is obstructed. be done. In other words, the flow path of the return passage HK is narrowed by the pressure regulating valve UA, and the orifice effect of the pressure regulating valve UA is exhibited. As a result, the hydraulic pressure Pu (servo pressure) on the upstream side of the pressure regulating valve UA is increased from "0". That is, in the circulating flow KN, a hydraulic pressure difference (differential pressure) between the upstream hydraulic pressure Pu (servo pressure) and the downstream hydraulic pressure (atmospheric pressure) is generated with respect to the pressure regulating valve UA. Since the pressure regulating valve UA adjusts the differential pressure between its upstream side and its downstream side, it is also called a "differential pressure valve". The differential pressure is adjusted by the amount of energization Ia (for example, supply current) to the pressure regulating valve UA. When the servo pressure Pu reaches the desired hydraulic pressure (that is, the target pressure Pt), the energization amount Ia is kept constant.

A check valve GC is provided in the return path HK. The check valve GC permits the flow of the braking fluid BF (that is, the flow of the circulating flow KN) in the direction (the direction of the dashed arrow) from the pressure regulating valve UA toward the suction portion Qi, but the reverse pressure regulating valve UA The flow of the braking fluid BF in the direction from the discharge port Qo is blocked. That is, the check valve GC prevents the backflow of the brake fluid BF in the return passage HK.

<<Pressurization method when power is supplied from the auxiliary power supply BU>>
A pressurization method in the case where power is supplied to the braking control device SC (particularly, pressurizing unit CA) by the main power supply BT instead of the main power supply BT (that is, in the second state) will be described. In the second state, the pressure regulating valve UA is fully closed, and the entire amount of the braking fluid BF discharged by the fluid pump QA driven by the electric motor MA is moved to the servo chamber Ru and the rear wheel chamber Rwr. , the servo pressure Pu is increased. Specifically, the brake fluid BF is drawn from the master reservoir RV into the fluid pump QA. Then, the entire amount of the sucked braking fluid BF is discharged into the servo chamber Ru and the rear wheel chamber Rwr. That is, the fluid pump QA moves the brake fluid BF from the master reservoir RV to the servo chamber Ru and the rear wheel chamber Rwr. This pressurization method is called a “static pressure method or static pressurization”. "Static pressure", as opposed to dynamic pressure, is the pressure in the absence of flow (or when there is little flow). Static pressurization (pressurization by static pressure) will be described in detail below.

Power is supplied to the normally open pressure regulating valve UA, and the pressure regulating valve UA is completely closed. A fluid pump QA is driven by the electric motor MA, and brake fluid BF is discharged from the fluid pump QA. All of the brake fluid BF discharged from the fluid pump QA is moved to the servo chamber Ru and the rear wheel chamber Rwr. Since the braking control device SC and the braking device SX have rigidity, the amount (volume) of the braking fluid BF flowing into the fluid pressure chambers Ru and Rwr from the fluid pump QA increases, and accordingly the servo pressure Pu increases. . When the servo pressure Pu (that is, the wheel pressure Pw) reaches the desired hydraulic pressure (that is, the target pressure Pt), the rotation of the electric motor MA is stopped, and the discharge of the brake fluid BF from the fluid pump QA is terminated. . At this time, the fluid pressure chambers Ru and Rwr are fluidly locked by closing the check valve GC and the pressure regulating valve UA. Therefore, even if the power supply to the electric motor MA is stopped, the servo pressure Pu is maintained.

<<First controller EA>>
A pressure unit CA is controlled by a first controller EA (corresponding to a “control unit”). Specifically, the controller EA uses the main power supply BT or the auxiliary power supply BU as a power supply source to adjust the electric power supplied to the electric motor MA and the pressure regulating valve UA. The controller EA is composed of a microprocessor MP and a drive circuit DR.

A braking operation amount Ba, a master pressure Pm, a rotation angle Ka, and the like are input to the controller EA. The braking operation amount Ba is a general term for state quantities representing the amount of operation of the braking operation member BP. Specifically, the detection signal Sp (operation displacement) of the operation displacement sensor SP and the detection signal Pz (simulator pressure) of the simulator pressure sensor PZ are input as the braking operation amount Ba. A master pressure Pm (a value detected by the master pressure sensor PM) and a motor rotation angle Ka (a value detected by the rotation angle sensor KA) are input to control the pressure regulating valve UA and the electric motor MA.

Furthermore, the required deceleration Gs is input to the controller EA. The required deceleration Gs is a required value for decelerating the vehicle. The controller EA is connected to a communication bus BS so as to share signals (detected values, calculated values, control flags, etc.) with other controllers. For example, the required deceleration Gs is calculated by the driving assistance device and transmitted to the controller EA via the communication bus BS. Alternatively, the required deceleration Gs is instructed to the braking control device SC by a device (also called an "external operating device") different from the braking operating member BP.

A pressure regulation control algorithm is programmed in the controller EA (in particular, the microprocessor MP). "Pressure adjustment control" is control for adjusting the servo pressure Pu (finally the wheel pressure Pw). The pressure regulation control includes the above dynamic and static pressurization. The pressure regulation control is executed based on the braking operation amount Ba (operation displacement Sp, simulator pressure Pz) and the required deceleration Gs. Here, the braking operation amount Ba and the required deceleration Gs are collectively referred to as "braking required amount Bs". The braking demand amount Bs is an input value for instructing (requesting) the wheel pressure Pw to be generated by the braking control device SC.

Based on a pressure regulation control algorithm, the drive circuit DR drives the electric motor MA constituting the pressurizing unit CA and the pressure regulation valve UA. In the drive circuit DR, an H-bridge circuit is configured with switching elements (for example, MOS-FETs) so as to drive the electric motor MA. Further, the drive circuit DR is provided with a switching element so as to drive the pressure regulating valve UA. In addition, the drive circuit DR includes a motor current sensor (not shown) for detecting a supply current Im (actual value) to the electric motor MA, and a supply current Ia (actual value) to the pressure regulating valve UA. A current sensor (not shown) is included to detect the current.

In the pressure regulation control, the target pressure Pt is calculated based on the braking demand amount Bs. In the control of the pressure regulating valve UA in dynamic pressurization, a target current It (target value) corresponding to the supply current Ia of the pressure regulating valve UA is calculated based on the target pressure Pt. Then, the supply current Ia is controlled so as to approach and match the target current It. Further, in the control of the electric motor MA in dynamic pressurization, a target rotation speed Nt (target value) corresponding to the actual rotation speed Na is calculated based on the target pressure Pt. Then, the motor supply current Im is controlled so that the actual rotational speed Na approaches and matches the target rotational speed Nt. Note that the motor rotation speed Na is calculated based on the motor rotation angle Ka.

Based on the dynamic pressurization control algorithm, the drive signal Ma for controlling the electric motor MA and the drive signal Ua for controlling the pressure regulating valve UA are calculated. The switching element of the drive circuit DR is driven according to the drive signal (Ma, etc.) to control the electric motor MA and the pressure regulating valve UA.

A preset current ia is supplied in the control of the pressure regulating valve UA in static pressurization. As a result, the pressure regulating valve UA is completely closed. The "predetermined current ia" is a preset predetermined value (constant) that can sufficiently maintain the fully closed state of the pressure regulating valve UA. In the control of the electric motor MA in static pressurization, a target current In (target value) corresponding to the supply current Im of the electric motor MA is calculated based on the target pressure Pt. Then, the supply current Im is controlled so as to approach and match the target current In. Alternatively, a target angle Kn (target value) corresponding to the rotation angle Ka of the electric motor MA is calculated based on the target pressure Pt. Then, the actual rotation angle Ka (the value detected by the rotation angle sensor KA) is controlled so as to approach and match the motor target angle Kn.

Based on the static pressurization control algorithm, the drive signal Ma for controlling the electric motor MA and the drive signal Ua for controlling the pressure regulating valve UA are calculated. The switching elements forming the H bridge of the drive circuit DR are driven according to the drive signal Ma. In static pressurization, the drive signal Ua completely closes the pressure regulating valve UA.

<Pressure regulation control process>
The pressure regulation control process will be described with reference to the flowchart of FIG. 2 . Pressure regulation control is control of servo pressure Pu (result, wheel pressure Pw) based on braking demand Bs (Ba, Gs, etc.). A pressure regulation control algorithm is programmed in the microprocessor MP of the first controller EA.

At step S110, various signals (Ba, Gs, etc.) are read. The braking operation amount Ba (Sp, Pz, etc.) is acquired from the braking operation amount BA (SP, PZ, etc.). The required deceleration Gs is acquired from a driving assistance device or the like via the communication bus BS. The suitability flag FB is obtained from the power monitoring device via the communication bus BS. The propriety flag FB is a control flag indicating propriety of the main power supply BT, and "0" indicates that "the main power supply BT is normal" and "1" indicates that "the main power supply BT is abnormal". Is displayed. In addition, the supply voltage Vd (also referred to as “power supply voltage”) of the controller EA is acquired. The power supply voltage Vd is detected by a power supply voltage sensor VD (not shown) provided in the drive circuit DR.

In step S120, the braking demand amount Bs is calculated based on the braking operation amount Ba and the demand deceleration Gs. For example, the braking operation amount Ba and the requested deceleration Gs are compared in terms of the vehicle deceleration, and the larger one of them is determined as the requested braking amount Bs. The braking demand amount Bs is a value for indicating the servo pressure Pu (=Pw) demanded by the braking control device SC.

Furthermore, in step S120, the target pressure Pt is calculated based on the braking demand amount Bs and the calculation map Zpt. "Target pressure Pt" is a target value corresponding to the servo pressure Pu (actual value). The target pressure Pt is calculated to be "0" when the braking demand amount Bs is less than the predetermined amount bo according to the calculation map Zpt. When the braking demand Bs is greater than or equal to the predetermined amount bo, the target pressure Pt is calculated to increase from "0" as the braking demand Bs increases from "0". Here, the "predetermined amount bo" is a preset predetermined value (constant).

At step S130, it is determined whether or not the main power supply BT is normal. This determination is referred to as a "suitability determination." For example, the propriety determination is made based on the propriety flag FB transmitted from the power monitoring device (not shown) through the communication bus BS. When "FB=0" and the main power supply BT is normal (in the first state), the main power supply BT is employed as the power supply for the pressure unit CA. The suitability determination is affirmative, and the process proceeds to step S140. On the other hand, when "FB=1" and the main power supply BT is abnormal (second state), the auxiliary power supply BU is adopted as the power supply for the pressure unit CA instead of the main power supply BT. . The suitability determination is denied, and the process proceeds to step S160.

The suitability determination may be made based on the power supply voltage Vd. The power supply voltage Vd is a voltage that can be supplied to the pressure unit CA (UA, MA, etc.) and is detected by the power supply voltage sensor VD. Specifically, the propriety of the main power supply BT is determined based on "whether or not the power supply voltage Vd is equal to or higher than the predetermined voltage vd". , the second state is determined when the power supply voltage Vd is less than the predetermined voltage vd. Here, the predetermined voltage vd is a threshold value for judging suitability, and is a preset predetermined value (constant). If "Vd≧vd", the suitability determination is affirmative, and the process proceeds to step S140. On the other hand, if "Vd<vd", the suitability determination is negative, and the process proceeds to step S160.

<<Dynamic pressurization when power is supplied from the main power supply BT>>
In the first state in which the main power supply BT is normal (when power is supplied to the pressurizing unit CA by the main power supply BT), in steps S140 and S150, the dynamic pressure is applied. be.

At step S140, the target rotation speed Nt (target value) is calculated based on the target pressure Pt. Specifically, the target rotation speed Nt is determined based on a preset calculation map so that the target rotation speed Nt increases as the target pressure Pt increases. Alternatively, the target rotation speed Nt may be determined to be a preset predetermined value (constant). Then, the electric motor MA is driven so that the actual rotation speed Na approaches and matches the target rotation speed Nt. Here, the actual motor rotation speed Na is determined by time-differentiating the motor rotation angle Ka.

At step S150, a target current It (target value) corresponding to the supply current Ia of the pressure regulating valve UA is calculated based on the target pressure Pt. Specifically, based on a preset calculation map, the target current It is determined to increase as the target pressure Pt increases. Then, current feedback control is performed so that the supply current Ia, which is the value detected by the supply current sensor IA, approaches and matches the target current It.

Furthermore, the pressure regulating valve UA is controlled so that the master pressure Pm (actual value) approaches and coincides with the target pressure Pt (target value). Specifically, first, based on the target pressure Pt and the master pressure Pm, a deviation hP (referred to as a “hydraulic pressure deviation”) between the target pressure Pt and the master pressure Pm is calculated (that is, “hP=Pt -Pm"). Then, the target current It of the pressure regulating valve UA is adjusted based on the hydraulic pressure deviation hP. In other words, in the control of the pressure regulating valve UA in dynamic pressurization, feedback control (master loop) based on the master pressure Pm is performed so that the master pressure Pm approaches and matches the target pressure Pt with respect to the current feedback control (slave loop). is added.

<<Static pressurization when power is supplied from the auxiliary power supply BU>>
In the second state in which the main power supply BT is abnormal (when the power to the pressurizing unit CA is supplied by the auxiliary power supply BU), in steps S160 and S170, static pressure pressurization is performed. be.

At step S160, a predetermined current ia (preset predetermined value) is supplied to the pressure regulating valve UA to close the pressure regulating valve UA. By supplying the predetermined current ia, the pressure regulating valve UA is maintained in a completely closed state, and the circulation flow KN cannot be generated in the return path HK.

At step S170, a target current In (target value) corresponding to the supply current Im of the electric motor MA is calculated based on the target pressure Pt. Specifically, based on a preset calculation map, the motor target current In is determined so as to increase as the target pressure Pt increases. Then, current feedback control is performed so that the supply current Im, which is the value detected by the motor current sensor IM, approaches and matches the target current In.

Further, the electric motor MA is controlled so that the master pressure Pm (actual value) approaches and matches the target pressure Pt (target value). Specifically, similarly to the case of dynamic pressurization, the deviation hP (hydraulic pressure deviation) between the target pressure Pt and the master pressure Pm is calculated based on the target pressure Pt and the master pressure Pm (that is, , “hP=Pt−Pm”). Then, the target current In of the electric motor MA is adjusted based on the hydraulic pressure deviation hP. That is, in the control of the electric motor MA in static pressurization, feedback control (master loop) based on the master pressure Pm is performed so that the master pressure Pm approaches and matches the target pressure Pt, as opposed to the current feedback control (slave loop). is added.

At step S170, the electric motor MA may be controlled based on the rotation angle Ka. In this control, a target angle Kn (target value) corresponding to the rotation angle Ka of the electric motor MA is calculated. Specifically, based on a preset calculation map, the motor target angle Kn is determined so as to increase as the target pressure Pt increases. Then, rotation angle feedback control is performed so that the rotation angle Ka, which is the value detected by the rotation angle sensor KA, approaches and coincides with the motor target angle Kn. Further, in the same manner as described above, the motor target angle Kn is adjusted based on the hydraulic pressure deviation hP. That is, the control of the electric motor MA in static pressurization employs a cascade configuration in which hydraulic pressure feedback control (master loop) based on the master pressure Pm is added to rotation angle feedback control (slave loop).

In the braking control device SC, dynamic pressurization is performed when driven by the main power supply BT (first state). Dynamic pressurization excels in pressure adjustment accuracy, but power consumption is a problem. This is due to the fact that the electric motor MA must continue to be driven in order to continuously generate the circulating flow KN. Therefore, in the braking control device SC, static pressurization is executed instead of dynamic pressurization when driven by the auxiliary power supply BU (second state). In static pressurization, pressurization is performed by moving the entire amount of the brake fluid BF from the fluid pump QA to the hydraulic pressure chamber Ru (servo chamber) and Rwr (rear wheel chamber), thereby reducing the power consumption of the electric motor MA. can be In addition, since the return path HK is provided with a check valve GC, the hydraulic pressure chambers Ru and Rwr are fluid-locked (liquid-tightly sealed) by the pressure regulating valve UA and the check valve GC. Therefore, the servo pressure Pu (=Pwf, Pwr) can be maintained even when the power supply to the electric motor MA is completely stopped ("Im=0" state). Since the power consumption of the auxiliary power supply BU is suppressed in the braking control device SC, the capacity of the auxiliary power supply BU is reduced. As a result, the device as a whole can be miniaturized.

<Second Embodiment of Brake Control Device SC>
A second embodiment of the braking control device SC according to the present invention will be described with reference to the schematic diagram of FIG. A braking control device SC according to the second embodiment is a device that pumps a master pressure Pm from a master cylinder CM according to the operation of the braking operation member BP by the driver. Although the brake-by-wire type is adopted in the first embodiment, this is not adopted in the second embodiment. Therefore, in the second embodiment, the operating force Fp of the braking operating member BP is generated by the rigidity of the braking control device SC, the braking device SX, and the like.

FIG. 3 (in particular, the second pressurizing part CB) schematically illustrates the lower fluid unit YL of Patent Document 1 (Japanese Patent Application Laid-Open No. 2019-059294). The pressurizing unit CB is a general-purpose device for executing antilock brake control (so-called ABS control), skid prevention control (so-called ESC), and traction control. FIG. 3 shows from the master cylinder CM to one wheel of the wheel cylinder CW.

In the first embodiment, the servo pressure Pu (control pressure) generated by the first pressurizing unit CA is supplied to the front wheel cylinder CWf as the front wheel pressure Pwf via the master cylinder CM/master piston NM. , in the rear wheel cylinder CWr, it was directly supplied to the rear wheel chamber Rwf. In the second embodiment, the wheel pressure Pw (corresponding to “control pressure”) generated by the second pressurizing part CB is applied to the front and rear wheel chambers of the front and rear wheel cylinders CWf and CWr (=CW). It is directly supplied to Rwf, Rwr (=Rw) (corresponding to a "hydraulic chamber"). Differences from the first embodiment will be mainly described below.

As in the first embodiment, the vehicle is also provided with a brake operating member BP and a braking device SX in the second embodiment. In addition, the vehicle is equipped with two power supply sources, a main power supply BT and an auxiliary power supply BU. The braking control device SC (especially the controller EB, the pressure unit CB, etc.) is powered by the main power supply BT or the auxiliary power supply BU. The first state is when power is supplied from the main power supply BT (that is, when the main power supply BT is normal), and the second state is when power is supplied from the auxiliary power supply BU (that is, when the main power supply BT is abnormal).

The braking control device SC executes automatic braking control in addition to anti-lock braking control, skid prevention control, and the like. Automatic braking control automatically decelerates the vehicle based on the deceleration Gs requested from the driving support device so as to avoid a collision with an obstacle or reduce damage in the event of a collision. In addition, in automatic braking control, the vehicle is decelerated based on the requested deceleration Gs indicated by the external operation device. The braking control device SC includes a braking operation amount sensor BA, a master cylinder CM, a second pressurizing section CB (also simply referred to as "pressurizing section"), and a second controller EB (simply referred to as "controller"). consists of

An operation displacement sensor SP that detects an operation displacement Sp of the braking operation member BP is employed as the braking operation amount sensor BA. A master pressure sensor PM that detects the hydraulic pressure Pm (master pressure) in the master chamber Rm of the master cylinder CM is used as the braking operation amount sensor BA. The braking operation amount Ba is input to the second controller EB.

A master piston NM is inserted into the master cylinder CM to form a master chamber Rm. A braking operation member BP is connected to the master piston NM, and the master piston NM is moved in conjunction with the operation of the braking operation member BP. Master cylinder CM (especially master chamber Rm) and wheel cylinder CW (especially wheel chamber Rw) are connected by communication path HS. By moving the master piston NM, the master pressure Pm is supplied from the master cylinder CM to the wheel cylinder CW as the wheel pressure Pw. A second pressure member CB is provided between the master cylinder CM and the wheel cylinder CW.

[Second pressure part CB]
The master pressure Pm is individually adjusted (increased or decreased) in each wheel cylinder CW by the second pressurizing unit CB (corresponding to the “pressurizing unit”), and supplied as the wheel pressure Pw to the wheel chamber Rw of the wheel cylinder CW. be. The pressure unit CB is supplied with power from the controller EB. Similarly, in the second embodiment as well, the pressure applied to the pressure unit CB depends on whether power is supplied from the main power supply BT or the auxiliary power supply BU. different way. The state in which power is supplied from the main power supply BT to the controller EB is the first state, and the state in which power is supplied to the controller EB from the auxiliary power supply BU is the second state. The second pressure unit CB is composed of a second electric motor MB, a second fluid pump QB, a second pressure regulating valve UB, a pressure regulating reservoir RB, an inlet valve VI, a regulating pressure sensor PP, and an outlet valve VO. .

A second electric motor MB (also simply referred to as an "electric motor") drives a second fluid pump QB (also simply referred to as a "fluid pump"). The electric motor MB includes a second rotation angle sensor KB (also simply referred to as a "rotation angle sensor") to detect a second rotation angle Kb (also simply referred to as a "rotation angle") of the rotor. be provided. The actual rotation angle Kb is input to the controller EB.

A normally open second pressure regulating valve UB is provided in the communication path HS. The second pressure regulating valve UB (simply referred to as “pressure regulating valve”) is a linear electromagnetic valve whose valve opening amount is continuously controlled based on the energized state (for example, supply current Ib). An upper portion Bm (closer to the master cylinder CM) of the communication passage HS and a lower portion Bw (closer to the wheel cylinder CW) of the communication passage HS are connected to the pressure regulating valve UB by a return passage HT (fluid passage). be done. A second fluid pump QB is provided in the return path HT. In addition, in the return path HT, a pressure regulating reservoir RB is provided on the suction portion Qj side of the fluid pump QB.

As in the first embodiment, in the second embodiment as well, in the fluid pump QB, there is a second return passage HL (also simply referred to as a "return passage") that connects the second intake portion Qj and the second discharge portion Qp. ) is formed by part of the connecting path HS and the return path HT. In addition, a check valve GC is provided in the vicinity of the discharge portion Qp of the return passage HL. Specifically, a check valve is arranged between the discharge portion Qp and the pressure regulating valve UB in the return passage HL (particularly, the return passage HT). In other words, the return path HL includes the fluid pump QB, the check valve GC, the pressure regulating valve UB, and the pressure regulating reservoir RB. The return path HL is connected to the wheel chamber Rw of the wheel cylinder CW by the communication path HS between the pressure regulating valve UB and the check valve GC.

In the communication path HS, a normally open inlet valve VI is provided below the pressure regulating valve UB. A communication path HS between the pressure regulating valve UB and the inlet valve VI is provided with a regulating pressure sensor PP to detect the hydraulic pressure Pp (referred to as 'regulating pressure') regulated by the pressure regulating valve UB and the like. Below the inlet valve VI, the communication passage HS is connected to the return passage HT (that is, the return passage HL) at the portion Bg between the suction portion Qj of the fluid pump QB and the pressure regulating reservoir RB, and the pressure reducing passage HG (fluid passage). connected through A normally closed outlet valve VO is provided in the pressure reducing passage HG. On/off solenoid valves are employed as the inlet valve VI and the outlet valve VO. An inlet valve VI and an outlet valve VO are provided for each wheel cylinder CW so that each wheel pressure Pw can be individually adjusted.

<<Dynamic pressurization in the first state>>
In the first state, power is supplied from the main power supply BT to the controller EB and the pressure unit CB. In the first state, pressurization by dynamic pressure is performed in the same manner as described above. At this time, power is not supplied to the inlet valve VI and the outlet valve VO. Therefore, inlet valve VI is open and outlet valve VO is closed.

When the electric motor MB is driven, the fluid pump QB sucks the braking fluid BF from the upper portion Bm of the pressure regulating valve UB and discharges it to the lower portion Bw of the pressure regulating valve UB. As a result, the second circulation flow KL of the brake fluid BF containing the pressure regulating reservoir RB is formed in the second circulation path HL (composed of the communication path HS and the return path HL, and may be simply referred to as the "return path"). (indicated by dashed arrows and simply referred to as “circulating flow”) occurs. When the flow path of the communication passage HS is narrowed by the pressure regulating valve UB and the circulating flow KL of the braking fluid BF is throttled, the orifice effect at that time causes the fluid pressure Pp (adjusting pressure) at the lower portion Bw of the pressure regulating valve UB to be It is increased from the hydraulic pressure Pm (master pressure) above the pressure regulating valve UB. In other words, in the circulating flow KL, the hydraulic pressure difference (differential pressure) between the downstream side hydraulic pressure Pm (master pressure) and the upstream side hydraulic pressure Pp (adjustment pressure) with respect to the pressure regulating valve UB adjusted by Note that, regarding the magnitude relationship between the master pressure Pm and the regulated pressure Pp, the regulated pressure Pp is greater than or equal to the master pressure Pm (that is, "Pp≧Pm"). The difference between the first pressurizing part CA and the second pressurizing part CB is that the servo pressure Pu is increased from "0 (atmospheric pressure)" while the adjustment pressure Pp is increased from the master pressure Pm. be. However, in the first state, the method of increasing the adjustment pressure Pp is dynamic pressurization, which is the same as the method of increasing the servo pressure Pu.

<<Static pressurization in the second state>>
In the second state, electric power is supplied to the controller EB and the pressure unit CB from the auxiliary power supply BU instead of the main power supply BT. In the second state, static pressure is applied in the same manner as described above. Similarly to the above, power is not supplied to the inlet valve VI and the outlet valve VO, the inlet valve VI is opened and the outlet valve VO is closed.

In the second state, power is supplied to the normally open pressure regulator UB, and the pressure regulator UB is completely closed. A fluid pump QB is driven by the electric motor MB, and brake fluid BF is discharged from the fluid pump QB. All of the brake fluid BF discharged from the fluid pump QB is moved to the wheel chamber Rw. Specifically, the brake fluid BF is sucked into the fluid pump QB from the master cylinder CM (in particular, the master chamber Rm). Then, the entire amount of the sucked braking fluid BF is discharged into the wheel chamber Rw. Brake fluid BF flows into master chamber Rm from master reservoir RV via a cup seal. That is, the fluid pump QB moves the brake fluid BF from the master reservoir RV to the wheel chamber Rw via the master cylinder CM.

Since the braking control device SC and the braking device SX have rigidity, the adjustment pressure Pp (“control pressure”) increases as the amount (volume) of the braking fluid BF flowing from the fluid pump QB into the hydraulic pressure chamber Rw increases. equivalent) increases sequentially. When the adjustment pressure Pp (that is, the wheel pressure Pw) reaches the desired hydraulic pressure (that is, the target pressure Pt), the rotation of the electric motor MB is stopped, and the discharge of the brake fluid BF from the fluid pump QB is terminated. . At this time, the wheel chamber Rw is fluidly locked by closing the check valve GC and the pressure regulating valve UB. Therefore, even if power supply to the electric motor MB is stopped, the wheel pressure Pw is maintained.

<<Second controller EB>>
A second controller EB (corresponding to a "control section") controls the second pressurizing section CB based on the braking demand amount Bs. Specifically, the second controller EB uses the main power supply BT or the auxiliary power supply BU as a power supply source to adjust the power supplied to the second electric motor MB and the second pressure regulating valve UB. The second controller EB, like the first controller EA, is composed of a microprocessor MP and a drive circuit DR.

A braking operation amount Ba, an adjustment pressure Pp, a rotation angle Kb, a propriety flag FB, a power supply voltage Vd, and the like are input to the controller EB. A detection signal Sp (operation displacement) of the operation displacement sensor SP and a detection signal Pm (master pressure) of the master pressure sensor PM are acquired as the braking operation amount Ba. In order to control the pressure regulating valve UB and the electric motor MB, the regulating pressure Pp (detection value of the regulating pressure sensor PP) and the rotation angle Kb (detection value of the rotation angle sensor KB) are acquired. Further, the controller EB acquires the required deceleration Gs. Further, the controller EB acquires a propriety flag FB (a control flag representing propriety of the main power supply BT) and a power supply voltage Vd (a detected value of the power supply voltage sensor VD) in order to identify an abnormality in the main power supply BT. .

The controller EB is connected to a communication bus BS so as to share signals (detected values, calculated values, control flags, etc.) with other controllers. For example, the required deceleration Gs is calculated by the driving assistance device and transmitted to the controller EB via the communication bus BS. Alternatively, the required deceleration Gs is indicated by an external operating device different from the braking operating member BP. The suitability flag FB is transmitted from the power monitoring device to the controller EB through the communication bus BS.

A pressure regulation control algorithm is programmed in the controller EB (particularly, the microprocessor MP). The pressure regulation control according to the second embodiment is also control for adjusting the wheel pressure Pw. Specifically, in FIG. 2, it is indicated by [ ]. Also in the second embodiment, dynamic pressurization is performed in steps S140 and S150 in the first state. On the other hand, in the case of the second state, static pressurization is performed in steps S160 and S170. The method of dynamic and static pressurization is the same as in the first embodiment, so the description is omitted.

Furthermore, in the second embodiment, when anti-lock brake control, skid prevention control, etc. are executed, each wheel cylinder CW is controlled by the normally open inlet valve VI and the normally closed outlet valve VO. Wheel pressure Pw is adjusted individually. Inlet valve VI is closed and outlet valve VO is opened to reduce wheel pressure Pw. Since the inflow of the brake fluid BF to the wheel cylinder CW is blocked and the brake fluid BF in the wheel cylinder CW flows out to the pressure regulating reservoir RB, the wheel pressure Pw is reduced. In order to increase the wheel pressure Pw (however, the upper limit of the increase is up to the adjustment pressure Pp), the inlet valve VI is opened and the outlet valve VO is closed. The brake fluid BF is prevented from flowing out to the pressure regulating reservoir RB, and the regulating pressure Pp from the pressure regulating valve UB is supplied to the wheel cylinder CW, thereby increasing the wheel pressure Pw. In order to maintain the wheel pressure Pw, both the inlet valve VI and the outlet valve VO are closed. Since the hydraulic pressure chamber Rw of the wheel cylinder CW is fluidly sealed, the wheel pressure Pw is kept constant.

In the second embodiment, similarly to the above, dynamic pressurization is performed when driven by the main power supply BT (first state), and when driven by the auxiliary power supply BU (second state). static pressurization is performed. In static pressurization, the wheel pressure Pw is pressurized by moving the entire amount of the brake fluid BF from the fluid pump QB to the wheel pressure Pw, so the power consumption of the electric motor MB is reduced. In addition, since the return passage HL (part of the communication passage HS and the return passage HT) is provided with a check valve GC, the wheel chamber Rw, which is a fluid chamber, is closed by the pressure regulating valve UB and the check valve GC. It is fluidly locked (sealed). Therefore, the wheel pressure Pw can be maintained even when the power supply to the electric motor MB is completely stopped. Therefore, in the braking control device SC, similarly to the above, the power consumption of the auxiliary power supply BU is suppressed, so the capacity of the auxiliary power supply BU is reduced. As a result, the entire device is miniaturized.

<Other embodiments>
Other embodiments will be described below. In other embodiments, the same effects as described above (power saving, downsizing of the auxiliary power supply BU, etc.) can be obtained.

In the first embodiment described above, a single-type master cylinder CM is employed, and the servo pressure Pu is transmitted to the front wheel chamber Rwf via the master cylinder CM/master piston NM and directly to the rear wheel chamber Rwr. was done. Alternatively, a tandem-type master cylinder CM may be employed, and the servo pressure Pu may be transmitted to the front and rear wheel chambers Rwf and Rwr via the master cylinder CM/master piston NM. In this configuration, a diagonal type (also referred to as "X type") may be employed as the two braking systems. In the second embodiment, either a front-rear type or a diagonal type may be employed as the braking system.

In the first embodiment described above, the pressure receiving area rm (master area) of the master chamber Rm and the pressure receiving area ru (servo area) of the servo chamber Ru are set equal. Even if the master area rm and the servo area ru are different, it is possible to convert the master pressure Pm and the servo pressure Pu based on the ratio between the servo area ru and the master area rm. Therefore, the master area rm and the servo area ru do not have to be equal.

In the above-described second embodiment, the adjustment pressure sensor PP is provided in the second pressure member CB so as to detect the adjustment pressure Pp. However, the adjustment pressure sensor PP may be omitted. This is because the regulating pressure Pp (that is, the difference between the master pressure Pm, the regulating pressure Pp, and the hydraulic pressure) is determined by the electric power Ib supplied to the second pressure regulating valve UB.

<Summary of embodiment>
Embodiments of the braking control device SC are summarized below. The braking control device SC includes "pressure units CA and CB for increasing the wheel pressure Pw of the wheel cylinder CW of the vehicle,""control units EA and EB for driving the pressure units CA and CB," and "control unit A main power supply BT that supplies power to EA and EB, and an auxiliary power supply BU that supplies power to the control units EA and EB instead of the main power supply BT when the main power supply BT is abnormal. Further, the pressurizing units CA, CB of the braking control device SC include "fluid pumps QA, QB driven by electric motors MA, MB" and "discharge units Qo, Qp of the fluid pumps QA, QB and the fluid pump QA. , QB connecting the intake portions Qi and Qj of the , QB; pressure regulating valves UA and UB provided in the circulating passages HN and HL; Hydraulic pressure chambers Ru, Rw connected to return paths HN, HL between. In the braking control device SC, the wheel pressure Pw is increased by increasing the control pressures Pu and Pw of the hydraulic pressure chambers Ru and Rw by the controllers EA and EB. Here, the "hydraulic pressure chamber" corresponds to the servo chamber Ru in the first embodiment and the wheel chamber Rw in the first and second embodiments. The "control pressure" corresponds to the servo pressure Pu in the first embodiment, and the wheel pressure Pw in the first and second embodiments.

In the brake control device SC, in the first state in which power is supplied from the main power supply BT, the electric motors MA and MB are driven to generate circulating flows KN and KL of the brake fluid BF in the return paths HK and HL. . The control pressures Pu and Pw are increased by throttling the circulation flows KN and KL (that is, narrowing the flow paths of the return paths HK and HL) by the pressure regulating valves UA and UB. That is, in the first state, the control pressures Pu and Pw are increased by the dynamic pressure of the brake fluid BF. Regarding the amount balance of the brake fluid BF, most of the amount of the brake fluid BF discharged by the fluid pumps QA and QB passes through the pressure regulating valves UA and UB, but part of it is moved to the hydraulic pressure chambers Ru and Rw. , the control pressures Pu and Pw are increased. Further, when the control pressures Pu, Pw are maintained constant, the entire amount of the braking fluid BF discharged by the fluid pumps QA, QB is moved through the pressure regulating valves UA, UB and circulated as circulation flows KN, KL. . In any event, in the first state, when braking, the fluid pumps QA, QB (ie, electric motors MA, MB) continue to rotate.

In the braking control device SC, in the second state in which power is supplied from the auxiliary power supply BU, the pressure regulating valves UA and UB are closed. Then, the electric motors MA and MB are driven to move the brake fluid BF from the fluid pumps QA and QB to the fluid pressure chambers Ru and Rw, thereby increasing the control pressures Pu and Pw. That is, in the second state, the static pressure of the brake fluid BF increases the control pressures Pu and Pw. In the balance of the amount of the brake fluid BF, the control pressures Pu and Pw are increased by moving the entire amount of the brake fluid BF discharged by the fluid pumps QA and QB to the hydraulic pressure chambers Ru and Rw. Therefore, when the control pressures Pu, Pw are maintained constant, the rotation of the fluid pumps QA, QB (that is, the electric motors MA, MB) is stopped. When the control pressures Pu and Pw need to be reduced, the currents supplied to the pressure regulating valves UA and UB are reduced to slightly open the pressure regulating valves UA and UB.

In the braking control device SC, the method of applying the control pressures Pu and Pw (finally, the wheel pressure Pw) is switched depending on whether it is driven by the main power supply BT or by the auxiliary power supply BU. Specifically, when driven by the main power supply BT (first state), dynamic pressurization with excellent pressure adjustment accuracy is employed. In dynamic pressurization, circulating flows KN and KL of brake fluid BF discharged by fluid pumps QA and QB are throttled by pressure regulating valves (linear solenoid valves) UA and UB to increase wheel pressure Pw. However, dynamic pressurization requires that the fluid pumps QA, QB continue to be driven. In order to suppress power consumption, the braking control device SC switches from dynamic pressurization to static pressurization when driven by the auxiliary power supply BU (second state). In static pressurization, the wheel pressure Pw is increased by moving the brake fluid BF from the fluid pumps QA, QB to the fluid pressure chambers Ru, Rw. Thus, in the second state, fluid pumps QA, QB (ie, electric motors MA, MB) are driven only when needed. Since static pressurization consumes less power than dynamic pressurization, the size of the auxiliary power supply BU is reduced. In other words, in the braking control device SC, the pressurization method is appropriately selected according to the switching of the power supply source, so that it is possible to ensure pressure regulation accuracy and reduce power consumption.

Further, in the brake control device SC, check valves GC are provided in the return paths HK and HL. The check valve GC allows the flow of the brake fluid BF in the direction from the pressure regulating valves UA, UB to the suction ports Qi, Qj, but the flow of the braking fluid BF in the direction from the pressure regulating valves UA, UB to the discharge ports Qo, Qp is allowed. The flow of liquid BF is blocked. In other words, the circulating flows KN and KL are allowed to occur, but their reverse flow is prevented. In the second state, when the control pressures Pu and Pw reach the target pressure Pt, the control units EA and EB stop the rotation of the electric motors MA and MB and supply power to the electric motors MA and MB. is stopped. Here, the target pressure Pt is calculated according to the braking demand amount Bs of the vehicle. In the first state, even when the control pressures Pu and Pw reach the target pressure Pt, the electric motors MA and MB continue to be supplied with power so that the electric motors MA and MB continue to rotate. be done.

In the brake control device SC, in the second state, the hydraulic chambers Ru and Rw are sealed (fluid locked) by the check valve GC and the pressure regulating valves UA and UB. Therefore, the control pressures Pu and Pw are not reduced unless the pressure regulating valves UA and UB are opened. Therefore, the control pressures Pu and Pw are maintained even if the power supply to the electric motors MA and MB is completely stopped. As a result, the power consumption of the braking control device SC can be reduced. It should be noted that the power supply to the electric motors MA, MB is only required to compensate for leaks in the regulator valves UA, UB, etc. FIG.

SC: Braking control device, BT: Main power supply, BU: Auxiliary power supply, BP: Braking operation member (brake pedal), CW: Wheel cylinder, CA, CB: Pressure unit, EA, EB: Control unit (controller), CM Master cylinder, NM, Master piston, UA, UB, Pressure regulating valve, MA, MB, Electric motor, QA, QB, Fluid pump, Qi, Qj, Suction part of fluid pump, Qo, Qp, Discharge part of fluid pump, HN, HL... Return path, PM... Pressure sensor, PP... Adjustment pressure sensor, Pt... Target pressure, Pu... Servo pressure (an example of control pressure), Pm... Master pressure, Pp... Adjustment pressure, Pw... Wheel pressure (control pressure), Bs... required braking amount, Ba... braking operation amount, Gs... required deceleration, Ru... servo chamber (an example of hydraulic pressure chamber), Rw... wheel chamber (an example of hydraulic pressure chamber), Rm... master room.

Claims (2)

a pressure unit for increasing wheel pressure in a vehicle wheel cylinder;
a control unit that drives the pressure unit;
a main power supply that supplies power to the control unit;
an auxiliary power supply that supplies power to the control unit instead of the main power supply when the main power supply is abnormal;
In a vehicle braking control device comprising
The pressurizing section includes a fluid pump driven by an electric motor, a return passage connecting a discharge portion of the fluid pump and a suction portion of the fluid pump, a pressure regulating valve provided in the return passage, and the discharge portion. a hydraulic chamber connected to the return path between the pressure regulating valve;
The control unit
increasing the wheel pressure by increasing the control pressure in the hydraulic chamber;
In the first state in which power is supplied from the main power supply, the electric motor is driven to generate a circulating flow of brake fluid in the return passage, and the circulating flow is throttled by the pressure regulating valve to reduce the control pressure. increase,
In the case of the second state in which power is supplied from the auxiliary power supply, the control pressure is increased by closing the pressure regulating valve and driving the electric motor to move brake fluid to the hydraulic pressure chamber. braking control device. A braking control device for a vehicle according to claim 1,
a check valve that blocks a flow of the brake fluid in a direction from the pressure regulating valve toward the discharge part;
In the case of the second state, the control unit stops supplying power to the electric motor when the servo pressure reaches a target pressure calculated according to a braking demand amount of the vehicle. Device.