JP2017074890A - Braking control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking control device of a vehicle, which when the device fails, can accurately notify a driver of the failure of the device without giving a sense of incongruity to a driver.SOLUTION: A braking control device of a vehicle comprises: a simulator SSM which absorbs braking liquid that a master cylinder MCL discharges and imparts operation force to a braking operation member BP; opening/closing means VSM which is interposed between the master cylinder MCL and the simulator SSM; a first pressure-adjusting mechanism CA1 that adjusts liquid pressure of a first wheel cylinder WC1; a second pressure-adjusting mechanism CA2 that adjusts liquid pressure of a second wheel cylinder WC2; determining means HNT that determines whether operations of the first and second pressure-adjusting mechanisms are in a proper state or in an improper state; and control means SOL that controls the opening/closing means VSM. The control means SOL, when the determining means HNT determines that the operations of the first and second pressure-adjusting mechanisms CA1 and CA2 are in the improper state, puts the opening/closing means VSM into a shut-off state.SELECTED DRAWING: Figure 6

Description

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

  Patent Document 1 states that “the solenoid 36L of the fail-safe electromagnetic switching valve 27L is excited in response to the start of the engine mounted on the vehicle. Normally, the solenoid 36L is in an excited state and is used for the left front wheel. The output fluid pressure of the electric fluid pressure output means AFL can be transmitted to the disc brake BFL for the front left wheel, and the output pressure of the master cylinder M is absorbed by the accumulator AC. The valve 27L can transmit the output fluid pressure of the master cylinder M to the left front wheel disc brake BFL, so that the solenoid 36L of the fail-safe electromagnetic switching valve 27L can be turned off when the left front wheel electric fluid pressure output means AFL fails. By demagnetizing, the output pressure of the master cylinder M acts on the disc brake BFL for the left front wheel. Similarly, when the electric fluid pressure output means AFR for the right front wheel fails, the output of the master cylinder M can be output by demagnetizing the solenoid 36R of the fail-safe electromagnetic switching valve 27R. The pressure is applied to the right front wheel disc brake BFR to ensure the braking force ".

  In the apparatus described in Patent Document 1, it is assumed that both the solenoids 36L and 36R are demagnetized, such as when the power supply fails. In this case, the master cylinder is connected to a wheel cylinder and an accumulator (also referred to as a stroke simulator). For this reason, the amount of liquid from the master cylinder is also consumed by the accumulator, and there may be a concern that the operation displacement (stroke) of the brake pedal becomes inappropriately long.

  Furthermore, in the apparatus described in Patent Document 1, three types of operation characteristics (relationship between operation force and operation displacement) can occur depending on the state of failure of the electric fluid pressure output means. That is, when two electric fluid pressure output means are normal, when one electric fluid pressure output means is malfunctioning and one electric fluid pressure output means is normal, and when two electric fluid pressure output means are normal There are three cases where the pressure output means is malfunctioning. The operating status of the braking control device should be notified to the driver not only by display, but also by operating characteristics. At this time, if there are a plurality of malfunction characteristics of the device operation, the driver may be confused. In addition, when the normal characteristic and the malfunction characteristic are similar, there may be a case where sufficient notification is not given to the driver via the operation characteristic.

Japanese Patent Laid-Open No. 04-362454

  An object of the present invention is to provide an apparatus capable of accurately notifying a driver of a failure state of a vehicle without giving a sense of discomfort to a driver when a vehicle braking control device fails.

  The vehicle braking control apparatus according to the present invention applies a braking torque to one side of a master cylinder (MCL) driven by a vehicle braking operation member (BP) and left and right front wheels (WHfl, WHfr) of the vehicle. The first wheel cylinder (WC1), the second wheel cylinder (WC2) for applying a braking torque to the other of the left and right front wheels (WHfl, WHfr), and the brake fluid discharged from the master cylinder (MCL). A stroke simulator (SSM) that absorbs and applies an operating force to the braking operation member (BP); a first fluid path (H1) that connects the master cylinder (MCL) and the first wheel cylinder (WC1); In the middle of the first fluid path (H1), the brake fluid is communicated between the master cylinder and the first wheel cylinder (WC1). A first opening / closing means (VM1) that selectively realizes the shut-off state, a second fluid path (H2) that connects the master cylinder (MCL) and the second wheel cylinder (WC2), and the second Second opening / closing means that is interposed in the middle of the fluid path (H2) and selectively realizes a brake fluid communicating state and a blocking state between the master cylinder (MCL) and the second wheel cylinder (WC2). (VM2), a third fluid path (H3) connecting the master cylinder (MCL) and the stroke simulator (SSM), and a middle part of the third fluid path (H3), the master cylinder ( MCL) and the stroke simulator (SSM), the third opening / closing means (VSM) for selectively realizing the communication state and the cutoff state of the brake fluid, and the operation amount (Bpa) of the brake operation member (BP) Is connected to the first fluid path (H1) between the first opening / closing means (VM1) and the first wheel cylinder (WC1), and the operation amount (Bpa) ) Based on the first pressure regulating mechanism (CA1) for adjusting the pressure of the brake fluid in the first wheel cylinder (WC1), the second opening / closing means (VM2) and the second wheel cylinder (WC2). A second pressure regulating mechanism (CA2) that is connected to the second fluid path (H2) and adjusts the pressure of the brake fluid in the second wheel cylinder (WC2) based on the operation amount (Bpa), The control means (SOL) for controlling the first, second and third opening / closing means (VM1, VM2, VSM) and the first and second pressure regulating mechanisms (CA1, CA2) are in an appropriate state or inappropriate. Determination means (HNT) for determining whether the state; Is provided.

  The vehicle braking control apparatus according to the present invention is characterized in that the control means (SOL) and the determination means (HNT) are in proper operation of the first and second pressure regulating mechanisms (CA1, CA2). In the determination, the first and second opening / closing means (VM1, VM2) are turned off and the third opening / closing means (VSM) are brought into communication, and the determining means (HNT) is connected to the first pressure regulating means. When it is determined that the operation of the mechanism (CA1) is inappropriate and the operation of the second pressure regulating mechanism (CA2) is appropriate, the first and third opening / closing means (VM1, VSM) are When the second opening / closing means (VM2) is shut off and the determination means (HNT) determines that the operation of the first and second pressure regulating mechanisms (CA1, CA2) is in an inappropriate state The first and second opening / closing means (VM1, VM, The M2) is to be configured to a cutoff state the third switching means (VSM) as well as in communication with.

  According to the above configuration, when the determination unit HNT is in an inappropriate state of operation of the first and second pressure regulating mechanisms CA1 and CA2, the simulator SSM causes the master cylinder MCL to turn off the third opening / closing unit VSM. The brake fluid is not consumed. For this reason, when two braking systems fail, it can be suppressed that the operation displacement Sbp with respect to the operation force Fbp of the brake operation member BP becomes excessive.

  In the vehicle braking control apparatus according to the present invention, the stroke simulator (SSM) is constituted by a plurality of elastic members (SPA, SPB, STA, STB), and the first and second opening / closing means (VM1, VM2) are shut off. Simulator characteristic (CHsm) which is the relationship between the operating force (Fbp) and the operating displacement (Sbp) of the braking operation member (BP) when the third opening / closing means (VSM) is in the communication state However, the operating force (Fbp) of the braking operation member (BP) when the first opening / closing means (VM1) is brought into a communication state and the second and third opening / closing means (VM2, VSM) are put into a cutoff state. ) And the operation displacement (Sbp) and the first system characteristic (CHa) and the first and second opening / closing means (VM1, VM2) are brought into communication and the third Between the two-system failure characteristic (CHb) that is the relationship between the operation force (Fbp) and the operation displacement (Sbp) of the braking operation member (BP) when the closing means (VSM) is in the shut-off state. The rigidity of the plurality of elastic members (SPA, SPB, STA, STB) is set so as to be within the appropriate region (ARa).

  According to the above configuration, the failure state (one system failure) when any one of the first and second pressure regulating mechanisms CA1 and CA2 malfunctions without the operation feeling being reduced. The driver can be appropriately notified of the change in characteristics.

  Furthermore, in the vehicle braking control apparatus according to the present invention, the simulator characteristic (CHsm) includes an intermediate characteristic (CHc) that divides the appropriate area (ARa) into two equal parts in the operation displacement (Sbp), and the one-system characteristic. The rigidity of the plurality of elastic members (SPA, SPB, STA, STB) is set so as to fit in a region sandwiched between (CHa).

  According to the above configuration, since the one-system failure characteristic CHf and the two-system failure characteristic CHb are approximate characteristics, the failure states of the first and second pressure regulating mechanisms CA1 and CA2 are reduced without causing confusion for the driver. The driver can be appropriately notified.

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 explaining a pressure regulation mechanism. It is sectional drawing for demonstrating a stroke simulator. It is a functional block diagram for demonstrating the arithmetic processing in an electronic control unit. It is a circuit diagram for demonstrating the drive means for electric motors. It is a flowchart for demonstrating a solenoid valve control block. It is a characteristic view which shows the relationship between the operation force of a braking operation member, and operation displacement. It is a whole block diagram which shows 2nd Embodiment of the braking control apparatus of the vehicle which concerns on this invention. It is the schematic for demonstrating the electric braking means for rear wheels.

  An embodiment of a vehicle braking control device according to the present invention will be described with reference to the drawings. In the following description, suffixes (such as “fl”) added to the end of various symbols indicate which wheel the various symbols relate to. Specifically, “fl” indicates a left front wheel, “fr” indicates a right front wheel, “rl” indicates a left rear wheel, and “rr” indicates a right rear wheel. For example, each wheel cylinder is represented as a left front wheel wheel cylinder WCfl, a right front wheel wheel cylinder WCfr, a left rear wheel wheel cylinder WCrl, and a right rear wheel wheel cylinder WCrr.

  Also, the numbers (“1” or “2”) attached to the end of the various symbols are the two of the left front wheel wheel cylinder WCfl and the right front wheel wheel cylinder WCfr in the two fluid paths (hydraulic pressure system). It indicates which one is connected. Specifically, the system connected to the left front wheel wheel cylinder WCfl (referred to as the first system) is expressed using “1”, and the system connected to the right front wheel wheel cylinder WCfr (referred to as the second system) is expressed using “2”. To do. For example, the first pressure adjusting mechanism CA1 adjusts the hydraulic pressure of the left front wheel wheel cylinder WCfl (for example, equivalent to the first wheel cylinder WC1), and the second pressure adjusting mechanism CA2 is the right front wheel wheel cylinder WCfr (for example, The hydraulic pressure of the second wheel cylinder WC2) is adjusted. 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>
As shown in the overall configuration diagram of FIG. 1, a vehicle including a braking control apparatus according to the present invention includes a braking operation member BP, an operation amount acquisition unit BPA, an electronic control unit ECU, a tandem master cylinder MCL, a stroke simulator SSM, an electromagnetic Valves VM1, VM2, VSM, and first and second pressure regulating mechanisms CA1, CA2 are provided. Further, each wheel WHfl, WCfr, WHrl, WHrr of the vehicle includes a brake caliper CPfl, CPfr, CPrl, CPrr, a wheel cylinder WCfl, WCfr, WCrl, WCrr, and a rotating member (for example, brake disc) KTfl, KTfr. , KTrl, and KTrr.

  The braking operation member (for example, brake pedal) BP is a member that the driver operates to decelerate the vehicle. By operating the braking operation member BP, the braking torque of the wheel (WHfl etc.) is adjusted, and a braking force is generated on the wheel. Specifically, a rotating member (for example, a brake disc) is fixed to the vehicle wheel. A brake caliper (CPfl, etc.) is arranged so as to sandwich the rotating member (KTfl, etc.). The brake caliper is provided with a wheel cylinder (WCfl or the like). By increasing the pressure (hydraulic pressure) of the brake fluid in the wheel cylinder, the friction member (for example, a brake pad) is pressed against the rotating member. A braking torque is generated on the wheel by the frictional force generated at this time.

  The braking operation member (brake pedal) BP is provided with an operation amount acquisition means BPA. The operation amount acquisition means BPA acquires (detects) an operation amount (braking operation amount) Bpa of the braking operation member BP by the driver. Specifically, as the operation amount acquisition means BPA, the first and second master cylinder hydraulic pressure acquisition means (pressure sensors) PM1, PM2 for acquiring the pressure of the tandem master cylinder MCL, and the operation displacement Sbp of the brake operation member BP are acquired. At least one of the operation displacement acquisition means (stroke sensor) SBP that performs the operation force acquisition means (stepping force sensor) FBP (not shown) that acquires the operation force Fbp of the braking operation member BP may be employed. In other words, the operation amount acquisition means BPA is a general term for the master cylinder hydraulic pressure acquisition means, the operation displacement acquisition means, and the operation force acquisition means. The brake operation amount Bpa is determined based on at least one of the first and second master cylinder hydraulic pressures Pm1 and Pm2, the operation displacement Sbp of the brake operation member, and the operation force Fbp of the brake operation member. Any one of the first and second master cylinder hydraulic pressure acquisition means PM1, PM2 may be omitted.

  The braking operation amount Bpa (Pm1, Sbp, etc.) is input to the electronic control unit ECU. Electric power is supplied to the electronic control unit ECU by a storage battery (battery) BAT and a generator (alternator) ALT. The electronic control unit ECU controls the first and second pressure regulating mechanisms CA1, CA2 and the electromagnetic valves VM1, VM2, VSM based on the braking operation amount Bpa. Specifically, a control algorithm for controlling the electric motors MT1 and MT2 and the electromagnetic valves VM1, VM2, and VSM is programmed in the electronic control unit ECU.

  The electronic control unit ECU receives the first and second control cylinder hydraulic pressures Pc1 and Pc2 acquired by the first and second control cylinder hydraulic pressure acquisition units PC1 and PC2. The electronic control unit ECU outputs drive signals It1, It2 of the first and second electric motors MT1, MT2 and command signals Vm1, Vm2, Vsm of the electromagnetic valves VM1, VM2, VSM.

  A dandem master cylinder (also simply referred to as a master cylinder) MCL converts an operation force (brake pedal depression force) of the brake operation member BP into a hydraulic pressure, and pumps the brake fluid to the wheel cylinder of each wheel. Specifically, first and second master cylinder chambers Rm1 and Rm2 defined by two master pistons MP1 and MP2 are formed in the master cylinder MCL, and are connected to the wheel cylinders of each wheel by fluid paths (piping). Has been. When the brake operation member BP is operated and the volumes of the master cylinder chambers Rm1 and Rm2 are reduced, the brake fluid is moved from the master cylinder toward the wheel cylinder, and the hydraulic pressure in the wheel cylinder is increased. Conversely, when the volumes of the master cylinder chambers Rm1 and Rm2 are increased, the brake fluid is moved from the wheel cylinder toward the master cylinder, and the hydraulic pressure in the wheel cylinder is reduced. When the braking operation member BP is not operated, the master cylinder chambers Rm1 and Rm2 are in communication with the master reservoir RSV, and the hydraulic pressure in the master cylinder is atmospheric pressure.

<Two fluid paths (diagonal piping)>
The path (fluid path) through which the brake fluid (brake fluid) is moved between the tandem master cylinder MCL and the four wheel cylinders WCfl, WCfr, WCrl, WCrr is composed of two systems. In one system (first fluid path H1), the first hydraulic chamber Rm1 of the master cylinder MCL, the wheel cylinder WCfl (corresponding to the first wheel cylinder WC1), and WCrr are connected. In the other system (second fluid path H2), the second hydraulic chamber Rm2 of the master cylinder MCL, the wheel cylinder WCfr (corresponding to the second wheel cylinder WC2), and WCrl are 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 master cylinder shut-off valve VM1 (corresponding to first opening / closing means) is provided in a fluid passage H1 connecting the first hydraulic chamber (first master cylinder chamber) Rm1 of the master cylinder MCL and the wheel cylinders WCfl, WCrr ( Intervened). The first master cylinder cutoff valve VM1 is a two-position electromagnetic valve having an open position and a closed position. When the first master cylinder shutoff valve VM1 is in the open position, the first master cylinder chamber Rm1 and the left front wheel wheel cylinder WCfl are in communication with each other, and when VM1 is in the closed position, Rm1 and WCfl are shut off. State (non-communication state). As the first master cylinder cutoff valve VM1, a normally open solenoid valve (NO valve) may be employed.

  A first hydraulic unit HU1 is interposed in a fluid passage HW1 (part of H1) that connects the first master cylinder cutoff valve VM1 and the wheel cylinders WCfl, WCrr. Here, the first fluid path (first brake pipe) includes a fluid path (pipe) HM1 and a fluid path (pipe) HW1. The first hydraulic pressure unit HU1 includes a pressure increasing valve and a pressure reducing valve, and individually controls the hydraulic pressures of the wheel cylinders WCfl and WCrr in the execution of anti-skid control, vehicle stabilization control, and the like.

  In the fluid path HW1, the first pressure regulating mechanism CA1 and the first control cylinder hydraulic pressure acquisition means PC1 are provided between the first master cylinder cutoff valve VM1 and the first hydraulic pressure unit HU1. The first pressure regulating mechanism CA1 is composed of a first control cylinder SC1 and a first electric motor MT1. When the first master cylinder cutoff valve VM1 is in the closed position, the hydraulic pressures of the wheel cylinders WCfl and WCrr are adjusted (increased or decreased). The hydraulic pressure (control cylinder hydraulic pressure) Pc1 adjusted by the first pressure regulating mechanism CA1 is acquired (detected) by the first control cylinder hydraulic pressure acquisition means PC1. In other words, the pressure at the outlet of the first pressure regulating mechanism CA1 (SC1) is acquired by the first control cylinder hydraulic pressure acquisition means PC1.

  A first master cylinder hydraulic pressure acquisition means PM1 is provided in a fluid passage HM1 (a part of H1) that connects the first master cylinder chamber Rm1 and the first master cylinder cutoff valve VM1. The master cylinder hydraulic pressure Pm1 generated by the master cylinder MCL is acquired (detected) by the first master cylinder hydraulic pressure acquisition means PM1.

  A stroke simulator (also simply referred to as a simulator) SSM is provided to generate an operating force on the braking operation member BP. A stroke simulator shut-off valve VSM (corresponding to the third opening / closing means) is provided in the fluid passage HSM (corresponding to the third fluid passage H3) connecting the first hydraulic chamber Rm1 of the master cylinder MCL and the stroke simulator SSM (interposition). ) A stroke simulator cutoff valve (also simply referred to as a simulator cutoff valve) VSM is a two-position electromagnetic valve having an open position and a closed position. When the simulator cutoff valve VSM is in the open position, the first master cylinder chamber Rm1 and the simulator SSM are in communication with each other, and when the VSM is in the closed position, Rm1 and SSM are in a cutoff state (non-communication state). It becomes. As the simulator cutoff valve VSM, a normally closed electromagnetic valve (NC valve) can be adopted.

  Inside the simulator SSM, a piston and an elastic body (for example, a compression spring) are provided. The braking fluid is moved from the master cylinder MCL (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. An operating force (for example, a brake pedal depression force) when the braking operation member BP is operated is formed by the elastic body.

  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 is Rm2, WHfl (WC1) is WCfr (WC2), WCrr is WCrl, HM1 is HM2, HW1 is HW2, HU1 is HU2, and VM1 (corresponding to the first opening / closing means) is VM2 ( (Corresponding to the second opening / closing means), CA1 corresponds to CA2, PM1 corresponds to PM2, and PC1 corresponds to PC2. That is, in the description of the components related to the first fluid path H1, the configuration in which “first” is replaced with “second” and “1” at the end of the symbol is replaced with “2” is related to the second fluid path H2. Corresponds to the element description. Here, although the stroke simulator is omitted in the components related to the second fluid path H2, an individual stroke simulator can also be installed in the second fluid path H2.

<Pressure control mechanism>
Details of the pressure adjusting mechanism will be described with reference to the partial cross-sectional view of FIG. The first pressure regulating mechanism CA1 (particularly corresponding to the left front wheel WHfl) and the second pressure regulating mechanism CA2 (particularly corresponding to the right front wheel WHfr) have the same configuration, and therefore the first pressure regulating mechanism CA1. Will be described. For the description of the second pressure regulating mechanism CA2, “first” is “second”, subscript “1” is subscript “2”, subscript “fl” is subscript “fr”, and subscript “rr” is subscript “rr”. rl "can be explained.

  The first pressure regulating mechanism CA1 is provided on the opposite side to the master cylinder MCL (that is, the wheel cylinder WCfl side) with respect to the first master cylinder shut-off valve (electromagnetic valve) VM1 in the first fluid path H1. Therefore, when the electromagnetic valve VM1 is in the closed position (cut-off state), the hydraulic pressure of the wheel cylinder WCfl and the like is adjusted by taking in and out the brake fluid from the first pressure regulating mechanism CA1.

  The first pressure adjusting mechanism CA1 includes a first electric motor MT1, a reduction gear GSK, a rotation / linear motion conversion mechanism (screw member) NJB, 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 regulating mechanism CA1 to adjust the pressure of the brake fluid in the wheel cylinder (pressurization, decompression, etc.). The first electric motor MT1 is driven by the electronic control unit ECU. A brushless DC motor may be employed as the first electric motor MT1.

  The reduction gear GSK is composed of a small diameter gear SKH and a large diameter gear DKH. Here, the number of teeth of the large diameter gear DKH is larger than the number of teeth of the small diameter gear SKH. Therefore, the rotational power of the electric motor MT1 is decelerated by the reduction gear GSK and transmitted to the screw member NJB. Specifically, the small diameter gear SKH is fixed to the output shaft Jmt of the electric motor MT1. The large-diameter gear DKH and the bolt member BLT are fixed so that the large-diameter gear DKH is engaged with the small-diameter gear SKH, and the rotation axis Jsc of the large-diameter gear DKH is aligned with the rotation axis of the bolt member BLT of the screw member NJB. The That is, 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 member NJB.

  In the screw member NJB, the rotational power of the reduction gear 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 member NJB 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 nut member NUT (that is, the pressing member PSH) screwed with the bolt member BLT moves in the direction of the rotation axis of the large-diameter gear DKH by the rotation of DKH. Is done. That is, the rotational power of the first electric motor MT1 is converted into the linear power Fs of the pressing member PSH by the screw member NJB.

  The first control piston PS1 is moved by the pressing member PSH. The first control piston PS1 is inserted into the inner hole of the first control cylinder SC1, and a combination of the piston and the cylinder is formed. Specifically, a seal member GSC is provided on the outer periphery of the first control piston PS1, and liquid tightness is ensured between the inner hole (inner wall) of the first control cylinder SC1. That is, a fluid chamber (control cylinder chamber) Rsc defined by the first control cylinder SC1 and the first control piston PS1 is formed. The control cylinder chamber Rsc is connected to the fluid path (pipe) HW1 via the port Ksc. As the first control piston PS1 is moved in the axial direction (center axis Jsc), the volume of the control cylinder chamber Rsc changes. At this time, since the electromagnetic valve VM1 is in the closed position, the brake fluid is not moved in the direction of the master cylinder MCL (that is, the master cylinder chamber Rm1), but is moved toward the wheel cylinder WCfl.

  The first pressure regulating mechanism CA1 is provided with a return spring (elastic body) SPR. When the energization of the first electric motor MT1 is stopped by the return spring SPR, the first control piston PS1 is returned to the initial position (position corresponding to zero braking hydraulic pressure). Specifically, the stopper portion Stp is provided inside the first control cylinder SC1, and when the output of the first electric motor MT1 is zero, the first control piston PS1 contacts the stopper portion Stp by the return spring SPR. It is pushed to the position (initial position).

  The brake caliper CPfl is a floating type, and a wheel cylinder WCfl is provided here. A wheel piston PWC is inserted into the inner hole of the wheel cylinder WCfl to form a piston / cylinder combination. A seal member GWC is provided on the outer periphery of the wheel piston PWC, and liquid tightness is exhibited between the GWC and the inner hole (inner wall) of the wheel cylinder WCfl. That is, a fluid chamber (wheel cylinder chamber) Rwc defined by the wheel cylinder WCfl and the wheel piston PWC is formed by the wheel cylinder seal member GWC. The wheel piston PWC is connected to the friction member MSB and configured to press the MSB.

  The wheel cylinder chamber Rwc formed by the combination of the wheel piston PWC and the wheel cylinder WCfl is filled with the brake fluid. Moreover, it is connected to the fluid path (pipe) HW1 via the fluid chamber Rwc and the port Kwc. Accordingly, when the first control piston PS1 is reciprocated in the direction of the central axis Jsc by the first electric motor MT1, and the volume of the control cylinder chamber Rsc is increased or decreased, the brake fluid flows into or is discharged from the wheel cylinder chamber Rwc. A change in the pressure of the brake fluid in the wheel cylinder chamber Rwc occurs. As a result, the force with which the friction member (eg, brake pad) MSB presses the rotating member (eg, brake disc) KTfl is adjusted, and the braking torque of the wheel WHfl is controlled.

  Specifically, when the first electric motor MT1 is rotationally driven in the forward rotation direction Fwd, the first control piston PS1 is moved so as to reduce the volume of the control cylinder chamber Rsc (moving leftward in the drawing). The brake fluid is moved from the first control cylinder SC1 to the first wheel cylinder WCfl. As a result, the volume of the wheel cylinder chamber Rwc is increased, the pressing force of the friction member MSB against the rotating member KTfl is increased, and the braking torque of the wheel WHfl is increased. On the other hand, when the first electric motor MT1 is rotationally driven in the reverse rotation direction Rvs, the first control piston PS1 is moved so as to increase the volume of the control cylinder chamber Rsc (moving in the right direction in the figure), and the braking fluid is The first wheel cylinder WCfl is moved to the first control cylinder SC1. As a result, the volume of the wheel cylinder chamber Rwc is reduced, the pressing force of the friction member MSB against the rotating member KTfl is reduced, and the braking torque of the wheel WHfl is reduced.

  In order to control the brake fluid pressure independently for each wheel, such as anti-skid control and vehicle stabilization control, the first between the first pressure regulating mechanism CA1 (that is, the first control cylinder SC1) and the wheel cylinders WCfl, WCrr. A hydraulic unit HU1 is provided. The first hydraulic unit HU1 is configured by a combination of a pressure increasing valve (electromagnetic valve) and a pressure reducing valve (electromagnetic valve). When maintaining the wheel cylinder hydraulic pressure, the pressure increasing valve and the pressure reducing valve are closed, and the flow of braking fluid from the first pressure regulating mechanism CA1 to the wheel cylinder is prevented. When the wheel cylinder hydraulic pressure is decreased, the pressure reducing valve is set to the open position while the pressure increasing valve is set to the closed position, and the brake fluid is returned to the master reservoir RSV. Further, when increasing the wheel cylinder hydraulic pressure, the pressure reducing valve is set to the closed position, the pressure increasing valve is set to the open position, and the brake fluid flows from the first pressure regulating mechanism CA1 into the wheel cylinder.

  In the first fluid path (braking pipe) HW1, a first control cylinder hydraulic pressure acquisition means (pressure sensor) PC1 is provided between the first master cylinder cutoff valve VM1 and the first hydraulic pressure unit HU1. The first control cylinder hydraulic pressure acquisition means PC1 acquires (detects) the hydraulic pressure (the hydraulic pressure in the control cylinder chamber Rsc, referred to as the first control cylinder hydraulic pressure) output from the first control cylinder.

<Stroke simulator>
The stroke simulator SSM will be described with reference to the cross-sectional view of FIG. In the simulator housing HSM, a flow connected to the pressure chamber Rm1 of the master cylinder MCL via the simulator cutoff valve VSM (corresponding to the third opening / closing means) and the fluid passage HSM (corresponding to the third fluid passage H3). A path and a flow path communicating with the master cylinder reservoir RSV are formed. A small-diameter hole into which the simulator piston PSM is inserted and a large-diameter hole having a larger diameter than the small-diameter hole are formed in the housing HSM. One end of the large-diameter hole is connected to the small-diameter hole, and the other end is closed by a closing member HSB. The large-diameter hole always communicates with the reservoir RSV, and an atmospheric pressure chamber Rtk is formed by the large-diameter hole and the closing member HSB. Here, the pressure inside the atmospheric pressure chamber Rtk is equal to the atmospheric pressure.

  The simulator piston PSM in the small-diameter hole is disposed so as to be slidable in the axial direction via a seal member (O-ring) GSL, and the simulator chamber Rsm between one end (pressure receiving portion) Peb and the housing HSM. Is formed. That is, a space defined by the small-diameter hole of the housing HSM and one end (pressure receiving portion) Peb of the piston PSM is the simulator chamber Rsm. The simulator chamber Rsm is connected to the fluid passage HSM, and communicates with the master cylinder chamber Rm1 when the simulator cutoff valve VSM is in the open position (communication state). That is, when the brake operation member (brake pedal) BP is operated, the hydraulic pressure corresponding to the operation force is supplied to the simulator room Rsm. The simulator piston PSM is moved in a direction (right direction in the drawing) in which the volume of the simulator chamber Rsm is increased by the hydraulic pressure from the master cylinder MCL supplied to the simulator chamber Rsm.

  Inside the atmospheric pressure chamber Rtk, a cup-shaped large-diameter holding member RTB is disposed coaxially with the simulator piston PSM. The large diameter holding member RTB has an opening at one end (the left end in the figure) and a bottom Psb at the other end (the right end in the figure). The other end Pea of the simulator piston PSM is disposed inside the large-diameter holding member RTB. When the braking operation member BP is not operated, the other end Pea of the simulator piston PSM and the bottom Psb of the large-diameter holding member RTB. Are opposed to each other at a predetermined distance.

  A small diameter holding member RTA is fixed to the shoulder Ptk of the simulator piston PSM. The small-diameter holding member RTA has a hat shape, and a small-diameter spring member (corresponding to an elastic member) SPA is held by the flange portion (collar portion) Fla. That is, the small-diameter spring member SPA is disposed between the flange portion Pfa of the small-diameter holding member RTA and the bottom portion Psb of the large-diameter holding member RTB. The small-diameter spring member SPA applies a spring force to the simulator piston PSM in the direction in which the volume of the simulator chamber Rsm decreases (the left direction in the drawing). Further, a flange portion Pfb is provided at the opening side end of the large diameter holding member RTB, and a large diameter spring member SPB (corresponding to an elastic member) is disposed between the flange portion Pfb and the closing member HSB. . Like the small diameter spring member SPA, the large diameter spring member SPB applies a spring force (elastic force) to the simulator piston PSM in the direction in which the volume of the simulator chamber Rsm decreases (the left direction in the drawing). Here, the spring constant (rigidity) of the small diameter spring member SPA is set smaller than the spring constant of the large diameter holding member RTB.

  A through hole is formed at the center of the bottom Psb of the large diameter holding member RTB, and a buffer member (rubber member) is press-fitted into the through hole and fixed. The buffer member includes an inner buffer member (corresponding to an elastic member) STA on the simulator piston PSM side and an outer buffer member (corresponding to an elastic member) STB on the side of the closing member HSB with respect to the bottom portion Psb of the large-diameter holding member RTB. It consists of.

  The inner buffer member STA contacts the bottom portion Psb of the large-diameter holding member RTB and is spaced from the other end portion Pea of the simulator piston PSM from the bottom portion Psb of the large-diameter holding member RTB when the brake pedal BP is not operated. It is provided to project in the direction of the other end portion Pea of the simulator piston PSM. When the simulator piston PSM moves more than a predetermined displacement in the direction opposite to the spring force of the small diameter spring member SPA, the inner buffer member STA moves between the other end portion Pea of the simulator piston PSM and the bottom portion Psb of the large diameter holding member RTB. Compressed between.

  The outer shock-absorbing member STB contacts the bottom portion Psb of the large-diameter holding member RTB, and when the brake pedal BP is not operated, the direction opposite to the protruding direction of the inner shock-absorbing member STA from the bottom portion Psb of the large-diameter holding member RTB (that is, Projecting in a direction away from the PSM) and facing the blocking member HSB at a distance. When the large diameter holding member RTB moves beyond a predetermined displacement in the direction opposite to the spring force of the large diameter spring member SPB, the large diameter holding member RTB is compressed between the bottom Psb of the large diameter holding member RTB and the closing member HSB.

  When the brake pedal BP is operated, the master cylinder hydraulic pressure corresponding to the operation force is a fluid path (third fluid path) HSM (H3) connecting the master cylinder MCL and the simulator SSM, and an open position simulator. It is supplied to the simulator room Rsm via the cutoff valve VSM. As the hydraulic pressure in the simulator chamber Rsm increases, the simulator piston PSM slides in a direction that increases the volume of the simulator chamber Rsm against the spring force of the small-diameter spring member SPA. And the small diameter spring member SPA with a small spring constant is compressed. When the simulator piston PSM moves by a predetermined displacement, the other end portion Pea of the piston PSM contacts the inner buffer member STA, and the inner buffer member STA is between the other end portion Pea of the piston PSM and the bottom portion Psb of the large-diameter holding member RTB. It is compressed with.

  Furthermore, when the operating force of the brake pedal BP is increased, the simulator piston PSM presses the large-diameter holding member RTB via the inner buffer member STA. For this reason, the large diameter holding member RTB moves integrally with the simulator piston PSM in a direction that opposes the spring force of the large diameter spring member SPB. As a result, the large-diameter spring member SPB having a large spring constant is compressed. When the large-diameter holding member RTB moves in this state by a predetermined displacement, the outer buffer member STB comes into contact with the closing member HSB, and the outer buffer member STB is compressed between the bottom portion Psb of the large-diameter holding member RTB and the closing member HSB. The

  As described above, as the simulator piston PSM moves, the small-diameter spring member SPA, the inner buffer member STA, the large-diameter spring member SPB, and the outer buffer member STB are sequentially compressed. For this reason, the relationship between the reaction force (counterforce against the spring force) and displacement of the piston PSM in the stroke simulator SSM is a nonlinear characteristic in which the displacement is “convex upward” with respect to the reaction force. Accordingly, at the initial stage of the braking operation, the operation displacement Sbp increases rapidly with respect to the change in the operation force Fbp by the small-diameter spring member SPA whose rigidity (spring constant) is relatively small. Then, in the later stage of the braking operation, the large-diameter spring member SPB having a relatively large rigidity (spring constant) gradually increases the operation displacement Sbp with respect to the change in the operation force Fbp (the slope of Sbp with respect to Fbp). Is small).

  Further, the inner buffer member STA smoothly switches from the compression operation of the small diameter spring member SPA to the compression operation of the large diameter spring member SPB. Similarly, the outer buffer member STB smoothly switches from the compression operation of the large-diameter spring member SPB to the subsequent operation. That is, the smooth non-linear characteristics of the stroke simulator SSM can be obtained by the rigidity (degree of deformation with respect to force) of the inner buffer member STA and the outer buffer member STB.

  As described above, the stroke simulator SSM includes a plurality of elastic members (spring members, buffer members) SPA, SPB, STA, and STB. The characteristics of the simulator SSM are set by the rigidity (combination of various rigidity) of the plurality of elastic members SPA, SPB, STA, and STB.

<Processing in electronic control unit ECU>
Next, processing in the electronic control unit ECU will be described with reference to the functional block diagram of FIG. The electronic control unit ECU receives power supply from a power source (storage battery BAT, generator ALT), and includes first, second electric motors MT1, MT2, and a stroke simulator cutoff valve (solenoid valve) VSM, first, second. Master cylinder shutoff valves (solenoid valves) VM1 and VM2 are controlled. The processing in the electronic control unit ECU is configured by an appropriateness determination unit (adequacy determination block) HNT, a motor control unit CMT, and an electromagnetic valve control unit CSL.

≪Appropriateness determination unit (appropriateness determination block) HNT≫
The suitability determination block HNT (corresponding to determination means) is an arithmetic algorithm and is programmed in a microcomputer in the electronic control unit ECU. The propriety determination block HNT determines the propriety of the operation state of the entire system including the propriety of the operation state of the first and second electric motors MT1 and MT2. Appropriateness of the operating state of the first and second electric motors MT1 and MT2 depends on the power supply state (for example, supply voltage) to the electric motors MT1 and MT2, the operating state of the electronic control unit ECU that drives the electric motors MT1 and MT2, And at least one of the operating states of the acquisition means (PM1, PM2, SBP, FBP, MK1, MK2, IMA, ISA, PC1, PC2) for acquiring the state quantity used for controlling the electric motors MT1, MT2 It is determined based on.

  The suitability determination block HNT includes an initial diagnosis block CHK and an operation monitoring block MNT. In the initial diagnosis block CHK, an initial diagnosis (so-called initial check) is performed before the operation of the braking control device is started. In the operation monitoring block MNT, the operation of the entire system is constantly monitored. From the suitability determination block HNT, a signal Shn indicating suitability of the operating state is output to the solenoid valve control unit CSL (solenoid valve command block SOL). Information indicating which one of the first and second electric motors MT1 and MT2 (that is, the first and second pressure regulating mechanisms CA1 and CA2) is in an appropriate state and which is in an unsuitable state based on the determination signal Shn. Is transmitted to the electromagnetic valve control unit CSL.

  In the initial diagnosis block CHK, the state of power supply to the braking control device, diagnosis of the electronic control unit ECU itself (for example, memory diagnosis), first and second electric motors MT1 and MT2, bridge circuit elements SWA to SWF, and electric motor Energization amount acquisition means IMA, first and second rotation angle acquisition means MK1, MK2, solenoid valves VSM, VM1, VM2, energization amount acquisition means ISA for solenoid valves, braking operation amount acquisition means BPA (SBP, etc.), And diagnosis (operation check) of at least one of fluid pressure acquisition means PM1, PM2, PC1, and PC2 is executed. Specifically, when the voltage supplied to the electronic control unit ECU transitions from a state below the predetermined voltage v10 to a state above the predetermined voltage v10, based on the trigger signal of the initial diagnosis, At least one operation diagnosis (initial check) is executed. The time point at which the supply voltage in the electronic control unit ECU transitions from less than the value v10 to more than the value v10 is referred to as “at the time of activation”. For example, the trigger signal is determined based on a signal received from the communication bus CAN.

  In the initial diagnosis block CHK, the initial operation diagnosis is started after the activation of the electronic control unit ECU and when the trigger signal is received. The trigger signal is received when the driver is close to the vehicle, when the vehicle door is opened and closed, when the driver is seated on the vehicle seat, when the ignition switch is turned on, And at least one of the states in which the vehicle is traveling. Therefore, these states are determined based on at least one of the proximity signal of the electronic key in the smart entry, the opening / closing signal of the vehicle door, the seating signal on the vehicle seat, the ON signal of the ignition switch, and the vehicle speed. The Here, the smart entry is a function of an automobile that can lock and unlock a door of a vehicle and start an engine without using a mechanical key. In smart entry, communication is performed between the driver's key (portable device) and the electronic control unit (computer) installed in the vehicle. When communication is established, the door is locked and unlocked. Is called.

  In the initial diagnosis (initial check), a diagnosis signal is transmitted from the initial diagnosis block CHK toward the bridge circuit and each electromagnetic valve. As a result, at least one of the acquisition results (detection results of each sensor) of the energization amount acquisition means IMA, ISA, rotation angle acquisition means MK1, MK2, and hydraulic pressure acquisition means PM1, PM2, PC1, PC2 Two changes are received in the initial diagnostic block CHK. Based on the reception result, a bridge circuit (ie, switching element), electric motors MT1 and MT2, solenoid valves VSM, VM1, and VM2, energization amount acquisition means IMA, ISA, rotation angle acquisition means MK1, MK2, and hydraulic pressure It is diagnosed whether at least one of the acquisition means PM1, PM2, PC1, and PC2 is in a state in which it can operate normally (appropriate state) or not (inappropriate state). If there is an inconvenience in function (operation), a notification signal Huc is transmitted from the suitability determination block HNT to the notification means HUC to notify the driver.

  Similarly, in the operation monitoring block MNT, the power supply state to the braking control device, the bridge circuit (that is, the switching element), the electric motors MT1, MT2, the electromagnetic valves VSM, VM1, VM2, the energization amount acquisition means IMA, ISA, rotation It is diagnosed whether or not at least one of the corner acquisition means MK1, MK2 and the hydraulic pressure acquisition means PM1, PM2, PC1, PC2 is in a state where it can operate normally. Diagnosis of these components is based on a comparison between the target values (command signals in the case of solenoid valves) and the results (actual values) of the electric motors MT1 and MT2 and the solenoid valves VSM, VM1 and VM2. Suitability is determined. Specifically, the appropriate state is determined when the deviation between the target value and the actual value is less than a predetermined value set in advance, and the inappropriate state is determined when the deviation is equal to or greater than the predetermined value. When an unsuitable state exists in the function of each component (MT1, MT2, etc.), a preset action (for example, notification to the driver) is performed as in the arithmetic processing in the initial diagnosis block CHK. .

≪Motor control unit CMT≫
The motor control unit CMT includes an instruction hydraulic pressure calculation block PWS, a target hydraulic pressure calculation block PWT, an instruction energization amount calculation block IST, a hydraulic pressure feedback control block PFB, and a target energization amount calculation block IMT.

  In the command hydraulic pressure calculation block PWS, the first and second command hydraulic pressures Ps1 and Ps2 are calculated based on the braking operation amount Bpa and the calculation characteristics (calculation map) CHpw. Here, the first and second indicating hydraulic pressures Ps1 and Ps2 are target values of the braking hydraulic pressure generated by the first and second pressure regulating mechanisms CA1 and CA2. Specifically, in the calculation characteristic CHpw, the first and second command hydraulic pressures Ps1 and Ps2 are zero in the range where the braking operation amount Bpa is greater than zero (corresponding to the case where the braking operation is not performed) and less than the predetermined value bp0. When the manipulated variable Bpa is greater than or equal to the predetermined value bp0, the command hydraulic pressures Ps1 and Ps2 are calculated so as to simply increase from zero.

  In the target hydraulic pressure calculation block PWT, the first and second indicating hydraulic pressures Ps1 and Ps2 are corrected, and final target values Pt1 and Pt2 for the braking hydraulic pressures of the first and second pressure regulating mechanisms CA1 and CA2 are obtained. Calculated. Specifically, the target hydraulic pressure calculation block PWT includes an anti-skid control block ABS, a traction control block TCS, and a vehicle stabilization control block ESC, and the anti-skid control, traction control, and vehicle stabilization control are included. The first and second target hydraulic pressures Pt1 and Pt2 necessary for the execution are calculated. Accordingly, there may occur a case where the values of the first target hydraulic pressure Pt1 and the second target hydraulic pressure Pt2 are different. Note that when it is not necessary to execute anti-skid control, traction control, and vehicle stabilization control, the first and second target fluid pressures Ps1 and Ps2 are not corrected, and the first and second target fluids remain as they are. The pressures Pt1 and Pt2 are output from the target hydraulic pressure calculation block PWT.

  In the anti-skid control block ABS, first and second target liquids for executing anti-skid control so as to prevent wheel lock based on the acquisition result (wheel speed Vwa) of the wheel speed acquisition means VWA provided in each wheel. The pressures Pt1 and Pt2 are calculated. Specifically, in the anti-skid control block ABS, a wheel slip state amount Slp (a variable representing the state of deceleration deceleration of the wheel) is calculated based on the acquisition result (wheel speed) Vwa of the wheel speed acquisition means VWA of each wheel. Is done. In the anti-skid control block ABS, the first and second command hydraulic pressures Ps1 and Ps2 are corrected based on the wheel slip state quantity Slp, and the first and second target hydraulic pressures Pt1 and Pt2 are determined.

  Similarly, in the traction control block TCS, the first and second target liquids are used to execute the traction control so as to suppress the wheel spin (overspeed) based on the acquisition result (wheel speed Vwa) of the wheel speed acquisition means VWA. The pressures Pt1 and Pt2 are calculated. Specifically, the first and second target hydraulic pressures Pt1 and Pt2 are determined based on the wheel slip state amount Slp (a variable indicating the state of acceleration slip of the wheel).

  Furthermore, in the vehicle stabilization control block ESC, based on the acquisition results (steering angle Saa, yaw rate Yra, lateral acceleration Gya) of the steering angle acquisition means SAA and the vehicle behavior acquisition means (yaw rate sensor YRA, lateral acceleration sensor GYA). The first and second target hydraulic pressures Pt1 and Pt2 for executing the vehicle stabilization control are calculated so as to maintain the stability of the vehicle. Specifically, based on the steering angle Saa, the yaw rate Yra, and the lateral acceleration Gya, the first and second command hydraulic pressures Ps1, so as to suppress at least one of excessive understeer and oversteer of the vehicle. Ps2 is corrected, and first and second target hydraulic pressures Pt1 and Pt2 are determined.

  In the command energization amount calculation block IST, commands of the first and second electric motors MT1 and MT2 for driving the first and second pressure regulating mechanisms CA1 and CA2 based on the first and second target hydraulic pressures Pt1 and Pt2 and the like. Energization amounts Is1 and Is2 (target values of energization amounts for controlling MT1 and MT2) are calculated. Here, the “energization amount” is a state amount (variable) for controlling the output torque of the first and second electric motors MT1 and MT2. Since the first and second 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 the target value of the energization amount (target energization amount). Further, if the supply voltage to the first and second 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 energization amount. Further, 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 used as the energization amount.

  In the command energization amount calculation block IST, the signs of the first and second command energization amounts Is1 and Is2 (based on the direction in which the first and second electric motors MT1 and MT2 are to be rotated (that is, the hydraulic pressure increase / decrease direction) ( The sign of the value is determined. Further, the magnitudes of the first and second command energization amounts Is1 and Is2 are calculated based on the rotational power to be output from the first and second electric motors MT1 and MT2 (that is, the increase / decrease amount of the hydraulic pressure). Specifically, when increasing the brake hydraulic pressure, the signs of the first and second command energization amounts Is1 and Is2 are calculated as positive signs (It1, It2> 0), and the first and second electric motors MT1 are calculated. , MT2 is driven in the forward rotation direction Fwd. On the other hand, when the braking hydraulic pressure is decreased, the signs of the first and second command energization amounts Is1 and Is2 are determined to be negative signs (Is1, Is2 <0), and the first and second electric motors MT1 and MT2 are Driven in the reverse direction Rvs. Furthermore, the absolute values of It1 and It2 are controlled such that the output torque (rotational power) of the first and second electric motors MT1 and MT2 increases as the absolute values of the first and second command energization amounts Is1 and Is2 increase. The smaller the is, the smaller the output torque is controlled.

  In the hydraulic pressure feedback control block PFB, the first and second target values (target hydraulic pressures) Pt1 and Pt2 of the hydraulic pressure and the first and second actual values (actual hydraulic pressures) Pc1 and Pc2 of the hydraulic pressure are used. The feedback energization amounts Ib1 and Ib2 of the first and second electric motors MT1 and MT2 are calculated. The actual hydraulic pressure values Pc1 and Pc2 are actual hydraulic pressure values (actual hydraulic pressures) acquired (detected) by the control cylinder hydraulic pressure acquisition means (pressure sensors) PC1 and PC2. In the hydraulic pressure feedback control block PFB, deviations eP1 and eP2 between the first and second target hydraulic pressures Pt1 and Pt2 and the first and second actual hydraulic pressures Pc1 and Pc2 are calculated. The hydraulic pressure deviations eP1 and eP2 are differentiated and integrated, and multiplied by gains Kp, Kd, and Ki, whereby the first and second feedback energization amounts Ib1 and Ib2 are calculated. In the hydraulic pressure feedback control block PFB, so-called PID control based on hydraulic pressure is executed.

  In the target energization amount calculation block IMT, the first and second instruction energization amounts Is1, Is2 and the first and second feedback energization amounts Ib1, Ib2 are used as the first and second target energization amount target values. Second target energization amounts It1, It2 are calculated. Specifically, in the energization amount adjustment calculation block IMT, the first and second feedback energization amounts Ib1 and Ib2 are added to the first and second instruction energization amounts Is1 and Is2, and the sum thereof is the first, It is calculated as the second target energization amount It1, It2 (It1 = Is1 + Ib1, It2 = Is2 + Ib2).

  In the electric motor drive means (drive circuit) DRM, the rotational power (output) and the rotation direction of the first and second electric motors MT1 and MT2 are adjusted based on the first and second target energization amounts It1 and It2. Is done. Details of the drive means DRM will be described later.

≪Solenoid valve control unit CSL≫
The solenoid valve control unit CSL includes a solenoid valve command block SOL and a solenoid valve drive means DRS. In the solenoid valve command block SOL, the command signals Vsm, Vm1, and Vm2 of the solenoid valves VSM, VM1, and VM2 are calculated based on the braking operation amount Bpa and the determination signal Shn that indicates the suitability state. The electromagnetic valve drive means DRS selectively realizes (controls) a communication state (open position) and a cutoff state (closed position) of the electromagnetic valves VSM, VM1, and VM2 based on the command signals Vsm, Vm1, and Vm2. The

  In the solenoid valve command block SOL, when it is determined that the suitability determination signal Shn is “the entire system is in a proper state”, energization or non-energization of each solenoid valve (VSM, etc.) is performed based on the braking operation amount Bpa. The state is controlled. First, the presence or absence of a braking operation by the driver is determined based on the operation amount Bpa. Specifically, when the operation amount Bpa is greater than or equal to a predetermined value bp0, it is determined that “braking operation is present (braking operation is being performed)”, and when the operation amount Bpa is less than the value bp0, "None (no braking operation is performed)" is determined.

  In the solenoid valve command block SOL, a command is issued so that the drive state of the solenoid valves VSM, VM1, and VM2 is switched from non-energized to energized when the condition “with braking operation (ie, Bpa ≧ bp0)” is satisfied. Signals Vsm, Vm1, and Vm2 are transmitted to the electromagnetic valve drive means DRS.

  In the electromagnetic valve drive means DRS, the simulator cutoff valve VSM is changed from the closed position to the open position based on the command signals Vsm, Vm1, and Vm2, and the first and second master cylinder cutoff valves VM1 and VM2 are closed from the open position. Changed to position. The drive means DRS is provided with solenoid valve energization amount acquisition means (current sensor) ISA for acquiring the energization amount Isa to the solenoid valves VSM, VM1, and VM2.

  Also in the electronic control unit ECU, electric power is supplied from an electric power source (BAT or the like) to perform its function. For this reason, when the power source is malfunctioning (that is, when the supplied power is insufficient), the ECU itself does not function and power is supplied to the electric motors MT1 and MT2 and the electromagnetic valves VSM, VM1 and VM2. I don't get it. For this reason, a normally closed solenoid valve (NC valve) is adopted as the solenoid valve VSM, and a normally open solenoid valve (NO valve) is adopted as the solenoid valves VM1 and VM2. As a result, when the power source is in an inappropriate state, communication between the master cylinder MCL and the simulator SSM is interrupted, and communication between the master cylinder MCL and the wheel cylinders (WCfl, WCfr, etc.) can be ensured.

<Driving means DRM for electric motor (example of three-phase brushless motor)>
FIG. 5 is an example of drive means (drive circuit) DRM when the first electric motor MT1 is a brushless motor. The electric motor drive means DRM is an electric circuit that drives the first electric motor MT1, and is a bridge circuit composed of six switching elements SWA to SWF, and performs pulse width modulation based on the first target energization amount It1. Based on the pulse width modulation block PWM to be performed, and the switching control block SWT that controls the energization / non-energization states of SWA to SWF based on the first duty ratio Du1 determined by the PWM, and the energization amount acquisition unit IMA Is done.

  The six switching elements SWA to SWF are elements that can turn on / off a part of the electric circuit, and for example, MOS-FETs can be used. In the brushless motor, the first position acquisition means MK1 acquires the rotor position (rotation angle) Mk1 of the first electric motor MT1. Then, by controlling the switching elements SWA to SWF constituting the bridge circuit (three-phase bridge circuit), coil energization of the U phase (Tu terminal), the V phase (Tv terminal), and the W phase (Tw terminal) is performed. The direction of the quantity (that is, the excitation direction) is sequentially switched based on the first rotation angle Mk1, and the first electric motor MT1 is rotationally driven. That is, the rotation direction of the brushless motor (forward rotation direction Fwd or reverse rotation direction Rvs) is determined by the relationship between the rotor and the excitation position. Here, the forward rotation direction Fwd of the first electric motor MT1 is a rotation direction corresponding to an increase in braking fluid pressure, and the reverse rotation direction Rvs of the first electric motor MT1 is a rotation direction corresponding to a decrease in braking fluid pressure. is there.

  In the pulse width modulation block PWM, 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 rotational direction of the first electric motor MT1 is determined based on the sign (positive sign or negative sign) 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 Fwd is a positive (plus) value and the reverse rotation direction Rvs 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 controlled.

  In the switching control block SWT, based on the first duty ratio (target value) Du1, whether each switching element constituting the bridge circuit is turned on (energized state) or turned off (non-energized state) Drive signals Sa to Sf are calculated. The drive signals Sa to Sf control the energization or non-energization of the switching elements SWA to SWF. 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 electric motor drive unit DRM includes an energization amount acquisition unit (for example, a current sensor) IMA, and acquires (detects) an actual energization amount (for example, an actual current value) Ima. In the switching control block SWT, so-called current feedback control is executed. The first duty ratio Du1 is corrected (finely adjusted) based on the deviation ΔIm between the actual energization amount Ima and the first target energization amount It1. With this current feedback control, highly accurate motor control can be achieved.

<Processing in solenoid valve control unit CSL>
With reference to the flowchart of FIG. 6, the process in the solenoid valve control unit CSL will be described. First, in step S100, the braking operation amount Bpa and the determination signal Shn are read. Next, the process proceeds to step S110.

  In step S110, based on the braking operation amount Bpa, “whether or not braking is being performed” is determined. Specifically, when the braking operation amount Bpa is equal to or greater than a predetermined value bp0, it is determined that “the brake is being performed”. Further, when the braking operation amount Bpa is less than the predetermined value bp0, it is determined that “not braking (not braking)”. When it is affirmed in Step S110 that “the brake is being performed” (in the case of “YES”), the process proceeds to Step S120. On the other hand, when it is denied in step S110 that “the brake is being performed” (that is, in the case of non-braking and “NO”), the process proceeds to step S180.

  In step S120, based on the determination signal Shn, it is determined whether or not the first pressure regulating mechanism CA1 is in an appropriate state. Here, the determination signal Shn is a signal that represents the propriety of the operation of the first and second pressure regulating mechanisms CA1 and CA2 calculated in the propriety determination block HNT (see FIG. 4). When it is affirmed in Step S120 that “the first pressure regulating mechanism CA1 is in an appropriate state” (in the case of “YES”), the process proceeds to Step S130. On the other hand, when it is denied in Step S120 that “the first pressure regulating mechanism CA1 is in an appropriate state” (that is, in an inappropriate state and “NO”), the process proceeds to Step S140.

  In step S130, based on the determination signal Shn, “whether or not the second pressure regulating mechanism CA2 is in an appropriate state” is determined. In step S130, when it is affirmed (in the case of “YES”) that “the second pressure regulating mechanism CA2 is in an appropriate state”, the process proceeds to step S150. On the other hand, when it is denied in step S130 that "the second pressure regulating mechanism CA2 is in an appropriate state" (that is, in an inappropriate state and "NO"), the process proceeds to step S160.

  In step S140, based on the determination signal Shn, “whether or not the second pressure regulating mechanism CA2 is in an appropriate state” is determined. When it is affirmed in Step S140 that “the second pressure regulating mechanism CA2 is in an appropriate state” (in the case of “YES”), the process proceeds to Step S170. On the other hand, when it is denied in Step S140 that “the second pressure regulating mechanism CA2 is in an appropriate state” (that is, in an inappropriate state and “NO”), the process proceeds to Step S180.

  In step S150, the simulator cutoff valve VSM (corresponding to the third opening / closing means) is opened, and the first and second master cylinder cutoff valves VM1 (corresponding to the first opening / closing means), VM2 (second opening / closing means). Is equivalent to the closed position. That is, when the first and second pressure regulating mechanisms CA1 and CA2 are in an appropriate state, the communication state of the simulator cutoff valve VSM and the cutoff state of the first and second master cylinder cutoff valves VM1 and VM2 are selectively realized. Is done. As a result, the wheel cylinder WCfl (corresponding to the first wheel cylinder WC1) and WCrr are regulated by the first pressure regulating mechanism CA1, and the wheel cylinder WCfr (corresponding to the second wheel cylinder WC2) and WCrl are adjusted to the second regulation. The pressure is adjusted by the pressure mechanism CA2. Thereafter, the process returns to step S100.

  In step S160, the simulator cutoff valve VSM is opened, the first master cylinder cutoff valve VM1 is closed, and the second master cylinder cutoff valve VM2 is opened. That is, when the first pressure regulating mechanism CA1 is in an appropriate state and the second pressure regulating mechanism CA2 is in an inappropriate state, the communication state of the simulator cutoff valve VSM, the cutoff state of the first master cylinder cutoff valve VM1, The communication state of the master cylinder shut-off valve VM2 is selectively realized. As a result, the wheel cylinders WCfl and WCrr are regulated by the first pressure regulating mechanism CA1. On the other hand, the wheel cylinders WCfr and WCrl are regulated by the master cylinder MCL. Thereafter, the process returns to step S100.

  In step S170, the simulator cutoff valve VSM is opened, the first master cylinder cutoff valve VM1 is opened, and the second master cylinder cutoff valve VM2 is closed. That is, when the first pressure regulating mechanism CA1 is in an inappropriate state and the second pressure regulating mechanism CA2 is in an appropriate state, the communication state of the simulator cutoff valve VSM, the communication state of the first master cylinder cutoff valve VM1, The cutoff state of the master cylinder cutoff valve VM2 is selectively realized. As a result, the wheel cylinders WCfl and WCrr are regulated by the master cylinder MCL. On the other hand, the wheel cylinders WCfr and WCrl are regulated by the second pressure regulating mechanism CA2. Thereafter, the process returns to step S100.

  In step S180, the simulator cutoff valve VSM is closed, and the first and second master cylinder cutoff valves VM1, VM2 are opened. That is, when the first and second pressure regulating mechanisms CA1 and CA2 are in an inappropriate state, the shut-off state of the simulator shut-off valve VSM and the communication state of the first and second master cylinder shut-off valves VM1 and VM2 are selectively realized. Is done. As a result, all the wheel cylinders WCfl, WCfr, WCrr, WCrl are regulated by the master cylinder MCL. Thereafter, the process returns to step S100.

  In the first embodiment, the operation characteristics (relationship between operation force and operation displacement) of the brake operation member BP connected to the master cylinder MCL are determined by the following three patterns.

  The first pattern (referred to as “normal characteristics”) is a case where both the first and second pressure regulating mechanisms CA1 and CA2 operate normally (when step S150 is executed). In this case, the simulator cutoff valve VSM is opened and the master cylinder MCL and the simulator SSM are in fluid communication. The first and second master cylinder shutoff valves VM1, VM2 are closed and the master cylinder MCL and all wheel cylinders are fluidly shut off. Therefore, in the first pattern, the operation characteristic is determined by the relationship between the master cylinder MCL and the simulator SSM.

  In the second pattern (“one-system failure characteristic”), when one of the first and second pressure regulating mechanisms CA1 and CA2 is operating normally and the other is in failure (step S160 or step S170 is executed). ). In this case, the simulator cutoff valve VSM is opened, and the master cylinder MCL and the simulator SSM are brought into communication. Of the first and second master cylinder shutoff valves VM1, VM2, the solenoid valve connected to the normally operating pressure regulating mechanism is set to the closed position, and the electromagnetic valve connected to the malfunctioning pressure regulating mechanism. The valve is in the open position. That is, the master cylinder MCL and the wheel cylinder connected to the malfunctioning pressure regulation mechanism are fluidly connected, and the master cylinder MCL and the wheel cylinder connected to the normally operating pressure regulation mechanism are fluidly connected. Will be blocked. Therefore, in the second pattern, the operating characteristics are determined by the relationship between the master cylinder MCL, the simulator SSM, and the wheel cylinders in one braking system.

  The third pattern (referred to as “two-system failure characteristic”) is a case where both the first and second pressure regulating mechanisms CA1 and CA2 have failed (when step S180 is executed). In this case, the simulator cutoff valve VSM is closed and the master cylinder MCL and the simulator SSM are fluidly shut off. Further, the first and second master cylinder shutoff valves VM1, VM2 are set to the open position, and the master cylinder MCL and all the wheel cylinders are in fluid communication. Therefore, in the third pattern, the operation characteristics are determined by the relationship between the master cylinder MCL and the wheel cylinders (that is, all wheel cylinders) in the two braking systems.

<Operating characteristics and actions / effects of braking operation member BP>
Referring to the operation characteristic diagram of FIG. 7, in the first to third patterns described above, the static relationship between the operation force Fbp of the braking operation member BP and the operation displacement Sbp (operation characteristic with an operation speed less than a predetermined value). Will be described in detail. In addition, the operation and effect of the first embodiment will be described.

  First, the characteristic CHa is that the simulator cutoff valve (electromagnetic valve) VSM is in the closed position, and one of the first and second master cylinder cutoff valves (electromagnetic valves) VM1 and VM2 is in the closed position and the other is in the open position. Operating characteristics (relationship of the operation displacement Sbp to the operation force Fbp). That is, in the characteristic CHa, since only one of the two braking systems (fluid path) is brought into communication with the master cylinder MCL, it is referred to as “one system characteristic”. For example, when the operation force Fbp is the value fbx, the operation displacement Sbp is the value sba in the one system characteristic CHa.

  The one-system characteristic CHa is determined by the relationship among the master cylinder MCL, one wheel cylinder connected to the master cylinder, a caliper including the wheel cylinder, and the friction member MSB. The case where the first master cylinder cutoff valve VM1 is in the open position and the second master cylinder cutoff valve VM2 is in the closed position (that is, the first fluid passage H1 is in communication with the master cylinder MCL) will be described as an example. . In this example, the master cylinder MCL is not in communication with the simulator SSM and the wheel cylinders WCfr and WCrl, and is in communication with the wheel cylinders WCfl and WCrr. The brake fluid discharged from the master cylinder MCL by the operation displacement Sbp of the brake operation member BP is sent to the wheel cylinders WCfl and WCrr (particularly, the wheel cylinder chamber Rwc). First, a gap between the friction member MSB and the rotating members KTfl and KTrr is filled with the brake fluid flowing into the wheel cylinders WCfl and WCrr. Further, as the brake fluid flows in, the hydraulic pressure in the wheel cylinder chamber Rwc increases, compressing the friction member MSB and deforming the calipers CPfl and CPrr (deforming in the direction F shown in FIG. 2). The operating force Fbp is generated by deformation of the friction member MSB and the calipers CPfl and CPrr. Here, the movement of the brake fluid and the deformation of the caliper depend on the piston cross-sectional areas and the rigidity (spring constant) of the master cylinder MCL, the wheel cylinders WCfl and WCrr. In the characteristic CHa, the operation displacement Sbp increases in a “convex upward” characteristic with respect to an increase in the operation force Fbp.

  Next, the characteristic CHb is an operation characteristic when the simulator cutoff valve VSM is in the closed position and both the first and second master cylinder cutoff valves VM1 and VM2 are in the open position. That is, the characteristic CHb is a characteristic when the first and second pressure regulating mechanisms CA1 and CA2 are in an inappropriate state and step S180 in the flowchart is executed, and is a two-system failure characteristic corresponding to the third pattern. is there. In the characteristic CHb, since two systems (first and second fluid paths) are brought into communication with the master cylinder MCL, this corresponds to the two-system failure characteristic. In this state, all the wheel cylinders are pressurized by the master cylinder MCL by setting the first and second master cylinder cutoff valves VM1 and VM2 to the open position. At this time, the simulator cutoff valve VSM is in the closed position (shut-off state), and the brake fluid of the master cylinder MCL is not consumed by the simulator SSM. For this reason, the operation characteristic suitable for notifying the failure of the braking control device can be obtained without the operation displacement Sbp being excessive with respect to the operation force Fbp.

  Specifically, in the two-system failure characteristic CHb (the above third pattern), the operation displacement Sbp is doubled with respect to the same operation force Fbp as compared with the one-system characteristic CHa. For example, when the operation force Fbp is the value fbx, the operation displacement Sbp is the value “2 × sba” in the two-system failure characteristic CHb. Note that a normally closed solenoid valve is used as the simulator shutoff valve VSM, and a normally open solenoid valve is adopted as the first and second master cylinder shutoff valves VM1 and VM2, so that if the power supply fails, the braking operation member BP Is the two-system failure characteristic CHb. Similar to the one-system characteristic CHa, the two-system failure characteristic CHb has a characteristic of “operating upward” with respect to the operation force Fbp.

  In the first pattern (when the first and second pressure regulating mechanisms CA1 and CA2 are both in an appropriate state and step S150 in the flowchart is executed), the first and second master cylinder cutoff valves VM1 are used. , VM2 is brought into the closed position (cut-off state), so that the master cylinder MCL is fluidly disconnected from all the wheel cylinders, and the simulator cut-off valve VSM is put into the open position (communication state). The MCL is in fluid communication with the simulator SSM. That is, the master cylinder MCL is not communicated with the two systems (first and second fluid paths), but is communicated only with the simulator SSM. Accordingly, the wheel cylinders of the two systems (fluid paths) are pressurized by the first and second pressure regulating mechanisms CA1 and CA2.

  In the first pattern (normal characteristic), the wheel cylinder is not involved in the operation characteristic, and the operation characteristic CHsm is determined based on the relationship between the master cylinder MCL and the simulator SSM. The characteristic CHsm is also referred to as “simulator characteristic”. Similar to the characteristics CHa and CHb, the simulator characteristic CHsm is also set to a “convex upward” characteristic in the relationship between the operation force Fbp and the operation displacement Sbp.

  The simulator characteristic CHsm is set to an area ARa (an area indicated by a broken line in the figure, referred to as “appropriate area”) sandwiched between the one-system characteristic CHa and the two-system failure characteristic CHb. For example, in the simulator characteristic CHsm, the operation displacement Sbp when the operation force Fbp is the value fbx is set as the value sbs. At this time, the value sbs is set to “value sba or more and value“ 2 × sba ”or less”.

  As described above, the simulator characteristic CHsm is formed by the spring members SPA and SPB and the buffer members STA and STB. Specifically, the spring constants of the small-diameter spring member SPA, the large-diameter spring member SPB, the inner shock-absorbing member STA, and the outer shock-absorbing member STB (that is, the rigidity of the plurality of elastic members) are such that the simulator characteristic CHsm is within the appropriate range ARa. Is set in advance so as to be within the range.

  Second pattern (one system failure characteristic, one of the first and second pressure regulating mechanisms CA1 and CA2 is in an appropriate state and the other is in an unsuitable state, and step S160 or step S170 in the flowchart is When executed), the simulator cutoff valve VSM is in the open position, and one of the first master cylinder cutoff valve VM1 and the second master cylinder cutoff valve VM2 is in the closed position and the other is in the open position. That is, the wheel cylinder connected to the pressure regulating mechanism in the inappropriate state is fluidly communicated with the master cylinder MCL, and the wheel cylinder connected to the pressure regulating mechanism in the proper state is fluidly disconnected from the master cylinder MCL. The Furthermore, the master cylinder MCL is in fluid communication with the simulator SSM. Therefore, the wheel cylinder in the inappropriate state is pressurized by the master cylinder MCL, and the wheel cylinder in the appropriate state is pressurized by the pressure adjusting mechanism. The brake fluid in the master cylinder MCL is also consumed by the simulator SSM. That is, in the second pattern, the operation characteristic CHf is determined by the simulator SSM and the wheel cylinder, caliper, and friction member in an inappropriate state.

  For example, when the first pressure regulating mechanism CA1 is in an inappropriate state and the second pressure regulating mechanism CA2 is in an appropriate state, the first master cylinder cutoff valve VM1 is in the open position (communication state), and the second master cylinder The shutoff valve VM2 is set to the closed position (shutoff state). The wheel cylinders WCfl and WCrr in the first fluid path (failure side system) are pressurized by the master cylinder MCL, and the wheel cylinders WCfr and WCrl in the second fluid path (normal side system) are the second pressure regulating mechanism. Pressurized by CA2. The one-system failure characteristic CHf is set based on the characteristics (piston cross-sectional area, rigidity, etc.) of the simulator SSM, the wheel cylinders WCfl, WCrr, the calipers CPfl, CPrr, and the friction member MSB.

  Specifically, the one-system failure characteristic CHf is obtained by superimposing the one-system characteristic CHa on the simulator characteristic (normal characteristic) CHsm. Therefore, in the one-system failure characteristic CHf, when the operation force Fbp is the value fbx, the value of the operation displacement Sbp is “sbs + sba”. Since the simulator characteristic CHsm is set in the appropriate area ARa, the one-system failure characteristic CHf is determined as a characteristic that is slightly larger in the operation displacement Sbp than the two-system failure characteristic CHb.

  Assume that the simulator cutoff valve VSM is in the closed position (non-communication state) when one of the first and second pressure regulating mechanisms CA1 and CA2 is in an appropriate state and the other is in an inappropriate state. In this state, the operation characteristic is the one system characteristic CHa, but the simulator characteristic CHsm and the one system characteristic CHa can be similar characteristics. For this reason, it may be difficult for the driver to notice the malfunction of the first and second pressure regulating mechanisms CA1 and CA2 based on the change in the operation characteristics.

  In addition, in order to notify the driver of an inappropriate state due to a change in the operation characteristics, it is also conceivable to set the simulator characteristics CHsm to characteristics smaller than the one-system characteristics CHa (operation characteristics that fall within the area ARb). However, in this setting, since the change in the operation displacement Sbp is small with respect to the change in the operation force Fbp, the operation feeling is inferior (so-called plate brake feeling is generated).

  When the simulator characteristic CHsm is set in the appropriate area ARa, and one of the first and second pressure regulating mechanisms CA1 and CA2 is in the proper state and the other is in the unsuitable state, the simulator cutoff valve VSM is in the open position. Therefore, the malfunction of the first and second pressure regulating mechanisms CA1 and CA2 can be notified to the driver by the operation characteristics without lowering the operation feeling.

  Furthermore, the simulator characteristic CHsm can be set as a characteristic closer to the one system characteristic CHa than the two system failure characteristic CHb in the appropriate region ARa. Specifically, the simulator characteristic CHsm is within a region sandwiched between a characteristic CHc (referred to as “intermediate characteristic”) that divides the appropriate area ARa into two equal parts in the operation displacement Sbp (Y-axis direction in the figure) and one system characteristic CHa. Is set. That is, the above-described value sbs is “value sba or more and value“ 1.5 × sba ”or less”.

  Since the simulator characteristic CHsm is set in a region sandwiched between the intermediate characteristic CHc and the one-system characteristic CHa by setting the rigidity of the plurality of elastic members, the one-system failure characteristic CHf and the two-system failure characteristic CHb are similar. Made to operating characteristics. As a result, it is possible to appropriately notify the malfunction of the first and second pressure regulating mechanisms CA1 and CA2 without causing confusion for the driver.

<Second Embodiment of Braking Control Device According to the Present Invention>
Next, a second embodiment of 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 wheel cylinders WCfl, WCfr, WCrl, and WCrr are pressurized by the pressure adjusting mechanisms CA1 and CA2. In the second embodiment, the pressure adjusting mechanism The front wheel cylinders WCfl and WCfr are pressurized by CA1 and CA2 to apply braking torque. Further, braking torque is applied to the rear wheels WHrl and WHrr by electric braking means DSrl and DSrr that do not use fluid. Therefore, for the rear wheels WHrl and WHrr, there are no wheel cylinders WCrl and WCrr, and there is no fluid piping from the master cylinder MCL to the rear wheel wheel cylinders WCrl and WCrr. That is, there is no fluid path (pipe), solenoid valve, or wheel cylinder corresponding to the rear wheel.

  In each figure and the description using it, like the above, members (components) given the same symbol, such as MCL, exhibit the same function. In addition, similarly to the above, the suffix attached to the end of the symbol of each component indicates which of the four wheels corresponds. Specifically, the subscripts are related to “fl” for “left front wheel”, “fr” for “right front wheel”, “rl” for “left rear wheel”, and “rr” for “right rear wheel”. Each of them is expressed.

  Since the components denoted by the same reference numerals are the same as those in the first embodiment, the differences will be mainly described briefly.

  Master cylinder MCL (first master cylinder chamber Rm1) and left front wheel wheel cylinder (corresponding to first wheel cylinder WC1) WCfl are connected by a first fluid path H1. A first master cylinder shut-off valve VM1 (corresponding to a first opening / closing means) that is a two-position solenoid valve is interposed in the middle of the first fluid path H1. A first pressure regulating mechanism CA1 driven by a first electric motor MT1 is connected to a first fluid path H1 between the first master cylinder cutoff valve VM1 and the left front wheel wheel cylinder WCfl.

  The master cylinder MCL (second master cylinder chamber Rm2) and the right front wheel cylinder (corresponding to the second wheel cylinder WC2) WCfr are connected by the second fluid path H2. A second master cylinder shut-off valve VM2 (corresponding to a second opening / closing means) that is a two-position electromagnetic valve is interposed in the middle of the second fluid path H2. A second pressure regulating mechanism CA2 driven by the second electric motor MT2 is connected to the second fluid path H2 between the second master cylinder cutoff valve VM2 and the right front wheel wheel cylinder WCfr. Further, the master cylinder MCL is connected to the simulator SSM via a simulator cutoff valve VSM (corresponding to a third opening / closing means) that is a two-position electromagnetic valve.

  As in the first embodiment, when both the first and second pressure regulating mechanisms CA1 and CA2 are operating properly, the simulator cutoff valve VSM is in the open position, and the first and second master cylinder cutoff valves VM1. , VM2 is brought into the closed position.

  When one of the first and second pressure regulating mechanisms CA1 and CA2 is operating normally and the other is malfunctioning, the simulator cutoff valve VSM is in the open position, and the master cylinder cutoff valve in the normal side fluid path is The master cylinder shut-off valve in the closed position and the failure side fluid passage is set in the open position. Here, the operation characteristic CHsm by the simulator SSM is set within an appropriate area ARa sandwiched between one system characteristic CHa (for example, a characteristic by only WCfr) and two system failure characteristics CHb (a characteristic by WCfl and WCfr). Similarly to the first embodiment, the malfunction of the first and second pressure regulating mechanisms CA1 and CA2 can be notified to the driver by the operation characteristics without lowering the operation feeling.

  Furthermore, it is desirable to set the characteristic between one system characteristic CHa and an intermediate characteristic CHc (characteristic that divides the appropriate region ARa into two equal parts in the operation displacement Sbp). With this setting, the one-system failure characteristic CHf and the two-system failure characteristic CHb are approximated, so that the failure of the first and second pressure regulating mechanisms CA1 and CA2 is appropriately notified without causing confusion for the driver. Can be done.

  When both the first and second pressure regulating mechanisms CA1 and CA2 are out of order, the simulator cutoff valve VSM is in the closed position, and the first and second master cylinder cutoff valves VM1 and VM2 are in the open position. Since the brake fluid of the master cylinder MCL is not consumed by the simulator SSM, it can be suppressed that the operation displacement Sbp is excessive with respect to the operation force Fbp.

  In the second embodiment, even if at least one of the first and second pressure regulating mechanisms CA1 and CA2 is out of regulation, the braking torque is generated by the electric braking means DSrl and DSrr provided in the rear wheels WHrr and WHrr. As a result, the vehicle deceleration can be ensured.

<Electric braking means provided on the rear wheels in the second embodiment>
With reference to the schematic diagram of FIG. 9, the electric braking means provided on the rear wheel will be described by taking the electric braking means DSrl for the left rear wheel as an example. The electric braking means DSrl is driven by the electric motor MTW (that is, the braking torque of the rear wheels is adjusted). Here, the electric motor MTW is distinguished from the first and second electric motors MT1 and MT2 for driving the first and second pressure regulating mechanisms CA1 and CA2 provided on the vehicle body side. ". In the same manner as described above, constituent elements to which the same symbol is attached exhibit the same function, and thus description thereof is omitted.

  The vehicle includes a braking operation member BP, an electronic control unit ECU, and electric braking means (brake actuator) DSrl. The electronic control unit ECU and the electric braking means DSrl are connected by a signal line (signal line) SGL and a power line (power line) PWL, and are supplied with a drive signal and electric power for the electric motor MTW for the electric braking means DSrl. Is done.

  In addition to the above-described suitability determination block HNT and the like, the electronic control unit ECU is provided with an instruction pressing force calculation block FBS. The target pressing force calculation block FBS calculates a target value (indicating pressing force) Fsrl for driving the electric motor MTW for the electric braking means DSrl. Specifically, in the command pressure calculation block FBS, the command pressure Fsrl of the right rear wheel WHrl is calculated based on the braking operation amount Bpa and the command pressure calculation characteristic CHfb set in advance. The command pressing force Fsrl 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) KTrl in the electric braking means DSrl for the right rear wheel. The instruction pressing force Fsrl is transmitted to the DSrl on the wheel side via the serial communication bus SGL.

  The left rear wheel electric braking means DSrl includes a brake caliper CPrl, a pressing piston PSW, a wheel side electric motor MTW, a rotation angle detection means MKW, a reduction gear GSW, an output member OSF, a screw member NJW, a pressing force acquisition means FBA, and The driving circuit DRW is configured.

  The brake caliper CPrl is configured to sandwich a rotating member (brake disc) KTrl via two friction members (brake pads) MSB. Within the caliper CPrl, the pressing piston (brake piston) PSW is slid and moved forward or backward toward the rotating member KTrl. The pressing piston PSW presses the friction member MSB against the rotating member KTrl to generate a frictional force. Since the rotating member KTrl is fixed to the rear wheel WHrl, the braking force of the left rear wheel WHrl is adjusted by this frictional force.

  The wheel side electric motor MTW for driving the electric braking means DSrl generates power for pressing the friction member MSB against the rotating member KTrl. Specifically, the output of the electric motor MTW (rotational power around the motor shaft) is transmitted to the output member OSF via the speed reducer GSW. The rotational power (torque around the shaft axis) of the output member OSF is converted into linear power (thrust in the direction of the central axis of the PSW) by the motion converting member (for example, screw member) NJW and transmitted to the pressing piston PSW.

  A rotation angle acquisition means (for example, a rotation angle sensor) MKW for the wheel side electric motor MTW is provided. Further, a pressing force acquisition means FBA is provided to acquire (detect) a reaction force (reaction) of a force (pressing force) Fba that the pressing piston PSW presses the friction member MSB. Then, the pressing force feedback control is executed based on the pressing force target value Fsrl and the actual value Fba.

  The driving means (driving circuit) DRW drives the wheel-side electric motor MTW based on the instruction pressing force (signal) Fsrl transmitted from the instruction pressing force calculation block FBS. Specifically, the driving means DRW is provided with a bridge circuit for driving the wheel side electric motor MTW, and the rotation direction of the electric motor MTW is determined by the driving signal for each switching element calculated based on the target value Fsrl. The output torque is controlled.

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

  In the first embodiment, the first and second hydraulic pressure units HU1 and HU2 are provided so that the braking torque can be adjusted independently at each wheel, such as anti-skid control. In the second embodiment, the first The pressure adjusting mechanism CA1 can independently adjust the hydraulic pressure of the wheel cylinder WCfl, and the second pressure adjusting mechanism CA2 can independently adjust the hydraulic pressure of the wheel cylinder WCfr. Therefore, in the second embodiment, the first and second hydraulic units HU1 and HU2 can be omitted.

  BP ... braking operation member, MCL ... master cylinder, SSM ... stroke simulator, VM1 ... first opening / closing means (first master cylinder cutoff valve), VM2 ... second opening / closing means (second master cylinder cutoff valve), VSM ... third Opening / closing means (stroke simulator cutoff valve), CA1 ... first pressure regulating mechanism, CA2 ... second pressure regulating mechanism, HNT ... judging means

Claims (3)

A master cylinder driven by a braking operation member of the vehicle;
A first wheel cylinder for applying braking torque to one side of the left and right front wheels of the vehicle;
A second wheel cylinder for applying braking torque to the other side of the left and right front wheels;
A stroke simulator that absorbs braking fluid discharged from the master cylinder and applies an operating force to the braking operation member;
A first fluid path connecting the master cylinder and the first wheel cylinder;
First opening / closing means interposed in the middle of the first fluid path and selectively realizing a communication state and a blocking state of a brake fluid between the master cylinder and the first wheel cylinder;
A second fluid path connecting the master cylinder and the second wheel cylinder;
A second opening / closing means interposed in the middle of the second fluid path for selectively realizing a communication state and a blocking state of the brake fluid between the master cylinder and the second wheel cylinder;
A third fluid path connecting the master cylinder and the stroke simulator;
A third opening / closing means interposed in the middle of the third fluid path for selectively realizing a communication state and a blocking state of the brake fluid between the master cylinder and the stroke simulator;
An operation amount obtaining means for obtaining an operation amount of the braking operation member;
A first pressure regulating mechanism that is connected to the first fluid path between the first opening / closing means and the first wheel cylinder and that adjusts the pressure of the brake fluid in the first wheel cylinder based on the operation amount; ,
A second pressure regulating mechanism that is connected to the second fluid path between the second opening / closing means and the second wheel cylinder, and that adjusts the pressure of the brake fluid in the second wheel cylinder based on the operation amount; ,
Control means for controlling the first, second and third opening and closing means;
Determination means for determining whether the operation of the first and second pressure regulating mechanisms is appropriate or inappropriate;
In a vehicle braking control apparatus comprising:
The control means includes
When the determination means determines that the operation of the first and second pressure regulating mechanisms is in an appropriate state, the first and second opening / closing means are shut off and the third opening / closing means is connected. ,
When the determination means determines that the operation of the first pressure regulating mechanism is in an inappropriate state and the operation of the second pressure regulating mechanism is in an appropriate state, the first and third opening / closing means are in communication state. And turning off the second opening / closing means,
When the determination means determines that the operation of the first and second pressure regulating mechanisms is in an inappropriate state, the first and second opening / closing means are brought into a communication state and the third opening / closing means is brought into a blocking state. A braking control device for a vehicle configured to The vehicle braking control device according to claim 1,
The stroke simulator is composed of a plurality of elastic members,
A simulator characteristic that is a relationship between an operation force and an operation displacement of the braking operation member when the first and second opening / closing means are in a shut-off state and the third opening / closing means is in a communicating state,
One system characteristic that is a relationship between an operation force and an operation displacement of the braking operation member when the first opening / closing means is in a communication state and the second and third opening / closing means are in a cutoff state;
A two-system failure characteristic that is a relationship between an operation force and an operation displacement of the braking operation member when the first and second opening / closing means are in a communication state and the third opening / closing means is in a cutoff state;
A braking control device for a vehicle, wherein rigidity of the plurality of elastic members is set so as to be within an appropriate region sandwiched between the two. The vehicle braking control device according to claim 2,
The simulator characteristics are
An intermediate characteristic that divides the appropriate area into two equal parts in the operation displacement;
A braking control device for a vehicle, wherein rigidity of the plurality of elastic members is set so as to be within an area sandwiched between the one system characteristic.