JP2017202766A - Vehicular brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate an electromagnetic valve in a brake control device comprising a fluid passage in which a pressure is regulated by an electric motor.SOLUTION: In a brake control device, a pressure regulation unit is constituted of a control cylinder which is combined with a master cylinder, a simulator and a wheel cylinder by a fluid passage, and a control piston which is moved by an electric motor with respect to the control cylinder. The pressure regulation unit selectively realizes any one of "first connection state in which connection between the master cylinder and the wheel cylinder is opened, and connection between the master cylinder and the simulator is blocked" and "second connection state in which connection between the master cylinder and the wheel cylinder is blocked, and connection between the master cylinder and the simulator is opened" according to a position of the control piston. A controller controls the electric motor on the basis of a rotational angle so that a position of the control piston is transited from the first connection state to the second connection state in the case where operation displacement exceeds a preset specified value.SELECTED DRAWING: Figure 4

Description

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

  The applicant controls the hydraulic pressures of the two fluid paths (braking pipes) independently and individually by the pressure adjusting unit CLK driven through the electric motor MTR as described in Patent Document 1. Develop what you want. In this configuration, when the driver performs a braking operation, the electromagnetic valves VSM, VM1, and VM2 are excited, and the fluid liquid in the wheel cylinder is pressurized by the pressure adjustment unit CLK. In order to excite the solenoid valves VSM, VM1, and VM2, electric power is required. Therefore, from the viewpoint of energy saving, what does not require these solenoid valves is desired.

Japanese Patent Laying-Open No. 2006-043788

  An object of the present invention is to provide a vehicle braking control apparatus having a fluid path that is regulated by an electric motor, in which the number of solenoid valves that are excited during braking operation can be reduced.

  A vehicle brake control device according to the present invention includes a master cylinder (MCL) mechanically connected to a vehicle brake operation member (BP), and a brake fluid drawn from the master cylinder (MCL). ), A wheel cylinder (WC) that applies braking torque to the wheels of the vehicle, and the brake fluid applied to the wheel cylinder (WC) by an electric motor (for example, MT1). A pressure adjusting unit (for example, CA1) for discharging and a controller (ECU) for controlling the electric motor (MT1) are provided. Further, the vehicle braking control device includes a displacement sensor (SBP) that detects an operation displacement (Sbp) of the braking operation member (BP), and a rotation angle sensor that detects a rotation angle (Mk1) of the electric motor (MT1). (MK1).

  In the vehicle braking control apparatus according to the present invention, the pressure adjusting unit (CA1) includes fluid paths (HM1, HSM, HW1) to the master cylinder (MCL), the simulator (SSM), and the wheel cylinder (WC). ) And a control piston (SPS) that is moved relative to the control cylinder (SC1) by the electric motor (MT1). Then, the pressure adjusting unit (CA1) is configured so that “the fluid connection between the master cylinder (MCL) and the wheel cylinder (WC) is released and the master cylinder (MCL) is opened according to the position of the control piston (SPS). ) And the simulator (SSM) fluid connection between the first connection state (AJT) "and" the fluid connection between the master cylinder (MCL) and the wheel cylinder (WC) is interrupted, and Any one of the second connection states (BJT) in which the fluid connection between the master cylinder (MCL) and the simulator (SSM) is released is selectively realized.

  In the vehicle braking control apparatus according to the present invention, the controller (ECU) is configured such that when the operation displacement (Sbp) exceeds a predetermined value (sb0) set in advance, the position of the control piston (SPS) is The electric motor (MT1) is controlled based on the rotation angle (Mk1) so as to transition from the first connection state (AJT) to the second connection state (BJT). Here, the predetermined value (sb0) is set to a value smaller than a value (bp0) corresponding to the play of the braking operation member (BP).

  A vehicle brake control device according to the present invention includes a master cylinder (MCL) mechanically connected to a vehicle brake operation member (BP), and a brake fluid drawn from the master cylinder (MCL). ), A wheel cylinder (WC) that applies braking torque to the wheels of the vehicle, and the brake fluid applied to the wheel cylinder (WC) by an electric motor (for example, MT1). A pressure adjusting unit (for example, CA1) for discharging and a controller (ECU) for controlling the electric motor (MT1) are provided. Further, the vehicle braking control device includes a brake switch (BSW) that detects the start of operation of the braking operation member (BP), and a rotation angle sensor (MK1) that detects a rotation angle (Mk1) of the electric motor (MT1). And comprising.

  In the vehicle braking control apparatus according to the present invention, the pressure adjusting unit (CA1) includes fluid paths (HM1, HSM, HW1) to the master cylinder (MCL), the simulator (SSM), and the wheel cylinder (WC). ) And a control piston (SPS) that is moved relative to the control cylinder (SC1) by the electric motor (MT1). Then, the pressure adjusting unit (CA1) is configured so that “the fluid connection between the master cylinder (MCL) and the wheel cylinder (WC) is released and the master cylinder (MCL) is opened according to the position of the control piston (SPS). ) And the simulator (SSM) fluid connection between the first connection state (AJT) "and" the fluid connection between the master cylinder (MCL) and the wheel cylinder (WC) is interrupted, and Any one of the second connection states (BJT) in which the fluid connection between the master cylinder (MCL) and the simulator (SSM) is released is selectively realized.

  In the vehicle braking control apparatus according to the present invention, the controller (ECU) is configured such that when the signal (Bsw) from the brake switch (BSW) transitions from off to on, the position of the control piston (SPS) is The electric motor (MT1) is controlled based on the rotation angle (Mk1) so as to transition from the first connection state (AJT) to the second connection state (BJT).

  According to the above configuration, the first connection state AJT in which the master cylinder MCL and the wheel cylinder WC are fluidly connected and the second connection state BJT in which the master cylinder MCL and the simulator SSM are fluidly connected are controlled according to the position of the control piston SPS. Any one of them is selectively realized. Then, based on the rotation angle Mk1, the controller ECU causes the position of the control piston SPS to transition from the first connection state AJT to the second connection state BJT when the operation displacement Sbp exceeds a preset predetermined value sb0. To control the electric motor MT1.

  Since the movement of the control piston SPS is switched from the first connection state AJT to the second connection state BJT, a brake-by-wire configuration can be formed without employing a solenoid valve. For this reason, the apparatus is reduced in size and simplified, and energization of the solenoid valve is not required, so that energy saving of the apparatus can be achieved.

  Furthermore, when the operation displacement Sbp exceeds a predetermined value sb0 set in advance, the electric motor MT1 is based on the rotation angle Mk1 so that the position of the control piston SPS transitions from the first connection state AJT to the second connection state BJT. Is controlled, so that the driver feels uncomfortable. The predetermined value sb0 is set to a value smaller than the value bp0 corresponding to “play” of the braking operation member BP.

  Further, in place of the operation displacement Sbp, when the signal Bsw from the brake switch BSW transits from OFF to ON, the rotation angle is set so that the position of the control piston SPS transits from the first connection state AJT to the second connection state BJT. The electric motor MT1 is controlled based on Mk1. As in the case of the operation displacement Sbp, the number of solenoid valves is reduced, a brake-by-wire configuration is formed, and a sense of discomfort to the driver can be eliminated.

1 is an overall configuration diagram showing a first embodiment of a braking control device for a vehicle according to the present invention. It is a fragmentary sectional view for demonstrating a pressure adjustment unit. It is a functional block diagram for demonstrating the process in an electronic control unit. It is a flowchart for demonstrating standby control. It is an operation view for explaining switching of fluid connection state and standby control. It is a circuit diagram for demonstrating an electric motor and its drive circuit. It is a fragmentary sectional view for explaining other examples of a pressure regulation unit. It is a whole block diagram which shows 2nd Embodiment of the braking control apparatus of the vehicle which concerns on this invention.

<Symbols of components, subscripts and numbers at the end of symbols>
An embodiment of a vehicle braking control apparatus according to the present invention will be described with reference to the drawings. In the following description, components, arithmetic processing, signals, and values having the same symbols, such as ECUs, have the same functions. Further, a suffix (such as “fr”) added to the end of each symbol indicates which wheel it relates to. Specifically, “fr” indicates the right front wheel, “fl” indicates the left front wheel, “rr” indicates the right rear wheel, and “rl” indicates the left rear wheel. For example, in each wheel cylinder, they are expressed as a right front wheel wheel cylinder WCfr, a left front wheel wheel cylinder WCfl, a right rear wheel wheel cylinder WCrr, and a left rear wheel wheel cylinder WCrl.

  In addition, the numbers (“1” or “2”) attached to the end of various symbols indicate the right front wheel cylinder WCfr and the left front wheel cylinder WCfl in the two fluid paths (hydraulic pressure system). It indicates which one is connected. In the following, the system connected to the right front wheel cylinder WCfr is referred to as “first system”, expressed using the last numeral “1”, and the system connected to the left front wheel cylinder WCfl is “second system”. And is expressed using the number “2” at the end. For example, the first pressure adjusting unit CA1 adjusts the hydraulic pressure of the right front wheel wheel cylinder WCfr (corresponding to the first wheel cylinder WC1), and the second pressure adjusting unit CA2 is the left front wheel wheel cylinder WCfl (second wheel cylinder). (Corresponding to WC2). The “first system” and “second system” may be reversed. In various components, the one related to the first system (first fluid path) and the one related to the second system (second fluid path) are the same. For this reason, below, the component which concerns on a 1st system | strain is mainly demonstrated.

<First embodiment of braking control device according to the present invention>
A vehicle provided with a first embodiment of a braking control device according to the present invention will be described with reference to the overall configuration diagram of FIG. As shown in the overall configuration diagram, the vehicle includes a braking operation member BP, an operation displacement sensor SBP, a brake switch BSW, an electronic control unit ECU, a tandem master cylinder MCL, a stroke simulator SSM, and first and second pressure adjustment units. CA1 and CA2 are provided. Further, each wheel WHfr, WHfl, WHrr, WHrl (simply referred to as “WH”) of the vehicle includes a brake caliper CPfr, CPfl, CPrr, CPrl (simply also referred to as “CP”), wheel cylinders WCfr, WCfl. , WCrr, WCrl (also simply referred to as “WC”), and rotating members KTfr, KTfl, KTrr, KTrl (also simply referred to as “KT”). In the following description, the fluid path (such as HM1) and the fluid chamber (such as Rm1) are in a liquid-tight state.

  The braking operation member (for example, brake pedal) BP is a member that the driver operates to decelerate the vehicle. By operating the braking operation member BP, the braking torque acting on 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 that rotates integrally with the wheel WH is fixed to the wheel WH of the vehicle. A brake caliper CP is disposed so as to sandwich the rotating member KT. The brake caliper CP is provided with a wheel cylinder WC. By increasing the pressure (hydraulic pressure) of the brake fluid in each wheel cylinder WC, the friction member (for example, brake pad) MSB is pressed against the rotating member (for example, brake disc) KT. The frictional force generated at this time generates a braking torque on the wheel WH, and a braking force is generated.

  The braking operation member BP is provided with an operation displacement sensor (stroke sensor) SBP for detecting an operation displacement Sbp of the braking operation member BP as an operation amount by the driver. Similarly, a master cylinder hydraulic pressure sensor PM1 (pressure sensor) is provided in the master cylinder MCL in order to detect the master cylinder hydraulic pressure Pm1 as an operation amount of the braking operation member BP by the driver. In addition, in order to detect the operation force Fbp of the brake operation member BP as the operation amount of the brake operation member BP by the driver, the brake operation member BP is provided with an operation force sensor (stepping force sensor) (not shown). obtain. By these operation amount detection sensors, the operation amount of the brake operation member BP by the driver (“master cylinder hydraulic pressure Pm1”, “operation displacement Sbp of the brake operation member BP”, and “operation force Fbp of the brake operation member BP”). Are acquired (detected).

  The electronic control unit (also referred to as a controller) ECU includes an electric circuit board on which a microprocessor and the like are mounted, and a control algorithm programmed in the microprocessor. Electric power is supplied to the electronic control unit ECU from a storage battery (battery) BAT and a generator (alternator) ALT. The operation displacement Sbp and the like are input to the electronic control unit ECU. Further, the electronic control unit ECU includes first and second control cylinder hydraulic pressures (detected values) Pc1 and Pc2 acquired by first and second control cylinder hydraulic pressure sensors (also referred to as control hydraulic pressure sensors) PC1 and PC2. Is entered.

  The electronic control unit ECU controls the first and second pressure adjusting units (also referred to as pressure adjusting units) CA1 and CA2 based on the braking operation displacement Sbp, the master cylinder hydraulic pressure Pm1, and the like. Specifically, in the electronic control unit ECU, the first and second electric motors MT1 and MT2 that drive the first and second pressure regulating units CA1 and CA2 according to a control algorithm programmed in the microprocessor are used. Two target signals It1, It2 are calculated, and a process for controlling the first and second electric motors MT1, MT2 is executed.

  A tandem master cylinder (also simply referred to as a master cylinder) MCL converts the operating force of the braking operation member BP into a hydraulic pressure, and pumps the braking fluid to the wheel cylinder WC of each wheel. Specifically, the braking operation member BP is mechanically connected to the first and second master pistons MP1 and MP2 in the master cylinder MCL via a brake rod. In the master cylinder MCL, first and second master cylinder chambers (also referred to as pressurizing chambers) Rm1 and Rm2 defined by two master pistons MP1 and MP2 are formed, and wheel cylinders WC and fluid paths ( Connected by brake piping). When the braking operation member BP is not operated, the first and second pressurizing chambers Rm1 and Rm2 are in communication with the master reservoir RSV, and the hydraulic pressure in the master cylinder MCL is atmospheric pressure.

≪Two fluid paths (diagonal piping) ≫
Next, the two fluid paths will be described with reference to the hydraulic circuit. The path (fluid path) through which the brake fluid (brake fluid) is moved between the master cylinder MCL and the four wheel cylinders WCfr, WCfl, WCrr, WCrl is composed of two systems. In one system (system of the first fluid path H1), the first master cylinder chamber (also referred to as a first pressurizing chamber) Rm1 of the master cylinder MCL and the wheel cylinders WCfr and WCrl are fluidly connected. In the other system (system of the second fluid path H2), the second master cylinder chamber (also referred to as second pressurizing chamber) Rm2 of the master cylinder MCL and the wheel cylinders WCfl, WCrr are fluidly connected. A so-called diagonal piping (also referred to as X piping) is employed. Since the configuration related to the first fluid path (first brake piping) H1 and the configuration related to the second fluid path (second brake piping) H2 are basically the same, the configuration related to the first fluid path H1. explain.

  A first pressure adjusting unit (also referred to as a first pressure adjusting unit) CA1 is provided in a fluid passage H1 connecting the first pressurizing chamber Rm1 of the master cylinder MCL and the wheel cylinders WCfr, WCrl. That is, the first pressure adjusting unit CA1 is interposed in the first fluid path H1.

  The first pressure adjusting unit CA1 is composed of a first control cylinder SC1 and a first electric motor MT1. When the braking operation is performed and when the automatic pressurization is necessary, the pressure adjustment unit CA1 cuts off the fluid connection between the master cylinder MCL and the wheel cylinders WCfr and WCrl (disconnected state), and the wheel cylinder WCfr. , Adjust (increase, hold, or decrease) the hydraulic pressure of WCrl. The hydraulic pressure (actual control hydraulic pressure) Pc1 adjusted by the first pressure adjustment unit CA1 is acquired (detected) by the first control hydraulic pressure sensor PC1.

  The first fluid path H1 includes a first master cylinder fluid path (braking pipe) HM1 from the master cylinder MCL to the pressure regulating unit CA1, and a first wheel cylinder fluid path (braking) from the pressure regulating unit CA1 to the wheel cylinders WCfr and WCrl. Piping) formed by HW1. The master cylinder fluid pressure sensor PM1 is provided in the first master cylinder fluid passage HM1 so as to detect the fluid pressure in the pressurizing chamber Rm1. The first hydraulic unit HU1 is interposed in a first wheel cylinder fluid passage HW1 (corresponding to a part of the first fluid passage H1) that connects the pressure adjustment unit CA1 and the wheel cylinders WCfr, WCrl. In the first wheel cylinder fluid path HW1, the first control hydraulic pressure Pc1 of the first pressure regulating unit CA1 (particularly the control cylinder SC1) is detected between the first pressure regulating unit CA1 and the first hydraulic pressure unit HU1. A first control hydraulic pressure sensor PC1 is provided.

  The first hydraulic pressure unit (also referred to as a modulator) HU1 includes a pressure increasing valve and a pressure reducing valve, and in the execution of wheel slip control such as anti-skid control and vehicle stabilization control, the hydraulic pressures of the wheel cylinders WCfr and WCrl are respectively set. Control individually and independently.

  A stroke simulator (also simply referred to as a simulator) SSM is provided to generate an operating force on the braking operation member BP. The simulator SSM is fluidly connected to the first control cylinder SC1 of the first pressure regulating unit CA1 via a simulator fluid path (for example, a brake pipe, a fluid path of a fluid unit block) HSM. When the braking operation member BP is not operated, the fluid connection between the master cylinder MCL and the wheel cylinder WC is released (communication state) by the pressure adjustment unit CA1, and the fluid connection between the simulator SSM and the master cylinder MCL is cut off (not connected). Communication state). On the other hand, when the braking operation member BP is operated, the fluid connection between the master cylinder MCL and the wheel cylinder WC is cut off by the pressure adjusting unit CA1, and the master cylinder MCL and the simulator SSM are connected via the simulator fluid path HSM. The fluid connection is opened (communication).

  Inside the simulator SSM, a piston and an elastic body (for example, a compression spring) are provided. Therefore, when the braking operation member BP is operated, the braking fluid is moved from the master cylinder MCL (pressurizing chamber Rm1) to the simulator SSM, and the piston is pushed by the flowing braking fluid. A force is applied to the piston in a direction to prevent the inflow of the brake fluid by the elastic body. By this elastic body, an operation force (for example, a brake pedal depression force) when the brake operation member BP is operated is formed.

  Next, the configuration related to the second fluid path H2 will be briefly described. As described above, the configuration related to the first fluid path H1 and the configuration related to the second fluid path H2 are basically the same. Therefore, Rm1 corresponds to Rm2, WHfr corresponds to WHfl, WCrl corresponds to WCrr, HM1 corresponds to HM2, HW1 corresponds to HW2, HU1 corresponds to HU2, CA1 corresponds to CA2, and PC1 corresponds to PC2. In other words, in the description of the components related to the first fluid path H1, “first” is replaced with “second” and the last numeral “1” is replaced with “2”, which relates to the second fluid path H2. This corresponds to the description of the component. Note that, in the components related to the second fluid path H2, the simulator and the master cylinder hydraulic pressure sensor are omitted, but these are also provided in the second fluid path H2 as in the first fluid path H1. obtain.

<Pressure adjustment unit (pressure adjustment unit)>
The details of the pressure adjusting unit will be described with reference to the partial cross-sectional view of FIG. Since the first pressure adjusting unit CA1 (for example, corresponding to the right front wheel WHfr) and the second pressure adjusting unit CA2 (for example, corresponding to the left front wheel WHfl) have the same structure, the first pressure adjusting unit ( The CA1 will be described.

  The first pressure adjusting unit CA1 is fluidly connected to the master cylinder MCL (particularly the pressurizing chamber Rm1) and the wheel cylinders WCfr and WCrl in a fluid-tight state. The first fluid path (first braking pipe) H1 is a fluid path (braking pipe) HM1 between the master cylinder MCL and the pressure regulating unit CA1, and a fluid between the pressure regulating unit CA1 and the wheel cylinders WCfr, WCrl. A road (braking pipe) HW1 is used. The hydraulic pressure of the wheel cylinders WCfr and WCrl is adjusted by taking in and out the brake fluid from the first pressure regulating unit CA1.

  The first pressure adjusting unit CA1 includes a first electric motor MT1, a reduction gear GSK, a rotation / linear motion conversion mechanism (screw mechanism) NJK, a pressing member PSH, a first control cylinder SC1, a first control piston PS1, and a return spring. Consists of SPR.

  The first electric motor MT1 is a power source for the first pressure adjusting unit CA1 to adjust (pressurize, hold, depressurize) the pressure of the brake fluid in the wheel cylinder WC. The first electric motor MT1 is driven by the electronic control unit ECU. The first electric motor MT1 is provided with a first rotation angle sensor MK1 so as to detect the first motor rotation angle Mk1. As the first electric motor MT1, a brushless DC motor (also simply referred to as a brushless motor) can be employed.

  The reduction gear GSK is composed of a small diameter gear SKH and a large diameter gear DKH. The rotational power of the electric motor MT1 is decelerated by the reduction gear GSK and transmitted to the screw mechanism NJK. Specifically, in the reduction gear GSK, the rotational power from the electric motor MT1 is input to the small diameter gear SKH, which is decelerated and output from the large diameter gear DKH to the screw mechanism NJK.

  In the screw mechanism NJK, the rotational power of the speed reducer GSK is converted into the linear power Fs of the pressing member PSH. A nut member NUT is fixed to the pressing member PSH. The bolt member BLT of the screw mechanism NJK is fixed coaxially with the large-diameter gear DKH. Since the rotational movement of the nut member NUT is constrained by the key member KYB, the rotation of the large diameter gear DKH causes the nut member NUT (that is, the pressing member PSH) to be screwed with the bolt member BLT to rotate around the rotational shaft of the large diameter gear DKH. Moved in the direction. That is, the rotational power of the first electric motor MT1 is converted into linear power of the pressing member PSH by the screw mechanism NJK. The control piston SPS is moved in the direction of the central axis Jsc of the bottomed cylindrical hole Yte of the control cylinder SC1 by the pressing member PSH.

  The first control cylinder SC1 discharges the brake fluid to the wheel cylinder WC. The control cylinder SC1 has a bottomed cylindrical hole Yte. Here, the bottomed cylindrical hole Yte is a cylindrical hole in which one end of the cylinder is closed to form a bottom, and the other end has an opening. In the bottomed cylindrical hole Yte, the closed bottom surface is referred to as a “bottom surface Mcb”. The inner surface (side surface) of the cylindrical hole is referred to as “cylindrical surface Mce”. The cylindrical surface Mce is “a straight line (a generatrix that is parallel to the central axis Jsc) drawn perpendicularly to this circle from all points of one circle (cross section perpendicular to the central axis Jsc of the bottomed cylindrical hole Yte). It is defined as “a curved surface formed by an aggregate of straight lines”.

  A control piston SPS is inserted into the bottomed cylindrical hole Yte of the first control cylinder SC1. One end surface of the control piston SPS is pressed by a pressing member PSH driven by the first electric motor MT1. Therefore, the control piston SPS can be moved in the direction of the central axis Jsc of the control cylinder SC1 (bottomed cylindrical hole Yte) by the pressing member PSH. The outer peripheral surface (side surface) Mps of the control piston SPS has a cylindrical shape. Similarly to the cylindrical surface Mce, the side surface Mps is “a straight line (bus line) drawn perpendicularly to this circle from all points of one circle (cross section perpendicular to the central axis Jsc of the bottomed cylindrical hole Yte) It is defined as a “curved surface formed by an aggregate of straight lines parallel to the central axis Jsc”.

  Further, in the direction of the central axis Jsc of the bottomed cylindrical hole Yte, a flange portion (flange portion) Tsu is formed at the other end portion opposite to the one end surface of the control piston SPS (the pressing surface of the pressing member PSH). The A seal groove is formed in the flange portion Tsu. In this groove, a tip seal SSL that is in sliding contact with the inner cylindrical surface Mce of the control cylinder SC1 is provided. Therefore, the tip seal SSL moves integrally with the control piston SPS, and the tip seal SSL seals the space between the cylindrical surface Mce and the control piston SPS and maintains a liquid-tight state. For example, an O-ring can be adopted as the tip seal SSL.

  A space defined by the cylindrical surface (inner surface) Mce of the control cylinder SC1, the bottom surface Mcb of the control cylinder SC1, the end surface Mpt of the control piston SPS, and the tip seal SSL is referred to as “pressure regulating chamber Rca”. The control cylinder SC1 forming the pressure regulating chamber Rca is provided with a pressure regulating hole Aca. The pressure regulating chamber Rca is always in communication with the wheel cylinder WC through the pressure regulating hole Aca and the first wheel cylinder fluid passage HW1. The pressure regulation chamber Rca, the brake pipe HW1, and the wheel cylinder WC are filled with the brake fluid. Here, a first control hydraulic pressure sensor PC1 is provided to detect the hydraulic pressure (first control hydraulic pressure) Pc1 in the pressure adjusting chamber Rca.

  The control piston SPS is provided with a rear end seal KSL, which is a separate member from the front end seal SSL, on the side close to the pressing member PSH with respect to the front end seal SSL. The rear end seal KSL is fitted into a seal groove provided in the control piston SPS. The rear end seal KSL seals the cylindrical surface (inside surface) Mce of the control cylinder SC1 and the side surface (outside surface) Mps of the control piston SPS. For example, a cup seal can be adopted as the rear end seal KSL. Here, the rear end seal KSL may be constituted by two cup seals.

  The cylindrical surface Mce and the side surface Mps are in sliding contact with each other via two different seal members (a front end seal SSL and a rear end seal KSL). A space defined by the cylindrical surface Mce of the control cylinder SC1, the side surface Mps of the control piston SPS, the front end seal SSL, and the rear end seal KSL is referred to as a “communication chamber Rrn” (see the AA cross section). . The communication chamber Rrn is located on the opposite side of the pressure regulation chamber Rca with respect to the tip seal SSL.

  In a state where the control piston SPS is assembled to the control cylinder SC1, the simulator hole Asm is located at a position intermediate between the portion where the control cylinder SC1 is in contact with the front end seal SSL and the portion where the control cylinder SC1 is in contact with the rear end seal KSL. Provided. The simulator hole Asm opened in the control cylinder SC1 is fluidly connected to the simulator SSM via the simulator fluid path HSM. Therefore, the communication room Rrn and the simulator SSM are always in communication. The communication chamber Rrn, the simulator fluid path HSM, and the simulator SSM are filled with braking fluid. Here, the master cylinder hydraulic pressure sensor PM1 may be provided in the simulator fluid path (braking pipe) HSM or the simulator SSM.

  The cylindrical surface Mce of the control cylinder SC1 is provided with a pressure hole Aka on the side close to the pressure adjustment hole Aca with respect to the simulator hole Asm. In other words, in the direction of the central axis Jsc, the simulator hole Asm, the pressurizing hole Aka, and the pressure adjusting hole Aca are arranged in this order from the side closer to the pressing member PSH. The pressurizing hole Aka is fluidly connected to the master cylinder MCL (pressurizing chamber Rm1) via the master cylinder fluid path HM1. The pressurizing chamber Rm1 and the fluid path HM1 are filled with the brake fluid.

  When the braking operation member BP is not operated, the electric motor MT1 is not energized, and the pressing member PSH does not press the control piston SPS. A return spring SPR is compressed and attached between the bottom surface (inside Yte) Mcb in the pressure regulating chamber Rca and the end surface Mpt of the control piston SPS. For this reason, the control piston SPS is pressed by the return spring SPR so as to come into contact with the stopper STP provided in the first control cylinder SC1. The position of the control piston SPS when the output of the first electric motor MT1 is zero is referred to as “initial position”.

  When the control piston SPS is in the initial position, the pressure hole Aka is in communication with the pressure regulating chamber Rca in the positional relationship between the pressure hole Aka and the tip seal SSL. Therefore, the fluid connection between the pressure regulating chamber Rca and the pressurizing chamber Rm1 is opened (communication state), and the fluid connection between the pressurizing chamber Rm1 and the communication chamber Rrn is shut off (non-communication state). . This state is referred to as “first connection state AJT”. In the first connection state AJT, the first pressurizing chamber Rm1 of the master cylinder MCL is communicated with the wheel cylinder WC via the pressure regulating chamber Rca. Even if the power supply malfunctions and the electric motor MT1 is not driven, the brake fluid in the pressurizing chamber Rm1 does not flow into the simulator SSM but flows into the wheel cylinder WC. For this reason, the wheel cylinder WC can be effectively pressurized by the master cylinder MCL.

  When the brake operation member BP is not operated, the master cylinder MCL is brought into communication with the master reservoir RSV. Accordingly, the hydraulic pressure in each wheel cylinder WC is atmospheric pressure. In this case, the pressing member PSH driven by the first electric motor MT1 is returned to the initial position (also referred to as zero point). Since the pressing member PSH and the control piston SPS are separate members that can be separated, the control piston SPS may not be returned due to the friction of the seal members SSL and KSL. However, the elastic force of the return spring SPR returns the control piston SPS to the position (initial position) where it abuts against the stopper STP, and the influence of the friction of the seal members SSL, KSL is eliminated.

  When the braking operation member BP is operated and the electric motor MT1 is driven, the pressing member PSH presses the control piston SPS in the forward direction. Here, the forward direction corresponds to the forward rotation direction of the electric motor MT1, and is a direction in which the hydraulic pressure of the wheel cylinder WC is increased. On the other hand, the reverse direction of the control piston SPS corresponds to the reverse direction of the electric motor MT1 and is a direction in which the hydraulic pressure of the wheel cylinder WC is decreased. When the control piston SPS is moved in the forward direction, the tip seal SSL passes through the pressure hole Aka. As a result, the pressure hole Aka that has been in communication with the pressure regulating chamber Rca is blocked from communication, and this time, the pressure hole Aka is in communication with the communication chamber Rrn. This state is referred to as “second connection state BJT”.

  Although the brake fluid is discharged from the pressurizing chamber Rm1 of the master cylinder MCL by the operation of the brake operation member BP, in the second connection state BJT, the brake fluid is absorbed by the simulator SSM through the communication chamber Rrn. Due to the inflow of the brake fluid, the elastic body in the simulator SSM is compressed, the fluid pressure in the pressurizing chamber Rm1 is increased, and the operation force of the brake operation member BP is increased. In order to detect the hydraulic pressure in the pressurizing chamber Rm1, a master cylinder hydraulic pressure sensor PM1 is provided. The hydraulic pressure (actual value of the master cylinder hydraulic pressure) Pm1 detected by the master cylinder hydraulic pressure sensor PM1 is employed to control the electric motors MT1 and MT2 as one of the braking operation amounts.

  When the control piston SPS is moved in the forward direction, the volume of the pressure adjusting chamber Rca is reduced, and the brake fluid is discharged from the pressure adjusting chamber Rca to the wheel cylinder WC through the pressure adjusting hole Aca and the brake pipe HW1. . Due to this movement of the brake fluid, the hydraulic pressure in the wheel cylinder WC increases, and the brake torque for the wheel WH is increased. Conversely, when the control piston SPS is moved in the backward direction, the volume of the pressure regulating chamber Rca is increased, and the brake fluid is returned from the wheel cylinder WC to the pressure regulating chamber Rca. Due to this movement of the brake fluid, the hydraulic pressure in the wheel cylinder WC is reduced, and the brake torque for the wheel WH is reduced.

  As described above, in the brake control device according to the present invention, in the brake-by-wire configuration, the fluid connection between the master cylinder MCL and the wheel cylinder WC is released depending on the position of the control piston SPS, and The first connection state AJT, which is a fluid connection state in which the fluid connection between the master cylinder MCL and the simulator SSM is cut off, and “the fluid connection between the master cylinder MCL and the wheel cylinder WC is cut off, and the master cylinder Any one of the second connection states BJT, which is a fluid connection state in which the fluid connection between the MCL and the simulator SSM is released, is selectively realized. For this reason, a plurality of solenoid valves are reduced, and power saving during braking operation is achieved.

<Processing in electronic control unit ECU>
Next, processing in an electronic control unit (also referred to as a controller) ECU will be described with reference to the functional block diagram of FIG. The electronic control unit ECU receives power supply from the power source (storage battery BAT, generator ALT) and controls the first and second electric motors MT1, MT2. Processing in the electronic control unit ECU includes a braking operation amount calculation block BPE, a target hydraulic pressure calculation block PCT, an instruction energization amount calculation block ISJ, a hydraulic pressure feedback control block PFB, a standby control block SBC, a target energization amount calculation block IMT, and The drive circuit DRV is used.

  In the braking operation amount calculation block BPE, the braking operation amount (calculated value) Bpe is calculated based on the operation displacement Sbp, the master cylinder hydraulic pressure Pm1, and the weighting coefficient (calculation map). When the braking operation is small, the operation displacement Sbp changes to some extent, but the change of the master cylinder hydraulic pressure Pm1 is small. In this case, the weighting coefficient Ksb of the operation displacement Sbp is increased, and the weighting coefficient Kpm of the master cylinder hydraulic pressure Pm1 is decreased, and the braking operation amount calculation value Bpe (= Sbp · Ksb + Pm1 · Kpm) is determined. On the other hand, what is required as a final result of the braking control is a braking force. Therefore, when the braking operation is large, the weighting coefficient Ksb of the operation displacement Sbp is decreased, and the weighting coefficient Kpm of the master cylinder hydraulic pressure Pm1 is increased, so that the braking operation amount Bpe is determined. The coefficients Ksb and Kpm are set in advance so as to change based on the magnitude of the braking operation amount (for example, the operation displacement Spb). For the calculation of the braking operation amount Bpe, the operation force Fbp of the braking operation member BP can be employed. Since the operating force Fbp is a control parameter related to “force”, it is handled in the same manner as the master cylinder hydraulic pressure Pm1.

  In the target hydraulic pressure calculation block PCT, the first and second target hydraulic pressures Pt1 and Pt2 are calculated based on the calculated value Bpe of the braking operation amount and the calculation characteristics (calculation map) CPct. Here, the first and second target hydraulic pressures Pt1 and Pt2 are target values of the braking hydraulic pressure generated by the first and second pressure regulating units CA1 and CA2. Specifically, in the calculation characteristic CPct, the first and second target hydraulic pressures Pt1 are within a range where the braking operation amount Bpe is greater than or equal to “0 (zero, corresponding when no braking operation is performed)” and less than a predetermined value bp0. , Pt2 is calculated to be “0 (zero)”. When the operation amount Bpe is equal to or greater than the predetermined value bp0, the target hydraulic pressures Pt1 and Pt2 are calculated so as to increase from “0” as the operation amount Bpe increases. Here, the value bp0 is a predetermined value that corresponds to “play” of the braking operation member BP, and is referred to as “play value”.

  In the command energization amount calculation block ISJ, the first and second target pressure regulating units CA1 and CA2 are driven based on the first and second target hydraulic pressures Pt1 and Pt2 and the calculation maps CIsa and CIsb. First and second command energization amounts Is1 and Is2 of the electric motors MT1 and MT2 are calculated. The first and second instruction energization amounts Is1 and Is2 are target values of energization amounts for controlling the first and second electric motors MT1 and MT2.

  The “energization amount” is a state amount (state variable) for controlling the output torque of the first and second electric motors MT1 and MT2. Since the electric motors MT1 and MT2 output torque that is substantially proportional to the current, the current target values of the electric motors MT1 and MT2 can be used as target values of the energization amounts. Further, if the supply voltage to the electric motors MT1 and MT2 is increased, the current is increased as a result, so that the supply voltage value can be used as the target state variable. Furthermore, since the supply voltage value can be adjusted by the duty ratio in the pulse width modulation, this duty ratio (ratio of energization time in one cycle) can be adopted as the control state variable.

  In the hydraulic pressure feedback control block PFB, the first and second target values Pt1 and Pt2 of the hydraulic pressure and the first and second actual values (detected values) Pc1 and Pc2 of the hydraulic pressure are first and second. First and second hydraulic pressure compensation energization amounts (also simply referred to as compensation energization amounts) If1 and If2 for the electric motors MT1 and MT2 are calculated. Here, the first and second hydraulic pressure actual values (actual control fluid pressures) Pc1 and Pc2 are detected by the first and second control cylinder fluid pressure sensors (also simply referred to as control fluid pressure sensors) PC1 and PC2. It is a detected value of hydraulic pressure.

  In the hydraulic pressure feedback control block PFB, first, deviations eP1 and eP2 between the first and second target hydraulic pressures Pt1 and Pt2 and the first and second actual control hydraulic pressures Pc1 and Pc2 are calculated. The first and second hydraulic pressure deviations eP1 and eP2 are differentiated and integrated, and these are multiplied by gains Kp (proportional gain), Kd (differential gain), and Ki (integral gain). Second compensation energization amounts If1 and If2 are calculated. In the hydraulic pressure feedback control block PFB, so-called so-called hydraulic pressure is used so that the target values Pt1 and Pt2 coincide with the actual values Pc1 and Pc2 (that is, the hydraulic pressure deviations eP1 and eP2 approach “0”). Feedback control (PID control) is executed.

  In the standby control block SBC, the first and second standby energization amounts for controlling the first and second electric motors MT1 and MT2 when the operation is changed from the state where the brake operation member BP is not operated to the state where the operation is performed. Ib1 and Ib2 are calculated. The processing of the standby control block SBC is started in a state where the braking operation amount Bpe is less than the play value bp0 (that is, the target hydraulic pressures Pt1 and Pt2 are “0” in the target hydraulic pressure calculation map CPct). Therefore, it is called “standby control”.

  The standby control is executed based on the first and second rotation angles Mk1, Mk2, the operation displacement (actual value) Sbp, and the brake switch signal Bsw. Before the start of the standby control, the fluid connection between the master cylinder MCL and the wheel cylinder WC is in an open state, and the fluid connection between the simulator SSM and the master cylinder MCL is cut off (the above-described first connection state AJT). By executing the standby control, the flow path of the brake fluid is switched by the pressure adjusting units CA1, CA2, the communication state between the master cylinder MCL and the wheel cylinder WC is canceled, the master cylinder MCL is communicated with the simulator SSM, and the wheel cylinder The WC is brought into communication with the first and second control cylinders SC1 and SC2 (the second connection state BJT described above). When the braking operation member BP is operated after the connection state is switched by the standby control, the hydraulic pressure in the wheel cylinder WC is changed by the first and second pressure adjustment units CA1 and CA2 according to the operation of the braking operation member BP. Adjusted.

  In the target energization amount calculation block IMT, based on the first and second instruction energization amounts Is1, Is2, the first and second compensation energization amounts If1, If2, and the first and second standby energization amounts Ib1, Ib2, The first and second target energization amounts It1 and It2 that are target values of the effective energization amount are calculated. Specifically, in the target energization amount calculation block IMT, the first and second compensation energization amounts If1 and If2 and the first and second standby energization amounts with respect to the first and second instruction energization amounts Is1 and Is2. Ib1 and Ib2 are added, and the sum thereof is calculated as the first and second target energization amounts It1 and It2. That is, the first and second target energization amounts It1 and It2 are determined as “It1 = Is1 + If1 + Ib1” and “It2 = Is2 + If2 + Ib2”.

  Here, when the standby energization amounts Ib1 and Ib2 are calculated to be larger than “0”, the braking operation is not performed. At this time, the command energization amounts Is1 and Is2 and the compensation energization amounts If1 and If2 are “0”. Therefore, in the target energization amount calculation block IMT, “Ib1, Ib2” is output as “It1, It2”, and “Is1 + If1, Is2 + If2” is output as “Ib1, Ib2”. Can be configured to be switched by. Specifically, when the braking operation has already been performed and “Ib1, Ib2” matches “0” (when standby control is unnecessary), “It1, It2” is set to “Is1 + If1, Is2 + If2”. Is output. On the other hand, when “Ib1, Ib2” is larger than “0” (immediately after the start of the braking operation and within the range of play of the braking operation member BP), “Ib1, Ib2” is set as “It1, It2”. Is output.

  In the target energization amount calculation block IMT, the direction in which the two electric motors MT1 and MT2 are to be rotated (that is, the increase / decrease direction of the hydraulic pressure) is determined by the sign (the sign of the value) of the target energization amounts It1 and It2. Further, the rotational power to be output from the electric motors MT1 and MT2 (that is, the increase / decrease amount of the hydraulic pressure) is determined by the magnitudes (absolute values) of the target energization amounts It1 and It2. Specifically, when increasing the brake hydraulic pressure, the signs of the target energization amounts It1, It2 are calculated as positive signs (It1, It2> 0), and the electric motors MT1, MT2 are driven in the forward rotation direction. . On the other hand, when the braking hydraulic pressure is decreased, the signs of the target energization amounts It1, It2 are determined to be negative signs (It1, It2 <0), and the electric motors MT1, MT2 are driven in the reverse direction. Further, the output torque (rotational power) of the electric motors MT1 and MT2 is controlled to increase as the absolute values of the target energization amounts It1 and It2 increase, and the output torque decreases as the absolute values of the target energization amounts It1 and It2 decrease. It is controlled to become.

  In the drive circuit DRV for the first and second electric motors MT1 and MT2, the rotational power (output) of the first and second electric motors MT1 and MT2 is based on the first and second target energization amounts It1 and It2. The direction of rotation is adjusted. Details of the drive circuit DRV will be described later.

<Standby control processing>
Processing in the standby control block SBC will be described with reference to the flowchart of FIG. The standby control is started in the range of “play” in the operation of the braking operation member BP. Here, “play” is provided in a mechanism for operating the device (that is, the braking operation member BP), and the range in which the operation does not affect the actual operation (that is, the hydraulic pressure in the wheel cylinder WC) (braking). It is a range in the stroke of the operation member BP). In the standby control, the first and second standby energization amounts Ib1 and Ib2 are calculated based on the first and second motor rotation angles Mk1 and Mk2. The first and second standby energization amounts Ib1 and Ib2 are target values for the energization amounts of the first and second electric motors MT1 and MT2.

  In the initial state of standby control (before the start of standby control), the fluid connection state is in the first connection state AJT. That is, the fluid connection between the master cylinder MCL and the wheel cylinder WC is released (communication), and the fluid connection between the master cylinder MCL and the simulator SSM is cut off (not communicated).

  In step S110, first, an operation displacement (detected value) Sbp and a brake switch signal Bsw are read. Next, in step S120, based on the operation displacement Sbp, it is determined whether or not the operation displacement Sbp is equal to or greater than a predetermined displacement sb0. Here, the predetermined displacement sb0 is set as a value smaller than the value corresponding to the play value bp0 in the operation displacement Sbp. If “Sbp ≧ sb0” and step S120 is affirmative (“YES”), the process proceeds to step S130. On the other hand, if “Sbp <sb0” and step S120 is negative (“NO”), the process returns to step S110.

  In step S130, based on the brake switch signal Bsw, it is determined whether or not the brake switch signal Bsw is on. If step S130 is positive (if “YES”), the process proceeds to step S140. On the other hand, when step S130 is negative (in the case of “NO”), the process returns to step S110. Here, the brake switch BSW is attached to the vehicle so as to be switched on and off within the range of play of the braking operation member BP.

  In step S140, time counting is started by a timer process. Here, the time point at which the determination in step S130 is satisfied for the first time (that is, the calculation cycle in which step S130 transitions from negative determination to positive determination) is set as the starting point of time (T = 0), and the elapsed time from this starting point T is determined.

  In step S150, the first and second rotation angles Mk1 and Mk2 are read. Next, in step S160, “whether or not the first and second rotation angles Mk1 and Mk2 are smaller than a predetermined angle mk0” is determined. Here, the predetermined angle mk0 is a value corresponding to the “standby position” of the control piston SPS, and is set in advance. The standby position of the control piston SPS is a position where the fluid connection between the control cylinders SC1 and SC2 and the wheel cylinder WC is surely opened, and is closest to the initial position (zero point). , CA2 is set in advance on the structure of CA2.

  If “Mk1, Mk2 ≧ mk0” and the determination in step S160 is negative (in the case of “NO”), since the control piston SPS has already reached the standby position, the process proceeds to step S110. Returned. That is, the case where the determination in step S160 is negative corresponds to the end of the standby control. At this time, the fluid connection state is in the second connection state BJT. That is, the fluid connection between the master cylinder MCL and the wheel cylinder WC is cut off (not communicated), and the fluid connection between the master cylinder MCL and the simulator SSM is opened (communication).

  If the determination in step S160 is affirmative (“YES”), the control piston SPS has not yet reached the standby position. Therefore, the process proceeds to step S170.

  In step S170, the first and second predicted standby energization amounts (target values) Ic1 and Ic2 are determined based on the elapsed time T by the timer process in step S140 and the preset calculation characteristic (calculation map) CIc. Calculated. The predicted standby energization amounts Ic1 and Ic2 are determined by the computation map CIc so as to increase from “0” and be held at a predetermined maximum value icm according to the elapsed time T from the starting point “T = 0”. Here, the first and second predicted standby energization amounts Ic1 and Ic2 correspond to feedforward components of the first and second standby energization amounts Ib1 and Ib2.

  In step S180, the first and second compensation standby energization amounts Id1 and Id2 are calculated based on the first and second rotation angle deviations eM1 and eM2 between the first and second rotation angles Mk1 and Mk2 and the predetermined angle mk0. Is done. Specifically, in step S180, the motor rotation angles Mk1, Mk2 and the predetermined angle mk0 are compared, and the first and second rotation angle deviations eM1, eM2 are determined.

  In the rotation angle compensation energization amount calculation block IDE in step S180, the deviations eM1 and eM2 are differentiated and integrated, respectively. The deviations eM1, eM2 themselves, differentiated ones, and integrated ones are multiplied by respective gains to calculate first and second compensation standby energization amounts Id1, Id2. In step S180, the predetermined angle mk0 is set as a target value, and feedback control (PID control) is executed. That is, the first and second compensation standby energization amounts Id1 and Id2 are determined so that the first and second rotation angles Mk1 and Mk2 coincide with the predetermined angle mk0. The first and second standby energization amounts Ib1 and Ib2 This corresponds to the feedback component.

  In step S190, the first and second compensated standby energization amounts Id1 and Id2 are added to the first and second predicted standby energization amounts Ic1 and Ic2, and the first and second standby energization amounts Ib1 and Ib2 are calculated. The Then, the first and second standby energization amounts Ib1 and Ib2 are output toward the target energization amount calculation block IMT. The process is returned to step S140, and the standby control is continued until the determination in step S160 is negative.

  In the prior art (for example, Patent Document 1), the opening or closing of the fluid connection in the hydraulic circuit is instantaneously switched by a plurality of solenoid valves VSM, VM1, and VM2. In the braking control device according to the present invention, the solenoid valve is eliminated, and the switching of the fluid connection is performed by the movement (forward or backward) of the control piston SPS. In order to switch the fluid connection, it is necessary for the control piston SPS to move a predetermined distance (at least the length of the pressure hole Aka plus two times the width of the tip seal SSL). It takes time. By the standby control, this movement (corresponding to the rotation angle mk0 of the electric motor) is started in a range corresponding to the play of the braking operation member BP. For this reason, the uncomfortable feeling to the driver due to the time required for displacement of the control piston SPS (opening or blocking switching time) can be suppressed.

  When the operation of the braking operation member BP is fast, the first and second target energization amounts It1, It2 are rapidly increased. That is, the play of the braking operation member BP at the operation displacement Sbp is instantaneously eliminated, and the tip seal SSL instantaneously passes through the pressure hole Aka, so that the driver feels uncomfortable and does not become a problem. Therefore, it is important that the switching of the fluid connection by the control piston SPS (that is, standby control) is started within the range of play of the braking operation member BP.

  A signal related to “displacement” (that is, the displacement Sbp of the braking operation member) is adopted as the physical quantity in the execution start determination so that the standby control is started within a range corresponding to the play of the braking operation member BP. The The play of the braking operation member BP is a so-called play of the device. For this reason, when the braking operation member BP is operated within the range of play, almost no reaction force is generated. Therefore, signals (detected values) relating to “force” such as the master cylinder hydraulic pressure Pm1 and the operation force Fbp of the brake operation member BP are not used for the start determination of the standby control.

  The brake switch BSW is attached so that the signal Bsw from the brake switch BSW shifts from off to on within a range corresponding to the play of the braking operation member BP. For this reason, the brake switch signal Bsw can be adopted as a signal related to “displacement”. Any one of step S120 (determination based on the operation displacement Sbp of the braking operation member) and step S130 (determination based on the brake switch signal Bsw) may be omitted. Therefore, the standby control start determination is performed based on at least one of the operation displacement (brake pedal stroke) Sbp and the brake switch signal Bsw.

<Switching of fluid connection state and standby control operation>
With reference to the operation diagram of FIG. 5, switching in the fluid connection state and operation in standby control will be described. FIG. 5A shows a case where the control piston SPS is in the initial position (also referred to as zero point), and FIG. 5B shows a case where the control piston SPS is in the standby position. Here, the initial position is a position where the control piston SPS is pressed against the stopper STP by the return spring SPR. Further, the standby position is a position closest to the initial position (zero point) after the pressure regulating chamber Rca is reliably in communication with the wheel cylinder WC. This standby position is set in advance as a predetermined rotation angle mk0 at the rotation angles of the electric motors MT1 and MT2.

  First, the case where the control piston SPS is at the initial position (zero point) will be described with reference to FIG. At the initial position, the tip seal SSL is positioned on the simulator hole Asm side with respect to the pressurizing hole Aka, and the master cylinder MCL is in communication with the wheel cylinder WC via the pressure regulating chamber Rca. In other words, the pressure regulating chamber Rca is brought into communication with the pressurizing chamber Rm1 through the pressurizing hole Aka. On the other hand, since the front end seal SSL is located between the pressurizing hole Aka and the simulator hole Asm, the communication chamber Rrn is sealed by the front end seal SSL and the rear end seal KSL.

  When the power supply (ALT or BAT) is malfunctioning, the electric motors MT1 and MT2 are not driven, and the control piston SPS remains at the initial position. The brake fluid discharged from the master cylinder MCL is not consumed by the simulator SSM because the flow path to the communication chamber Rrn is sealed by the tip seal SSL. For this reason, the brake fluid discharged from the master cylinder MCL is moved to the wheel cylinder WC through the pressure regulating chamber Rca in accordance with the operation of the brake operation member BP. As a result, even when the power supply is malfunctioning, the minimum necessary braking force can be ensured.

  Next, the case where the control piston SPS transitions from the initial position toward the standby position will be described with reference to FIG. When the control piston SPS is pressed by the pressing member PSH, it is moved in the forward direction (left direction in the figure). Here, the forward direction of the control piston SPS is the forward rotation direction of the electric motors MT1 and MT2, and corresponds to the direction in which the hydraulic pressure in the wheel cylinder WC is increased. As the control piston SPS advances, the volume of the pressure regulating chamber Rca is reduced, and the tip seal SSL passes through the pressure hole Aka, and the fluid connection between the pressure regulating chamber Rca and the master cylinder MCL is interrupted. The master cylinder MCL communicates with the simulator SSM via the pressurizing hole Aka, the communication chamber Rrn, the simulator hole Asm, and the simulator fluid path HSM. For the first time with the advance of the control piston SPS, the master cylinder MCL and the simulator SSM communicate with each other, and the position where the master cylinder MCL and the pressure regulating chamber Rca are completely disconnected is the standby position. This standby position is determined by the structure and dimensions of the pressure adjusting unit, and is stored in the controller ECU as a predetermined angle mk0.

  When the operation amount of the brake operation member BP is increased and the control piston SPS is further advanced, the brake fluid discharged from the master cylinder MCL is absorbed by the simulator SSM. The elastic body in the simulator SSM is compressed by the brake fluid flowing into the simulator SSM, the hydraulic pressure in the master cylinder MCL is increased, and the operation force of the brake operation member BP is increased. Further, as the control piston SPS advances, the volume of the pressure regulating chamber Rca decreases, so that the brake fluid is discharged from the pressure regulating chamber Rca toward the wheel cylinder WC. As a result, the braking torque of the wheel WH is increased.

  When the operation amount of the braking operation member BP is decreased, the pressing member PSH is moved in the backward direction. The control piston SPS is moved in the backward direction by the hydraulic pressure in the pressure regulating chamber Rca and the return spring SPR. Since the volume of the pressure regulating chamber Rca increases, the brake fluid flows from the wheel cylinder WC into the pressure regulating chamber Rca, and the braking torque of the wheel WH is reduced.

  As a connection destination of the pressure adjusting chamber Rca in the control cylinder SC1, which is in communication with the wheel cylinder WC through the pressure adjusting hole Aca by the movement (forward or backward) of the control piston SPS, the master cylinder MCL and the simulator SSM Is selected. For this reason, the functions (fluid connection switching function) of the electromagnetic valves VSM, VM1, and VM2 described in Patent Document 1 are achieved by the pressure adjusting units CA1 and CA2. That is, in the brake-by-wire configuration, these solenoid valves (the solenoid valve that opens and closes the fluid connection between the master cylinder MCL and the wheel cylinder WC, and the fluid connection between the master cylinder MCL and the simulator SSM are opened and closed). Electromagnetic valve) is omitted, the braking control device is simplified, and the power consumption is reduced.

<3-phase brushless motor and its drive circuit (example of 3-phase brushless motor)>
With reference to the circuit diagram of FIG. 6, a three-phase brushless motor having three coils (windings) of a U-phase coil CLU, a V-phase coil CLV, and a W-phase coil CLW is adopted as the electric motors MT1 and MT2. An example will be described. In a brushless motor, a magnet is disposed on the rotor (rotor) side, a winding circuit (coil) is disposed on the stator (stator) side, and commutation is performed by the drive circuit at a timing that matches the magnetic pole of the rotor. Driven by rotation.

  Since the first and second electric motors MT1 and MT2 have the same configuration, the first electric motor MT1 will be described. The first electric motor MT1 is provided with a first rotation angle sensor MK1 that detects a first rotation angle (rotor position) Mk1 of the electric motor MT1. A Hall element type sensor is employed as the first rotation angle sensor MK1. In addition, a variable reluctance resolver may be employed as the first rotation angle sensor MK1. The detected rotation angle Mk1 is input to the controller ECU.

  The drive circuit DRV is an electric circuit that drives the first electric motor MT1, and corresponds to a part of the controller ECU. The drive circuit DRV includes a switching control unit SWT, a three-phase bridge circuit (also simply referred to as a bridge circuit) BRG, and a stabilization circuit LPF. The bridge circuit BRG is formed by six switching elements (power transistors) SUX, SUZ, SVX, SVZ, SWX, SWZ (also referred to as “SUX to SWZ”). The bridge circuit BRG is driven based on the drive signals Sux, Suz, Svx, Svz, Swx, Swz (also referred to as “Sux to Swz”) of each phase from the switching control unit SWT in the drive circuit DRV, and the first electric The output of the motor MT1 is adjusted.

  In the switching control unit SWT, an instruction value (target value) for performing pulse width modulation for each switching element is calculated based on the first target energization amount It1. Based on the magnitude of the first target energization amount It1 and a preset characteristic (calculation map), the duty ratio of the pulse width (ratio of on-time to one cycle) is determined. At the same time, the rotation direction of the first electric motor MT1 is determined based on the sign (positive or negative) of the first target energization amount It1. For example, the rotation direction of the first electric motor MT1 is set such that the forward rotation direction is a positive (plus) value and the reverse rotation direction is a negative (minus) value. Since the final output voltage is determined by the input voltage (battery BAT voltage) and the first duty ratio Du1, the rotation direction and output torque of the first electric motor MT1 are determined.

  Further, in the switching control unit SWT, each switching element constituting the bridge circuit BRG is turned on (energized state) or is turned off (non-energized state) based on the first duty ratio (target value) Du1. The drive signals Sux to Swz are calculated. Energization or non-energization of the switching elements SUX to SWZ is controlled by these drive signals Sux to Swz. Specifically, the larger the first duty ratio Du1, the longer the energization time per unit time in the switching element, the larger current flows through the first electric motor MT1, and the greater the output (rotational power). Is done.

  The storage battery BAT is connected to the input side of the three-phase bridge circuit (also referred to as an inverter circuit) BRG via the stabilization circuit LPF, and the electric motor MT1 is connected to the output side of the bridge circuit BRG. In the bridge circuit BRG, three phases (U phase, V phase, W phase) are formed with a voltage-type bridge circuit having an upper and lower arm configuration in which switching elements are connected in series as one phase. The upper arms of the three phases are connected to a power line PWX connected to the anode side of the storage battery BAT. Further, the lower arms of the three phases are connected to a power line PWZ connected to the cathode side of the storage battery BAT. In the bridge circuit BRG, the upper and lower arms of each phase are connected to the power lines PWX and PWZ in parallel with the storage battery BAT.

  The six switching elements SUX to SWZ are elements that can turn on or off a part of the electric circuit. For example, MOS-FETs and IGBTs are employed as the switching elements SUX to SWZ. In the brushless motor MT1, the switching elements SUX to SWZ constituting the bridge circuit BRG are controlled based on the detected value Mk1 of the rotation angle (rotor position). And the direction (namely, excitation direction) of the energizing amount of the coils CLU, CLV, CLW of the three phases (U phase, V phase, W phase) is sequentially switched, and the first electric motor MT1 is rotationally driven. . That is, the rotation direction (forward rotation direction or reverse rotation direction) of the brushless motor MT1 is determined by the relationship between the rotor and the excitation position. Here, the forward rotation direction of the electric motor MT1 is a rotation direction corresponding to an increase in the hydraulic pressure Pc1 by the pressure adjustment unit CA1, and the reverse rotation direction of the electric motor MT1 is a rotation direction corresponding to a decrease in the hydraulic pressure Pc1. .

  An energization amount sensor IMA that detects an actual energization amount Ima (a generic name of each phase) between the bridge circuit BRG and the electric motor MT1 is provided in each of the three phases. For example, a current sensor is provided as the energization amount sensor IMA, and the current value is detected as the actual energization amount Ima. The detected energization amount Ima of each phase is input to the switching control unit SWT.

  In the switching control unit SWT, so-called current feedback control is executed. Based on the deviation eIm between the actual energization amount Ima and the first target energization amount It1, the first duty ratio Du1 is corrected (finely adjusted). By this current feedback control, the actual value Ima and the target value It1 are controlled to coincide with each other (that is, the energization amount deviation eIm approaches “0”), so that highly accurate motor control can be achieved.

  The drive circuit DRV is supplied with power from a power source (storage battery BAT, generator ALT). In order to reduce fluctuations in the supplied power (voltage), the drive circuit DRV is provided with a stabilization circuit LPF. The stabilization circuit LPF is configured by a combination of at least one capacitor (capacitor) and at least one inductor (coil), and is a so-called LC circuit.

  As the first electric motor MT1, a brush motor (simply referred to as a brush motor) may be employed instead of the brushless motor. In this case, an H bridge circuit formed by four switching elements (power transistors) is used as the bridge circuit BRG. In other words, in the brush motor bridge circuit BRG, one of the three phases of the brushless motor is omitted. As in the case of the brushless motor, the rotation angle sensor MK1 is provided in the first electric motor MT1, and the stabilization circuit LPF is provided in the drive circuit DRV. Furthermore, the drive circuit DRV is provided with an energization amount sensor IMA.

<Other examples of pressure adjustment unit>
Another example of the pressure adjustment units CA1 and CA2 will be described with reference to the partial cross-sectional view of FIG. In the example of the pressure adjusting units CA1 and CA2 described with reference to FIG. 2, the control piston side surface Mps is cylindrical, and the rear end seal KSL is fixed to the control piston SPS. However, the control piston side surface Mps is not limited to the cylindrical shape, and it is only required that the communication chamber Rrn that connects the pressurizing hole Aka and the simulator hole Asm is formed. Further, the rear end seal KSL is only required to seal the cylindrical surface Mce of the bottomed cylindrical hole Yte and the control piston SPS. Therefore, in another example of the pressure adjusting units CA1 and CA2, an example in which the control piston side face Mps is not cylindrical and the rear end seal KSL is fixed to the control cylinder SC1 side is shown.

  First, the side surface Mps of the control piston SPS that forms the communication chamber Rrn will be described. As shown in the BB cross section, a part of the side surface of the control piston SPS having a cylindrical shape may be scraped off to form a plane Mps (corresponding to the side surface of the control piston SPS). A seal groove is formed at the end of the control piston SPS having a cylindrical shape, and a tip seal SSL is fitted into the seal groove. The tip seal SSL is in sliding contact with the cylindrical surface Mce of the bottomed cylindrical hole Yte to form a communication chamber Rrn and a pressure regulating chamber Rca.

  The tip seal SSL reciprocates on the pressure hole Aka along the center axis Jsc, thereby switching the fluid connection described above. For this reason, it is an essential requirement of the braking control device according to the present invention that the tip seal SSL is fixed to the control piston SPS and moves together with the control piston SPS.

  On the other hand, the rear end seal KSL, which is a seal member different from the front end seal SSL, is a component necessary for forming the liquid-tight communication chamber Rrn. Therefore, the tip seal SSL can be fixed to the control cylinder SC1 in addition to being fixed to the control piston SPS. In this case, a seal groove is formed in the cylindrical surface Mce of the control cylinder SC1, and the rear end seal KSL is fitted therein. Therefore, the rear end seal KSL is expressed as a seal member that “slidably contacts any one of the cylindrical surface Mce of the control cylinder SC1 and the side surface Mps of the control piston SPS, unlike the front end seal SSL”.

<Action and effect>
Hereinafter, the configuration, operation, and effect of the braking control device according to the present invention will be summarized using the pressure adjustment unit CA1 as an example. A feature of the braking control device according to the present invention is that, in a so-called brake-by-wire configuration, a plurality of solenoid valves can be reduced, and in this configuration, a driver's uncomfortable feeling about braking operation is suppressed. It is.

  In a vehicle equipped with the braking control device according to the present invention, a master cylinder MCL mechanically connected to the braking operation member BP, a wheel cylinder WC that applies braking torque to the wheels, and a brake fluid is sucked from the master cylinder MCL, And a simulator SSM for applying an operating force to the braking operation member BP. Further, the vehicle is provided with a pressure adjusting unit (also referred to as a pressure adjusting unit) CA1 that adjusts the pressure of the brake fluid in the wheel cylinder WC by the electric motor MT1.

  The pressure adjustment unit CA1 discharges the brake fluid to the wheel cylinder WC, is inserted into the control cylinder SC1 having the bottomed cylindrical hole Yte, and the bottomed cylindrical hole Yte, and is centered in the center axis direction of the bottomed cylindrical hole Yte by the electric motor MT1. A control piston SPS that can move to Jsc, a tip seal SSL that moves integrally with the control piston SPS and that is in sliding contact with the cylindrical surface Mce of the control cylinder SC1, and a cylindrical surface Mce of the control cylinder SC1 are different from the tip seal SSL. And a rear end seal KSL that is in sliding contact with any one of the side surface Mps of the control piston SPS.

  In the pressure regulating unit CA1, the pressure regulating chamber Rca is partitioned by the cylindrical surface Mce of the control cylinder SC1, the bottom surface Mcb of the control cylinder SC1, the end surface Mpt of the control piston SPS, and the tip seal SSL, and fluidly connected to the wheel cylinder WC. And a communication chamber Rrn defined by a cylindrical surface Mce of the control cylinder SC1, a side surface Mps of the control piston SPS, a front end seal SSL, and a rear end seal KSL and fluidly connected to the simulator SSM.

  In the pressure adjusting unit CA1, at the initial position (ie, zero point) of the electric motor MT1, the fluid connection between the master cylinder MCL and the pressure adjusting chamber Rca is opened and the fluid connection between the master cylinder MCL and the communication chamber Rrn is interrupted. The When the electric motor MT1 rotates by a predetermined angle mk0 from the initial position, the fluid connection between the master cylinder MCL and the pressure regulating chamber Rca is cut off and the fluid connection between the master cylinder MCL and the communication chamber Rrn is released. The

  Specifically, the controller ECU that controls the electric motor MT1 based on the operation amount Bpe opens the fluid connection between the master cylinder MCL and the pressure regulating chamber Rca when the braking operation member BP is not operated. The fluid connection between the master cylinder MCL and the communication chamber Rrn is cut off. On the other hand, when the braking operation member BP is operated, the fluid connection between the master cylinder MCL and the pressure regulating chamber Rca is cut off and the fluid connection between the master cylinder MCL and the communication chamber Rrn is opened.

  With the above configuration, when the braking control device has a so-called brake-by-wire configuration, the solenoid valve that opens and closes the fluid connection between the master cylinder MCL and the wheel cylinder WC, and the master cylinder MCL and the simulator SSM. The solenoid valve that shuts off and opens the fluid connection to the can be eliminated. For this reason, the braking control device is simplified, and power saving can be achieved when the braking operation member BP is operated.

  On the other hand, instead of the solenoid valve, the first connection state AJT in which the master cylinder MCL and the wheel cylinder WC are fluidly connected according to the position of the control piston SPS, and the second connection state in which the master cylinder MCL and the simulator SSM are fluidly connected. In the configuration in which any one of the connection states BJT is selectively realized, it may be uncomfortable for the driver that the control piston SPS needs to move. For this reason, the braking control device is provided with a displacement sensor SBP that detects the operation displacement Sbp of the braking operation member BP, and a rotation angle sensor MK1 that detects the rotation angle Mk1 of the electric motor MT1. When the displacement Sbp exceeds a predetermined value sb0 set in advance, the electric motor MT1 is controlled based on the rotation angle Mk1 so that the position of the control piston SPS changes from the first connection state AJT to the second connection state BJT. It is configured as follows. This control is referred to as “standby control”.

  In the standby control, the predetermined value sb0 in the operation displacement Sbp can be set to a value smaller than the value bp0 corresponding to the play of the braking operation member BP. Since the standby control is started within the range corresponding to the play of the braking operation member BP, the driver's operation can be suppressed.

  Further, the brake control device is provided with a brake switch BSW that detects the start of operation of the brake operation member BP. When the signal Bsw from the brake switch BSW transits from OFF to ON, the controller ECU detects the control piston SPS. The electric motor MT1 may be configured to be controlled based on the motor rotation angle Mk1 so that the position transitions from the first connection state AJT to the second connection state BJT. The brake switch BSW is attached to the vehicle body so that the signal Bsw changes from OFF to ON within a range corresponding to the play of the braking operation member BP. For this reason, as in the case of the operation displacement Sbp, a sense of discomfort to the driver can be suppressed.

<Second Embodiment of Braking Control Device According to the Present Invention>
A second embodiment of the braking control device according to the present invention will be described with reference to the overall configuration diagram of FIG. In the first embodiment (see FIG. 1), the four wheel cylinders WCfr, WCfl, WCrr, and WCrl are pressurized by the two pressure adjusting units CA1 and CA2, but in the second embodiment, two The front wheel cylinders WCfr and WCfl are separately pressurized by the pressure adjusting units CA1 and CA2, and braking torque is applied. In addition, braking torque is applied to the rear wheels WHrr and WHrl by electric braking means (electric actuators) DSrr and DSrl that do not use fluid. Therefore, for the rear wheels WHrr and WHrl, there is no wheel cylinder WCrr and WCrl, and there is no fluid piping from the master cylinder MCL to the rear wheel wheel cylinders WCrr and WCrl. That is, the fluid path (braking pipe) and the wheel cylinder corresponding to the rear wheel are omitted.

  In each drawing and the description using it, like the above, members (components) having the same symbols, such as MCL, exhibit the same function. In addition, as described above, the subscript attached to the end of the symbol of each component indicates which wheel of the four wheels corresponds to. The subscripts are related to “fr” as “right front wheel”, “fl” as “left front wheel”, “rr” as “right rear wheel”, and “rl” as “left rear wheel”, Each expresses. The symbol end numeral “1” corresponds to the first system connected to the right front wheel wheel cylinder WCfr, and the symbol end numeral “2” corresponds to the second system connected to the left front wheel wheel cylinder WCfl. Since the components denoted by the same reference numerals are the same as those in the first embodiment, different portions will be mainly described.

  The first pressurizing chamber Rm1 of the master cylinder MCL and the right front wheel wheel cylinder WCfr are connected by the first fluid path H1. A first pressure regulating unit CA1 driven by a first electric motor MT1 is connected to the first fluid path H1 between the master cylinder MCL and the right front wheel wheel cylinder WCfr. Furthermore, the master cylinder MCL is connected to the simulator SSM via the pressure adjustment unit CA1 (particularly the control cylinder SC1).

  Further, the second pressurizing chamber Rm2 of the master cylinder MCL and the left front wheel wheel cylinder WCfl are connected by the second fluid path H2. A second pressure regulating unit CA2 driven by the second electric motor MT2 is connected to the second fluid path H2 between the master cylinder MCL and the left front wheel wheel cylinder WCfl.

≪Electric braking actuator for rear wheel≫
Next, the electric braking means (electric actuator) provided on the rear wheel will be described by taking the electric braking means DSrr for the right rear wheel as an example. The electric braking means DSrr is driven by the electric motor MTW (that is, the braking torque of the rear wheels is adjusted). Here, in order to distinguish from the first and second electric motors MT1 and MT2 for driving the first and second pressure regulating units CA1 and CA2 provided on the vehicle body side, the electric motor MTW is “wheel-side electric motor”. It is called.

  The vehicle includes a braking operation member BP, an electronic control unit ECU, and an electric braking means (brake actuator) DSrr. The electronic control unit ECU and the electric braking means DSrr are connected by a signal line (for example, a serial communication bus) SGL and a power line (power line) PWL, and a drive signal of the electric motor MTW for the electric braking means DSrr, and Power is supplied.

  Specifically, the electronic control unit (controller) ECU calculates a target value (target pressing force) for driving the electric motor MTW. The target pressing force is a target value of the pressing force that is a force with which the friction member (brake pad) MSB presses the rotating member (brake disc) KTrr in the right rear wheel WHrr. The target pressing force is transmitted to the electric actuator DSrr fixed to the wheel side via the signal line SGL.

  The electric braking means DSrr for the right rear wheel WHrr includes a caliper CPrr, a pressing piston PSW, a wheel side electric motor MTW, a rotation angle sensor MKW, an input member SFI, a reduction gear GSW, an output member SFO, a screw mechanism NJW, a pressing force sensor FBA, And it is comprised by the drive circuit DRW.

  Similar to the front wheel hydraulic system, the caliper CPrr is configured to sandwich the rotating member (brake disc) KTrr via the two friction members (brake pads) MSB. Within the caliper CPrr, the pressing piston (brake piston) PSW is linearly moved and moved forward or backward toward the rotating member KTrr. The pressing piston PSW presses the friction member MSB against the rotating member KTrr to generate a frictional force. Since the rotating member KTrr is fixed to the rear wheel WHrr, the braking force of the right rear wheel WHrr is adjusted by this frictional force.

  The wheel-side electric motor MTW generates power for pressing the friction member MSB against the rotating member KTrr. Specifically, the output (rotational power around the motor shaft) of the electric motor MTW is transmitted to the output member SFO via the input member SFI and the speed reducer GSW. The rotational power (torque) of the output member SFO is converted into linear power (thrust in the direction of the central axis of the piston PSW) by a motion converting member (for example, a screw mechanism) NJW and transmitted to the pressing piston PSW.

  A rotation angle sensor MKW for the wheel side electric motor MTW is provided. In addition, a pressing force sensor FBA is provided to detect a force (pressing force) by which the pressing piston PSW presses the friction member MSB. Then, the pressing force feedback control is executed based on the target value and the actual value (detected value) of the pressing force. This pressing force feedback control corresponds to the hydraulic pressure feedback control in the first embodiment.

  The drive circuit DRW drives the wheel side electric motor MTW based on the target pressing force (signal). Specifically, the drive circuit DRW is provided with a bridge circuit composed of switching elements that drive the wheel-side electric motor MTW. The rotation direction and output torque of the electric motor MTW are controlled by the drive signal for each switching element calculated based on the target value of the pressing force.

  The electric braking device DSrr for the right rear wheel WHrr has been described above. Since the electric braking device DSrl for the left rear wheel WHrl is the same as the electric braking device DSrr, the description thereof will be omitted. However, by replacing the subscript “rr” of various symbols with the subscript “rl”, the electric braking device DSrl Can be explained.

  Also in the second embodiment, the same effects as described in the first embodiment can be obtained. That is, since the fluid connection of the master cylinder MCL, the simulator SSM, and the wheel cylinder WC is switched by the movement of the control piston SPS, a plurality of electromagnetic valves are reduced, and power saving is achieved. Further, the uncomfortable feeling to the driver due to the reduction of the solenoid valves can be eliminated by the standby control.

  In the first embodiment, the first and second hydraulic units HU1 and HU2 are provided so that the braking torque can be adjusted independently for each wheel by wheel slip control such as anti-skid control and traction control. However, in the second embodiment, the hydraulic pressure of the wheel cylinder WCfr can be adjusted independently by the first pressure regulating unit CA1, and the hydraulic pressure of the wheel cylinder WCfl can be independently adjusted by the second pressure regulating unit CA2. For this reason, in the second embodiment, the first and second hydraulic units HU1 and HU2 are omitted.

BP: braking operation member, CA1, CA2: first and second pressure regulating units (first and second pressure adjusting units), MT1, MT2: first and second electric motors, SC1, SC2: first, second Control cylinder, SPS ... control piston, MK1, MK2 ... first and second rotation angle sensors, ECU ... controller.

Claims (3)

A master cylinder mechanically connected to a braking operation member of the vehicle;
A simulator that draws in brake fluid from the master cylinder and applies an operating force to the braking operation member;
A wheel cylinder for applying braking torque to the wheels of the vehicle;
A pressure adjusting unit that discharges the brake fluid to the wheel cylinder by an electric motor;
A controller for controlling the electric motor;
A vehicle braking control device comprising:
A displacement sensor for detecting an operation displacement of the braking operation member;
A rotation angle sensor for detecting a rotation angle of the electric motor;
With
The pressure regulating unit is
The master cylinder, the simulator, and a control cylinder connected to the wheel cylinder by a fluid path, and a control piston moved relative to the control cylinder by the electric motor,
Depending on the position of the control piston, “the first connection state in which the fluid connection between the master cylinder and the wheel cylinder is released and the fluid connection between the master cylinder and the simulator is interrupted”, and “the master A fluid connection between the cylinder and the wheel cylinder is cut off, and a fluid connection between the master cylinder and the simulator is selectively realized.
The controller is
When the operation displacement exceeds a predetermined value set in advance,
In order for the position of the control piston to transition from the first connection state to the second connection state,
A vehicle braking control device that controls the electric motor based on the rotation angle. The vehicle braking control device according to claim 1,
The braking control device for a vehicle, wherein the predetermined value is set to a value smaller than a value corresponding to play of the braking operation member. A master cylinder mechanically connected to a braking operation member of the vehicle;
A simulator that draws in brake fluid from the master cylinder and applies an operating force to the braking operation member;
A wheel cylinder for applying braking torque to the wheels of the vehicle;
A pressure adjusting unit that discharges the brake fluid to the wheel cylinder by an electric motor;
A controller for controlling the electric motor;
A vehicle braking control device comprising:
A brake switch for detecting the operation start of the braking operation member;
A rotation angle sensor for detecting a rotation angle of the electric motor;
With
The pressure regulating unit is
The master cylinder, the simulator, and a control cylinder connected to the wheel cylinder by a fluid path, and a control piston moved relative to the control cylinder by the electric motor,
Depending on the position of the control piston, “the first connection state in which the fluid connection between the master cylinder and the wheel cylinder is released and the fluid connection between the master cylinder and the simulator is interrupted”, and “the master A fluid connection between the cylinder and the wheel cylinder is cut off, and a fluid connection between the master cylinder and the simulator is selectively realized.
The controller is
When the signal from the brake switch transitions from off to on,
In order for the position of the control piston to transition from the first connection state to the second connection state,
A vehicle braking control device that controls the electric motor based on the rotation angle.