BRAKE CONTROL DEVICE FOR A VEHICLE

Abstract

A brake control device includes: operation amount obtaining means that obtains an operation amount Bpa for a brake operation member; a pressurizing unit that presses a friction member onto a rotating member fixed to a wheel by using an electric motor; control means that controls the output of the electric motor based on the operation amount Bpa; pressing force obtaining means that obtains the actual pressing force Fpa of the friction member pressing the rotating member; and rotation angle obtaining means that obtains the actual rotation angle Mka of the electric motor.The controller stores the correlation between the actual pressing force Fpa and the actual rotation angle Mka; approximates a functional map CMkt specified by a second-order or higher-order polynomial Knj based on the correlation, calculates a target rotation angle Mkt based on the operation amount Bpa and the functional map CMkt; and controls the electric motor such that the actual rotation angle Mka agrees with the target rotation angle Mkt.

Description

TECHNICAL FIELD

[0001] The present invention relates to a brake control device for a vehicle. STATE OF THE ART

[0002] Patent Literature 1 discloses an arrangement comprising a master cylinder that generates hydraulic pressure in response to a driver's braking force, a wheel cylinder that generates a braking force in each vehicle wheel by setting at least the master cylinder as a hydraulic pressure source, a hydraulic pressure source capable of supplying hydraulic pressure to the wheel cylinder in a manner different from the master cylinder, a hydraulic pressure control device capable of appropriately controlling the wheel cylinder pressure, a plurality of hydraulic pressure supply passages connecting the hydraulic pressure source and each wheel cylinder, and a communication passage allowing the hydraulic pressure supply passages to communicate with each other, and having a normally closed cut-off valve,in which the hydraulic pressure control device performs brake-by-wire control of supplying a brake hydraulic pressure to the wheel cylinder by driving the hydraulic pressure source in response to the driver's braking operation.

[0003] Specifically, when a master cylinder pressure change rate is less than -ePo, a solenoid valve is in an open position and a pump rotates reversely, so that the hydraulic pressure of the wheel cylinder decreases. If a determination that the "master cylinder pressure change rate is greater than "0" and less than ePo (step 107)" is positive, the pump is stopped and the solenoid valve is placed in the closed position, so that the hydraulic pressure of the wheel cylinder is maintained. Furthermore, if the determination that the "master cylinder pressure change rate is greater than "0" and less than ePo" is negative, an isolation valve and the solenoid valve are placed in the open position, and the pump rotates normally, so that the hydraulic pressure of the wheel cylinder increases.Accordingly, even if a pressure generated by the transmission pump is not uniform, the hydraulic pressure supplied to the wheel cylinder is balanced on the left and right sides, and thus stable braking operation can be ensured.

[0004] As disclosed in Patent Literature 2, the applicant has developed a technique of independently and individually controlling hydraulic pressures of two-system fluid passages (brake lines) through a pressure adjusting mechanism CLK driven by an electric motor MTR. A case is assumed where this configuration is adopted and two electric motors are controlled while the two-system fluid passages are in a connected state through a connecting passage, as disclosed in Patent Literature 1. In this case, there is a case where a difference in the rotation angle of two electric motors is generated due to a difference in efficiency or the like of the two pressure adjusting mechanisms. Since the rotation angle difference corresponds to the positions of control pistons within the pressure adjusting mechanisms, it is desirable to suppress the difference in the rotation angle of the two electric motors. CITATION LISTPATENT LITERATURE Patent literature 1: JP 2005 -119 426 A Patent literature 2: JP 2016 - 043 788 A

[0005] JP 2005-132306 A discloses a braking device in which a conduit connected to a fluid pressure chamber communicating with a stroke simulator is connected to a wheel cylinder of a front wheel of the vehicle. The conduit is connected via a fail-safe valve provided on the conduit. During the initial phase of a brake pedal operation, the brake fluid pressure of the fluid pressure chamber is supplied to the wheel cylinder of the front wheel of the vehicle. The conduit is then shut off.

[0006] DE 10 2007 000 123 A1 discloses a vehicle brake control device. When ABS control is performed by an ABS control section, the vehicle brake control device calculates first rotational speeds of a first and a second motor necessary to achieve corresponding pressure rise rates, and calculates second rotational speeds of the first and second motors as the upper limits caused by unlock pressure limits. Then, the vehicle brake control device controls current values ​​of currents to be supplied to the first and second motors so that they rotate at the rotational speeds obtained in the range from the first rotational speeds to the second rotational speeds. SUMMARY OF THE INVENTION TECHNICAL PROBLEMS

[0007] An object of the invention is to provide a brake control device for a vehicle having two-system fluid passages whose pressures are adjusted by electric motors, and capable of suppressing a rotation angle difference between two electric motors when the fluid passages are in communication with each other. SOLVING THE PROBLEMS

[0008] This object is achieved by a brake control device as defined in claim 1.

[0009] When the connecting valve VRN is in the open position, a rotation angle difference may be generated between the first and second electric motors MT1 and MT2 due to a left-right efficiency difference or the like between the first and second pressure adjusting mechanisms CA1 and CA2. According to the above-described configuration, the rotation angle difference is suppressed, and the positions of the first and second control pistons PS1 and PS2 of the first and second pressure adjusting mechanisms CA1 and CA2 are equalized. For this reason, even when the vehicle wheel slip control starts with the connecting valve VRN in the closed position, it is possible to appropriately adjust the hydraulic pressure by the first and second pressure adjusting mechanisms CA1 and CA2. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an overall configuration diagram illustrating a first embodiment of a brake control device for a vehicle according to the invention. Fig. 2 shows a partial cross-sectional view illustrating a pressure adjustment mechanism. Fig. 3 shows a functional block diagram illustrating a calculation process of an electronic control unit. Fig. 4 is a circuit diagram illustrating an electric motor and a drive circuit thereof. Fig. 5 shows a flowchart illustrating a first example of a process of left-right difference minimization control. Fig. Figure 6 shows a flowchart illustrating a second example of the left-right difference minimization control process. Fig. 7 is an overall configuration diagram illustrating a second embodiment of the brake control device for a vehicle according to the invention. Fig. Figure 8 is a schematic diagram illustrating an electric braking element for a rear wheel. DESCRIPTION OF EMBODIMENTS

[0010] Embodiments of a brake control device for a vehicle according to the invention will be described below with reference to the drawings. In the following description, suffixes ("fl" and the like) added to the ends of various symbols indicate the locations of the vehicle wheels corresponding to the symbols. Specifically, "fl" indicates the left front wheel, "fr" indicates the right front wheel, "rl" indicates the left rear wheel, and "rr" indicates the right rear wheel. For example, the wheel cylinders may be described as left front wheel cylinder WCfl, right front wheel cylinder WCfr, left rear wheel cylinder WCrl, and right rear wheel cylinder WCrr.

[0011] Furthermore, the numbers ("1" or "2") attached to the ends of various symbols indicate which of two fluid channels (hydraulic pressure systems) the left front wheel cylinder WCfl and the right front wheel cylinder WCfr are connected to. In the following description, the system connected to the left front wheel cylinder WCfl is referred to as the "first system" and is expressed using the suffix number "1", and the system connected to the right front wheel cylinder WCfr is referred to as the "second system" and is expressed using the suffix number "2". For example, a first pressure adjusting mechanism CA1 is used to adjust the hydraulic pressure of the left front wheel cylinder WCfl (corresponding to the first wheel cylinder WC1), and a second pressure adjusting mechanism CA2 is used to adjust the hydraulic pressure of the right front wheel cylinder WCfr (corresponding to the second wheel cylinder WC2).Additionally, the "first system" and the "second system" can be interchanged. In various components, the components involved in the first system (the first fluid channel) are the same as the components involved in the second system (the second fluid channel). For this reason, the following description primarily describes the components involved in the first system. <Erstes Ausführungsbeispiel für eine Bremssteuerungsvorrichtung gemäß der Erfindung>

[0012] With reference to the overall configuration representation of Fig. 1 describes a vehicle with the brake control device according to a first embodiment of the invention. As illustrated in the overall configuration diagram, the vehicle is provided with a brake operating member BP, an operation amount sensor BPA, an electronic control unit ECU, a tandem master cylinder MCL, a stroke simulator SSM, solenoid valves VM1, VM2, VSM, and VRN, and first and second pressure adjusting mechanisms CA1 and CA2. Furthermore, the vehicle wheels WHfl, WHfr, WHrl, and WHrr of the vehicle are each provided with brake calipers CPfl, CPfr, CPrl, and CPrr, wheel cylinders WCfl, WCfr, WCrl, and WCrr, and rotary elements KTfl, KTfr, KTrl, and KTrr.

[0013] The brake operating member (e.g., the brake pedal) BP is an operating member that reduces the speed of the vehicle by the driver. When the brake operating member BP is operated, a braking torque applied to the vehicle wheel is adjusted, and a braking force is generated in the vehicle wheel. Specifically, a rotating member (e.g., a brake disc) is fixed to the vehicle wheel of the vehicle. Brake calipers are arranged to sandwich the rotating member. The brake caliper is provided with the wheel cylinder (WCfl or the like). When the pressure (hydraulic pressure) of the brake fluid within each wheel cylinder increases, a friction member (e.g., a brake pad) is pressed against the rotating member (e.g., the brake disc). Due to the friction generated at this time, braking torque is generated in the vehicle wheel, thereby generating a braking force.

[0014] The brake operating member BP is provided with an operation amount sensor BPA. An operation amount (a brake operation amount) Bpa of the driver's brake operating member BP is acquired (detected) by the operation amount sensor BPA. Specifically, as the operation amount sensor BPA, "first and second master cylinder pressure sensors (pressure sensors) PM1 and PM2 for acquiring the pressure within the tandem master cylinder MCL," an "operation displacement sensor (stroke sensor) SBP for acquiring the operation displacement Sbp of the brake operating member BP," and / or an "operation force sensor (pedaling force sensor) FBP (not illustrated) for acquiring an operation force Fbp of the brake operating member BP" may be employed. In other words, the operation amount sensor BPA generally indicates the master cylinder pressure sensor, the operation displacement sensor, and the operation force sensor.The brake application amount Bpa is determined based on the "first and second master cylinder hydraulic pressures Pm1 and Pm2," the "application displacement Sbp of the brake operating member BP," and / or the "application force Fbp of the brake operating member BP." Any of the first and second master cylinder hydraulic pressure sensors PM1 and PM2 may be omitted.

[0015] An electronic control unit (ECU) (corresponding to a control device) is implemented by an electrical circuit board having a microprocessor and the like mounted thereon, and a control algorithm programmed in the microprocessor. Electric power is supplied to the electronic control unit (ECU) from a battery (BAT) and an alternator (ALT). The operation amount (Bpa) (Pm1, Sbp, or the like) is input to the electronic control unit (ECU). Furthermore, the first and second control cylinder hydraulic pressures (detection values) Pc1 and Pc2, acquired by first and second control cylinder hydraulic pressure sensors (PC1 and PC2), are input to the electronic control unit (ECU).The first and second pressure adjusting mechanisms CA1 and CA2 and the solenoid valves VM1, VM2, VSM and VRN are controlled by the electronic control unit ECU based on the brake application amount Bpa.

[0016] Specifically, the electronic control unit (ECU) calculates the target signals It1 and It2 of the electric motors MT1 and MT2 and the command signals Vm1, Vm2, Vsm, and Vrn of the solenoid valves VM1, VM2, VSM, and VRN according to the control algorithm programmed in the microprocessor. Based on these signals, a process is performed to control the electric motors MT1 and MT2 and the solenoid valves VM1, VM2, VSM, and VRN.

[0017] The tandem master cylinder (simply referred to as the master cylinder) MCL converts the operating force of the brake operating element BP into hydraulic pressure and supplies brake fluid under pressure to each of the wheel cylinders of the vehicle's wheels. Specifically, first and second master cylinder chambers Rm1 and Rm2, defined by two master pistons MP1 and MP2, are formed within the master cylinder MCL and connected to the wheel cylinders of the vehicle's wheels through a fluid passage (brake line). When the brake operating element BP is not applied, the master cylinder chambers Rm1 and Rm2 are connected to a master reservoir RSV, so that the hydraulic pressure within the master cylinder is equal to atmospheric pressure. <<Zwei-System-Fluidkanäle (Diagonalleitungen) > >

[0018] Two-system fluid passages are described below with reference to the hydraulic pressure circuit. A passage (a fluid passage) through which brake fluid moves between the master cylinder MCL and the four wheel cylinders WCfl, WCfr, WCrl, and WCrr is formed as two systems. In one system (a first fluid passage H1), the first master cylinder chamber (referred to as the first hydraulic pressure chamber) Rm1 of the master cylinder MCL is connected to the wheel cylinders WCfl (corresponding to, for example, the first wheel cylinder WC1) and WCrr. In the other system (a second fluid passage H2), the second master cylinder chamber (also referred to as the second hydraulic pressure chamber) Rm2 of the master cylinder MCL is connected to the wheel cylinders WCfr (corresponding to, for example, the second wheel cylinder WC2) and WCrl. A configuration called a diagonal line (also referred to as an X-line) is adopted.Since a configuration corresponding to the first fluid channel (the first brake line) H1 and a configuration corresponding to the second fluid channel (the second brake line) H2 are substantially the same, a configuration corresponding to the first fluid channel H1 will be described.

[0019] A first master cylinder cut-off valve (also referred to as a first cut-off valve) VM1 is provided (installed) in the fluid passage H1, which connects the first hydraulic pressure chamber Rm1 of the master cylinder MCL with the wheel cylinders WCfl and WCrr. The first cut-off valve VM1 is a two-position solenoid valve having an open position and a closed position. When the first cut-off valve VM1 is in the open position, the hydraulic pressure chamber Rm1 and the left front wheel cylinder WCfl or the like are in a communication state. Then, when the cut-off valve VM1 is in the closed position, the first hydraulic pressure chamber Rm1 and the first front wheel cylinder WCfl or the like are in the cut-off state (the non-communication state). A normally open solenoid valve (NO valve) can be used as the first cut-off valve VM1.

[0020] A first hydraulic pressure unit HU1 is installed in a fluid passage HW1 (corresponding to a part of the first fluid passage H1) connecting the first cutoff valve VM1 and the wheel cylinders WCfl and WCrr. The first fluid passage (the first brake line) H1 includes a fluid passage (the brake line) HM1 and the fluid passage (the brake line) HW1. The first hydraulic pressure unit HU1 includes a pressure increase valve and a pressure decrease valve, and individually and independently controls the hydraulic pressure of each of the wheel cylinders WCfl and WCrr during vehicle wheel slip control such as anti-skid control and vehicle stability control.

[0021] In the fluid passage HW1, the first pressure adjusting mechanism CA1 and the first control cylinder hydraulic pressure sensor (also referred to as the first control hydraulic pressure sensor) PC1 are provided between the first cut-off valve VM1 and the first hydraulic pressure unit HU1. The first pressure adjusting mechanism CA1 includes a first control cylinder SC1 and the first electric motor MT1. When the first cut-off valve VM1 is in the closed position, the hydraulic pressure of each of the wheel cylinders WCfl and WCrr is adjusted (increased, maintained, or decreased). The hydraulic pressure Pc1 adjusted by the first pressure adjusting mechanism CA1 is acquired (detected) by the first control hydraulic pressure sensor PC1.

[0022] The first master cylinder hydraulic pressure sensor PM1 is provided in the fluid passage HM1 (a part of the first fluid passage H1) connecting the first master cylinder chamber Rm1 and the first master cylinder cut-off valve VM1. The master cylinder hydraulic pressure Pm1 generated by the master cylinder MCL is acquired (detected) by the first master cylinder hydraulic pressure sensor PM1.

[0023] The stroke simulator (simply referred to as simulator) SSM is provided in the brake operating member BP to generate an operating force. The simulator cut-off valve (also referred to as simulator valve) VSM is provided in a fluid passage HSM that connects the simulator SSM and the first hydraulic pressure chamber Rm1 of the master cylinder MCL. The simulator valve VSM is a two-position solenoid valve that has an open position and a closed position. When the simulator valve VSM is in the open position, the first hydraulic pressure chamber Rm1 and the simulator SSM are in a connected state. Conversely, when the simulator valve VSM is in the closed position, the first hydraulic pressure chamber Rm1 and the simulator SSM are in a cut-off (non-connected) state.A normally closed solenoid valve (NC valve) can be used as the simulator cut-off valve VSM.

[0024] The SSM simulator includes a piston and an elastic body (e.g., a compression spring). The piston is pushed by the brake fluid flowing from the master cylinder MCL (the hydraulic pressure chamber Rm1) to the SSM simulator. The piston is subjected to a force in a direction in which the flow of brake fluid is prevented by the elastic body. An operating force (e.g., a brake pedal depression force) for operating the brake operating element BP is formed by the elastic body.

[0025] A configuration of the second fluid channel H2 will be briefly described below. As described above, the configuration corresponding to the first fluid channel H1 is substantially the same as the configuration corresponding to the second fluid channel H2. That is, Rm1 corresponds to Rm2, WHfl (corresponding to WC1) corresponds to WCfr (corresponding to WC2), WCrr corresponds to WCrl, HM1 corresponds to HM2, HW1 corresponds to HW2, HU1 corresponds to HU2, VM1 corresponds to VM2, CA1 corresponds to CA2, PM1 corresponds to PM2, and PC1 corresponds to PC2. That is, the description obtained by replacing "first" and the suffix number "1" in the description of the components corresponding to the first fluid channel H1 with "second" and the suffix number "2", respectively, corresponds to the description of the components corresponding to the second fluid channel H2.The simulator is omitted in the components corresponding to the second fluid channel H2, but an individual simulator can also be provided in the second fluid channel H2.

[0026] Furthermore, a communication fluid passage HRN (a third fluid passage H3) is provided, which connects the first fluid passage H1 and the second fluid passage H2. That is, the first pressure adjusting mechanism CA1 and the second pressure adjusting mechanism CA2 are fluidly connected to each other through the communication fluid passage HRN. The communication fluid passage HRN is provided with a communication valve VRN. The communication valve VRN is a normally closed two-position solenoid valve. When the communication valve VRN is in the open position, the first pressure adjusting mechanism CA1 (i.e., the first wheel cylinder WC1) and the second pressure adjusting mechanism CA2 (i.e., the second wheel cylinder WC2) are in a communication state. In contrast, when the communication valve VRN is in the closed position, the first pressure adjusting mechanism CA1 and the second pressure adjusting mechanism CA2 are in a non-communication state.

[0027] When the brake operating element BP is not applied, the solenoid valves VSM and VRN are in the closed positions, and the solenoid valves VM1 and VM2 are in the open positions. Conversely, when the brake operating element BP is applied, the solenoid valves VSM and VRN are in the open positions, and the solenoid valves VM1 and VM2 are in the closed positions. Furthermore, when vehicle wheel slip control such as anti-skid control is being performed, the solenoid valve VSM is in the open position, and the solenoid valves VRN, VM1, and VM2 are in the closed positions. <druckjustierungsmechanismus>

[0028] With reference to the partial cross-sectional view of Fig. 2 describes a detailed configuration of the pressure adjustment mechanism. Since the first pressure adjustment mechanism CA1 (corresponding to, for example, the left front wheel WHfl) and the second pressure adjustment mechanism CA2 (corresponding to, for example, the right front wheel WHfr) have the same configuration, the first pressure adjustment mechanism CA1 is described. In the same manner as described above, for the description of the second pressure adjustment mechanism CA2, "first" can be read as "second," the suffix number "1" can be read as "2," the suffix "fl" can be read as "fr," and the suffix "rr" can be read as "rl."

[0029] The first pressure adjusting mechanism CA1 is provided in the first fluid passage H1 on the side opposite the master cylinder MCL (i.e., on the wheel cylinder WCfl side) with respect to the first master cylinder cut-off valve (solenoid valve) VM1. Thus, when the solenoid valve VM1 is in the closed position (the cut-off state), the hydraulic pressure of the wheel cylinder WCfl or the like is adjusted by the flow of brake fluid from the first pressure adjusting mechanism CA1. The first pressure adjusting mechanism CA1 includes the first electric motor MT1, a speed reducer GSK, a rotary / linear motion conversion mechanism (a screw element) NJB, a pressing element PSH, the first control cylinder SC1, a first control piston PS1, and a return spring SPR.

[0030] The first electric motor MT1 is a power source that allows the first pressure adjustment mechanism CA1 to adjust (increase, maintain, and decrease) the brake fluid pressure within the wheel cylinder. The first electric motor MT1 is driven by the electronic control unit (ECU). A brushless DC motor (also simply referred to as a brushless motor) can be used as the first electric motor MT1.

[0031] The speed reducer GSK includes a small-diameter gear SKH and a large-diameter gear DKH. The rotational force of the electric motor MT1 is reduced by the speed reducer GSK and transmitted to the screw element NJB. Specifically, in the speed reducer GSK, the rotational force from the electric motor MT1 is supplied to the small-diameter gear SKH for reduction and is output from the large-diameter gear DKH to the screw element NJB.

[0032] In the screw element NJB, the rotational force of the speed reducer GSK is converted into a linear force Fs of the pressing element PSH. A nut element NUT is fixed to the pressing element PSH. A bolt element BLT of the screw element NJB is fixed coaxially with the large-diameter gear DKH. Since the rotational movement of the nut element NUT is restricted by a key element KYB, the nut element NUT (i.e., the pressing element PSH) screwed into the bolt element BLT moves in the direction of the rotating shaft of the large-diameter gear DKH according to the rotation of the large-diameter gear DKH. That is, the rotational force of the first electric motor MT1 is converted into the linear force Fs of the pressing element PSH by the screw element NJB.

[0033] The first control piston PS1 is moved by the pressing member PSH. The first control piston PS1 is inserted into an inner opening of the first control cylinder SC1, and a combination of the piston and the cylinder is formed. In particular, the outer periphery of the first control piston PS1 is provided with a sealing member GSC, thus ensuring fluid tightness with respect to the inner opening (inner wall) of the first control cylinder SC1. That is, a fluid chamber (a control cylinder chamber) Rsc is formed, which is defined by the first control cylinder SC1 and the first control piston PS1. The control cylinder chamber Rsc is connected to the fluid passage (brake pipe) HW1 through a port Ksc. As the first control piston PS1 moves in the axial direction (a center axis Jsc), the volume of the control cylinder chamber Rsc is changed.At this time, since the first cut-off valve VM1 is in the closed position, the brake fluid does not move toward the master cylinder MCL (i.e., the master cylinder chamber Rm1) and moves toward the wheel cylinder WCfl.

[0034] The first pressure adjustment mechanism CA1 is provided with the return spring (elastic body) SPR. When the current supply to the first electric motor MT1 is stopped by the return spring SPR, the first control piston PS1 is returned to an initial position (a position corresponding to zero brake hydraulic pressure). Specifically, when a stopper portion Stp is provided within the first control cylinder SC1 and the output of the first electric motor MT1 is zero, the first control piston PS1 is pushed by the return spring SPR to a position (the initial position) where the first control piston comes into contact with the stopper portion Stp.

[0035] The brake caliper (also simply referred to as a caliper) CPfl is of a floating type and is provided with the wheel cylinder WCfl. A wheel piston PWC is inserted into the inner opening of the wheel cylinder WCfl, forming a combination of the piston and cylinder. The outer periphery of the wheel piston PWC is provided with a sealing element GWC, thus ensuring fluid tightness between the sealing element GWC and the inner opening (inner wall) of the wheel cylinder WCfl. That is, a fluid chamber (a wheel cylinder chamber) Rwc, defined by the wheel cylinder WCfl and the wheel piston PWC, is formed by the sealing element GWC of the wheel cylinder. The wheel piston PWC is connected to a friction element MSB to press the friction element MSB.

[0036] The wheel cylinder chamber Rwc, formed by a combination of the wheel piston PWC and the wheel cylinder WCfl, is filled with brake fluid. Furthermore, the fluid chamber Rwc is connected to the fluid passage (pipe) HW1 through a port Kwc. Thus, when the first control piston PS1 moves in the direction of the center axis Jsc in a reciprocating manner by the first electric motor MT1, so that the volume of the control cylinder Rsc increases or decreases, a change in the pressure of the brake fluid within the wheel cylinder chamber Rwc is generated by the inflow or outflow of the brake fluid with respect to the wheel cylinder chamber Rwc. Accordingly, a force with which the friction element (e.g., the brake pad) MSB presses the rotary element (e.g., the disc brake) KTfl is adjusted to control the braking torque of the vehicle wheel WHfl.

[0037] Specifically, when the first electric motor MT1 is rotationally driven in the normal rotation direction, the first control piston PS1 (left in the drawing) moves such that the volume of the control cylinder chamber Rsc decreases and the brake fluid moves from the first control cylinder SC1 to the first wheel cylinder WCfl. Accordingly, the volume of the wheel cylinder chamber Rwc increases and the pressing force of the friction element MSB with respect to the rotating element KTfl increases, so that the braking torque of the vehicle wheel WHfl increases. In contrast, when the first electric motor MT1 is rotationally driven in the reverse rotation direction, the first control piston PS1 (right in the drawing) moves such that the volume of the control cylinder chamber Rsc increases and the brake fluid moves from the first wheel cylinder WCfl to the first control cylinder SC1.Accordingly, the volume of the wheel cylinder chamber Rwc decreases and the pressing force of the friction element MSB with respect to the rotating element KTfl decreases, so that the braking torque of the vehicle wheel WHfl decreases.

[0038] To independently control the brake hydraulic pressure of each vehicle wheel through anti-skid control, vehicle stability control, or the like, the first hydraulic pressure unit HU1 is provided between the first pressure adjusting mechanism CA1 (i.e., the first control cylinder SC1) and each of the wheel cylinders WCfl and WCrr. The first hydraulic pressure unit HU1 includes a combination of the pressure increasing valve (the solenoid valve) and the pressure decreasing valve (the solenoid valve). When the wheel cylinder hydraulic pressure is maintained, the pressure increasing valve and the pressure decreasing valve are in the closed positions, preventing the flow of brake fluid from the first pressure adjusting mechanism CA1 into the wheel cylinder.When the wheel cylinder hydraulic pressure decreases, the pressure-reducing valve is in the open position, while the pressure-increasing valve is in the closed position, and the brake fluid is returned to the main reservoir RSV. As the wheel cylinder hydraulic pressure continues to increase, the pressure-reducing valve is in the closed position and the pressure-increasing valve is in the open position, so that the brake fluid flows from the first pressure-adjusting mechanism CA1 into the wheel cylinder.

[0039] In the first fluid passage (brake line) HW1, the hydraulic pressure sensor (first control hydraulic pressure sensor) PC1 for the first control cylinder is provided between the first master cylinder cutoff valve VM1 and the first hydraulic pressure unit HU1. The hydraulic pressure (first control hydraulic pressure) Pc1 output from the first control cylinder SC1 is acquired (detected) by the first control hydraulic pressure sensor PC1.

[0040] The first fluid passage (brake line) HW1 between the first master cylinder cut-off valve VM1 and the first hydraulic pressure unit HU1 is connected to the communication fluid passage (brake line) HRN through the second fluid passage (brake line) HW2. The communication valve VRN is provided along the path of the communication fluid passage HRN. The communication fluid passage HRN is in the communication state when the communication valve VRN is in the open position, and the communication fluid passage HRN is in the cut-off state when the communication valve is in the closed position. Thus, it is possible to selectively establish fluid communication (communication / non-communication).Non-communication) between the first wheel cylinder WC1 (i.e., the first pressure adjusting mechanism CA1) and the second wheel cylinder WC2 (i.e., the second pressure adjusting mechanism CA2) by opening or closing the communication valve VRN.

[0041] When the brake operating member BP is not applied, the cutoff valves VM1 and VM2 are in the open positions, so that the master cylinder MCL communicates with the master reservoir RSV. Thus, the hydraulic pressure within each wheel cylinder becomes an atmospheric pressure. In this case, the pressing member PSH, driven by the first electric motor MT1, is returned to the initial position (the zero point of the first electric motor MT1). Since the pressing member PSH and the first control piston PS1 are separate elements, there is a case where the first control piston PS1 is not returned due to the friction of the sealing member GSC or the like. However, the first control piston PS1 is returned by the elastic force of the return spring SPR to a position (the initial position) where the first control piston comes into contact with the stopper portion Stp. <Prozess der elektronischen Steuerungseinheit ECU>

[0042] The following is a process of the electronic control unit (also referred to as a control device) ECU with reference to the functional block diagram of Fig. 3. The electronic control unit (ECU) controls the first and second electric motors MT1 and MT2, the simulator cut valve VSM, the first and second master cylinder cut valves VM1 and VM2, and the connecting valve VRN by receiving power from the power source (the battery BAT or the generator ALT). The process of the electronic control unit (ECU) is realized by an electric motor control unit (CMT) and a solenoid valve control unit (CSL). <<Elektromotorsteuerungseinheit CMT> >

[0043] The electric motor control unit (CMT) is part of the ECU. The CMT includes a command hydraulic pressure calculation block (PWS), a target hydraulic pressure calculation block (PWT), a command line size calculation block (ISJ), a hydraulic pressure control block (PFB), a left-right differential suppression line size calculation block (IYS), and a target line size calculation block (IMT).

[0044] In the command hydraulic pressure calculation block PWS, first and second command hydraulic pressures Ps1 and Ps2 are calculated based on the brake application amount Bpa and a calculation map CPws. Here, the first and second command hydraulic pressures Ps1 and Ps2 are the target values ​​of the brake hydraulic pressures generated by the first and second pressure adjusting mechanisms CA1 and CA2. Specifically, in the calculation map CPws, when the brake application amount Bpa is in the range of "0 (which is zero and corresponds to a case where the brake application is not performed)" or greater to a value smaller than a predetermined value bp0, the first and second command hydraulic pressures Ps1 and Ps2 are calculated to be zero.Then, when the brake application amount Bpa is the predetermined value bp0 or greater, the command hydraulic pressures Ps1 and Ps2 are calculated to increase from zero in accordance with an increase in the brake application amount Bpa. Where, bp0 is a predetermined value corresponding to the "play" of the brake operating element BP.

[0045] In the target hydraulic pressure calculation block PWT, the first and second command hydraulic pressures Ps1 and Ps2 are corrected, and the final target values ​​Pt1 and Pt2 for the brake hydraulic pressures of the first and second pressure adjustment mechanisms CA1 and CA2 are calculated. Specifically, the target hydraulic pressure calculation block PWT includes an anti-skid control block ABS, a traction control block TCS, and a vehicle stability control block ESC, and calculates the first and second target hydraulic pressures Pt1 and Pt2 required to perform the anti-skid control, traction control, and vehicle stability control. Thus, there is a case where the first target hydraulic pressure Pt1 may be different from the second target hydraulic pressure Pt2.In addition, when there is no need to perform anti-skid control, traction control, and vehicle stability control, the first and second command hydraulic pressures Ps1 and Ps2 are not corrected and are output as the first and second target hydraulic pressures Pt1 and Pt2 from the target hydraulic pressure control block PWT. Furthermore, in the target hydraulic pressure control block PWT, a vehicle speed Vxa is calculated based on the acquired result (the vehicle wheel speed Vwa) of the vehicle wheel speed sensor VWA provided in each vehicle wheel.

[0046] In the anti-skid control block ABS, the first and second target hydraulic pressures Pt1 and Pt2 for performing the anti-skid control that prevents the vehicle wheel lock state are calculated based on the acquired result (the vehicle wheel speed Vwa) of the vehicle wheel speed sensor VWA provided in each vehicle wheel. Specifically, in the anti-skid control block ABS, the vehicle wheel slip state quantity Slp (a control variable indicating the deceleration slip state of the vehicle wheel) is calculated based on the acquired result (the vehicle wheel speed) Vwa of the vehicle wheel speed sensor VWA of each vehicle wheel. Then, the first and second command hydraulic pressures Ps1 and Ps2 are corrected based on the vehicle wheel slip state quantity Slp, and the first and second target hydraulic pressures Pt1 and Pt2 are determined.

[0047] Similarly, in the traction control block TCS, the first and second target hydraulic pressures Pt1 and Pt2 for performing traction control that suppresses the slippage (over-rotation) of the vehicle wheel are calculated based on the acquired result (the vehicle wheel speed Vwa) of the vehicle wheel speed sensor VWA. Specifically, the first and second target hydraulic pressures Pt1 and Pt2 are determined based on the vehicle wheel slip state quantity Slp (a control variable indicating the acceleration slip state of the vehicle wheel).

[0048] Furthermore, in the vehicle stability control block ESC, the first and second target hydraulic pressures Pt1 and Pt2 for performing vehicle stability control to maintain vehicle stability are calculated based on the acquired result (a steering angle Saa, a yaw rate Yra, and a lateral acceleration Gya) of a steering angle sensor SAA and the vehicle behavior sensor (the yaw rate sensor YRA and the lateral acceleration sensor GYA). Specifically, the first and second command hydraulic pressures Ps1 and Ps2 are corrected based on the steering angle Saa, the yaw rate Yra, the lateral acceleration Gya, and the vehicle speed Vxa to suppress excessive understeer and / or oversteer of the vehicle, and the first and second target hydraulic pressures Pt1 and Pt2 are determined.

[0049] In the target hydraulic pressure calculation block PWT, a signal FLpw of "1" is output when any of the anti-skid control, traction control, and vehicle stability control is being performed. Here, the anti-skid control, traction control, and vehicle stability control are generally referred to as "vehicle wheel slip control." The signal FLpw is a so-called control flag, and "1" is calculated as the control flag FLpw when the vehicle wheel slip control is being performed. Conversely, "FLpw = 0" is calculated when the vehicle wheel slip control is not being performed.

[0050] In the command line size calculation block ISJ, the first and second command line sizes Is1 and Is2 of the first and second electric motors MT1 and MT2 that drive the first and second pressure adjustment mechanisms CA1 and CA2 are calculated based on the first and second target hydraulic pressures Pt1 and Pt2 and calculation maps CIsa and CIsb. The first and second command line sizes Is1 and Is2 are target values ​​of the line sizes for controlling the first and second electric motors MT1 and MT2.

[0051] The "conduction quantity" is a state variable that controls the output torques of the electric motors MT1 and MT2. Since the electric motors MT1 and MT2 output torques that are essentially proportional to current, the target current values ​​of the electric motors MT1 and MT2 can be used as the target values ​​of the conduction quantity. Furthermore, since a current increases when a voltage applied to the electric motors MT1 and MT2 increases, a supply voltage value can be used as a target state variable. Furthermore, since the supply voltage value can be adjusted by the duty cycle of the pulse width modulation, the duty cycle (a proportion of a conduction time for one cycle) can be applied as a control state variable.

[0052] In the hydraulic pressure control block PFB, first and second hydraulic pressure compensation line quantities (also simply referred to as compensation line quantities) If1 and If2 of the first and second electric motors MT1 and MT2 are calculated based on the first and second target hydraulic pressures (the target values) Pt1 and Pt2 of the hydraulic pressure and the first and second actual values ​​(the detection values) Pc1 and Pc2 of the hydraulic pressure. Where, the first and second actual hydraulic pressures Pc1 and Pc2 are the hydraulic pressure detection values ​​(the actual hydraulic pressures) detected by the first and second control cylinder hydraulic pressure sensors PC1 and PC2. In the hydraulic pressure control block PFB, first, the deviations eP1 and eP2 of the first and second target hydraulic pressures Pt1 and Pt2 and the first and second actual hydraulic pressures Pc1 and Pc2 are calculated.When the first and second hydraulic pressure deviations eP1 and eP2 are differentiated and integrated, and multiplied by gains Kp (proportional gain), Kd (derivative gain), and Ki (integral gain), the first and second compensation line quantities If1 and If2 are calculated. In the hydraulic pressure control block PFB, control (PID control) is performed based on the hydraulic pressure so that the target values ​​Pt1 and Pt2 match the actual values ​​Pc1 and Pc2 (that is, the hydraulic pressure deviations eP1 and eP2 approach "0").

[0053] In the left-right differential suppression conduction amount calculation block IYS, the first and second left-right differential suppression conduction amounts (also simply referred to as suppression conduction amounts) Iy1 and Iy2 are calculated such that a difference eMk between the rotation angle (detection value) Mk1 of the first electric motor MT1 and the rotation angle (detection value) Mk2 of the second electric motor MT2 decreases. The first rotation angle Mk1 is detected by the first rotation angle sensor MK1 provided in the first electric motor MT1. Furthermore, the second rotation angle Mk2 is detected by the second rotation angle sensor MK2 provided in the second electric motor MT2. The first and second rotation angles Mk1 and Mk2 are input to the control unit ECU. A detailed process of the left-right differential suppression conduction amount calculation block IYS will be described later.

[0054] In the target line size calculation block IMT, the first and second target line sizes It1 and It2, which correspond to the target value of the final line size, are calculated based on the first and second command line sizes Is1 and Is2, the compensation line sizes If1 and If2, and the first and second suppression line sizes Iy1 and Iy2. Specifically, in the target line size calculation block IMT, the compensation line sizes If1 and If2 and the first and second suppression line sizes Iy1 and Iy2 are added to the first and second command line sizes Is1 and Is2, and the sum thereof is calculated as the first and second target line sizes It1 and It2. That is, the first and second target line sizes It1 and It2 are determined as "It1 = Is1 + If1 + Iy1" and "It2 = Is2 + If2 + Iy2."

[0055] In the target line size calculation block IMT, the signs (positive or negative values) of the target line sizes It1 and It2 are determined based on the rotation directions of the two electric motors MT1 and MT2 (i.e., the hydraulic pressure increase / decrease direction). Furthermore, the values ​​of the target line sizes It1 and It2 are calculated based on the rotational forces of the electric motors MT1 and MT2 (i.e., the hydraulic pressure increase / decrease amount). Specifically, when the brake hydraulic pressure increases, the signs of the target line sizes It1 and It2 are calculated as positive signs (It1, It2 > 0), and the electric motors MT1 and MT2 are driven in the normal rotation direction. In contrast, when the brake hydraulic pressure decreases, the signs of the target line quantities It1 and It2 are determined as negative signs (It1, It2 < 0), and the electric motors MT1 and MT2 are driven in the reverse rotation direction.Furthermore, the output torques (the rotating forces) of the electric motors MT1 and MT2 are controlled to increase when the absolute values ​​of the target power quantities It1 and It2 increase, and the output torques are controlled to decrease when the absolute values ​​of the target power quantities It1 and It2 decrease.

[0056] In a drive circuit DRM for the electric motors MT1 and MT2, the rotational forces (output power) and rotation directions of the electric motors MT1 and MT2 are adjusted based on the target power values ​​It1 and It2. The drive circuit DRM will be described in detail later. As described above, the electric motor control unit CMT has been described. <<Solenoidventil-Steuerungseinheit CSL> >

[0057] The solenoid valve control unit (CSL) is also part of the control unit (ECU). The solenoid valve control unit (CSL) is implemented by a solenoid valve command block (SOL) and a solenoid valve drive circuit (DRS). In the solenoid valve command block (SOL), the command signals Vsm, Vm1, Vm2, and Vrn, which command the opening and closing states of the solenoid valves VSM, VM1, VM2, and VRN, are calculated based on the brake application amount Bpa and the control flag FLpw. In the solenoid valve drive circuit (DRS), the connection states (open positions) and the disconnection states (closed positions) of the solenoid valves VSM, VM1, VM2, and VRN are selectively implemented (controlled) based on the command signals Vsm, Vm1, Vm2, and Vrn.

[0058] In the solenoid valve command block SOL, the energized or de-energized state of each solenoid valve (VSM or the like) is controlled based on the brake operation amount Bpa. First, it is determined whether the driver is performing the brake operation based on the operation amount Bpa. Specifically, if the operation amount Bpa is equal to or greater than the predetermined value bp0, it is determined that the "brake operation state is set (the brake operation is performed)." Then, if the operation amount Bpa is less than the value bp0, it is determined that the "brake operation state is set (the brake operation is not performed)." Here, the value bp0 is a predetermined value corresponding to the "clearance" of the brake operating member BP.

[0059] In the solenoid valve command block SOL, when the condition of "brake application state (i.e., Bpa ≥ bp0)" is satisfied, the command signals Vsm, Vm1, Vm2, and Vrn are transmitted to the solenoid valve drive circuit DRS to switch the energized states of the solenoid valves VSM, VM1, VM2, and VRN. Specifically, in the case of "Bpa ≥ bp0," based on the signals Vsm, Vm1, Vm2, and Vrn, the solenoid valves VSM and VRN are driven in the connected state, and the solenoid valves VM1 and VM2 are driven in the disconnected state.

[0060] Furthermore, in the solenoid valve command block SOL, the command signal Vrn is transmitted to the drive circuit DRS to switch the energized state of the solenoid valve VRN based on whether the "vehicle wheel slip control is being performed" using the control flag FLpw. Specifically, in the case of "FLpw = 0 (when control is not being performed)," the solenoid valve VRN is switched to the connected state. However, in the case of "FLpw = 1 (when control is being performed)," the solenoid valve VRN is switched to the disconnected state.

[0061] In the solenoid valve drive circuit DRS, the open / closed states of the solenoid valves VSM, VM1, VM2, and VRN are actually switched based on the command signals Vsm, Vm1, Vm2, and Vrn. Furthermore, the drive circuit DRS is equipped with a line size sensor (a current sensor) ISA for supplying the solenoid valve line sizes Isa to the solenoid valves VSM, VM1, VM2, and VRN.

[0062] Electric power is also supplied from the power source (BAT or the like) to the electronic control unit ECU, so that a function of a control calculation process or the like is shown. For this reason, when the power source is poor (that is, the supply power is insufficient), the control unit ECU itself does not function, and no power is supplied to the electric motors MT1 and MT2 and the solenoid valves VSM, VM1, VM2, and VRN. For this reason, the normally closed solenoid valve (NC valve) is applied to the solenoid valves VSM and VRN, and the normally open solenoid valve (NO valve) is applied to the solenoid valves VM1 and VM2. As a result, when the power source is inappropriate, the connection between the master cylinder MCL and the simulator SSM is interrupted, and the connection between the master cylinder MCL and the wheel cylinder is ensured.As described above, the solenoid valve control unit CSL has been described. <Bürstenloser Drei-Phasen-Motor und Antriebsschaltung davon (Beispiel für bürstenlosen Drei-Phasen-Motor)>

[0063] Referring to the circuit diagram of Fig. Figure 4 describes an example in which a three-phase brushless motor with three coils (a U-phase coil CLU, a V-phase coil CLV, and a W-phase coil CLW) is used for the electric motors MT1 and MT2. In the brushless motor, a magnet is arranged on the rotor side and a coil circuit is arranged on the stator side. Then, a current is supplied to the brushless motor through the drive circuit in rotation according to the timing of the rotor's magnetic poles.

[0064] Since the first and second electric motors MT1 and MT2 have the same configuration, the first electric motor MT1 is described below. The first electric motor MT1 is equipped with the first rotation angle sensor MK1, which detects the first rotation angle (rotor position) Mk1 of the electric motor MT1. A Hall element type sensor is used for the first rotation angle sensor MK1. Furthermore, a variable reluctance type resolver can be used for the first rotation angle sensor MK1. The detected rotation angle Mk1 is input to the control unit ECU.

[0065] The drive circuit DRM is an electrical circuit that drives the first electric motor MT1 and corresponds to a part of the control unit ECU. The drive circuit DRM includes a switching control unit SWT, a three-phase bridge circuit (also referred to simply as a bridge circuit) BRG, and a stabilizing circuit LPF. The bridge circuit BRG includes six switching elements (power transistors) SUX, SUZ, SVX, SVZ, SWX, and SWZ (also referred to as "SUX to SWZ"). Based on the drive signals Sux, Suz, Svx, Svz, Swx, and Swz (also referred to as "Sux to Swz") of the respective phases from the switching control unit SWT within the drive circuit DRM, the bridge circuit BRG is driven, and the output of the first electric motor MT1 is adjusted.

[0066] In the switching control unit SWT, a command value (a target value) for performing pulse width modulation on each switching element is calculated based on the first target conduction value It1. Based on the value of the first target conduction value It1 and a prescribed characteristic (a map), the duty cycle (a proportion of the conduction time for each cycle) of the pulse width modulation is determined. In addition, the rotation direction of the first electric motor MT1 is determined based on the sign (positive or negative sign) of the first target conduction value It1. For example, with respect to the rotation direction of the first electric motor MT1, a positive (plus) value is set to indicate the normal rotation direction, and a negative (minus) value is set to indicate the reverse rotation direction.Since the final output voltage is determined by the input voltage (the voltage of the battery BAT) and the first duty cycle Du1, the direction of rotation and the output torque of the first electric motor MT1 are determined.

[0067] Furthermore, in the switching control unit SWT, the drive signals Sux to Swz for setting the switching elements constituting the bridge circuit BRG to an on-state (energized state) or an off-state (deenergized state) are calculated based on the first duty cycle (the target value) Du1. These drive signals Sux to Swz control the energized or deenergized states of the switching elements SUX to SWZ. Specifically, as the first duty cycle Du1 increases, the conduction time per unit time of the switching element increases, so a large current flows to the first electric motor MT1 and its output (torque) increases.

[0068] The battery BAT is connected to the input side of the three-phase bridge circuit BRG (also called an inverter circuit) through the stabilizing circuit LPF, and the electric motor MT1 is connected to the output side of the bridge circuit BRG. In the bridge circuit BRG, three phases (U, V, and W phases) are formed by using a voltage-type bridge circuit with upper and lower arms, in which the switching elements for one phase are connected in series. The three-phase upper arms are connected to a power line PWX, which is connected to a cathode side of the battery BAT. Furthermore, the three-phase lower arms are connected to a power line PWZ, which is connected to an anode side of the battery BAT. In the bridge circuit BRG, the upper and lower arms of the respective phases are connected to the power lines PWX and PWZ in parallel with the battery BAT.

[0069] In the U-phase upper arm, a freewheeling diode DUX is connected to the switching element SUX in a reverse parallel state. In the U-phase sub-arm, a freewheeling diode DUZ is connected to the switching element SUZ in a reverse parallel state. Similarly, in the V-phase upper arm, a freewheeling diode DVX is connected to the switching element SVX in a reverse parallel state. In the V-phase sub-arm, a freewheeling diode DVZ is connected to the switching element SVZ in a reverse parallel state. Furthermore, in the W-phase upper arm, a freewheeling diode DWX is connected to the switching element SWX in a reverse parallel state. In the W-phase sub-arm, a freewheeling diode DWZ is connected to the switching element SWZ in a reverse parallel state. Connection portions PCU, PCV, PCW of the upper and lower arms of the respective phases constitute the output end (AC output end) of the bridge circuit BRG.The electric motor MT1 is connected to these output ends.

[0070] The six switching elements SUX to SWZ are elements capable of turning part of the electrical circuit on or off. For example, MOSFETs or IGBTs are used for the switching elements SUX to SWZ. In the brushless motor MT1, the switching elements SUX to SWZ, which form the bridge circuit BRG, are controlled based on the detection value Mk1 of the rotation angle (rotor position). Then, the conduction directions (i.e., the excitation directions) of the coils CLU, CLV, and CLW of the three phases (U, V, and W phases) are sequentially switched, and the first electric motor MT1 is rotationally driven. That is, the rotation direction (normal rotation direction or reverse rotation direction) of the brushless motor MT1 is determined by a relationship between the rotor and the excitation position.Here, the normal rotation direction of the electric motor MT1 is the rotation direction corresponding to an increase in the hydraulic pressure Pc1 due to the pressure adjusting mechanism CA1, and the reverse rotation direction of the electric motor MT1 is the rotation direction corresponding to a decrease in the hydraulic pressure Pc1.

[0071] A conduction size sensor IMA, which detects the actual conduction size Ima (the general name of each phase) between the bridge circuit BRG and the electric motor MT1, is provided for each of the three phases. For example, a current sensor is provided as the conduction size sensor IMA, and a current value is detected as the actual conduction size Ima. The detected conduction size Ima of each phase is fed to the switching control unit SWT.

[0072] Then, a so-called current control is performed by the switching control unit SWT. Based on the deviation eIm between the actual conduction value Ima and the first target conduction value It1, the first duty cycle Du1 is corrected (fine-tuned). Since the current control controls the actual value Ima and the target value It1 to match each other (i.e., to such an extent that the conduction value deviation eIm approaches "0"), highly accurate motor control can be achieved.

[0073] The drive circuit DRM receives power from the power source (the battery BAT, the generator ALT). To reduce fluctuations in the supplied power (voltage), the drive circuit DRM is equipped with the stabilization circuit LPF. The stabilization circuit LPF is formed by a combination of at least one capacitor and at least one inductor (coil), forming a so-called LC circuit.

[0074] For the first electric motor MT1, a brush-mounted motor (also simply referred to as a brush motor) can be used instead of the brushless motor. In this case, an H-bridge circuit equipped with four switching elements (power transistors) is used as the bridge circuit BRG. This means that in the bridge circuit BRG of the brush motor, one of the three phases of the brushless motor is omitted. Similar to the brushless motor, the first electric motor MT1 is equipped with the rotation angle sensor MK1, and the drive circuit DRM is equipped with the stabilization circuit LPF. Furthermore, the drive circuit DRM is equipped with the conductivity sensor IMA.

[0075] As described above, the first electric motor MT1 and its drive circuit DRM have been described. In the same manner as described above, a component in which "first" is replaced by "second" and "1" of the end number of the symbol is replaced by "2" corresponds to the description of the second electric motor MT2. <Prozess (erstes Beispiel) der Links-Rechts-Differenzminimierungssteuerung>

[0076] Referring to the flowchart of Fig. 5, an example (a first algorithm example) of a process of the left-right difference suppression line size calculation block IYS is described.

[0077] Here, when the connecting valve VRN is in the connecting state and the first rotation angle Mk1 and the second rotation angle Mk2 are different from each other, control of reducing the difference is performed, and this control is referred to as "left-right difference minimization control." The rotation angle difference is generated due to friction or the like of the pressure adjusting mechanisms CA1 and CA2. Based on the left-right difference minimization control, the first and second left-right difference suppression conduction amounts (also simply referred to as suppression conduction amounts) Iy1 and Iy2 are calculated. The suppression conduction amounts Iy1 and Iy2 are the target values ​​of the conduction amounts of the electric motors MT1 and MT2.

[0078] In the first example of the left-right difference minimization control, first, in step S110, the brake operation amount Bpa is read. Then, in step S120, it is determined whether the current state is the "braking state" based on the brake operation amount Bpa. Specifically, it is determined that the current state is the "braking state" when the operation amount Bpa is equal to or greater than the predetermined value bp0. Further, it is determined that the current state is not the "braking state (that the current state is the non-braking state)" when the operation amount Bpa is smaller than the predetermined value bp0. In step S120, if the determination that the current state is the "braking state" is affirmative (in the case of "YES"), the routine proceeds to step S130.On the other hand, in step S120, when the determination that the current state is the "braking state" is negative (that is, in the case of the non-braking state and "NO"), the routine is returned to step S110.

[0079] In step S130, the command signal Vrn and the first and second rotation angles (detection values) Mk1 and Mk2 are read. Next, in step S140, it is determined based on the command signal Vrn whether "the connecting valve VRN is in the open position (the connecting state)." In step S140, if the determination that "the connecting valve VRN is in the open position" is affirmative (in the case of "YES"), the routine proceeds to step S150. On the other hand, if the determination that "the connecting valve VRN is in the open position" in step S140 is negative (that is, in the case of "FLpw = 1 and "NO"), the routine returns to step S110.

[0080] In step S150, it is determined whether the "difference (the rotation angle difference) eMk between the first rotation angle Mk1 and the second rotation angle Mk2 (the absolute value) is greater than a predetermined value mkx." If the relationship of "|Mk1 - Mk2| > mkx" is satisfied and the condition in step S150 is affirmative (in the case of "YES"), the routine proceeds to step S160. On the other hand, if the relationship of "|Mk1 - Mk2| ≤ mkx" is satisfied and the condition in step S150 is negative (in the case of "NO"), the routine returns to step S110. Here, the value mkx is a predetermined determination value.

[0081] In step S160, it is determined whether "the first rotation angle Mk1 is greater than the second rotation angle Mk2." If a relationship of "Mk1 > Mk2" is established and a condition in step S160 is affirmative (in the case of "YES"), the routine proceeds to step S170. On the other hand, if a relationship of "Mk1 < Mk2" is established and a condition in step S160 is negative (in the case of "NO"), the routine proceeds to step S180.

[0082] In step S170, a "process of setting the first suppression line amount Iy1 as a predetermined value iyg (a value with the negative sign)" and / or a "process of setting the second suppression line amount Iy2 as a predetermined value iyz (a value with the positive sign)" is performed. A condition required for performing a process of step S170 is that the communication valve VRN is in the open position (the communication state) and the first rotation angle Mk1 is larger than the second rotation angle Mk2 by a predetermined value mkx.In the target conduction amount calculation block IMT, the first and second suppression conduction amounts Iy1 and Iy2 are added to the first and second command conduction amounts Is1 and Is2 or the like, but at least one of an "operation of setting the first suppression conduction amount Iy1 as a negative predetermined value iyg" and an "operation of setting the second suppression conduction value Iy2 as a positive predetermined value iyz" is applied.That is, at least one of a "process of correcting the first target conduction amount It1 (the target conduction amount for the electric motor corresponding to a larger rotation angle) to decrease the first target conduction amount It1 by the first suppression conduction amount Iy1" and a "process of correcting the second target conduction amount It2 (the target conduction amount of the electric motor corresponding to a smaller rotation angle) to increase the second target conduction amount It2 by the second suppression conduction amount Iy2" is performed. Where, iyg and iyz are predetermined conduction amount values.

[0083] When a value of any one of the first and second suppression line quantities Iy1 and Iy2 is not determined by the predetermined values ​​iyg and iyz, that one value is set to "0". That is, in the process of step S170, at least one of "1: Iy1 = iyg (It1 is corrected to decrease), Iy2 = 0 (It2 is not corrected)", "2: Iy1 = 0 (It1 is not corrected), Iy2 = iyz (It2 is corrected to increase)", and "3: Iy1 = iyg (It1 is corrected to decrease), Iy2 = iyz (It2 is corrected to increase)" is determined. Since the first and second target conduction amounts It1 and It2 are corrected such that the difference eMk between the first rotation angle Mk1 and the second rotation angle Mk2 decreases by the process of step S170, the positions of the first and second control pistons PS1 and PS2 of the first and second pressure adjusting mechanisms CA1 and CA2 can be adjusted to appropriate positions.

[0084] Step S180 is a process corresponding to a case opposite to step S170 (the case of "Mk1 < Mk2"). That is, in step S180, at least one of a "process of determining the first suppression line amount Iy1 as a predetermined value iyz (a value with a positive sign)" and a "process of determining the second suppression line amount Iy2 as a predetermined value iyg (a value with a negative sign)" is performed. A condition required to perform a process of step S180 is that the communication valve VRN is in the open position (the communication state) and the second rotation angle Mk2 is larger than the first rotation angle Mk1 by the predetermined value mkx.For this reason, at least one of a "process of correcting the first target conduction amount It1 (the target conduction amount of the electric motor corresponding to a smaller rotation angle) to increase the first target conduction amount It1 by the first suppression conduction amount Iy1" and a "process of correcting the second target conduction amount It2 (the target conduction amount of the electric motor corresponding to a larger rotation angle) to decrease the second target conduction amount It2 by the second suppression conduction amount Iy2" is performed.

[0085] The predetermined values ​​iyg and iyz can be adjusted based on the value of the difference (the rotation angle difference) eKm between the first rotation angle Mk1 and the second rotation angle Mk2 (the absolute value). Specifically, the absolute values ​​of the predetermined values ​​iyg and iyz are adjusted to increase as the absolute value of the rotation angle difference eKm increases. That is, an increase correction amount and a decrease correction amount of the target conduction amounts It1 and It2 using the suppression conduction amounts Iy1 and Iy2 become larger as the rotation angle difference eKm increases.

[0086] In addition, a case where step S150 is negative corresponds to a case where the rotation angle difference eMk exists between the first rotation angle Mk1 and the second rotation angle Mk2, and the difference eMk is equal to or smaller than the predetermined value mkx. Since the difference between the first rotation angle Mk1 and the second rotation angle Mk2 is not as large as required, the left-right difference minimization control of steps S170 and S180 is not performed, and the routine is returned to step S110.

[0087] When the connecting valve VRN is in the connecting state and the difference eMk between the first rotation angle Mk1 and the second rotation angle Mk2 is larger than the predetermined value mkx, at least one of an “operation of correcting the target conduction amount of the electric motor according to a larger detection value of the rotation angle to decrease the target conduction amount” and an “operation of correcting the target conduction amount of the electric motor according to a smaller detection value of the rotation angle to increase the target conduction amount” by the first and second suppression conduction amounts Iy1 and Iy2 is performed as the left-right difference minimization control.For this reason, when the VRN connecting valve is in the open position, the rotation angle difference caused by the left-right difference in efficiency or the like is suppressed, and the positions of the control pistons PS1 and PS2 are appropriately adjusted (equalized in the left and right vehicle wheels). As a result, the vehicle wheel slip control starts, and an appropriate hydraulic pressure can be obtained by the pressure adjustment mechanisms CA1 and CA2 when the VRN connecting valve is in the closed position. In addition, the brake hydraulic pressure changes as a result of the suppression line sizes Iy1 and Iy2, but the change is compensated by the hydraulic pressure control. <Prozess (zweites Beispiel) der Links-Rechts-Differenzminimierungssteuerung>

[0088] Referring to the flowchart of Fig. Figure 6 describes another example (a second algorithm example) of a process of the left-right differential suppression conduction amount calculation block IYS. In the first example, the suppression conduction amounts Iy1 and Iy2 are determined by the predetermined values ​​iyz and iyg, but in the second example, the suppression conduction amounts Iy1 and Iy2 are determined by feedback control. Since the processes from step S210 to step S250 of the second example are the same as the processes from step S110 to step S150 of the first example, their descriptions are omitted.

[0089] When the connecting valve VRN is in the connecting state and the difference eMk between the first rotation angle Mk1 and the second rotation angle Mk2 (the absolute value) is greater than the predetermined value mkx, a process of step S260 is performed. In step S260, hydraulic pressure control is inhibited in the control of at least one of the two electric motors MT1 and MT2. Then, rotation angle control is performed based on the rotation angle detection value of the other electric motor.

[0090] The process of step S260 will be described by taking as an example a case where the first electric motor MT1 according to the first system is applied as one electric motor, and the second electric motor MT2 according to the second system is applied as the other electric motor.

[0091] First, a case is described where the first rotation angle Mk1 is larger than the second rotation angle Mk2. Since the hydraulic pressure control for the first electric motor MT1 is prohibited, the first compensation piping amount If1 is calculated as "0 (zero)". Then, the rotation angle control is performed based on the second rotation angle Mk2 (the control target value). Specifically, the first suppression piping amount Iy1 is calculated such that the deviation eMk between the first rotation angle Mk1 and the second rotation angle Mk2 approaches "0" (that is, the first rotation angle Mk1 coincides with the second rotation angle Mk2). At this time, since a relationship "Mk1 > Mk2" is satisfied, the first suppression piping amount Iy1 is determined as a value with a negative sign in the rotation angle control based on the second rotation angle Mk2.As a result, the brake hydraulic pressure Pc1 (= Pc2) decreases because the first target hydraulic pressure It1 (the target hydraulic pressure of the electric motor corresponding to a larger rotation angle) is corrected to decrease by the first suppression hydraulic pressure Iy1. However, the second target hydraulic pressure It2 (the target hydraulic pressure of the electric motor corresponding to a smaller rotation angle) is corrected to increase by the second compensation hydraulic pressure If2, so that the second actual hydraulic pressure Pc2 coincides with the second target hydraulic pressure Pt2 through the hydraulic pressure control of the second electric motor MT2. In this case, the left-right difference minimization control of the second electric motor MT2 is not performed, and the second suppression hydraulic pressure Iy2 is set to "0."

[0092] A case where the first rotation angle Mk1 is smaller than the second rotation angle Mk2 will be described below. In the same manner as described above, the hydraulic pressure control of the first electric motor MT1 is prohibited, and "If1 = 0" is calculated. Since the first suppression pipe size Iy1 is calculated such that the first rotation angle Mk1 coincides with the second rotation angle Mk2, the first suppression pipe size Iy1 is determined as a positive-sign value based on the second rotation angle Mk2 in the rotation angle control. As a result, the first target pipe size It1 (the target pipe size of the electric motor corresponding to a smaller rotation angle) is corrected to be increased by the first suppression pipe size Iy1, and the first actual hydraulic pressure Pc1 (=Pc2) increases.However, the second target hydraulic pressure It2 (the target hydraulic pressure of the electric motor corresponding to a larger rotation angle) is corrected to be reduced by the second compensation hydraulic pressure If2, so that the second actual hydraulic pressure Pc2 matches the second target hydraulic pressure Pt2 through the hydraulic pressure control of the second electric motor MT2. As described above, the left-right difference minimization control of the second electric motor MT2 is not performed, and "Iy2 = 0" is calculated.

[0093] As described above, in the second example of the left-right difference minimization control, when the connecting valve VRN is in the connecting state and the difference eMk between the first rotation angle Mk1 and the second rotation angle Mk2 (the absolute value) is greater than the predetermined value mkx, the target conduction amount corresponding to one electric motor is corrected to increase, and the target conduction amount corresponding to the other electric motor is corrected to decrease. Also, by combining the hydraulic pressure control and the rotation angle control, it is possible to appropriately adjust the hydraulic pressure even when the left-right positions of the first and second control spools PS1 and PS2 are equalized and the connecting valve VRN is in the closed position, similarly to the first example. <Zweites Ausführungsbeispiel der Bremssteuerungsvorrichtung gemäß der Erfindung>

[0094] A second embodiment of the brake control device according to the invention will be described below with reference to the overall configuration diagram of Fig. 7. According to the first embodiment (see Fig. 1) The wheel cylinders WCfl, WCfr, WCrl, and WCrr of the four wheels are pressurized by the pressure adjusting mechanisms CA1 and CA2. However, according to the second embodiment, the front wheel cylinders WCfl, WCfl, and WCfr are pressurized by the pressure adjusting mechanisms CA1 and CA2 to generate braking torque. Furthermore, the rear wheels WHrl and WHrr generate braking torque through electric brake elements (electric actuators) DSrl and DSrr that do not use fluid. Thus, the rear wheels WHrl and WHrr are not provided with the wheel cylinders WCrl and WCrr, and are also not provided with a fluid line extending from the master cylinder MCL to the rear wheel cylinders WCrl and WCrr. This means that the fluid passage (brake line), solenoid valve, and wheel cylinder corresponding to the rear wheel are omitted.

[0095] In the drawings and their description, the elements (components) denoted by the same symbols as MCL indicate the same functions in the same manner as described above. In addition, the suffixes added to the ends of the component symbols indicate the location of the four vehicle wheels in the same manner as described above. The suffixes are expressed such that "fl" indicates the "left front wheel," "fr" indicates the "right front wheel," "rl" indicates the "left rear wheel," and "rr" indicates the "right rear wheel." Since the components denoted by the same reference numerals are the same as those according to the first embodiment, the difference will be briefly described.

[0096] The master cylinder MCL (first hydraulic pressure chamber Rm1) and the left front wheel cylinder WCfl (corresponding to the first wheel cylinder WC1) are connected to the first fluid passage H1. The first cut-off valve VM1, which is a two-position solenoid valve, is installed along the path of the first fluid passage H1. The first pressure adjusting mechanism CA1, driven by the first electric motor MT1, is connected to the first fluid passage H1 between the first cut-off valve VM1 and the left front wheel cylinder WCfl.

[0097] Furthermore, the master cylinder MCL (the second hydraulic pressure chamber Rm2) and the right front wheel cylinder WCfr (corresponding to the second wheel cylinder WC2) are connected to the second fluid passage H2. The second cut-off valve VM2, corresponding to the two-position solenoid valve, is installed along the second fluid passage H2. The second pressure adjusting mechanism CA2, driven by the second electric motor MT2, is connected to the second fluid passage H2 between the second cut-off valve VM2 and the right front wheel cylinder WCfr. Furthermore, the master cylinder MCL is connected to the simulator SSM through the simulator valve VSM, corresponding to the two-position solenoid valve.

[0098] The first pressure adjusting mechanism CA1 (i.e., the first wheel cylinder WC1) and the second pressure adjusting mechanism CA2 (i.e., the second wheel cylinder WC2) are fluidly connected to each other through the communication fluid passage (the brake line) HRN. Then, the communication valve VRN is provided along the communication fluid passage HRN. When the communication valve VRN is in the open position, the communication fluid passage HRN is in the communication state. Conversely, when the communication valve is in the closed position, the communication fluid passage HRN is in the cutoff state.

[0099] According to the second embodiment, the same effect as that of the first embodiment is also obtained. That is, since the rotation angle difference eMk of the electric motor caused by the left-right difference in efficiency or the like is suppressed when the communication valve VRN is in the open position, the left-right positions of the two control pistons PS1 and PS2 are equalized. As a result, when the vehicle wheel slip control starts with the communication valve VRN in the closed position, it is possible to appropriately adjust the hydraulic pressure by the first and second pressure adjusting mechanisms CA1 and CA2. <Elektrisches Bremselement, das in dem Hinterrad vorgesehen ist, gemäß dem zweiten Ausführungsbeispiel>

[0100] With reference to the schematic representation of Fig. 8, the electric brake element (electric actuator) provided in the rear wheel is described by taking the electric brake element DSrl for the left rear wheel as an example. The electric brake element DSrl is driven by an electric motor MTW (that is, the braking torque of the rear wheel is adjusted). Here, the electric motor MTW is referred to as the "vehicle-wheel-side electric motor" to distinguish it from the first and second electric motors MT1 and MT2 for driving the first and second pressure adjusting mechanisms CA1 and CA2 provided in the vehicle body. Since the components indicated by the same symbols have the same functions in the same manner as described above, a description thereof is omitted.

[0101] The vehicle is equipped with the brake actuator BP, the electronic control unit ECU, and the electric brake element (the brake actuator) DSrl. The electronic control unit ECU and the electric brake element DSrl are connected to each other by a signal line SGL and a power line PWL, and power and drive signals from the electric motor MTW are supplied to the electric brake element DSrl.

[0102] The electronic control unit (ECU) is equipped with a command pressure force calculation block (FBS). The command pressure force calculation block (FBS) calculates a target value (command pressure force) Fsrl for driving the electric motor MTW for the electric brake element DSrl. Specifically, in the command pressure force calculation block (FBS), the command pressure force Fsrl of the right rear wheel WHrl is calculated based on the brake application amount Bpa and a predetermined command pressure force calculation curve CFbs. The command pressure force Fsrl is a target value of a pressure force corresponding to the force with which the friction element (brake pad) MSB presses against the rotating element (brake disc) KTrl in the electric brake element DSrl of the left rear wheel. The command pressure force Fsrl is transmitted to the vehicle-wheel-side actuator DSrl via a serial communication bus SGL.

[0103] The electric brake element DSrl of the left rear wheel comprises a brake caliper CPrl, a pressure piston PSW, the vehicle wheel-side electric motor MTW, a rotation angle sensor MKW, an input element SFI, a speed reduction device GSW, an output element SFO, a screw element NJW, a pressure sensor FBA and a drive circuit DRW.

[0104] The brake caliper CPrl sandwiches the rotating element (brake disc) KTrl with two friction elements (brake pads) MSB. The pressure piston (brake piston) PSW slides within the brake caliper CPrl to move toward or away from the rotating element KTrl. The pressure piston PSW presses the friction element MSB against the rotating element KTrl to create friction. Since the rotating element KTrl is attached to the rear wheel WHrl, the braking force of the left rear wheel WHrl is adjusted by friction.

[0105] The wheel-side electric motor MTW, which drives the electric braking element DSrl, generates power by pushing the friction element MSB against the rotating element KTrl. Specifically, the output of the electric motor MTW (the rotational force around the motor shaft) is transmitted to the output element SFO through the input element SFI and the speed reducer GSW. The rotational force (torque) of the output element SFO is converted into linear force (the thrust in the center axis direction of the PSW) by a motion conversion element (e.g., the screw element) NJW and transmitted to the pressure piston PSW.

[0106] The rotation angle sensor MKW is provided for the vehicle wheel-side electric motor MTW. Furthermore, the pressure sensor FBA is provided to acquire (detect) the force (the pressing force) Fba with which the pressure piston PSW presses the friction element MSB. Then, the pressing force control is performed based on the target value Fsrl and the actual value (detected value) Fba of the pressing force. The pressing force control corresponds to the hydraulic pressure control according to the first embodiment.

[0107] The drive circuit DRW drives the vehicle-wheel-side electric motor MTW based on the command thrust force (signal) Fsrl transmitted from the command thrust force calculation block FBS. Specifically, the drive circuit DRW is equipped with a bridge circuit that drives the vehicle-wheel-side electric motor MTW, and the rotation direction and output torque of the electric motor MTW are controlled by the drive signals for the switching elements calculated based on the command value Fsrl.

[0108] As described above, the electric brake device DSrl of the left rear wheel WHrl has been described. Since the electric brake device DSrr of the right rear wheel WHrr is the same as the electric brake device DSrl, its description is omitted. The electric brake device DSrr can be described by replacing the suffix "rl" of various symbols with the suffix "rr."

[0109] According to the first embodiment, the first and second hydraulic pressure units HU1 and HU2 are provided so that the braking torques of the vehicle wheels can be independently adjusted by the vehicle wheel slip control such as anti-skid control. However, according to the second embodiment, the first pressure adjusting mechanism CA1 can independently adjust the hydraulic pressure of the wheel cylinder WCfl, and the second pressure adjusting mechanism CA2 can independently adjust the hydraulic pressure of the wheel cylinder WCfr. Thus, according to the second embodiment, the first and second hydraulic pressure units HU1 and HU2 can be omitted.< / druckjustierungsmechanismus>

Claims

[1] Brake control device for a vehicle comprising: an operation amount sensor (BPA) that detects an operation amount (Bpa) of a brake operating element (BP) of the vehicle; a first wheel cylinder (WC1) applying a braking torque to one of left and right front wheels of the vehicle; a second wheel cylinder (WC2) which applies a braking torque to the other of the left and right front wheels; a first pressure adjusting mechanism (CA1) that pressurizes a brake fluid within the first wheel cylinder (WC1) by converting the rotation of a first electric motor (MT1) into the movement of a first control piston (PS1) inserted into an inner opening of a first control cylinder (SC1); a second pressure adjusting mechanism (CA2) that pressurizes a brake fluid within the second wheel cylinder (WC2) by converting the rotation of a second electric motor (MT2) into the movement of a second control piston (PS2) inserted into an inner opening of a second control cylinder; a communication valve (VRN) installed in a communication fluid passage (HRN) connecting the first wheel cylinder (WC1) and the second wheel cylinder (WC2), and selecting a connection state and an interruption state of the brake fluid between the first wheel cylinder (WC1) and the second wheel cylinder (WC2); a control device (ECU) that calculates first and second target conduction quantities (It1, It2) based on the operation amount (Bpa) and controls the first and second electric motors (MT1, MT2) based on the first and second target conduction quantities (It1, It2); a first rotation angle sensor (MK1) which detects a first rotation angle (Mk1) of the first electric motor (MT1); and a second rotation angle sensor (MK2) which detects a second rotation angle (Mk2) of the second electric motor (MT2), wherein, when the connecting valve (VRN) is in a connecting state and a difference between the first rotation angle (Mk1) and the second rotation angle (Mk2) is greater than a predetermined value (mkx), the control device (ECU) performs an operation of correcting the first or second target conduction size (It1, It2) according to a larger one of the first rotation angle (Mk1) and the second rotation angle (Mk2) to decrease the first or second target conduction size (It1, It2) and / or an operation of correcting the first or second target conduction size (It1, It2) according to a smaller one of the first rotation angle (Mk1) and the second rotation angle (Mk2) to increase the first or second target conduction size (It1, It2).

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