JP2015160607A - Vehicle braking controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking controller which comprises a master cylinder and a pressurization mechanism driven by an electric motor, has a relatively small ineffective displacement in the case of an improper operation of the system, and is not different in braking operation characteristic regardless of kinds of improper states.SOLUTION: In the braking controller, no hydraulic piping is present between a master cylinder MCL and rear-wheel wheel cylinders WC [r*]. When an operation of an electric motor MTR is judged to be proper, a pressurization mechanism CCL communicates with front-wheel and rear-wheel wheel cylinders (WC [**]), and the master cylinder communicates with a stroke simulator SSM, so that the communication between the master cylinder and the front-wheel wheel cylinders is interrupted. When an operation of the electric motor MTR is judged to be improper, the communication between the pressurization mechanism CCL and the front-wheel and rear-wheel wheel cylinders is interrupted, and the communication between the master cylinder and the stroke simulator is interrupted, so that the master cylinder communicates with the front-wheel wheel cylinders.

Description

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

  Patent Document 1 states that “the left and right fluid pressure systems that individually transmit the fluid pressure to brakes mounted on both sides of one axle and the brake pressure that is mounted on both sides of the other axle collectively. A braking device including a collective fluid pressure system for transmitting, which prevents a yaw motion from being generated in a vehicle when the braking force differs between the brakes of the left and right fluid pressure systems. Specifically, based on the fact that the differential pressure between the left and right fluid pressure systems exceeds a predetermined value, the same as the high pressure side of the left and right fluid pressure systems among the left and right brakes of the collective fluid pressure system The transmission of fluid pressure to the brake on the side is cut off ".

  By the way, in the braking device described in Patent Document 1, braking when the system operation is inappropriate is performed by pressure generated by the master cylinder operated by the driver. If the braking device is a perfect rigid body, the pressure that can be generated by the master cylinder is determined by the area ratio between the wheel cylinder and the master cylinder (the so-called Pascal principle). However, in practice, the pressure that can be generated depends on the rigidity of the braking device (deformation against pressure). In other words, there is an “invalid displacement” that does not directly contribute to the increase in hydraulic pressure (and hence the increase in braking torque of the wheels). Here, the “invalid displacement” is a displacement (for example, a stroke of the brake pedal) caused by the rigidity of the braking device. Specifically, the ineffective displacement includes the elasticity of the fluid piping (particularly flexible piping) from the master cylinder to the wheel cylinder, the clearance between the friction member (for example, brake pad) and the rotating member (for example, brake disc), caliper. The amount of braking fluid discharged from the master cylinder is consumed depending on the rigidity and the like. The amount of brake fluid required to increase the braking torque of the wheel, including the amount of brake fluid consumed by the above factors, is referred to as “consumed fluid amount”.

  In the braking device described in Patent Document 1, when the operation of the system is appropriate, the master cylinder is communicated with an accumulator (stroke simulator), and the brake fluid discharged from the master cylinder is absorbed by the accumulator. On the other hand, as an example of an inappropriate system, when it is determined that the electric fluid pressure output means for the left front wheel is malfunctioning, the electric fluid pressure output means for the right front wheel is in communication with the accumulator. The output port of the master cylinder communicates with the wheel cylinder for the left front wheel. Therefore, the brake fluid of the master cylinder is consumed by the accumulator, the fluid piping of the left front wheel system, and the wheel cylinder. That is, in the braking device described in Patent Document 1, the above-described ineffective displacement is large when the operation of the system is inappropriate.

  Further, the relationship between braking pedal displacement and operating force (braking operation characteristics) will be considered. When the operation of the system is proper, the master cylinder is communicated with the accumulator, and the braking operation characteristic (relationship between the displacement of the braking operation member and the operation force) is determined by the characteristics of the accumulator. Next, as an example of a case where the system is inappropriate, after it is determined that the electric fluid pressure output means for the left front wheel is faulty, the electric fluid pressure output means for the right front wheel is also determined to be faulty. Assuming that In this case, at the stage where “the electric fluid pressure output means for the left front wheel is determined to be faulty and the electric fluid pressure output means for the right front wheel is determined not to be faulty”, the master cylinder The accumulator communicates with the wheel cylinder for the left front wheel. The braking operation characteristic at this stage is determined by the rigidity of the accumulator and the left front wheel wheel cylinder. In a subsequent stage where “the electric fluid pressure output means for the left front wheel and the electric fluid pressure output means for the right front wheel are determined to be faulty”, the master cylinder communicates with the wheel cylinders of the left and right front wheels. The braking operation characteristic at this stage is determined by the rigidity of the wheel cylinders of the left and right front wheels. As described above, in the braking device described in Patent Document 1, the braking operation characteristics differ depending on the type of the state in which the system operation is inappropriate (unsuitable state), and as a result, the driver may feel uncomfortable. obtain.

JP-A-4-362454

  The present invention has been made to address the above-described problems, and an object thereof is a braking control device including a master cylinder driven by a driver and a pressurizing mechanism driven by an electric motor, In the case where the operation of the system is improper, the above-described ineffective displacement is relatively small, and the braking operation characteristic is not different depending on the type of improper state.

  A first braking control device for a vehicle according to the present invention applies a braking torque to a master cylinder (MCL) driven by a braking operation member (BP) of the vehicle and the front wheels (WH [f *]) of the vehicle. A front wheel cylinder (WC [f *]), a rear wheel cylinder (WC [r *]) that applies braking torque to the rear wheel (WH [r *]) of the vehicle, and the master cylinder (MCL) A stroke simulator (SSM) that absorbs the brake fluid to be discharged and applies an operating force to the braking operation member (BP), and an operation amount acquisition means (BPA) that acquires an operation amount (Bpa) of the braking operation member (BP) ), A first electric motor (MTR) controlled based on the operation amount (Bpa), and the first electric motor (MTR), and the front wheel cylinder (WC [f *]) And the rear wheel The pressurizing mechanism (CCL) that pressurizes the brake fluid in the control cylinder (WC [r *]) and the first electric motor (MTR) are in an appropriate state (FLsd = 1) or inadequate state (FLsd = 0) Determining means (HNT), the master cylinder (MCL), the front wheel cylinder (WC [f *]), the rear wheel cylinder (WC [r *]), the stroke simulator (SSM), And switching means (KRK) for switching the communication state of the brake fluid between the pressurizing mechanisms (CCL).

  The first braking control device is characterized in that the switching means (KRK) is configured so that when the determination means (HNT) determines the appropriate state (FLsd = 1), “the pressurizing mechanism (CCL) is , Communicating with the front wheel cylinder (WC [f *]) and the rear wheel cylinder (WC [r *]), communicating the master cylinder (MCL) with the stroke simulator (SSM), and The communication between the master cylinder (MCL), the front wheel cylinder (WC [f *]), and the rear wheel cylinder (WC [r *]) is cut off ”, and the determination means (HNT ) Determines the inappropriate state (FLsd = 0), “the pressurizing mechanism (CCL), the front wheel cylinder (WC [f *]), and the rear wheel cylinder (WC [r *]) And the communication between the master cylinder (MCL) and the stroke simulator (SSM) is cut off, the communication between the master cylinder (MCL) and the rear wheel wheel cylinder (WC [r *]) is cut off, and The master cylinder (MCL) communicates with the front wheel cylinder (WC [f *]) ”.

  Here, regarding the communication between the master cylinder (MCL) and the rear wheel wheel cylinder (WC [r *]), the communication is always cut off (without depending on the state of the switching means (KRK)). A configuration in which securing and blocking of communication are changed according to the state of the switching means (KRK) may be employed. Note that “they communicate with each other” refers to a state in which an internal fluid such as a fluid pipe connecting the two can freely move between the two.

  In the first braking control device according to the present invention, the wheel cylinders WC [f *] and WC [r *] are provided on each of the front wheel WH [f *] and the rear wheel WH [r *] of the vehicle. As the hydraulic pressure increases, braking torque is applied to the wheels WH [f *] and WH [r *]. When the determination means HNT determines that “the operating state of the first electric motor MTR is appropriate (control flag FLsd = 1)” (for example, when the power supply is sufficient), the master cylinder MCL moves to the stroke simulator SSM. The pressure mechanism CCL is communicated with the front and rear wheel cylinders (that is, all four wheel cylinders) WC [**], and the front and rear wheel cylinders WC [**] are disconnected from the master cylinder MCL ( Communication is cut off). In this case, the operation characteristic of the braking operation member depends on the characteristic (spring characteristic) of the stroke simulator SSM.

  On the other hand, when the determination means HNT determines that the operating state of the first electric motor MTR is not appropriate (FLsd = 0) (for example, when power supply is insufficient), the front and rear wheel cylinders (ie, 4 All of the two wheel cylinders) WC [**] are disconnected from the pressurizing mechanism CCL (the communication is cut off), the master cylinder MCL is disconnected from the stroke simulator SSM, and the rear wheel wheel cylinder WC [r *] is disconnected from the master cylinder MCL. The master cylinder MCL communicates only with the front wheel cylinder WC [f *]. In other words, the master cylinder MCL communicates with the front wheel cylinder WC [f *] but does not communicate with the rear wheel cylinder WC [r *]. In this case, the operation characteristic of the braking operation member depends on the rigidity of the front wheel cylinder WC [f *].

  In general, the master cylinder MCL is disposed directly connected to a braking operation member (brake pedal) P operated by the driver. That is, the length of the fluid piping from the master cylinder MCL to the rear wheel cylinder WC [r *] is significantly longer than that for the front wheel. In addition, the liquid piping has elasticity. The volume (volume) of the brake fluid is consumed not only for increasing the braking torque but also for expansion due to elasticity of the fluid piping and the like, and for filling the gap between the friction member (for example, brake pad) and the rotating member (for example, brake disc). The Accordingly, when the master cylinder MCL and the rear wheel wheel cylinder WC [r *] are communicated with each other, the master cylinder MCL is braked compared to the case where the master cylinder MCL and the front wheel cylinder WC [f *] are communicated. Except for increasing the braking torque, the amount of liquid consumed for expansion due to the elasticity of the fluid piping is significantly increased. In other words, the above-described invalid displacement is significantly increased.

  On the other hand, in the first braking control device according to the present invention, regardless of whether the first electric motor MTR is in an appropriate state or in an inappropriate state, the braking fluid in the master cylinder MCL is supplied to the rear wheel wheel cylinder WC [ r *] and the corresponding fluid piping (rear wheel piping) is not consumed for expansion due to elasticity. In other words, the ineffective displacement is small. For this reason, the braking torque can be effectively increased at the front wheels. In addition, when the first electric motor MTR is in an inappropriate state, the braking operation characteristic (the relationship between the displacement and the operating force in the braking operation member) is limited to one characteristic regardless of the type of the inappropriate state. Therefore, it becomes difficult for the driver to feel uncomfortable.

  In the second electric braking device according to the present invention, in contrast to the first electric braking device described above, “hydraulic means for braking (wheel cylinder, and wheel rear wheel (WH [r *])” , Rear wheel system piping) is not provided, and “electric braking means DS [r *] driven by the second electric motor MTW (wheel-side electric motor separate from the first electric motor MTR) is provided. The “provided” is different. Therefore, in the second electric braking device, even if the first electric motor (vehicle body side electric motor) MTR is in an inappropriate state, the electric braking means DS [r *] applies a braking torque to the rear wheel WH [r *]. Can be granted.

  In the second electric braking device, as in the first electric braking device described above, when the first electric motor (vehicle body side electric motor) MTR is in an inappropriate state, the rear wheel WH [r *] side The brake fluid is not consumed. In addition, regardless of the type of the unsuitable state, the braking operation characteristic (relationship between the displacement of the braking operation member and the operation force) is limited to one characteristic. Therefore, the same operation and effect as the above-described operation and effect (effective increase of the braking torque of the front wheels and suppression of change in the braking operation characteristic) can be achieved.

1 is an overall configuration diagram of an embodiment of a braking control device according to the present invention. It is a fluid circuit diagram for explaining a first embodiment of a braking control device according to the present invention. It is a fragmentary sectional view for demonstrating the hydraulic pressure generation means EH2 shown in FIG. It is a functional block diagram for demonstrating the process in electronic control unit ECU. It is a fluid circuit diagram for explaining a 2nd embodiment of the braking control device concerning the present invention. It is a fragmentary sectional view for demonstrating the hydraulic pressure generation means EH1 shown in FIG. FIG. 6 is an overall configuration diagram for explaining the electric braking means DS [r *] shown in FIG. 5 and its control method.

<Overall configuration of a vehicle including a braking control device according to the present invention>
As shown in FIG. 1, a vehicle including a braking control device according to the present invention includes a braking operation member BP, an operation amount acquisition means BPA, an electronic control unit ECU, a hydraulic pressure generation means EH2 (or EH1), a master cylinder MCL, A stroke simulator SSM and switching means KRK are provided. Further, the front wheel WH [f *] of the vehicle is provided with a front wheel cylinder WC [f *], and the rear wheel WH [r *] is provided with a rear wheel cylinder WC [r *]. The hydraulic pressure generating means EH2 (or EH1), the master cylinder MCL, the switching means KRK, and the front and rear wheel cylinders WC [f *], WC [r *] are brake piping HM [f *], HCF, HWF, HCR. , HWR. Here, the hydraulic pressure generating means EH2 is constituted by two fluid chambers, and the hydraulic pressure generating means EH1 is constituted by one fluid chamber.

  Subscripts (for example, [**]) in square brackets attached to the end of various symbols indicate which one of the four wheels corresponds to the same (hereinafter the same). The subscripts indicate that [fl] is related to “left front wheel”, [fr] is related to “right front wheel”, [rl] is related to “left rear wheel”, and [rr] is related to “right rear wheel”, respectively. ing. In addition, the subscripts in square brackets represent a generic name for “4 wheels” for [**], “front wheels” for [f *], and “rear wheels” for [r *]. For example, WC [**] indicates four wheel cylinders, WC [f *] indicates two front wheel cylinders, and WC [r *] indicates two rear wheel cylinders. Furthermore, “front wheel system” represents a front wheel, and “rear wheel system” represents a rear wheel.

  The braking operation member (for example, brake pedal) BP is a member that the driver operates to decelerate the vehicle. By operating the BP, the braking torque of the wheel WH [**] (that is, WH [f *] and WH [r *]) is adjusted, and the braking force is generated on the wheel WH [**]. The

  A rotating member (for example, a brake disc, a brake drum) KT [**] is fixed to each of the four wheels WH [**] of the vehicle. The wheel WH [**] is provided with a wheel cylinder WC [**]. By increasing the hydraulic pressure in the wheel cylinder WC [**], the friction member (for example, brake pad, brake shoe) is pressed against the rotating member KT [**]. Due to the frictional force generated at this time, a braking torque is generated on the wheel WH [**].

  The braking operation member 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. As the operation amount acquisition means BPA, a sensor (pressure sensor) for detecting the pressure of the master cylinder MCL, an operation force of the braking operation member BP, and / or a sensor for detecting the displacement amount (brake pedal depression force sensor, brake pedal displacement sensor) Is adopted. Accordingly, the braking operation amount Bpa is calculated based on at least one of the master cylinder pressure, the brake pedal depression force, and the brake pedal displacement. The braking operation amount Bpa is input to the electronic control unit ECU.

  The hydraulic pressure generating means EH2 (or EH1) and the switching means KRK are controlled by the electronic control unit ECU. Specifically, the ECU is provided with a control means CTL for controlling the hydraulic pressure generation means EH2 (or EH1) and a determination means HNT for controlling the switching means KRK. The hydraulic pressure generation means EH2 (or EH1) and the determination means HNT are control algorithms and are programmed in a microcomputer in the electronic control unit ECU. The control means CTL drives the hydraulic pressure generating means EH2 (or EH1) based on the operation amount Bpa. Further, the determination unit HNT determines whether or not the operating state of the electric motor MTR is appropriate, and controls the switching unit KRK based on the determination result.

  The hydraulic pressure generating means EH2 (or EH1) is provided on the vehicle body side and includes an electric motor MTR, a power transmission member DDB, and a control cylinder CCL (corresponding to a pressurizing mechanism). In the hydraulic pressure generating means EH2 (or EH1), the power of the electric motor MTR driven by the control means CTL is used to discharge or suck the brake fluid (also referred to as brake fluid) to the control cylinder CCL. Specifically, the rotational power of the electric motor MTR is converted into linear power by the power transmission member DDB. Then, with this linear power, the piston inside the control cylinder CCL is moved, and the brake fluid is moved (discharged, sucked). Here, the electric motor MTR that drives the hydraulic pressure generating means EH2 (or EH1) is referred to as "vehicle body side electric motor" or "first electric motor". Instead of the control cylinder CCL, a hydraulic pump (bidirectional rotary pump) driven by the electric motor MTR may be used as the pressurizing mechanism.

  The determination unit HNT determines “whether the operating state of the first electric motor (vehicle-side electric motor) MTR is appropriate or not (inappropriate)”. Specifically, the determination unit HNT includes a power supply state to the electric motor MTR, an operation state of the electronic control unit ECU that drives the MTR, and a state quantity used for controlling the MTR (the detection result of the pressure sensor, the rotation The suitability of the acquisition state of the angle Mka) is determined.

  When the determination unit HNT determines the appropriate state of the electric motor MTR, the hydraulic pressure generation unit EH2 (or EH1) is activated. That is, in an appropriate state (normal operation state) of the electric motor MTR, the control cylinder CCL of the hydraulic pressure generating means EH2 (or EH1) is communicated with the front and rear wheel cylinders WC [f *] and WC [r *]. (The liquid inside is moved freely).

  The master cylinder (also referred to as a brake master cylinder) MCL converts the operation force (brake pedal depression force) of the brake operation member BP into a hydraulic pressure, and pumps the brake fluid only to the front wheel cylinder WC [f *]. That is, the master cylinder MCL is connected to the front wheel cylinder WC [f *] by fluid piping, but is not connected to the rear wheel cylinder WC [r *]. Accordingly, the fluid piping can be omitted between the master cylinder MCL and the rear wheel cylinder WC [r *]. That is, there is no fluid piping between MCL and WC [r *].

  A stroke simulator (also simply referred to as a simulator) SSM generates an operation force on the braking operation member BP. For example, the simulator SSM is provided with a piston and an elastic body (for example, a compression spring). The braking fluid is moved from the master cylinder MCL to the 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.

  Based on the determination result of the determination unit HNT, the switching unit KRK communicates (connects) one of the master cylinder MCL and the control cylinder CCL with at least the front wheel cylinder WC [f *]. When the determination result is “appropriate”, the control cylinder CCL communicates with the front and rear wheel cylinders WC [f *] and WC [r *]. At this time, the master cylinder MCL communicates with the simulator SSM. On the other hand, when the determination result is “inappropriate state”, the communication between the control cylinder CCL and the front and rear wheel cylinders WC [f *] and WC [r *] is cut off, and the master cylinder MCL is connected to the front wheel cylinder WC [f *. ] Is communicated only to. In other words, the switching means KRK selects the brake fluid supply source (either the master cylinder MCL or the control cylinder CCL) to the front wheel cylinder WC [f *]. Between the wheel cylinders WC [f *] and WC [r *] provided on the front and rear wheels WH [f *] and WH [r *], the master and control cylinders MCL and CCL, and the stroke simulator SSM The communication state in the fluid path is switched (selected) by the switching means KRK.

  When the determination means HNT determines an appropriate state, the operation characteristic (relationship between stroke and operation force) of the braking operation member BP is determined by the simulator SSM (particularly, its spring characteristic). On the other hand, when the determination means HNT determines an inappropriate state, the operating characteristic of the braking operation member BP is determined by the rigidity of the braking means including the front wheel cylinder WC [f *]. Here, at least one of a brake caliper (disc brake) and a drum brake is adopted as the braking means.

  The switching means KRK includes switching means (front wheel switching means) KRF for the front wheel cylinder, switching means (rear wheel switching means) KRR for the rear wheel wheel cylinder, and switching means (simulator switching means) CSS for the stroke simulator. Configured. Specifically, the front wheel switching means KRF is connected to the master cylinder MCL via the pipe HM [f *], connected to the control cylinder CCL via the pipe HCF, and connected to the wheel cylinder WC [f *] via the pipe HWF. Is done. Then, the front wheel switching means KRF selects one of a state in which the pipe HWF and the pipe HCF are in communication and a state in which the pipe HWF and the pipe HM [f *] are in communication. Further, the rear wheel switching means KRR is connected to the control cylinder CCL by a pipe HCR, and is connected to the wheel cylinder WC [r *] by a pipe HWR. Here, the switching means KRR is not connected to the master cylinder MCL via the fluid piping. The rear wheel switching means KRR selects one of a state in which the pipe HWR and the pipe HCR are in communication and a state in which the pipe HWR is closed (a state in which the plug is covered with a plug). The simulator switching means CSS is connected to the master cylinder MCL by a pipe HMS, and is connected to the stroke simulator SSM by a pipe SSM. The simulator switching means CSS selects one of a state where the pipe HMS and the pipe HSS are in communication and a state where the pipe HMS is closed (a state where the plug is covered with a plug).

  The movement (pressure feeding) of the brake fluid when the hydraulic pressure of the wheel cylinders WC [f *] and WC [r *] provided in the front and rear wheels WH [f *] and WH [r *] is increased will be summarized. When the determination unit HNT in the electronic control unit ECU determines the appropriate state of the first electric motor MTR, the front wheel WH [f *] has “CCL → HCF → KRK (KRF) → HWF → WC [f *”. ] "And the brake fluid is moved in the order of" CCL → HCR → KRK (KRR) → HWR → WC [r *] "in the rear wheel WH [r *]. On the other hand, when the determination unit HNT determines an inappropriate state of the first electric motor MTR (when the appropriate state is denied), “MCL → HM [f *] → KRK ( The brake fluid is moved in the order of “KRF) → HWF → WC [f *]”, but the brake fluid is not moved to the wheel cylinder WC [r *] of the rear wheel WH [r *]. For this reason, since the amount of liquid consumption due to the rigidity of the rear wheel pipe HWR and the rear wheel wheel cylinder WC [r *] becomes zero, the brake fluid of the master cylinder MCL can be used efficiently. As a result, the inner diameter of the master cylinder MCL is made small, and a braking torque can be generated effectively.

  Here, the amount of consumed fluid is the amount (volume) of braking fluid that is consumed directly or indirectly because braking torque is generated. For example, when a disc brake is employed as a wheel braking device, the braking torque is generated by the force (pressing force) by which the brake pad pushes the brake disc. As the pressing force increases, the caliper is greatly deformed, and the amount of liquid required in the wheel cylinder (caliper cylinder) increases with the deformation. Further, the amount of brake fluid is also consumed for expansion of fluid piping (particularly, flexible piping connecting the vehicle body side and the wheel side) as pressure increases. Further, the amount of liquid is consumed to close the gap between the brake pad and the brake disk before the increase of the braking torque is started. Normally, this gap is maintained by the amount of elastic deformation of the seal member, but it is caused by sudden turning, running on a road surface with large irregularities, uneven wear of brake pads (non-uniform wear), vibration of the brake disk, etc. This gap can be increased. In this case, the amount of liquid consumed is further increased.

  Considering mountability on the vehicle, the longitudinal dimension (axial direction) of the master cylinder MCL and the longitudinal dimension of the hydraulic pressure generating means EH1, EH2 are substantially the same, and the braking control device is configured as an integrated type. It is desirable. However, in the hydraulic pressure generating means EH1, EH2, the control cylinder CCL is driven by the first electric motor MTR, so that a rotation / linear motion conversion mechanism (for example, a screw member NJB) may be provided at the end of the CCL. It is an essential requirement. Therefore, in order to achieve an integrated structure of the brake control device, it is necessary to reduce the longitudinal size of the hydraulic pressure generating means EH1, EH2 in consideration of the longitudinal dimension of the rotation / linear motion converting mechanism. is there. Further, in order to properly maintain the operation force of the brake operation member BP at the time of improper determination, a sufficient amount of brake fluid is discharged from the master cylinder MCL, and the front wheel cylinder WC with respect to the pressure-receiving area of the MCL. The ratio of the pressure receiving area of [f *] needs to be set large.

  The hydraulic pressure generating means EH2 (or EH1) includes a first electric motor MTR, a power transmission member DDB (NJB and GSK), and a control cylinder CCL. In the arrangement of each component, the central axis Jcc of the control cylinder CCL and the rotation axis Jmt of the first electric motor MTR are parallel to each other and are separate axes (configuration formed by two axes), and the speed is reduced. The control cylinder CCL and the first electric motor MTR can be arranged on the same side with respect to the machine GSK. With this two-axis arrangement, the size in the longitudinal direction (axial direction) can be reduced as compared with the case where the control cylinder CCL and the first electric motor MTR are coaxial (one-axis arrangement). The necessity for downsizing in the longitudinal direction is due to the improvement of the mountability to the vehicle and the collision safety.

  The inner diameter φDcc of the control cylinder CCL (that is, the pressure receiving area of the piston in the CCL) can be set larger than the inner diameter φDmc of the master cylinder MCL (that is, the pressure receiving area of the piston in the MCL). Further, the length (longitudinal dimension) of the control cylinder CCL in the central axis direction Jcc can be set shorter than the length (longitudinal dimension) of the master cylinder MCL in the central axis direction Jmc.

  Control cylinder CCL with respect to reduction gear GSK, arrangement of first electric motor MTR (arrangement on the same side), magnitude relationship (φDcc> φDmc) between inner diameter φDcc of control cylinder CCL and inner diameter φDmc of master cylinder MCL, and control cylinder By adopting at least one of the magnitude relationship between the length of the CCL and the length of the master cylinder MCL, the longitudinal dimension of the hydraulic pressure generating means EH1, EH2 is compared with the longitudinal dimension of the master cylinder MCL. And can be further shortened. As a result, the dimensions in the longitudinal direction of the master cylinder MCL and the hydraulic pressure generating means EH1 and EH2 are substantially the same, and the mountability to the vehicle can be improved. In addition, when determining the inappropriateness of the first electric motor MTR, the braking torque of the vehicle can be ensured with the minimum necessary operating force.

  The control cylinder CCL can cover the amount of braking fluid required for a plurality of braking operations. This is to cope with a case where the driver suddenly depresses again after the brake operation member BP is suddenly returned during the braking operation. Therefore, the volume Vcc of the control cylinder CCL can be set larger than the volume Vmc of the master cylinder MCL. Here, the “volume of the cylinder” is the volume of the liquid that can enter the cylinder, and is the volume of the brake fluid contained in the CCL and MCL when no brake fluid pressure is generated.

  Further, in the above configuration, the fluid path in the rear wheel WH [r *] can be omitted. Specifically, the fluid piping HCR, HWR, the switching means KRR, and the wheel cylinder WC [r *] in the rear wheel system can be omitted. In this case, the braking torque of the rear wheel WH [r *] is applied by the electric braking means (braking means DS [r *] that does not use the brake fluid described later). Even in this case, the same effects as described above are obtained.

<First Embodiment>
Next, a first embodiment of the present invention will be described with reference to the fluid circuit diagram of FIG. In the first embodiment, the brake fluid (brake fluid) is supplied from the hydraulic pressure generating means EH2 to the front wheel cylinders WC [f *] (WC [fl], WC [fr]) and the rear wheel cylinder WC [r *] (WC [rl], WC [rr]). The configuration of FIG. 2 shows so-called diagonal piping.

  As in the case of FIG. 1, the subscripts in square brackets (for example, [**]) attached to the end of various symbols indicate which of the four wheels corresponds to each symbol. , [Fl] is related to "left front wheel", [fr] is related to "right front wheel", [rl] is related to "left rear wheel", and [rr] is related to "right rear wheel", respectively. . In addition, the subscripts in square brackets represent a generic name for “4 wheels” for [**], “front wheels” for [f *], and “rear wheels” for [r *]. For example, WC [**] indicates a four-wheel wheel cylinder, WC [f *] indicates a front two-wheel wheel cylinder, and WC [r *] indicates a rear two-wheel wheel cylinder. Furthermore, “front wheel system” represents a front wheel, and “rear wheel system” represents a rear wheel.

  The members (components, for example, MCL) denoted by the same symbols as those shown in FIG. 1 correspond to each other and have the same function (hereinafter the same). The switching means KRF, KRR correspond to the electromagnetic valves VC1, VC2, MC [fl], MC [fr]. In the fluid piping, the piping HCF and HCR correspond to the piping HC1 and HC2, and the piping HWF and HWR correspond to the piping HV1, HV2, and HW [**].

  Operation amount acquisition means BPA for acquiring the operation amount Bpa of the braking operation member (brake pedal) BP is provided. The braking operation amount Bpa is transmitted to the electronic control unit ECU. The electronic control unit ECU controls the first electric motor MTR that drives the hydraulic pressure generating means EH2 and each electromagnetic valve (VC1 and the like) based on the braking operation amount Bpa.

[Connection status of each component via fluid piping]
First, the state where each component is connected by fluid piping will be described. Here, the connection state of the fluid piping represents the connection of each mechanical component (solenoid valve, piping, etc.), and does not represent the fluid connection (communication or non-communication) by opening / closing the solenoid valve. . Note that “communication” represents a state in which fluids inside a plurality of members can freely move with respect to each other, and “non-communication” refers to a state in which this fluid movement is not possible.

  A braking operation member (brake pedal) BP that is operated by the driver to maintain the vehicle deceleration or stop state is connected to the piston MP1 in the master cylinder MCL via the push rod PRD. The master cylinder MCL is connected to the reservoir RSV so that the brake fluid can be replenished. The master cylinder MCL is connected to an electromagnetic valve MC [f *] (also referred to as a cutoff valve) via a pipe HM [f *]. The electromagnetic valve MC [f *] is connected to the wheel cylinder WC [f *] via the pipe HV [f *] and the pipe HW [f *]. That is, the master cylinder MCL is connected to the wheel cylinder WC [f *] via HM [f *], MC [f *], HV [f *], and HW [f *]. The master cylinder MCL is connected to the stroke simulator SSM via a solenoid valve CSS.

  The control cylinder CCL driven by the electric motor MTR is connected to the reservoir RSV. The control cylinder CCL is connected to electromagnetic valves VC1 and VC2 (also referred to as introduction valves) via pipes HC1 and HC2. VC1 and VC2 are connected to a solenoid valve EN [**] (also referred to as a pressure booster valve) via pipes HV1 and HV2. The solenoid valve EN [**] is connected to the wheel cylinder WC [**] via the pipe HW [**]. That is, the control cylinder CCL is connected to the wheel cylinder WC [**] via the pipes HC1, HC2, the introduction valves VC1, VC2, the pipes HV1, HV2, the pressure increasing valve EN [**], and the pipe HW [**]. Connected to. Further, the wheel cylinder WC [**] is connected to the RSV via the pipe HW [**] and the electromagnetic valve OT [**] (also referred to as a pressure reducing valve).

  In order to detect the pressure generated by the master cylinder MCL, hydraulic pressure acquisition means (pressure sensor) PM [f *] is provided in the fluid path from the master cylinder MCL to the electromagnetic valve MC [f *]. In order to detect the pressure generated by the control cylinder CCL, hydraulic pressure acquisition means (pressure sensors) PC1 and PC2 are provided in the fluid path from the control cylinder CCL to the wheel cylinder WC [**]. Furthermore, hydraulic pressure acquisition means (pressure sensor) PW [**] for detecting the pressure of the wheel cylinder WC [**] can be provided in the WC [**] of each wheel.

[Function and operation of each solenoid valve]
The function (role) and operation of each solenoid valve (MC [f *] etc.) will be described. The shutoff valve (solenoid valve) MC [f *] switches between communication and non-communication between the master cylinder MCL and the wheel cylinder WC [f *]. As the electromagnetic valve MC [f *], a normally open type (also referred to as NO valve) that is open when not energized and closed when energized is employed. The introduction valves (electromagnetic valves) VC1 and VC2 switch between communication and non-communication between the control cylinder CCL and the wheel cylinder WC [**] of each wheel. As VC1 and VC2, a normally closed type (also referred to as an NC valve) that is closed when not energized and opened when energized is employed.

  The pressure increasing valve (solenoid valve) EN [**] and the pressure reducing valve (solenoid valve) OT [**] are used for each wheel cylinder when anti-skid control, traction control, or vehicle stabilization control is executed. It is used to adjust the hydraulic pressure of WC [**] individually and independently. Specifically, in order to increase the hydraulic pressure of the wheel cylinder WC [**] by each control described above, the electromagnetic valve EN [**] is set to the open position and the electromagnetic valve OT [**] is In the closed position, the brake fluid is moved from the control cylinder CCL toward the wheel cylinder WC [**]. On the other hand, in order to reduce the hydraulic pressure of the wheel cylinder WC [**] by the above control, the solenoid valve EN [**] is set to the closed position and the solenoid valve OT [**] is set to the open position. The brake fluid in the wheel cylinder WC [**] is moved to the reservoir RSV. Here, a normally open (normally open) type solenoid valve is employed as the pressure increasing valve EN [**], and a normally closed (normally closed) type solenoid valve is employed as the pressure reducing valve OT [**]. In addition, an electromagnetic proportional valve may be employed as at least one of the electromagnetic valve EN [**] and the electromagnetic valve OT [**]. By adopting an electromagnetic proportional valve, the hydraulic pressure of the wheel cylinder WC [**] can be adjusted not only to a value corresponding to the open position or the closed position, but also continuously between them.

[Communication status at proper judgment]
Next, the case where the determination unit HNT determines “the appropriate state of the electric motor MTR” (also referred to as the appropriate determination time) will be described. In this case, the introduction valves VC1 and VC2 and the pressure increasing valve EN [**] are opened (communication state), and the shutoff valve MC [f *] and pressure reducing valve OT [**] are closed. (Not connected). Therefore, the wheel cylinder WC [**] is communicated with the control cylinder CCL of the hydraulic pressure generating means EH2 via the electromagnetic valves VC1, VC2 and EN [**]. On the other hand, the communication between the wheel cylinder WC [f *] and the master cylinder MCL is blocked by the cutoff valve MC [f *], and the wheel cylinder WC [**] is connected by the pressure reducing valve OT [**]. Communication with the reservoir RSV is blocked. That is, the piston is moved in the control cylinder CCL and the volume of the fluid chamber in the CCL is reduced, so that the brake fluid is discharged from the CCL toward the wheel cylinder WC [**]. The brake fluid is moved in the order of “CCL → HC1, HC2 → VC1, VC2 → HV1, HV2 → EN [**] → HW [**] → WC [**]”. By increasing the hydraulic pressure of WC [**], the force with which the friction member (for example, brake pad) presses the rotating member (for example, brake disc) KT [**] increases, and the wheel WH [** ] Braking torque is increased. On the other hand, when the braking torque of the wheel WH [**] is decreased, the brake fluid is changed to “WC [**] → HW [**] → EN [**] → HV1, HV2 → VC1, VC2 → From the wheel cylinder WC [**], the control cylinder CCL is returned in the order of “HC1, HC2 → CCL” (the reverse direction to the case where the braking torque is increased). The hydraulic pressure of WC [**] is reduced, and the force that presses the friction member against the rotating member KT [**] is reduced. That is, the braking torque applied to the wheels is controlled by adjusting the volume of the control cylinder CCL. Note that when the braking torque is not applied to the wheel WH [**] (for example, when the driver does not operate the BP), the control cylinder CCL and the reservoir RSV are communicated with each other via the fluid pipe HRV. .

  Furthermore, at the time of the appropriateness determination, the electromagnetic valve CSS is brought into an open position (communication state), and the master cylinder MCL is fluidly connected (communicated) to a stroke simulator (also simply referred to as a simulator). An elastic body (for example, a compression spring) is provided inside the simulator SSM. By this elastic body, an operation force (for example, a brake pedal depression force) when the brake operation member BP is operated is formed.

[Communication status at inappropriate judgment]
When the determination means HNT determines “inappropriate state of the electric motor MTR” (also referred to as inappropriate determination), the introduction valves VC1 and VC2 and the pressure reducing valve OT [**] are in the closed position (non- The shutoff valve MC [f *] is closed (non-communication state). At this time, the pressure increasing valve EN [**] may be in the closed position, but may remain in the open position. The wheel cylinder WC [f *] is communicated with the master cylinder MCL via the electromagnetic valve MC [f *]. On the other hand, the communication between the wheel cylinder WC [f *] and the control cylinder CCL is blocked by the introduction valves VC1 and VC2, and the wheel cylinder WC [f *] and the reservoir RSV are connected by the pressure reducing valve OT [**]. Communication between and is interrupted. That is, the pistons MP1 and MP2 are moved in the master cylinder MCL, and the volume of the fluid chambers Rm1 and Rm2 in the master cylinder MCL is reduced, so that the brake fluid is transferred from the master cylinder MCL to the front wheel cylinder WC [f *]. It is discharged towards.

  The master cylinder MCL is a so-called tandem master cylinder, and is partitioned into two fluid chambers Rm1 and Rm2 by pistons MP1 and MP2. These fluid chambers communicate with the reservoir RSV through a relief port when the brake operation member BP is not operated. When an operating force is applied to the braking operation member BP, the master pistons MP1 and MP2 in the master cylinder MCL are moved via the push rod PRD. A cup (a cup-shaped rubber seal for holding the hydraulic pressure) is provided on the outer peripheral portion of the master pistons MP1 and MP2, and the relief port is closed by this cup so that the fluid chambers Rm1 and Rm2 communicate with the reservoir RSV. And the brake fluid is pumped from Rm1, Rm2 toward the front wheel cylinder WC [f *].

  The brake fluid is moved in the order of “MCL → HM [f *] → MC [f *] → HV [f *] → HW [f *] → WC [f *]”. As the hydraulic pressure of WC [f *] increases, the pressing force of the friction member against the rotating member KT [f *] is increased, and the braking torque of the front wheel WH [f *] is increased. On the other hand, when the braking torque of the front wheel WH [f *] is reduced, the braking fluid is changed to “WC [f *] → HW [f *] → HV [f *] → MC [f *] → HM [ In the order of “f *] → MCL” (the direction opposite to the case where the braking torque is increased), the front wheel cylinder WC [f *] is returned to the master cylinder MCL. The rear wheel wheel cylinder WC [r *] is not connected to the master cylinder MCL in fluid piping (there is no fluid piping connecting MCL and WC [r *]), so the rear wheel WH [r *] The braking torque of] is not applied at the time of inappropriate determination.

  Furthermore, at the time of improper determination, the solenoid valve CSS is closed (non-communication state), and communication between the master cylinder MCL and the simulator SSM is blocked. Therefore, the operating force (pedal pedaling force) when the braking operation member BP is operated is formed depending on the rigidity of the fluid path from the master cylinder MCL to the front wheel cylinder WC [f *].

  In the first embodiment, the hydraulic pressure of the wheel cylinder WC [**] is adjusted by hydraulic pressure generating means EH2 (that is, the control cylinder CCL which is a pressurizing mechanism) driven by the electric motor MTR at the time of appropriateness determination. Is done. On the other hand, since the master cylinder MCL is not connected to the rear wheel cylinder WC [r *] by fluid piping, the hydraulic pressure of the rear wheel cylinder WC [r *] is not increased at the time of inappropriate determination. Adjustment may be possible only with the hydraulic pressure of the cylinder WC [f *].

  Master cylinder MCL is provided at the front of the vehicle so as to be operated by the driver. Accordingly, the pipe length from the master cylinder MCL to the rear wheel cylinder WC [r *] provided at the rear of the vehicle is relatively long, and the amount of liquid consumed due to the expansion of the fluid pipe is large. Further, because of changes in the wheel load before and after the vehicle and the wheel load during vehicle deceleration, the contribution of the front wheels is much greater than the contribution of the rear wheels in the braking force acting on the entire vehicle. From the above points, at the time of improper determination in which braking torque is applied to the wheel only by the driver's operating force, the above configuration reduces the amount of liquid consumption that does not directly contribute to the application of braking torque. Can be smaller. Further, since the amount of liquid consumption can be reduced, the ratio (ratio) of the cross-sectional area of the rear wheel cylinder WC [f *] to the cross-sectional area of the master cylinder MCL is set to be relatively large, reducing the operating force of the driver. Can be done. In addition, at the time of improper determination, regardless of the type of improper state, the braking operation characteristic (the relationship between the displacement of the braking operation member and the operating force) is limited to one characteristic. Therefore, it becomes difficult for the driver to feel uncomfortable.

  In the first embodiment, the brake fluid is supplied to the wheel cylinders WC [**] provided on the four wheels WH [**] by one hydraulic pressure generating means EH2 (that is, one control cylinder CCL). . One master cylinder MCL supplies brake fluid only to the wheel cylinders WC [f *] provided to the two wheels WH [f *] in front of the vehicle. Further, considering the response to the case where the driver repeatedly operates the brake operation member BP repeatedly (depression and return), the CCL and the volume of the MCL (the brake fluid that can be accommodated inside when the hydraulic pressure is zero) Amount) is determined. Accordingly, the volume Vcc of the control cylinder CCL is set larger than the volume Vmc of the master cylinder MCL. For this reason, a braking control apparatus can be reduced in size.

  Although the first embodiment has been described with the example of the diagonal pipe, a front and rear pipe may be employed as the configuration of the fluid pipe. Even in the configuration of the front and rear piping, at the time of appropriateness determination, the control cylinder CCL and the four-wheel wheel cylinder WC [**] are in communication with each other, and communication between the master cylinder MCL and the wheel cylinder WC [**] is blocked. . On the other hand, when the determination is inappropriate, the communication between the control cylinder CCL and the wheel cylinder WC [**] is cut off, and the master cylinder MCL is communicated only with the front wheel cylinder WC [f *]. Accordingly, the same effect as described above is obtained.

<Hydraulic pressure generating means EH2 composed of two fluid chambers Rc1, Rc2>
Next, the hydraulic pressure generating means EH2 constituted by two fluid chambers will be described with reference to a partial sectional view of FIG. The hydraulic pressure generating means EH2 adjusts the hydraulic pressure of the wheel cylinder WC [**] based on the braking operation amount Bpa. The hydraulic pressure generating means EH2 is provided on the vehicle body side, and includes an electric motor (first electric motor) MTR, a power transmission member DDB, a control cylinder CCL, control pistons CP1 and CP2, and springs SP1 and SP2. .

  Since the electric motor MTR is provided on the vehicle body side, it is also referred to as “vehicle body side electric motor (corresponding to the first electric motor)”. The vehicle body side electric motor MTR is controlled by the electronic control unit ECU, and generates power for adjusting the hydraulic pressure of each of the four wheel cylinders WC [**]. As the vehicle body side electric motor MTR, a motor with a brush or a brushless motor can be adopted. The electric motor MTR is provided with rotation angle acquisition means MKA for acquiring the position (rotation angle) Mka of the rotor (rotor) with respect to the stator (stator). In the rotation direction of the electric motor MTR, the forward rotation direction corresponds to the direction in which the hydraulic pressure of the wheel cylinder WC [**] increases (that is, the direction in which the braking torque increases), and the reverse rotation direction corresponds to the wheel cylinder WC. [**] corresponds to the direction in which the hydraulic pressure decreases (that is, the direction in which the braking torque decreases).

  The power transmission member DDB converts the output (rotational power) of the electric motor MTR into the linear power of the control pistons CP1 and CP2, and transmits it. The power transmission member DDB includes a reduction gear GSK and a screw member NJB. The reduction gear GSK reduces the rotational speed of the power of the electric motor MTR and outputs it to the screw member NJB. That is, the rotational output (torque) of the electric motor MTR is increased according to the reduction ratio of the reduction gear GSK and transmitted to the screw member NJB as rotational force (torque). For example, the reduction gear GSK is configured by a small diameter gear SKH and a large diameter gear DKH.

  As the reduction gear GSK, a wrapping transmission mechanism using a belt can be employed instead of the gear transmission mechanism. In this case, instead of the large diameter gear DKH and the small diameter gear SKH, a set of a large diameter pulley and a small diameter pulley is employed. By employing the belt transmission mechanism, the distance between the two axes can be increased and the reduction ratio can be set large. As a result, a high rotation / small torque type electric motor is employed as the MTR, and the apparatus can be miniaturized. In addition, gear rattling noise and the like can be avoided, and the quietness of the apparatus can be improved.

  The screw member NJB is a member (rotation / linear motion conversion mechanism) that converts rotational power into linear power. The screw member NJB includes a nut member NUT and a bolt member BLT. The bolt member BLT is fixed coaxially (axis Jcc) to the large-diameter gear DKH. Key grooves are formed in the outer peripheral portion of the nut member NUT and the inner peripheral portion of the control cylinder CCL. When the key member KYB is fitted into the key groove, the nut member NUT is restricted from rotating around the central axis Jcc, but linear movement in the direction of the central axis Jcc (longitudinal direction of the key groove) is allowed. Is done. The control pistons CP1 and CP2 are moved by the linear movement of the nut member NUT.

  The screw member NJB has reversibility (has reverse efficiency) and can transmit power in both directions. That is, when the pressure in the wheel cylinder WC [**] is increased (when the braking torque is increased), power is transmitted from the electric motor MTR to the pistons CP1 and CP2 through the screw member NJB. Conversely, when the pressure in the wheel cylinder WC [**] is reduced (when the braking torque is reduced), power is transmitted from the pistons CP1 and CP2 to the electric motor MTR via the screw member NJB ( At this time, the reverse efficiency is larger than “0”).

  The screw member NJB is configured by a sliding screw (such as a trapezoidal screw) that transmits power by “sliding”. In this case, the nut member NUT is provided with a female screw (inner screw) MNJ. The bolt member BLT is provided with a male screw (outer screw) ONJ and is screwed to the MNJ of the NUT. The rotational power (torque) transmitted from the shaft member SFT is transmitted as linear power (thrust) of the pistons CP1 and CP2 via the screw members NJB (ONJ and MNJ). Instead of the sliding screw, a rolling screw (such as a ball screw) in which power is transmitted by “rolling” may be employed as the screw member NJB. In this case, a ball groove is provided in the nut member and the bolt member. Power is transmitted through a ball (steel ball) fitted in the ball groove.

  As the rotation / linear motion conversion mechanism of the power transmission member DDB, a conversion mechanism such as a ball ramp member, a rotation wedge member, a rack & pinion member, or the like can be employed instead of the screw member NJB.

  Similar to the structure of the master cylinder (tandem master cylinder) MCL, the inside of the control cylinder CCL is divided into two fluid chambers Rc1 and Rc2 by the control pistons CP1 and CP2. These fluid chambers Rc1 and Rc2 communicate with the reservoir RSV through the relief ports PE1 and PE2 and the fluid pipe HRV when braking torque is not required (for example, when the BP is not operated). .

  When the braking torque is increased, the vehicle body side electric motor MTR is driven in the forward rotation direction, whereby the nut member NUT pushes the piston CP1, and CP1 is moved in the direction of the white arrow. Further, the piston CP2 is pushed and moved through the spring SP1. Cups (cup-shaped rubber seals that are in contact with the inner periphery of the control cylinder CCL and maintain the hydraulic pressure) GC1 and GC2 are provided on the outer periphery of the pistons CP1 and CP2. As the control pistons CP1 and CP2 are moved in the control cylinder CCL, the relief ports PE1 and PE2 are closed by the cups GC1 and GC2, and the communication state between the fluid chambers Rc1 and Rc2 and the reservoir RSV is hindered. (Becomes out of communication). Further, when the pistons CP1 and CP2 are moved, the volumes of the fluid chambers Rc1 and Rc2 are reduced, and the brake fluid (brake fluid) is directed from the fluid chambers Rc1 and Rc2 to the four-wheel wheel cylinder WC [**]. And the hydraulic pressure of the wheel cylinder WC [**] is increased. That is, the brake fluid is pumped from the output ports PO1 and PO2 of the fluid chambers Rc1 and Rc2 to the fluid pipes HC1 and HC2.

  When the braking torque is decreased, the vehicle body side electric motor MTR is driven in the reverse direction, and the control pistons CP1 and CP2 are returned toward the original positions (positions where Rc1 and Rc2 communicate with RSV). Due to the movement of the pistons CP1, CP2, the volumes of the fluid chambers Rc1, Rc2 are increased, the brake fluid is returned from the wheel cylinder WC [**] to the control cylinder CCL, and the hydraulic pressure of the wheel cylinder WC [**] is decreased. The

  In the configuration of the hydraulic pressure generating means EH2, the central axis (that is, the rotation axis of NJB and DKH) Jcc of the control cylinder CCL and the rotation axis of the electric motor MTR (that is, the rotation axis of SKH) Jmt are parallel to each other. And can be on separate axes. The fluid chambers Rc1 and Rc2 (that is, the control cylinder CCL) are arranged on the same side as the electric motor MTR with respect to the reduction gear GSK. When the axis Jcc and the axis Jmt are configured coaxially, the hydraulic pressure generating means EH2 becomes longer in the axial direction. Similarly, even if Jcc and Jmt have different axes, if the fluid chambers Rc1 and Rc2 and the electric motor MTR are arranged on different sides with respect to the reduction gear GSK, hydraulic pressure is generated. The means EH2 becomes longer in the axial direction. The central axis Jcc of the control cylinder and the rotation axis Jmt of the electric motor are parallel and are arranged as different axes, and the control cylinder CCL and the electric motor MTR are placed on the same side with respect to the speed reducer GSK. The axial length (longitudinal dimension) of the pressure generating means EH2 can be shortened.

<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 vehicle includes a braking operation member BP, a power source BAT (storage battery), an ALT (generator), and an electronic control unit ECU. The storage battery BAT and the generator ALT are collectively referred to as “power source (power source)”. The electronic control unit ECU receives power supply from a power source (BAT or the like) via a power line (power line) PWL, and the electric motor MTR of the hydraulic pressure generating means EH2 and the switching means KRK (MC [f *] etc. ) To control. The processing in the electronic control unit ECU is configured by control means (control processing block) CTL and determination means (determination processing block) HNT.

  The control processing block CTL (corresponding to the control means) includes an anti-skid control block ABS, a traction control block TCS, a vehicle stabilization control block ESC, a command hydraulic pressure calculation block PWS, a target energization amount calculation block IMT, an electric motor control block DRV, And it is comprised by the solenoid valve control block SOL. The control means CTL includes a control algorithm, a drive circuit for the electric motor MTR, and a drive circuit for a solenoid valve (VC1 or the like). The control algorithm is programmed in a microcomputer in the ECU.

  In the anti-skid control block ABS, the target pressing force Fabs for executing the known anti-skid control (Anti-skid Control) is determined based on the acquisition result (wheel speed Vwa) of the wheel speed acquisition means VWA provided in each wheel. Calculated. That is, the target pressing force Fabs for anti-skid control is a target value of the pressing force for preventing wheel lock. Here, the “pressing force” is a force with which a friction member (for example, a brake pad or a brake shoe) presses a rotating member (for example, a brake disc or a brake drum). Accordingly, the pressing force corresponds to the hydraulic pressure of the wheel cylinder WC [**] (“pressing pressure” = “pressure receiving area of WC [**]” × “hydraulic pressure of WC [**]”).

  Similarly, in the traction control block TCS, a target pressing force Ftcs for executing a known traction control (Traction Control) is calculated based on the acquisition result (wheel speed Vwa) of the wheel speed acquisition means VWA. That is, the target pressing force Ftcs for traction control is a target value of pressing force (corresponding to hydraulic pressure) for suppressing wheel spin (over-rotation).

  Further, in the vehicle stabilization control block ESC, a well-known vehicle stabilization control (Electronic Stability Control) is performed based on the acquisition results (yaw rate Yra, lateral acceleration Gya) of the vehicle behavior acquisition means (yaw rate sensor YRA, lateral acceleration sensor GYA). The target pressing force Fesc for executing is calculated. That is, the target pressing force Fesc for vehicle stabilization control is a target value of a pressing force (corresponding to a hydraulic pressure) for suppressing excessive vehicle understeer and / or oversteer.

  In the command hydraulic pressure calculation block PWS, the command hydraulic pressure Pws is calculated based on the braking operation amount Bpa and the calculation characteristics (calculation map) CHpw. Here, the indicator hydraulic pressure Pws is a target value of the pressure generated by the hydraulic pressure generating means EH2. In the calculation characteristic CHpw, the indicated hydraulic pressure Pws is calculated to be zero in the range where the manipulated variable Bpa is greater than or equal to zero (corresponding to the case where no braking operation is performed) and less than the predetermined value bp0, and when the manipulated variable Bpa is greater than or equal to the predetermined value bp0. The indication hydraulic pressure Pws is calculated so as to simply increase from zero.

  In the target energization amount calculation block IMT, the target energization amount Imt (target value of the energization amount for controlling the MTR) of the electric motor MTR is calculated based on the command hydraulic pressure Pws and the like. Here, the “energization amount” is a state amount (variable) for controlling the output torque of the electric motor MTR. Since the electric motor MTR outputs a torque approximately proportional to the current, the current target value of the electric motor MTR can be used as the target value of the energization amount (target energization amount). Further, if the supply voltage to the electric motor MTR is increased, the current is increased as a result, so that the supply voltage value can be used as the target energization amount. Furthermore, since the supply voltage value can be adjusted by the duty ratio in the pulse width modulation, this duty ratio can be used as the energization amount.

  In the target energization amount calculation block IMT, the sign (value positive / negative) of the target energization amount Imt is determined based on the direction in which the first electric motor MTR should rotate (that is, the increase / decrease direction of the hydraulic pressure). Based on the rotational power to be output (that is, the amount of increase / decrease in hydraulic pressure), the magnitude of the target energization amount Imt is calculated. Specifically, when increasing the brake hydraulic pressure, the sign of the target energization amount Imt is calculated as a positive sign (Imt> 0), and the electric motor MTR is driven in the forward rotation direction. On the other hand, when reducing the brake fluid pressure, the sign of Imt is determined to be a negative sign (Imt <0), and the electric motor MTR is driven in the reverse direction. Furthermore, the output torque of the electric motor MTR is controlled to increase as the absolute value of the target energization amount Imt increases, and the output torque is controlled to decrease as the absolute value of Imt decreases.

  The target energization amount calculation block IMT includes a hydraulic pressure conversion calculation block and a hydraulic pressure control calculation block. In the hydraulic pressure conversion calculation block, one of the anti-skid control target pressing force Fabs, the traction control target pressing force Ftcs, and the vehicle stabilization control target pressing force Fesc is selected and converted into hydraulic pressure. . The selection order of the target pressing force is determined based on the traveling state of the vehicle and the state of the wheels. Note that when the corresponding wheel is not a driving wheel (when not connected to the drive train), Ftsc is not selected. Then, based on one of the target values Fabs, Ftcs, and Fesc converted in hydraulic pressure, and the indicated hydraulic pressure Pws, the final hydraulic pressure target value Pwt is determined. Specifically, the indicated hydraulic pressure Pws is corrected by the target pressure (Fabs, Ftcs, or Fesc) converted into the hydraulic pressure, and the target hydraulic pressure (hydraulic pressure target value) Pwt is calculated.

  In the hydraulic pressure control calculation block, the target energization amount Imt of the electric motor MTR is calculated based on the hydraulic pressure target value Pwt and the hydraulic pressure actual value Pwa. Here, the actual hydraulic pressure value Pwa is an actual value (actual hydraulic pressure) of the hydraulic pressure acquired (detected) by the hydraulic pressure acquisition means (pressure sensor) PC1, PC2. As the actual hydraulic pressure Pwa, an actual hydraulic pressure (actual value) acquired by the hydraulic pressure acquisition means PW [**] provided in each wheel cylinder WC [**] can be adopted. In addition, the actual hydraulic pressure Pwa can be estimated based on the acquired values of the hydraulic pressure acquisition means PC1 and PC2 and the operating state of each electromagnetic valve (for example, EN [**], OT [**]).

  In the hydraulic pressure control calculation block of the target energization amount calculation block IMT, first, the feedforward component Imt1 in the target energization amount Imt is calculated based on the target hydraulic pressure Pwt and a preset calculation map. Next, a feedback component Imt2 in Imt is calculated based on the deviation between the target value Pwt and the implementation value Pwa. Then, the feedforward component Imt1 is corrected by the feedback component Imt2, and the final target energization amount Imt is calculated (for example, Imt = Imt1 + Imt2).

  In the electric motor control block DRV, the output of the first electric motor MTR is adjusted based on the target energization amount Imt. The electric motor control block DRV includes a bridge circuit HBR composed of a plurality of switching elements for driving the electric motor MTR and an arithmetic process (control algorithm) for calculating a drive signal for driving each switching element. Configured. When a brush motor is employed as the electric motor MTR, the bridge circuit HBR is configured by four switching elements. When a brushless motor is employed, a bridge circuit HBR is configured with six switching elements (a so-called three-phase bridge circuit). In the three-phase bridge circuit, the directions of the coil energization amounts of the U-phase, V-phase, and W-phase (that is, the excitation direction) are sequentially switched based on the detection result (rotation angle Mka) of the rotation angle acquisition unit MKA. The electric motor MTR is driven. The rotation direction (forward rotation or reverse rotation) of the brushless motor is determined by the relationship between the rotor and the excitation position.

  Specifically, an instruction value (target value) for performing pulse width modulation (PWM) is calculated for each switching element based on the target energization amount Imt. For example, based on the target energization amount Imt and a preset characteristic (computation map), the pulse width duty ratio Dut (the ratio of the on-time to the cycle) is determined. At the same time, the rotation direction of the electric motor MTR is determined based on the sign (positive sign or negative sign) of the target energization amount Imt. The rotation direction of the electric motor MTR is set such that the forward rotation direction is a positive (plus) value and the reverse rotation direction is a negative (minus) value.

  Furthermore, so-called current feedback control is executed in the electric motor control block DRV. The electric motor control block DRV 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. The duty ratio Dut is corrected (finely adjusted) based on the deviation ΔIm between the actual energization amount Ima and the target energization amount Imt. With this current feedback control, highly accurate motor control can be achieved.

  In the electric motor control block DRV, a drive signal for the switching elements constituting the bridge circuit HBR is calculated based on the duty ratio (target value) Dut. Based on the drive signal, the energization or non-energization state of each switching element is controlled. Specifically, the larger the Dut, the longer the energization time per unit time in the switching element, the larger current flows through the electric motor MTR, and the greater the output (rotational power) of the MTR.

  In the solenoid valve control block SOL, the energization or non-energization state of each solenoid valve (VC1 etc.) is controlled based on the braking operation amount Bpa and the like. Based on the operation amount Bpa, the presence or absence of a braking operation by the driver is determined. When the operation amount Bpa is equal to or greater than the predetermined value bp0, it is determined that “braking operation is present (braking operation is performed)”, and when Bpa is less than the value bp0, “no braking operation is performed (braking operation is performed). Is not determined).

  In the traction control, the vehicle stabilization control, etc., the braking hydraulic pressure needs to be increased even when the driver does not perform the braking operation. For this reason, in the solenoid valve control block SOL, the signal FLcb indicating the operating states of the traction control (TCS) and the vehicle stabilization control (ESC) is received from the target energization amount calculation block IMT. For example, the signal FLcb is a control flag, and FLcb = 0 represents “inactive state” and FLcb = 1 represents “operated state”.

  In the solenoid valve control block SOL, when at least one of the conditions “braking operation (ie, Bpa ≧ bp0)” and “operation state of TCS or ESC (ie, FLcb = 1)” is satisfied. The driving state of the solenoid valve CSS and the switching means KRK (that is, the solenoid valves VC1, VC2, MC [f *]) is switched from non-energized to energized. As a result, the solenoid valves CSS, VC1, VC2 are changed from the closed position to the open position, and the solenoid valve MC [f *] is changed from the open position to the closed position. The SOL is provided with an energization amount acquisition means ISA for an electromagnetic valve that detects an energization amount Isa (actual value) to each electromagnetic valve.

  The determination processing block (corresponding to determination means) HNT determines whether the operating state of the entire system is appropriate, including the appropriateness of the operating state of the first electric motor (vehicle body side electric motor) MTR. The suitability of the operating state of the first electric motor MTR depends on the power supply state (for example, supply voltage) to the electric motor MTR, the operating state of the electronic control unit ECU that drives the MTR, and the state quantity used for controlling the MTR. It is determined based on at least one of the operating states of the acquisition means (MKA, IMA, etc.) for acquiring.

  The determination processing block HNT includes an initial diagnosis processing block CHK and an operation monitoring processing block MNT. The determination processing block HNT is a control algorithm and is programmed in a microcomputer in the ECU. In the initial diagnosis processing block CHK, an initial diagnosis (so-called initial check) including the operation of the system (braking device) including the electric motor MTR is executed. In the operation monitoring processing block MNT, the operation of the entire system including the electric motor MTR is constantly monitored. In the determination processing block HNT, a signal FLsd indicating the suitability of the operating state is output to the solenoid valve control block SOL. For example, the signal FLsd is a control flag, and FLsd = 0 represents an “inappropriate state”, and FLsd = 1 represents an “appropriate state”. When one of the determination results in the initial diagnosis processing block CHK and the operation monitoring processing block MNT is “inappropriate state”, FLsd = 0 (inappropriate determination) is output. Accordingly, FLsd = 1 (appropriate determination) is output only when the determination results in the initial diagnosis processing block CHK and the operation monitoring processing block MNT are both “appropriate”.

  In the initial diagnosis processing block CHK, the state of power supply to the braking device, diagnosis of the electronic control unit ECU itself (for example, memory diagnosis), first electric motor MTR, bridge circuit HBR, energization amount acquisition means IMA for the electric motor, rotation Diagnosis of at least one of angle acquisition means MKA, solenoid valves (VC1, VC2, MC [f *], etc.), energization amount acquisition means ISA for solenoid valves, and hydraulic pressure acquisition means (PC1, PC2, etc.) Operation check) is executed. Specifically, at the time when the voltage supplied to the ECU transits from a state below the predetermined voltage v10 to a state above the predetermined voltage v10, based on the trigger signal FLck of the initial diagnosis, At least one operation diagnosis (initial check) is executed. Note that the time point at which the supply voltage in the ECU changes from less than the value v10 to more than the value v10 is referred to as “start-up”. For example, the trigger signal (control flag) FLck is determined based on a signal received from the communication bus CAN.

  In the initial diagnosis processing block CHK, the initial operation diagnosis is started when the ECU is activated and FLck = 1. The state of FLck = 1 is a state where the driver is close to the vehicle, a state where the driver is closed after the vehicle door is opened, a state where the driver is seated on the vehicle seat, a state where the ignition switch is turned on, and It is 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 process (initial check), a diagnosis drive signal is transmitted from the initial diagnosis determination block CHK toward the bridge circuit HBR and each solenoid valve. As a result, at least one change among the acquisition results (detection results of each sensor) of the energization amount acquisition means IMA, ISA, the rotation angle acquisition means MKA, and the hydraulic pressure acquisition means (PC1 and the like) is CHK. Received at. Based on the reception result, at least one of the bridge circuit HBR (that is, the switching element), the electric motor MTR, the solenoid valve, the energization amount acquisition means IMA, ISA, the rotation angle acquisition means MKA, and the hydraulic pressure acquisition means. It is diagnosed whether the function is in a state where it can operate normally. If there is an inconvenience in function (operation), an inappropriate signal FLsd = 0 is output and a preset action (for example, notification to the driver and restriction or stop of the operation) is performed. .

  Similarly, in the operation monitoring processing block MNT, the power supply state to the braking device, the bridge circuit HBR (that is, the switching element), the electric motor MTR, the electromagnetic valve, the energization amount acquisition means IMA, ISA, the rotation angle acquisition means MKA, and Then, it is diagnosed whether or not at least one function of the fluid pressure acquisition means is in a state where it can operate normally. In the diagnosis of these constituent elements, the suitability is determined based on a comparison between the target value of the electric motor MTR and the electromagnetic valve and the result (actual value). 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 inappropriate state exists in the function of each component (MTR, etc.), an inappropriate signal FLsd = 0 is output and a preset action (for example, to the driver) is performed as in the arithmetic processing in CHK. Notification and operation restriction or stop).

  If at least one of the determination results in the initial diagnosis processing block CHK and the operation monitoring processing block MNT is determined to be “inappropriate state”, the determination result FLsd = 0 indicating that the system is inappropriate is determined. Output from means HNT. And only when it is determined that both the initial diagnosis processing block CHK and the operation monitoring processing block MNT determination result are in the “appropriate state”, the determination result FLsd = 1 (appropriate determination) indicating the system appropriateness is obtained. Are output from the determination processing block (determination means) HNT.

  In the electromagnetic valve control block SOL, the control flag FLsd indicating the propriety state is received, and the energization state of each electromagnetic valve is controlled based on the FLsd. When the entire system including the MTR is operating properly (when FLsd = 1 is received), as described above, “there is a braking operation (ie, Bpa ≧ bp0)” and “TCS or ESC The driving state (energized state) of the solenoid valve CSS and the switching means KRK (that is, the solenoid valves VC1, VC2, MC [f *]) is controlled based on the condition of the “operating state (ie, FLcb = 1)”. Is done. However, if the system operation (for example, the operating state of the MTR) is inappropriate (when FLsd = 0 is received), “there is a braking operation (ie, Bpa ≧ bp0)” and “TCS or ESC Regardless of the condition of “operating state (ie, FLcb = 1)”, the energization to the solenoid valve CSS and the switching means KRK is stopped. Accordingly, the electromagnetic valves CSS, VC1, VC2 are maintained or changed to the closed position, and the electromagnetic valve MC [f *] is maintained or changed to the open position. That is, when the system operation is malfunctioning, the brake fluid pressure is increased only by the front wheel cylinder WC [f *] by the master cylinder MCL.

  The electronic control unit ECU also performs its function by being supplied with power from a power source (BAT or the like). 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 cannot be supplied to the MTR and the electromagnetic valve (VC1 or the like). However, a normally closed solenoid valve (NC valve) is adopted as the introduction valves VC1 and VC2, and a normally open solenoid valve (NO valve) is adopted as the shutoff valve MC [f *]. Even in a state in which the engine is not suitable, the communication between the control cylinder CCL and the wheel cylinder WC [**] is interrupted, and the communication between the master cylinder MCL and the front wheel cylinder WC [f *] can be ensured.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to the fluid circuit diagram of FIG. In the first embodiment (see FIG. 2), the four-wheel wheel cylinder WC [**] is pressurized by the hydraulic pressure generating means EH2. In the second embodiment, the hydraulic pressure generating means EH1 The front wheel cylinder WC [f *] is pressurized and braking torque is applied. Further, the rear wheel WH [r *] is given a braking torque by the electric braking means DS [r *] that does not use fluid. Accordingly, for the rear wheel WH [r *], there is no wheel cylinder WC [r *], and there is no fluid piping from the master cylinder MCL to the rear wheel wheel cylinder WC [r *]. That is, there is no fluid piping, solenoid valve, or wheel cylinder in the rear wheel system. The hydraulic pressure generating means EH1 is also fixed to the vehicle body side, like the hydraulic pressure generating means EH2.

  In each figure and the description using it, like the above, members (components) given the same symbol, such as MCL, exhibit the same function. As for the relationship with FIG. 1, KRK corresponds to VCF and MC [f *], and HWF corresponds to HVF, HV [f *], and HW [f *], respectively.

  In addition, similarly to the above, the subscript in the square brackets attached to the end of the symbol of each component indicates which of the four wheels corresponds. Specifically, the subscripts are [fl] for "left front wheel", [fr] for "right front wheel", [rl] for "left rear wheel", [rr] for "right rear wheel", [**] Is related to “four wheels”, [f *] is related to “front wheels”, and [r *] is related to “rear wheels”. The “front wheel system” corresponds to the front wheel, and the “rear wheel system” corresponds to the rear wheel.

  Since the components denoted by the same reference numerals are the same as those in the first embodiment, the different parts will be mainly described. EN [r *], OT [r *], and HW [r *] are omitted in the connection state of each component and each component via the fluid piping. Further, since the fluid chamber of the control cylinder CCL of the hydraulic pressure generating means EH1 is changed from two to one, the introduction valves (solenoid valves) VC1, VC2 are connected to the introduction valves (solenoid valves) VCF, and the pipes HC1, HC2 Are changed (integrated) to the pipe HCF, the pipes HV1 and HV2 to the pipe HVF, and the hydraulic pressure acquisition means (pressure sensor) PC1 and PC2 to the hydraulic pressure acquisition means (pressure sensor) PCC, respectively. Here, VCF switches between communication and non-communication between the control cylinder CCL and the wheel cylinder WC [f *], similarly to VC1 and VC2. As the VCF, a normally closed type (NC valve, which is a closed position when not energized and an open position when energized) can be employed.

  At the time of appropriateness determination (when it is determined by HNT that the operation of the MTR is in an appropriate state), the introduction valve VCF and the pressure increasing valve EN [f *] are set to the open position (communication state) and shut off. The valve MC [f *] and the pressure reducing valve OT [f *] are brought into the closed position (non-communication state). Accordingly, the front wheel cylinder WC [f *] is communicated with the control cylinder CCL of the hydraulic pressure generating means EH1, but communication with the master cylinder MCL and the reservoir RSV is blocked. For this reason, the piston is moved in the control cylinder CCL, and the volume of the fluid chamber in the control cylinder CCL is reduced, whereby the brake fluid is discharged from the CCL toward the front wheel cylinder WC [f *]. The braking fluid is moved in the order of “CCL → HCF → VCF → HVF → EN [f *] → HW [f *] → WC [f *]”, and the braking torque of the front wheels WH [f *] is increased. . On the other hand, when the braking torque of the front wheel WH [f *] is reduced, the braking fluid is “WC [f *] → HW [f *] → EN [f *] → HVF → VCF → HCF → CCL”. (In the opposite direction to the case where the braking torque is increased), the front wheel cylinder WC [f *] returns to the control cylinder CCL.

  Similarly to the above, at the time of appropriateness determination, the solenoid valve CSS is brought into the open position (communication state), and the master cylinder MCL is communicated with a stroke simulator (also simply referred to as a simulator) SSM. An operating force (for example, brake pedal depression force) when the braking operation member BP is operated is generated by an elastic body (compression spring) inside the simulator SSM.

  At the time of improper determination (when it is determined by HNT that the operation of the MTR is in an inappropriate state), the introduction valve VCF and the pressure reducing valve OT [f *] are set to the closed position (non-communication state). Then, the shutoff valve MC [f *] is brought into the closed position (non-communication state). At this time, the pressure increasing valve EN [f *] may be in the closed position or may remain in the open position. The front wheel cylinder WC [f *] is in communication with the master cylinder MCL, but is disconnected from the control cylinder CCL and the reservoir RSV. That is, the pistons MP1 and MP2 are moved in the master cylinder MCL, and the volume of the fluid chambers Rm1 and Rm2 in the MCL is reduced, so that the brake fluid is discharged from the master cylinder MCL toward the wheel cylinder WC [f *]. Is done.

  At this time, the brake fluid is moved in the order of “MCL → HM [f *] → MC [f *] → HV [f *] → HW [f *] → WC [f *]”, and the front wheel WH [f *] Braking torque is increased. On the other hand, when the braking torque of the front wheel WH [f *] is reduced, the braking fluid is changed to “WC [f *] → HW [f *] → HV [f *] → MC [f *] → HM [ The wheel cylinders WC [f *] are returned to the master cylinder MCL in the order of “f *] → MCL” (the direction opposite to the case where the braking torque is increased). Since the rear wheel wheel cylinder WC [r *] and the like are omitted, the braking torque of the rear wheel is not applied by the master cylinder MCL.

  Furthermore, at the time of improper determination, the solenoid valve CSS is closed (non-communication state), and communication between the master cylinder MCL and the simulator SSM is blocked. Therefore, the operation force (pedal pedaling force) when the braking operation member BP is operated is generated according to the rigidity of the fluid path from the master cylinder MCL to the front wheel cylinder WC [f *].

  In the second embodiment, the front wheel WH [f * is determined by the hydraulic pressure generating means EH1 (that is, the control cylinder CCL which is a pressurizing mechanism) driven by the vehicle body side electric motor (first electric motor) MTR at the time of the appropriateness determination. ] Is adjusted to the hydraulic pressure of the wheel cylinder WC [f *]. Further, at the time of inappropriate determination, only the hydraulic pressure of the front wheel cylinder WC [f *] can be adjusted by the master cylinder MCL. In the second embodiment, the braking torque of the rear wheels is adjusted by the electric braking means DS [r *] that does not use any hydraulic pressure. Therefore, there are no rear wheel cylinder WC [r *], fluid piping from the master cylinder MCL to the rear wheel cylinder WC [r *], and no solenoid valve. The details of the electric braking means DS [r *] will be described later.

  In the second embodiment, braking fluid is supplied to the wheel cylinders WC [f *] provided to the two front wheels WH [f *] by one hydraulic pressure generating means EH1 (that is, one control cylinder CCL), The brake fluid is supplied to the wheel cylinder WC [f *] of the front wheel WH [f *] by one master cylinder MCL. Also in the second embodiment, similarly, the volume Vcc of the control cylinder CCL can be set larger than the volume Vmc of the master cylinder MCL. This is due to the case where the driver suddenly depresses the braking operation member BP again after suddenly returning the braking operation member BP during the braking operation.

  In the second embodiment as well, as in the first embodiment, the amount of liquid consumed due to the rigidity of the piping that does not directly contribute to the application of braking torque to the rear wheels, the gap with the friction agent, etc. is reduced. The “displacement” can be small. Further, since the amount of liquid consumption can be reduced, the ratio of the cross-sectional area of the front wheel cylinder WC [f *] to the cross-sectional area of the master cylinder MCL is set to be relatively large, and the operating force of the driver can be reduced. In addition, at the time of improper determination, regardless of the type of improper state, the braking operation characteristic (the relationship between the displacement of the braking operation member and the operating force) is limited to one characteristic. Therefore, it becomes difficult for the driver to feel uncomfortable.

  Furthermore, in the second embodiment, the braking torque can be adjusted by the electric braking means DS [r *] provided on the rear wheel WH [r *] even when the first electric motor MTR is malfunctioning. The deceleration can be ensured reliably.

<Hydraulic pressure generating means EH1 configured by one fluid chamber>
Next, the hydraulic pressure generating means EH1 constituted by one fluid chamber will be described with reference to a partial sectional view of FIG. The hydraulic pressure generating means EH1 is provided on the vehicle body side and includes an electric motor (first electric motor) MTR, a power transmission member DDB, a control cylinder CCL, a control piston CPN, and a spring SPR. In the first embodiment, the hydraulic pressure generating means EH2 configured by two fluid chambers Rc1 and Rc2 is adopted. However, in the second embodiment, instead of the hydraulic pressure generating means EH2, one fluid chamber is used. A hydraulic pressure generating means EH1 constituted by Rcc can be employed.

  In the hydraulic pressure generating means EH1, CP2, GC2, SP2, PE2, PO2, HC2, and Rc2 of the hydraulic pressure generating means EH2 are omitted. Components (members) denoted by the same symbols as the hydraulic pressure generating means EH2 exhibit the same function. In addition, CPN, GCP, SPR, PEN, POT, HCF, and Rcc of the hydraulic pressure generating means EH1 have the same functions as CP1, GC1, SP1, PE1, PO1, HC1, and Rc1 of the hydraulic pressure generating means EH2 ( Role). Therefore, detailed description of the hydraulic pressure generating means EH1 is omitted.

  Similar to the first embodiment, the rotational power of the vehicle body side electric motor (first electric motor) MTR is transmitted to the control piston CPN by the power transmission member DDB (GSK and NJB), and the CPN is transmitted in the control cylinder CCL. It is moved in the direction of the central axis Jcc of the CCL. The inside of the control cylinder CCL is partitioned into one fluid chamber Rcc by the control piston CPN. The fluid chamber Rcc communicates with the reservoir RSV through the relief port PEN and the fluid pipe HRV when generation of braking torque is not necessary.

  When the braking torque is increased, the first electric motor MTR is driven to rotate forward, and the control piston CPN is moved in the direction of the white arrow. After the port PEN is blocked by the cup GCP due to the movement of the piston CPN, the brake fluid (brake fluid) is discharged from the fluid chamber Rcc to the wheel cylinder WC [f *] of the front wheel, and the fluid of WC [f *] The pressure is increased.

  When the braking torque is decreased, the first electric motor MTR is driven in reverse, and the piston CPN is returned toward the original position (position where Rcc communicates with RSV). Due to the movement of the piston CPN, the volume of the fluid chamber Rcc is increased, the brake fluid is returned from the front wheel cylinder WC [f *] to the control cylinder CCL, and the hydraulic pressure of WC [f *] is decreased.

  Similar to the configuration of the hydraulic pressure generating means EH2, in the hydraulic pressure generating means EH1, the central axis Jcc of the control cylinder CCL and the rotation axis Jmt of the electric motor MTR are separated from each other, and are connected to the reduction gear GSK. On the other hand, the fluid chamber Rcc and the electric motor MTR are arranged on the same side. With this configuration, the axial length (longitudinal dimension) of the hydraulic pressure generating means EH1 can be shortened.

  In the first embodiment, EH1 may be employed instead of EH2. In this configuration, VC1 and VC2 are integrated into VCF, HC1 and HC2 are integrated into HCF, PC1 and PC2 are integrated into PCC, and HV1 and HV2 are integrated into HVF, respectively. In the second embodiment, EH2 can be adopted instead of EH1. In this configuration, VCF is divided into VC1 and VC2, HCF is divided into HC1 and HC2, PCC is divided into PC1 and PC2, and HVF is divided into HV1 and HV2.

<Electric braking means DS [r *] provided on the rear wheel>
The electric braking means DS [r *] provided on the rear wheel WH [r *] will be described with reference to the overall configuration diagram of FIG. The electric braking means DS [r *] is driven by the electric motor MTW (that is, the braking torque of the rear wheels is adjusted). Here, the electric motor MTW is referred to as “wheel-side electric motor (corresponding to a second electric motor)” in order to distinguish it from the vehicle body-side electric motor MTR. 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, a power supply BAT (storage battery), an ALT (generator), a manual switch MSW for parking brake, and an electric braking means (brake actuator) DS [r *]. It is done. The electronic control unit ECU and the electric braking means DS [r *] are connected to the signal line (signal line) SGL and the power line (power line) via the ECU side connector CNB and the DS [r *] side connector CNC. Connected by the PWL, a drive signal of the electric motor MTW for the electric braking means DS [r *] and electric power are supplied.

[Instruction calculation block (instruction means) CGS]
The electronic control unit ECU is provided with an instruction calculation block (instruction means) CGS in addition to the control processing block (control means) CTL and the determination processing block (determination means) HNT. The instruction calculation block CGS is a control algorithm and is programmed in a microcomputer in the electronic control unit ECU. A target value (drive signal) Fbt for driving the second electric motor MTW for the electric braking means DS [r *] is calculated by the CGS, and the DS [r *] on the wheel side is calculated via the serial communication bus SGL. Sent to. In addition, electric power for driving the second electric motor MTW is supplied to the wheel side via the electronic control unit ECU.

  The instruction means CGS includes an instruction pressing force calculation block FBS, a target pressing force calculation block FBT, and a parking brake necessity determination block FPK.

  In the command pressing force calculation block FBS, each wheel WHL is based on the braking operation amount Bpa and the preset command pressing force calculation characteristics (calculation map when an appropriate state is determined in the determination processing block HNT) CHfb. The instruction pressing force Fbs is calculated. Fbs 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) KT [r *] in the electric braking means DS [r *].

  In the command pressure calculation block FBS, when the inappropriate state of the first electric motor MTR is determined in the determination processing block HNT (FLsd = 0), the calculation characteristic CHfb is the calculation characteristic CHfc (characteristic indicated by the broken line). Thus, the calculation map in the inappropriate state is switched to. The characteristic CHfc at the time of improper determination outputs a larger command pressing force (target value) Fbs for the same operation amount Bpa than the characteristic CHfb at the time of appropriate determination. That is, when the operating state of the first electric motor MTR for the front wheels is not appropriate due to the change of the calculation characteristic map, the output of the electric braking means DS [r *] for the rear wheels (MSB becomes KT [r *] The pressing force is increased. As a result, even when the MTR is not satisfactory, the vehicle deceleration equivalent to that at the time of the appropriateness determination can be ensured for the driver's braking operation.

  The target pressing force calculation block FBT receives the anti-skid control target pressing force Fabs, the traction control target pressing force Ftcs, and the stabilization control target pressing force Fesc from the control processing block CTL. In the target pressing force calculation block FBT, the target pressing force Fbt is calculated based on the instruction pressing force Fbs, the anti-skid control target pressing force Fabs, the traction control target pressing force Ftcs, and the stabilization control target pressing force Fesc. Is done. Specifically, one of Fabs, Ftcs, and Fesc is selected, the instruction pressing force Fbs is corrected by the selected one, and the final target pressing force Fbt is calculated. The selection order of Fabs, Ftcs, and Fesc is determined based on the running state of the vehicle and the state of the wheels. Note that Ftsc is not calculated when the rear wheel is not a driving wheel (in the case of an FF vehicle).

  In the parking brake necessity determination block FPK, it is determined whether or not a parking brake (also referred to as a parking brake) for maintaining the stop state of the vehicle is necessary. That is, in FPK, the determination of the operation of the parking brake or the release of the parking brake is executed based on the operation of the parking switch MSW performed by the driver, and the determination result FLpk is calculated. Specifically, the switch signal Msw of the MSW is input to the vehicle brake necessity determination block FPK, and the “parking brake unnecessary state (FLpk = 0)” is selected according to the OFF state of the switch MSW, and the MSW is in the ON state. To select “Necessary parking brake (FLpk = 1)”. Here, the signal FLpk is a control flag indicating whether or not a parking brake is necessary. Specifically, the control flag FLpk is expressed by “0” or “1”. When it is determined that “the parking brake is unnecessary (unnecessary determination)”, FLpk = 0 is output as the instruction signal. When it is determined that “a parking brake is necessary (necessity determination)”, FLpk = 1 is output as an instruction signal.

  The target pressing force (signal) Fbt calculated by the instruction calculation block CGS and the parking brake control flag FLpk are transmitted from the electronic control unit ECU to the electric braking means DS [r * via a signal line (serial communication bus) SGL. ] Sent to.

[Electric braking means DS [r *]]
The electric braking means DS [r *] includes a brake caliper CRP, a pressing member PSN, an electric motor (second electric motor) MTW, a position detecting means MKW, a reduction gear GSW, a shaft member SFT, a screw member NJW, and a pressing force acquisition means. It is composed of an FBA, a parking brake lock mechanism LOK, and a drive circuit DRW.

  The brake caliper (simply called caliper) CRP is, for example, a floating caliper, and is configured to sandwich a rotating member (brake disc) KT [r *] via two friction members (brake pads) MSB. The Within the caliper CRP, the pressing member PSN is slid and moved forward or backward toward the rotating member KT [r *]. In the caliper CRP, a keyway is formed so as to extend in the direction of the rotation axis (shaft axis Jsf) of the shaft member SFT.

  The pressing member (brake piston) PSN presses the friction member MSB against the rotating member KT [r *] to generate a frictional force. The key member is fixed to the pressing member PSN and fitted into the key groove. With this key structure, the pressing member PSN is restricted from rotating around the shaft axis, but is allowed to move linearly in the direction of the shaft axis (that is, the longitudinal direction of the keyway).

  An electric motor MTW for driving the electric braking means DS [r *] is provided on the wheel side. The wheel side electric motor MTW for DS [r *] generates power for pressing the friction member MSB against the rotating member KT [r *]. Specifically, the output of the electric motor MTW (rotational power around the motor shaft Jmw) is transmitted to the shaft member SFT via the reduction gear GSW, and the rotational power of the SFT (torque around the shaft shaft Jsf) It is converted into linear power (thrust in the direction of the central axis of the PSN) by the conversion member (for example, screw member) NJW and transmitted to the pressing member PSN. Then, the pressing member (brake piston) PSN is moved forward or backward toward the rotating member (brake disc) KT [r *]. By this movement of the PSN, the force (pressing force) Fba for the friction member (brake pad) MSB to press the rotating member KT [r *] is adjusted. Since the rotating member KT [r *] is fixed to the rear wheel WH [r *], a frictional force is generated between the friction member MSB and the rotating member KT [r *], and the rear wheel WH [r *] The braking force is adjusted to, for example, the traveling vehicle is decelerated. As the electric motor MTW, a motor with a brush or a brushless motor is employed.

  The position acquisition means (for example, rotation angle sensor) MKW acquires (detects) the position (for example, rotation angle) Mkw of the rotor (rotor) of the electric motor MTW. The position acquisition means MKW is disposed inside the electric motor MTW and coaxially with the rotor and the commutator (that is, coaxial with the MTW and provided on the motor shaft Jmw).

  The reducer GSW reduces the rotational speed of the power of the wheel side electric motor MTW and outputs it to the shaft member SFT. That is, the rotational output (torque) of the MTW is increased according to the reduction ratio of the speed reducer GSW, and the rotational force (torque) of the shaft member SFT is obtained. For example, the speed reducer GSW includes a small diameter gear SKW and a large diameter gear DKW.

  The shaft member SFT is a rotating shaft member and transmits the rotational power transmitted from the reduction gear GSW to the screw member NJW. The end of the shaft member SFT is processed into a spherical shape and functions as a universal joint. This universal joint compensates for the influence of the swinging (swinging motion) of the pressing member PSN that occurs when the friction member MSB and the rotating member KT [r *] slide.

  The screw member NJW is a power conversion member (rotation / linear motion conversion mechanism) that converts the rotational power of the shaft member SFT into linear power of the pressing member PSN, and includes a nut member and a bolt member. The screw member NJW has reversibility (having reverse efficiency) and can transmit power in both directions. That is, when the braking torque is increased (when the pressing force Fba is increased), power is transmitted from the shaft member SFT to the pressing member PSN through the screw member NJW. Conversely, when the braking torque is reduced (when the pressing force Fba is reduced), power is transmitted from the pressing member PSN to the shaft member SFT via the screw member NJW (reverse efficiency is less than “0”). large).

  As the screw member NJW, a sliding screw (such as a trapezoidal screw) that transmits power by “sliding” is employed. Further, as the screw member NJW, a rolling screw (ball screw or the like) in which power transmission is performed by “rolling” may be employed instead of the sliding screw. Further, instead of the screw member NJW, a ball ramp mechanism, a rotary wedge mechanism, a rack and pinion mechanism, or the like may be employed as the rotation / linear motion conversion mechanism.

  The pressing force acquisition means FBA acquires (detects) the reaction force (reaction) of the force (pressing force) Fba that the pressing member PSN presses the friction member MSB. A strain generating body is formed in the FBA, and the strain is detected by a strain detection element, and Fba is acquired. The FBA is provided between the shaft member SFT and the caliper CRP. The pressing force acquisition means FBA is fixed to the caliper CRP.

  The parking brake locking mechanism (also simply referred to as a locking mechanism) LOK is a brake function (so-called parking brake) that maintains the vehicle in a stopped state, so that the electric motor MTW rotates in the reverse direction (direction in which braking torque decreases) The movement (rotation) is constrained (locked) so as not to occur. As a result, the pressing member PSN is prevented from moving away from the rotating member KT [r *], and the pressing state of KT [r *] by the friction member MSB is maintained. The lock mechanism LOK can be provided between the electric motor MTW and the speed reducer GSW.

  The lock mechanism LOK includes a ratchet gear (also referred to as a pawl gear) RCH, a pawl member (also referred to as a hook claw) TSU, and a parking brake solenoid (also referred to simply as a solenoid) SLW. The ratchet gear RCH is fixed coaxially with the electric motor MTW. The ratchet gear RCH is different from a general gear (for example, a spur gear), and the teeth have directionality. The claw member TSU is pushed in the direction of the ratchet gear RCH by the solenoid SLW, and the claw member TSU is moved toward the ratchet gear RCH. Then, when the pawl member TSU is engaged with the ratchet gear RCH, the movement of the pressing member PSN is restrained and functions as a parking brake.

  The drive circuit DRW drives the wheel-side electric motor MTW and the parking brake solenoid SLW based on the target pressing force (signal) Fbt transmitted from the instruction calculation block CGS and the parking brake control flag FLpk. Specifically, the drive circuit DRW is provided with a bridge circuit (for example, formed of four switching elements) that drives the wheel side electric motor (second electric motor) MTW, and is calculated based on Fbt. The rotation direction and output torque of the MTW are controlled by the drive signal for each switching element. The DRW is provided with a switching element for driving the SLW, and the switching element is controlled based on FLpk to excite the solenoid SLW. As a result, the parking brake locking mechanism LOK is controlled, and the parking brake is operated or released.

  In the following, a description will be given of suitable configurations for reducing the size of the braking control device, improving the mountability, suppressing the uncomfortable feeling to the driver, and the like.

  In order to improve the mountability of the braking control device on the vehicle, the device needs to be configured integrally. In order to obtain an integral structure, it is desirable that the longitudinal dimensions (axial lengths) of the master cylinder MCL and the hydraulic pressure generating means EH1, EH2 are substantially the same. However, in the hydraulic pressure generating means EH1 and EH2, since power is transmitted from MTR (rotational power) to CCL (linear power), a rotation / linear motion conversion mechanism (for example, screw member NJB) is required. For this reason, the dimension of the longitudinal direction of CCL needs to be shortened more. In addition, in order to reduce the operating force of the brake operating member BP at the time of the inappropriate determination, the amount of brake fluid discharged from the master cylinder MCL is secured and the front wheel cylinder WC [f * with respect to the pressure receiving area of the MCL is secured. The ratio of the pressure receiving area needs to be set large.

  Based on the above viewpoint, the inner diameter (φDcc) of the control cylinder (CCL) is set larger than the inner diameter (φDmc) of the master cylinder (MCL). The length of the control cylinder (CCL) in the central axis direction (Jcc) is set shorter than the length of the master cylinder (MCL) in the central axis direction (Jmc). Further, the first electric motor (MTR) includes a reduction gear (GSK) that decelerates the rotational power of the first electric motor (MTR) and transmits the rotational power to the control cylinder (CCL). Jmt) and the central axis (Jcc) of the control cylinder (CCL) are arranged in parallel and separately, and the control cylinder (CCL) is connected to the first electric machine with respect to the speed reducer (GSK). It is arranged on the same side as the motor (MTR).

  The inner diameter φDcc of the control cylinder CCL is set to be relatively large, and the length of the control cylinder CCL in the central axis direction Jcc is set to be relatively short, so the axial length of the CCL is shortened and mounting on the vehicle is improved. Can be done. Further, the inner diameter φDmc of the master cylinder MCL is set to be relatively small, and the length of the master cylinder MCL in the central axis direction Jmc is set to be relatively long. Therefore, when determining the inappropriateness of the first electric motor MTR, the minimum required The braking torque of the vehicle can be applied with a limited operating force, and the amount of braking fluid necessary to generate the braking torque can be ensured. Further, the inner diameter φDcc of the control cylinder CCL is set larger than the inner diameter φDmc of the master cylinder MCL, and the length of the control cylinder CCL in the central axis direction Jcc is set shorter than the length of the master cylinder MCL in the central axis direction Jmc. The dimensions in the longitudinal direction of the hydraulic pressure generating means EH1, EH2 can be further shortened compared to the master cylinder MCL. As a result, the longitudinal dimensions of the master cylinder MCL and the hydraulic pressure generating means EH1, EH2 can be substantially matched.

  In the arrangement of the components of the hydraulic pressure generating means EH1, EH2, the rotation axis Jmt of the first electric motor MTR and the center axis Jcc of the control cylinder CCL are arranged in parallel and separately, and with respect to the reduction gear GSK, The first electric motor MTR and the control cylinder CCL are arranged on the same side. For this reason, the dimension of the longitudinal direction of EH1 and EH2 is shortened, and can be made substantially the same as the dimension of the longitudinal direction of the master cylinder MCL. As a result, the braking control device can be integrated and the mountability on the vehicle can be improved.

  In addition, the volume (Vcc) of the control cylinder (CCL) may be set larger than the volume (Vmc) of the master cylinder MCL. For example, in order to cope with a case where the driver suddenly depresses the brake operation member BP immediately after the brake operation member BP is suddenly returned during the braking operation, the control cylinder CCL has a brake fluid amount necessary for a plurality of braking operations. The volume of the CCL is set so that it can be supplied. Here, the “volume of the cylinder” is the volume of the liquid that can enter the cylinder, and is the volume of the brake fluid contained in the CCL and MCL when no brake fluid pressure is generated.

  Rigidity equivalent value (Gss) in the braking operation member (BP) depending on the stroke simulator (SSM) and the braking operation member (BP) depending on braking means including the front wheel cylinder (WC [f *]) The rigidity equivalent value (Gwc) at is set to an equivalent value.

  In the braking operation member, the rigidity equivalent value Gss by the stroke simulator SSM and the rigidity equivalent value Gwc by the braking means (for example, brake caliper) including the front wheel cylinder WC [f *] can be set to coincide. In this case, a substantially constant braking operation characteristic can be ensured without depending on the suitability of the operating state. Here, “the rigidity equivalent value Gss by the stroke simulator SSM” is a value obtained by converting the ratio of the hydraulic pressure to the volume change of the brake fluid in the SSM into the ratio of the force to the displacement (spring constant) in the brake operation member BP. is there. For example, the value Gss depends on the pressure receiving area of the piston inside the SSM and the elastic member (spring) built in the SSM. Similarly, “the rigidity equivalent value Gwc by the braking means including the front wheel cylinder WC [f *]” indicates that the ratio of the hydraulic pressure to the volume change of the braking fluid at WC [f *] is the displacement with respect to the displacement in the braking operation member BP. It is a value converted into a force ratio (spring constant). For example, the value Gwc depends on the rigidity of the brake caliper, the rigidity of the friction member, and the pressure receiving area of the wheel cylinder WC [f *].

  BP ... braking operation member, WH [f *] ... front wheel, WH [r *] ... rear wheel, MCL ... master cylinder, WC [f *] ... front wheel wheel cylinder, WC [r *] ... rear wheel wheel cylinder, SSM ... Stroke simulator, MTR ... First electric motor, CCL ... Pressure mechanism (control cylinder), BPA ... Operating amount acquisition means, HNT ... Determination means, KRK ... Switching means, MTW ... Second electric motor, DS [r *] ... Electric braking means

Claims (2)

A master cylinder driven by a braking operation member of the vehicle;
A front wheel wheel cylinder for applying braking torque to the front wheel of the vehicle;
A rear wheel cylinder for applying braking torque to the rear wheel of the vehicle;
A stroke simulator that absorbs braking fluid discharged from the master cylinder and applies an operating force to the braking operation member;
An operation amount obtaining means for obtaining an operation amount of the braking operation member;
A first electric motor controlled based on the operation amount;
A pressure mechanism that is driven by the first electric motor and pressurizes the brake fluid in the front wheel cylinder and the rear wheel cylinder;
Determination means for determining whether the operation of the first electric motor is appropriate or inappropriate;
Switching means for switching the communication state of the brake fluid between the master cylinder, the front wheel cylinder, the rear wheel cylinder, the stroke simulator, and the pressurizing mechanism;
In a vehicle braking control apparatus comprising:
The switching means is
When the determination means determines the appropriate state, the pressurizing mechanism communicates with the front wheel cylinder and the rear wheel wheel cylinder, the master cylinder communicates with the stroke simulator, and the master A cylinder is configured to block communication between the front wheel cylinder and the rear wheel cylinder;
When the determination means determines the inappropriate state, the communication between the pressurizing mechanism, the front wheel cylinder, and the rear wheel cylinder is blocked, and the communication between the master cylinder and the stroke simulator is established. A braking control device for a vehicle configured to shut off, cut off communication between the master cylinder and the rear wheel wheel cylinder, and communicate the master cylinder with the front wheel wheel cylinder. A master cylinder driven by a braking operation member of the vehicle;
A front wheel wheel cylinder for applying braking torque to the front wheel of the vehicle;
A stroke simulator that absorbs braking fluid discharged from the master cylinder and applies an operating force to the braking operation member;
An operation amount obtaining means for obtaining an operation amount of the braking operation member;
A first electric motor controlled based on the operation amount;
A pressurizing mechanism that is driven by the first electric motor and pressurizes the brake fluid in the front wheel wheel cylinder;
A second electric motor different from the first electric motor;
Electric braking means driven by the second electric motor to apply braking torque to the rear wheels of the vehicle;
Determination means for determining whether the operation of the first electric motor is appropriate or inappropriate;
Switching means for switching the communication state of the brake fluid between the master cylinder, the front wheel wheel cylinder, the stroke simulator, and the pressurizing mechanism;
In a vehicle braking control apparatus comprising:
The braking torque of the rear wheel is given only by the electric braking means,
The switching means is
When the determination means determines the appropriate state, the pressurizing mechanism is communicated with the front wheel wheel cylinder, the master cylinder is communicated with the stroke simulator, and the master cylinder and the front wheel wheel cylinder are communicated with each other. Is configured to block
When the determination means determines the inappropriate state, the communication between the pressure mechanism and the front wheel cylinder is blocked, the communication between the master cylinder and the stroke simulator is blocked, and the master cylinder is A braking control device for a vehicle configured to communicate with a front wheel wheel cylinder.

Images