JP6428044B2 - Brake control device for vehicle - Google Patents

Description

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

  Patent Document 1 discloses a left and right fluid pressure system for individually transmitting fluid pressure to left and right brakes respectively mounted on both sides of at least one axle among a plurality of axles arranged at intervals in the longitudinal direction of the vehicle body. In addition, a vehicular braking device including a collective fluid pressure system that collectively transmits the same fluid pressure to left and right brakes respectively mounted on both sides of at least one other axle is described.

  An electric fluid pressure output means is described in which the piston is reciprocated in the axial direction by a ball screw in accordance with the forward / reverse rotation operation of the electric motor, and the corresponding fluid pressure is generated in the pressure chamber. Specifically, a piston that is slidably fitted in the cylinder, and a cylindrical nut member that is disposed in the guide cylinder while being prevented from rotating around the axis and is coaxially connected to the rear end of the piston. And a rotating shaft coupled to the nut member via a ball screw and coupled to the output shaft of the electric motor via an Oldham joint. Further, it is described that the output fluid pressure of the electric fluid pressure output means corresponding to the wheel which is about to be locked is controlled in accordance with the output signal of the antilock control circuit to prevent the wheel lock. .

Japanese Patent No. 3205570

  By the way, in the braking control apparatus using an electric motor as described in Patent Document 1, it is desired to downsize the electric motor and efficiently increase the fluid pressure (braking fluid pressure). For this reason, a configuration in which the output (rotational power) of the electric motor is decelerated and transmitted to a rotation / linear motion conversion mechanism (for example, a ball screw) is preferable. On the other hand, in order for the anti-lock control (also referred to as anti-skid control) to be properly executed, it is required that the brake fluid pressure is quickly reduced by the reverse rotation of the electric motor. In order to satisfy these conditions, it is necessary to reduce the moment of inertia of the braking control device.

  The present invention has been made in order to cope with the above-described problems, and an object of the present invention is to provide a vehicle braking control apparatus in which the braking hydraulic pressure can be adjusted by forward / reverse rotation of an electric motor. This is to reduce the electric pressure and to ensure the responsiveness of the hydraulic pressure adjustment, to appropriately execute the anti-skid control, and to reduce the size of the electric motor.

  The vehicle brake control apparatus according to the present invention includes wheel cylinders WCl and WCr provided on vehicle wheels WHl and WHr, operation amount acquisition means BPA for acquiring an operation amount Bpa of the brake operation member BP of the vehicle, and the operation An electric motor MTR controlled based on the amount Bpa; and a pressure adjusting mechanism CLK that is driven by the electric motor MTR and adjusts the pressure of the brake fluid BFL in the wheel cylinders WCl and WCr. Furthermore, the vehicle braking control apparatus according to the present invention adjusts the rotational speed Vwa by adjusting the wheel speed acquisition means VWA for acquiring the rotational speed (wheel speed) Vwa of the wheel and the rotational power Tq of the electric motor MTR. Control means CTL for executing anti-skid control for preventing the wheels WHl and WHr from being locked on the basis of the above.

  A feature of the present invention is that the pressure adjusting mechanism CLK is connected to the speed reducer GSK that decelerates the rotational power Tq, and the rotational / direct speed that is connected to the speed reducer GSK and converts the rotational power Tq to the linear power Fs of the control piston PSC. A dynamic conversion mechanism NJB, and a control cylinder SCL that is combined with the control piston PSC and moves the brake fluid BFL between the wheel cylinders WCl and WCr by a reciprocating motion of the control piston PSC. A speed transmission ratio Hs (= Ni / No), which is a value obtained by dividing the input rotational speed Ni from the electric motor MTR to the reduction gear GSK by the output rotational speed No of the reduction gear GSK, is the value of the wheel cylinders WCl, WCr. More than the area ratio Ha (= Awc / Asc) which is a value obtained by dividing the cross-sectional area Awc by the cross-sectional area Asc of the control cylinder SCL. In that it has been constructed by listening (i.e., Hs> Ha). Here, the reciprocating motion of the control piston PSC is caused by the linear power Fs converted from the rotational power Tq.

  When anti-skid control is performed by forward / reverse rotation of the electric motor MTR, one of the most severe operating states in the response of the brake fluid pressure is that anti-skid control is started immediately after sudden braking is performed. is there. Specifically, in the state where the electric motor MTR is rapidly accelerated in the forward rotation direction Fwd in order to rapidly increase the brake fluid pressure, the wheel slip Slp increases and the brake fluid pressure rapidly decreases. In order for this operation to be properly executed, the moment of inertia of the braking control device needs to be reduced.

  Since the moment of inertia is a function of the speed transmission ratio Hs, in order to evaluate the responsiveness of the entire apparatus driven by the electric motor MTR, the moment of inertia of each member (DKH or the like) is the output shaft of the electric motor MTR. It needs to be discussed after being converted into an inertia moment (referred to as an equivalent inertia moment) around Jmt (that is, the input shaft Jsk of the reduction gear GSK). The equivalent moment of inertia Ko around the output shaft Jmt (ie, Jsk) is the square of the reciprocal of the speed transmission ratio Hs (ie, (1 / Hs) ^ 2) to the moment of inertia Io around the output shaft Jdk of the reduction gear GSK. Is calculated by multiplying. The value “1 / Hs ^ 2” converges to “0 (zero)” as the speed transmission ratio Hs increases. For this reason, in the region where the speed transmission ratio Hs is larger than a certain value (predetermined value), the value “1 / Hs ^ 2” becomes very small, so the equivalent moment of inertia Ko is set to a sufficiently small value. The present invention is based on such knowledge. Specifically, the brake control device is configured so that the speed transmission ratio Hs is larger than the area ratio Ha, so that the equivalent moment of inertia Ko is set to a sufficiently small value, and the braking fluid at the start of the anti-skid control. Pressure responsiveness can be ensured.

  In the vehicle braking control apparatus according to the present invention, a value Ko (= Io / Hs ^ 2) obtained by dividing the moment of inertia Io around the output shaft Jdk of the reduction gear GSK by the square of the speed transmission ratio Hs is the electric power. The motor MTR is configured to be smaller than the inertia moment Im. That is, the inertia moment Io around the output shaft Jdk of the speed reducer GSK is converted into an equivalent inertia moment Ko around the input shaft Jsk of the speed reducer GSK in consideration of the speed transmission ratio Hs. The electric motor MTR is configured to be smaller than a single moment of inertia Im (that is, Ko <Im).

  According to the above feature of the present invention, in the inertia moment around the rotation axis Jmt of the electric motor MTR, the contribution degree (degree of influence) of the equivalent inertia moment Ko can be made smaller than the inertia moment Im of the MTR alone. . As a result, the influence of the moment of inertia around the output shaft Jdk of the reduction gear GSK (such as the moment of inertia of DKH) is reduced, and the response of the brake fluid pressure in anti-skid control (particularly at the time when anti-skid control is started). (Pressure reduction responsiveness) can be improved.

  In the braking control apparatus according to the present invention, the cross-sectional area Awc of the wheel cylinders WCl and WCr may be configured to be larger than the cross-sectional area Asc of the control cylinder SCL (that is, Awc> Asc).

  In a general vehicle, a value corresponding to a lever ratio (leverage ratio) (= Hs × Ha, “” in the power transmission path from the output of the electric motor MTR to the pressing force of the wheel piston PWC (ie, the hydraulic pressure of WCl). (Referred to as “lever ratio equivalent value”) is substantially constant. This is because the lever ratio equivalent value is determined by the required maximum hydraulic pressure in the wheel cylinder WCl and the output characteristics (lock torque, maximum rotation speed) of the electric motor MTR. Since the lever ratio equivalent value is constant, the area ratio Ha is reduced when the speed transmission ratio Hs is set large, and conversely when the speed transmission ratio Hs is set to a small value, the area ratio Ha. Needs to be increased.

  When the area ratio Ha is set to be relatively small, the lead of the screw member NJB (the distance that the PSC travels when the NJB is rotated once) needs to be reduced. This is because when the lead of the screw member NJB is reduced, the amount of the brake fluid BFL discharged from the control cylinder SCL is relatively small with respect to the output rotational speed of the reduction gear GSK. However, if the lead of the screw member NJB is extremely small, it may be difficult to establish the screw member NJB. Accordingly, the specifications of the wheel cylinder WCl and the control cylinder SCL are set so that the cross-sectional area Awc of one wheel cylinder WCl is larger than the cross-sectional area Asc of one control cylinder SCL. That is, the area ratio Ha is determined to be larger than “1”. As a result, in the lead of the screw member NJB, its feasibility is ensured, the area ratio Ha is set to a small value, and the speed transmission ratio Hs is set to a sufficiently large value. For this reason, the response of the brake fluid pressure by the anti-skid control can be suitably secured.

1 is an overall configuration diagram of an embodiment of a braking control device according to the present invention. It is a functional block diagram for demonstrating the process in electronic control unit ECU shown in FIG. It is a time chart for demonstrating the inertia compensation control and the sudden stop control in the target energization amount calculation block shown in FIG. It is a block diagram for demonstrating the pressure regulation mechanism shown in FIG. FIG. 5 is a drive circuit diagram for explaining the drive means shown in FIG. 4. It is a block diagram for demonstrating other embodiment about the reduction gear shown in FIG. It is a characteristic view for demonstrating the effect | action and effect of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle braking control apparatus according to the present invention will be described with reference to the drawings. In the following, unless otherwise specified, the suffix (“l” or “r”) attached to the end of each symbol indicates which one of the left and right wheels corresponds to it. ing. Specifically, the suffix “l” represents the left wheel and the suffix “r” represents the right wheel. For example, “WC1” indicates a wheel cylinder for the left front wheel, and “WCr” indicates a wheel cylinder for the right front wheel. Moreover, in each figure, what attached | subjected the same code | symbol has the same function, The description may be abbreviate | omitted.

<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 unit BPA, an electronic control unit ECU, a power source (battery) BAT, a master cylinder MCL, a reservoir, RSV, A stroke simulator SSM, electromagnetic valves VSM, VMl, VMr, an electric motor MTR, and a pressure regulating mechanism CLK are provided. Furthermore, the front wheels WHl and WCr of the vehicle are provided with brake calipers CPl and CPr, wheel cylinders WCl and WCr, and rotating members (for example, brake disks) KTl and KTr.

  In FIG. 1, the one corresponding to the left front wheel WHl (such as VMl) and the one corresponding to the left front wheel WHr (such as VMr) are the same, and therefore the one corresponding to the left front wheel WHl will be described. In addition, what corresponds to the left front wheel WHr can be described by replacing “left” with “right” and replacing the suffix “l” at the end of the symbol with the suffix “r” in the description.

  The braking operation member (for example, brake pedal) BP is a member that the driver operates to decelerate the vehicle. By operating the braking operation member BP, the braking torque of the front wheels WHl is adjusted, and a braking force is generated on each front wheel. A rotating member (for example, a brake disc) KTl is fixed to the front wheel WHl of the vehicle. The front wheel WHl is provided with a wheel cylinder WCl. As the brake fluid pressure in the wheel cylinder WCl is increased, the friction member (for example, brake pad) MSB is pressed against the rotating member KTl. A braking torque is generated on the front wheel WHl of the vehicle by the frictional force generated at this time.

  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) PMC for detecting the pressure of the master cylinder MCL, a sensor (brake pedal depression force sensor) for detecting the operation force of the braking operation member BP, and a sensor for detecting the displacement amount of the BP At least one of the (brake pedal displacement sensor) may be employed. Therefore, the braking operation amount Bpa is calculated based on at least one of the master cylinder pressure Pmc, the brake pedal depression force, and the brake pedal displacement. The braking operation amount Bpa is input to the electronic control unit ECU.

  The electric motor MTR and the electromagnetic valves VSM and VMl are controlled by the electronic control unit ECU based on the operation amount Bpa. Specifically, the electronic control unit ECU is provided with a control means CTL for controlling the electric motor MTR and the electromagnetic valves VSM, VMl. The control means CTL is a control algorithm and is programmed in a microcomputer in the electronic control unit ECU. Electric power is supplied to the electronic control unit ECU by the storage battery BAT and the generator ALT.

  The electronic control unit ECU includes a wheel speed (wheel rotation speed) Vwa acquired by the wheel speed acquisition means VWA, a yaw rate Yra acquired by the yaw rate acquisition means YRA, a lateral acceleration Gya acquired by the lateral acceleration acquisition means GYA, The master cylinder pressure Pmc acquired by the master cylinder pressure acquisition means PMC and the wheel cylinder pressure Pcl acquired by the wheel cylinder pressure acquisition means PCl are input. The electronic control unit ECU outputs a drive signal Svs for the electromagnetic valve VSM and a drive signal Svml for the electromagnetic valve VMl.

  A master cylinder (also referred to as a brake master cylinder) MCL converts an operation force (brake pedal depression force) of the brake operation member BP into a hydraulic pressure, and pumps the brake fluid to the front wheel cylinder WCl (left side). That is, the master cylinder MCL is connected to the front wheel wheel cylinder WCl by fluid pipes HMl and HWl.

  In order to generate an operation force on the braking operation member BP, a stroke simulator (also simply referred to as a simulator) SSM is provided. For example, the simulator SSM is provided with a piston and an elastic body (for example, a compression spring). The brake fluid BFL is moved from the master cylinder MCL to the simulator SSM, and the piston is pushed by the inflow brake fluid BFL. 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. In FIG. 1, the simulator SSM is provided for the wheel WHl, but may be provided for the wheel WHr instead of the wheel WHl. In this case, the simulator SSM is connected to the pipe HMr via the electromagnetic valve VSM.

  A solenoid valve VMl is provided between the master cylinder MCL and the wheel cylinder WCl. A pressure regulating mechanism CLK is provided on the wheel cylinder WCl side (that is, the side opposite to the MCL) with respect to the electromagnetic valve VMl. The pressure regulating mechanism CLK is driven by an electric motor MTR and is connected to a pipe HWl between the electromagnetic valve VMl and the wheel cylinder WCl.

  The pressure regulation mechanism CLK is configured by a reduction gear GSK, a rotation / linear motion conversion mechanism (screw member) NJB, a control piston PSC, and a control cylinder SCL. First, rotational power (output torque) Tq of the electric motor MTR is input to the reduction gear GSK. Then, the rotational power Tq is decelerated and output from the speed reducer GSK. The screw member NJB is connected to the output shaft Jdk of the reduction gear GSK. In the screw member NJB, the rotational power from the reduction gear GSK is converted into the linear power Fs. Furthermore, the screw member NJB is connected to the control piston PSC.

  The control piston PSC is combined with the control cylinder SCL to form one cylinder / piston. Specifically, the fluid chamber Rsc is formed (partitioned) by the control piston PSC and the control cylinder SCL. The control piston PSC is moved (reciprocated in the central axis direction of the SCL) by the linear power Fs converted from the rotational power Tq. The fluid chamber Rsc is filled with the brake fluid BFL, and the reciprocating motion causes the brake fluid BFL to move between the control cylinder SCL and the wheel cylinder WCl. As a result, the pressure of the brake fluid BFL in the wheel cylinder WCl is adjusted.

[Connection status of each component via fluid piping]
A state in which each component (WCl or the like) is connected by a fluid pipe 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. . “Communication” represents a state in which the fluids BFL inside the 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 operated by the driver is connected to a master piston MPl in the master cylinder MCL via a push rod. The master cylinder MCL is connected to the reservoir RSV so that the brake fluid BFL can be replenished. Master cylinder MCL is connected to electromagnetic valve VMl (also referred to as a shutoff valve) via pipe HMl. The electromagnetic valve VMl is connected to the wheel cylinder WCl via a pipe HWl. That is, the master cylinder MCL is connected to the wheel cylinder WCl via the pipes HMl and HWl and the electromagnetic valve VMl. The master cylinder MCL is connected to the stroke simulator SSM via a solenoid valve VSM.

  The pressure regulating mechanism CLK driven by the electric motor MTR is connected to the pipe HWl between the electromagnetic valve VMl and the wheel cylinder WCl. In order to detect the pressure generated by the pressure adjustment mechanism CLK, a hydraulic pressure acquisition means (pressure sensor) PCl is provided in the fluid path from the pressure adjustment mechanism CLK to the wheel cylinder WCl.

  Regarding the function (role) of each solenoid valve (VMl, etc.) and its operation, when the brake control device is operating properly (during proper determination) and when it is not operating properly (during inappropriate determination) Separately described. The electromagnetic valve (shutoff valve) VMl switches between a communication state (ie, an open position) and a non-communication state (ie, a closed position) between the master cylinder MCL and the wheel cylinder WCl. As the electromagnetic valve VM1, a normally open type (also referred to as NO valve) that is open when not energized and closed when energized is employed. The electromagnetic valve VMl is driven by a signal Svml from the electronic control unit ECU.

[Communication status at proper judgment]
A description will be given of a case where a determination unit HNT described later determines “appropriate state” (also referred to as appropriate determination). In this case, the electromagnetic valve VMl is set to the closed position (non-communication state). Therefore, the wheel cylinder WCl is not in communication with the master cylinder MCL and is in communication with the pressure regulating mechanism CLK.

  In this case, the piston is moved in the pressure adjusting mechanism CLK, and the volume of the fluid chamber Rsc in the pressure adjusting mechanism CLK is reduced, whereby the brake fluid BFL is discharged from the pressure adjusting mechanism CLK toward the wheel cylinder WCl. The brake fluid pressure in the wheel cylinder WCl is increased. By increasing the brake hydraulic pressure of the wheel cylinder WCl, the force with which the friction member (for example, brake pad) MSB presses the rotating member (for example, brake disc) KTl increases, and the braking torque of the wheel WHl is increased. . On the other hand, when the braking torque of the wheel WHl is decreased, the brake fluid BFL is returned from the wheel cylinder WCl to the pressure regulating mechanism CLK by increasing the volume of the fluid chamber Rsc. The brake hydraulic pressure of the wheel cylinder WCl is reduced, and the force that presses the friction member MSB against the rotating member KTl is reduced. That is, the braking torque applied to the wheels is controlled by adjusting the volume in the pressure regulating mechanism CLK (specifically, Rsc).

  Furthermore, at the time of the appropriateness determination, the electromagnetic valve VSM 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. The electromagnetic valve VSM is driven by a signal Svs from the ECU.

[Communication status at inappropriate judgment]
When the determination means HNT determines “inappropriate state” (also referred to as inappropriate determination), the solenoid valve VMl is opened (communication state) by the drive signal Svml, and the wheel cylinder WCl is It communicates with the cylinder MCL. That is, the piston MPl is moved in the master cylinder MCL, and the volume of the fluid chamber Rml in the master cylinder MCL is reduced, whereby the brake fluid BFL is discharged from the master cylinder MCL toward the front wheel cylinder WCl.

  The master cylinder MCL is a so-called tandem master cylinder, and is partitioned into two fluid chambers Rml and Rmr by master pistons MPl and MPr. These fluid chambers Rml and Rmr are communicated with the reservoir RSV through the relief port when the braking operation member BP is not operated. When an operating force is applied to the braking operation member BP, the master pistons MPl and MPr in the master cylinder MCL are moved via the push rod. Cup seals (cup-shaped rubber seals for maintaining the hydraulic pressure) are provided on the outer peripheral portions of the master pistons MPl and MPr. The relief ports are closed by the cup seals, and the fluid chambers Rml and Rmr, the reservoir RSV, , And the brake fluid BFL is pumped from the fluid chambers Rml and Rmr toward the wheel cylinders WCl and WCr.

  The brake fluid BFL is moved to the wheel cylinder WCl, and the brake fluid pressure with respect to the rotating member KTl of the friction member is increased by increasing the fluid pressure of the wheel cylinder WCl, and the brake torque of the front wheel WHl is increased. On the other hand, when the braking torque of the front wheel WHl is reduced, the brake fluid is returned from the front wheel wheel cylinder WCl to the master cylinder MCL.

  Further, at the time of inappropriate determination, the solenoid valve VSM is closed (non-communication state) by the drive signal Vsm, and the communication between the master cylinder MCL and the simulator SSM is blocked. That is, at the time of improper determination, the amount of braking fluid is not consumed in the simulator SSM. Therefore, the operation force (the brake pedal depression 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 wheel cylinder WCl.

  In FIG. 1, the left and right wheels WHl and WHr are shown in front of the vehicle (that is, corresponding to the front wheels). Instead of this, the left and right wheels WHl and WHr can be replaced with those on the rear side of the vehicle (that is, those corresponding to the rear wheels). Even this configuration has the same effect.

<Processing in electronic control unit ECU>
Next, calculation 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 (brake pedal) BP, a power supply 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 controls the electric motor MTR and the electromagnetic valves VSM, VMl, VMr. The processing in the electronic control unit ECU includes a control processing block (control means) CTL, a driving means DRV, and a solenoid valve control block SOL.

  The control means (control processing block) CTL 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, and a determination calculation block HNT. Composed. The control means CTL is a control algorithm and is programmed in a microcomputer in the electronic control unit ECU.

  In the anti-skid control block ABS, a target for executing anti-skid control (Anti-skid Control) so as to prevent wheel lock based on the acquisition result (wheel speed Vwa) of the wheel speed acquisition means VWA provided in each wheel. The hydraulic pressure Pabs is calculated. That is, the target hydraulic pressure Pabs for anti-skid control is a target value of the braking hydraulic pressure for preventing wheel lock. Here, the “braking hydraulic pressure” is a pressure at which the friction member (for example, brake pad) MSB presses the rotating members (for example, brake discs) KTl and KTr, and the hydraulic pressure in the wheel cylinders WCl and WCr Equivalent to.

  Specifically, in the anti-skid control block ABS, the vehicle speed (vehicle speed) Vso is calculated based on the wheel speed (rotational speed) Vwa of each wheel and a known method. For example, the fastest wheel speed Vwa can be selected and calculated as the vehicle speed Vso. Then, the slip speed Vslp of each wheel is calculated based on the vehicle speed Vso and the wheel speed Vwa. The wheel slip speed Vslp is calculated by subtracting the vehicle body speed Vso from the wheel speed Vwa. Furthermore, the wheel acceleration dVw is calculated based on the wheel speed Vwa of each wheel and a known method. For example, the wheel speed Vwa can be time differentiated to calculate the wheel acceleration dVw. The wheel slip state quantity Slp is a value (variable) based on at least one state quantity of the slip speed Vslp and the acceleration dVw. In the anti-skid control block ABS, the target braking hydraulic pressure Pabs is determined based on the wheel slip state amount Slp (Vslp, dVw).

  Similarly, in the traction control block TCS, a target hydraulic pressure for executing traction control (Traction Control) so as to suppress wheel spin (overspeed) based on the acquisition result (wheel speed Vwa) of the wheel speed acquisition means VWA. Ptcs is calculated. That is, the target hydraulic pressure Ptcs for traction control is a target value of the brake hydraulic pressure for suppressing wheel spin.

  Further, in the vehicle stabilization control block ESC, the vehicle stabilization is performed so as to maintain the stability of the vehicle based on the acquisition result (yaw rate Yra, lateral acceleration Gya) of the vehicle behavior acquisition means (yaw rate sensor YRA, lateral acceleration sensor GYA). A target hydraulic pressure Pesc for executing control (Electronic Stability Control) is calculated. That is, the target hydraulic pressure Pesc for vehicle stabilization control is a target value of the braking 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 command hydraulic pressure Pws is a target value of the brake hydraulic pressure generated by the pressure regulating mechanism CLK. Specifically, in the calculation characteristic CHpw, the command hydraulic pressure Pws is calculated to be zero in the range where the operation amount 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 the operation amount Bpa When the value is greater than or equal to the predetermined value bp0, the command 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 (the target value of the energization amount for controlling the MTR) of the electric motor MTR that drives the pressure adjusting mechanism CLK 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. Further, since the supply voltage value can be adjusted by the duty ratio in the pulse width modulation, this duty ratio (ratio of energization time in one cycle) can be used as the energization amount.

  In the 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 electric motor MTR should rotate (that is, the increase / decrease direction of the hydraulic pressure), and the output of the electric motor MTR is output. The magnitude of the target energization amount Imt is calculated based on the power of rotation (that is, the increase / decrease amount of the hydraulic pressure). Specifically, when increasing the brake fluid 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 Fwd. On the other hand, when decreasing the brake hydraulic pressure, the sign of Imt is determined to be a negative sign (Imt <0), and the electric motor MTR is driven in the reverse rotation direction Rvs. Furthermore, the output torque (rotational power) 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 control block EAS, an inertia compensation control block KHS, and a sudden stop control block QTC.

  In the hydraulic pressure control block EAS of the target energization amount calculation block IMT, one of the anti-skid control target hydraulic pressure Pabs, the traction control target hydraulic pressure Ptcs, and the vehicle stabilization control target hydraulic pressure Pesc is selected. . The selection order of the target hydraulic pressure is determined based on the traveling state of the vehicle and the state of the wheels. Note that Ptsc is not selected when the corresponding wheel is not a drive wheel (when it is not connected to a drive train). Then, the final target value Pwt of the hydraulic pressure is determined based on one of the hydraulic pressure target values Pabs, Ptcs, and Pesc and the indicated hydraulic pressure Pws. Specifically, the command hydraulic pressure Pws is corrected by the target brake hydraulic pressure (Pabs, Ptcs, or Pesc), and the final target hydraulic pressure Pwt is calculated.

  Further, in the hydraulic pressure control block EAS, the target energization amount Ist of the electric motor MTR is calculated based on the hydraulic pressure target value Pwt and the hydraulic pressure actual values Pcl and Pcr. Here, the actual hydraulic pressure values Pcl and Pcr are actual hydraulic pressure values (actual hydraulic pressures) acquired (detected) by the hydraulic pressure acquisition means (pressure sensors) PCl and PCr. In the hydraulic pressure control block EAS, first, the feedforward component Ist1 in the target energization amount Ist is calculated based on the target hydraulic pressure Pwt and a preset calculation map. Next, a feedback component Ist2 in Ist is calculated based on the deviation between the target value Pwt and the actual values Pcl, Pcr. Specifically, Ist2 is determined so that the hydraulic pressure deviation decreases. Then, the feedforward component Ist1 is corrected by the feedback component Ist2, and the target energization amount Ist is calculated (for example, Ist = Ist1 + Ist2).

  In the inertia compensation control block KHS of the target energization amount calculation block IMT, the influence of the inertia moment (inertia) of the electric motor MTR and the pressure adjusting mechanism CLK is compensated. Specifically, in the inertia compensation control block KHS, target values Ijt and Ikt of the energization amount for compensating for the influence of the inertia moment are calculated. When the electric motor is stopped or the movement (rotational movement) is accelerated from a state where the electric motor is moving at a low speed, it is necessary to improve the response of the generation of the brake fluid pressure. The inertia compensation energization amount Ijt at the time of acceleration corresponding to this case is calculated. Therefore, Ijt is a target value of the energization amount of the acceleration control in the inertia compensation control, and is a value that increases the target energization amount of the electric motor. In addition, when the electric motor is decelerated and stopped from a state of motion (rotational motion), it is also necessary to suppress the overshoot of the brake fluid pressure and improve its convergence. The inertia compensation energization amount Ikt during deceleration corresponding to this case is calculated. Therefore, Ikt is a target value of the energization amount of the deceleration control in the inertia compensation control, and is a value that decreases the target energization amount of the electric motor.

  In the sudden stop control block QTC of the target energization amount calculation block IMT, the target value (the sudden stop energization amount) Iqt of the sudden stop control is determined based on the motion state of the electric motor MTR at the time when the anti-skid control is started. Calculated. In the sudden stop control block QTC, in order to suppress an excessive slip (wheel locking tendency) caused by a delay in the follow-up of the actual hydraulic pressure with respect to the target hydraulic pressure, the electric motor MTR is rapidly decelerated at the maximum capacity, In other words, this is control for stopping the rotational movement of the electric motor MTR. Therefore, in QTC, as the target value (abrupt stop energization amount) Iqt of the sudden stop control, the maximum amount (energization) that can be energized in the rotation direction (reverse direction) Rvs of the electric motor in which the brake fluid pressure decreases. (Limit value) imm is indicated stepwise (discontinuous from previous Imt, stepwise, and instantaneously). Here, the energization limit value imm (a negative value corresponding to the Rvs direction) is set in advance based on a value corresponding to the maximum current of the electric motor MTR or the drive circuit DRV.

  In the target energization amount calculation block IMT, a target energization amount Imt that is a final target value of the electric motor MTR is calculated. In the IMT, the target energization amount Ist is adjusted by the inertia compensation energization amount Ijt (acceleration), Ikt (deceleration), and the sudden stop energization amount Iqt, and the final target energization amount Imt is calculated. Specifically, in the energization amount adjustment calculation block IMT, the feedback energization amount Ipt is added to the command energization amount Ist, and any of the inertia compensation energization amounts Ijt and Ikt and the sudden stop energization amount Iqt One of them is added and the sum is calculated as the target energization amount Imt. In prioritizing the inertia compensation control and the sudden stop control, the sudden stop energization amount Iqt is output with priority over the inertia compensation energization amounts Ijt and Ikt. That is, when the sudden stop energization amount Iqt is input simultaneously with the inertia compensation energization amounts Ijt and Ikt, the inertia compensation energization amounts Ijt and Ikt are set to zero, and the sudden stop energization amount Iqt is output.

  The determination calculation block (determination means) HNT determines the suitability of the operating state of the entire system including the suitability of the operating state of the electric motor MTR. The suitability of the operating state of the electric motor MTR is used for 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 electric motor MTR, and the control of the electric motor MTR. The determination is made based on at least one of the operating states of the acquisition means (MKA, IMA, etc.) for acquiring the state quantity.

  The determination calculation block HNT is composed of an initial diagnosis block CHK and an operation monitoring block MNT. The determination calculation block HNT is a control algorithm and is programmed in a microcomputer in the ECU.

  In the initial diagnosis 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 block MNT, the operation of the entire system including the electric motor MTR is constantly monitored. In the determination calculation 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 block CHK and the operation monitoring 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 block CHK and the operation monitoring block MNT are both “appropriate”.

  In the initial diagnosis block CHK, the state of power supply to the braking control device, diagnosis of the electronic control unit ECU itself (for example, memory diagnosis), electric motor MTR, bridge circuits S1 to S6, energization amount acquisition means IMA for the electric motor, rotation Diagnosis (operation check) of at least one of the angle acquisition unit MKA, the solenoid valve (VSM, etc.), the energization amount acquisition unit ISA for the solenoid valve, and the hydraulic pressure acquisition unit (PCl, etc.) 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 block CHK, the initial operation diagnosis is started when the electronic control unit 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 (initial check), a driving signal for diagnosis is transmitted from the initial diagnosis block CHK to the bridge circuit 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 (PCl etc.) Received at. Based on the reception result, at least one function of a bridge circuit (that is, switching element), electric motor MTR, electromagnetic valve, energization amount acquisition means IMA, ISA, rotation angle acquisition means MKA, and hydraulic pressure acquisition means. However, it is diagnosed whether or not it 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 block MNT, the power supply state to the braking control device, the bridge circuit (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 It is diagnosed whether or not at least one function of the hydraulic 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 block CHK and the operation monitoring block MNT is determined to be “inappropriate state”, the determination result FLsd = 0 indicating the system inappropriateness is determined by the determination means HNT. Is output from. And only when it is determined that both of the determination results of the initial diagnosis block CHK and the operation monitoring block MNT are in the “appropriate state”, the determination result FLsd = 1 (appropriate determination) indicating the system appropriateness is It is output from the determination calculation block (determination means) HNT.

  In an electromagnetic valve control block SOL, which will be described later, a control flag FLsd representing a propriety state is received, and the energization state of each electromagnetic valve is controlled based on FLsd. When the entire system including the electric motor MTR is operating properly (when FLsd = 1 is received), as described above, “with braking operation (ie, Bpa ≧ bp0)” and “TCS” Or, the drive state (energized state) of the solenoid valves VSM, VMl, VMr is controlled based on the condition of the operating state of the ESC (ie, FLcb = 1). However, if the system operation (for example, the operating state of the electric motor MTR) is inappropriate (when FLsd = 0 is received), “there is a braking operation (ie Bpa ≧ bp0)” and “TCS or Regardless of the condition of the operating state of ESC (ie, FLcb = 1), energization to the solenoid valves VSM, VMl, VMr is stopped. Therefore, the electromagnetic valve VSM is maintained or changed to the closed position, and the electromagnetic valves VMl and VMr are maintained or changed to the open position. That is, when the system operation is malfunctioning, the master cylinder MCL and the wheel cylinders WCl, WCr are brought into communication.

  In the electronic control unit ECU, electric power is supplied from an electric power source (BAT or the like) to perform its function. For this reason, when the power source is malfunctioning (that is, when the supplied power is insufficient), the ECU itself does not function and power supply to the electric motor MTR and the electromagnetic valve (VSM, etc.) cannot be performed. However, normally closed solenoid valves (NC valves) are employed as the solenoid valves VSM, and normally open solenoid valves (NO valves) are employed as the solenoid valves VMl and VMr. As a result, even when the power source is in an inappropriate state, the communication between the master cylinder MCL and the simulator SSM is cut off, and the communication between the master cylinder MCL and the wheel cylinders WCl and WCr can be ensured.

  In the drive circuit (drive means) DRV of the electric motor MTR, the rotational power (output) of the electric motor MTR and its direction are adjusted based on the target energization amount Imt. The driving unit DRV includes a bridge circuit configured by a plurality of switching elements for driving the electric motor MTR, a pulse width modulation block PWM, a switching control block SWT, and an energization amount acquisition unit IMA.

  When a brushless motor is employed as the electric motor MTR, the bridge circuit is configured by six switching elements (S1 to S6) (so-called three-phase bridge circuit). In the three-phase bridge circuit, the coil energization amounts of the U phase (terminal Tu), V phase (terminal Tv), and W phase (terminal Tw) are determined based on the detection result (rotation angle Mka) of the rotation angle acquisition unit MKA. The direction (that is, the excitation direction) is sequentially switched, and the electric motor MTR is driven. Note that the rotation direction (Fwd or Rvs) of the brushless motor is determined by the relationship between the rotor and the excitation position.

  In the pulse width modulation block PWM, based on the target energization amount Imt, an instruction value (target value) for performing pulse width modulation (PWM, Pulse Width Modulation) is calculated for each of the switching elements S1 to S6. 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 Fwd is a positive (plus) value and the reverse rotation direction Rvs is a negative (minus) value.

  In the switching control block SWT, drive signals for the switching elements S1 to S6 constituting the bridge circuit are calculated based on the duty ratio (target value) Dut. Based on these drive signals, the energization or non-energization states of the switching elements S1 to S6 are controlled. Specifically, the larger the duty ratio Dut, the longer the energization time per unit time in the switching elements S1 to S6, the larger current flows through the electric motor MTR, and the output (rotational power) of the electric motor MTR increases. Great.

  The drive means DRV includes an energization amount acquisition means (for example, a current sensor) IMA, and acquires (detects) an actual energization amount (for example, an actual current value) Ima. In the switching control block SWT, so-called current feedback control is executed. The 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 solenoid valve control block SOL, the energization or non-energization state of each solenoid valve (VSM, 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 the operation amount Bpa is less than the value bp0, “no braking operation (braking operation is performed) “Not done)” is 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 state of the traction control block TCS and the vehicle stabilization control block 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 valves VSM, VMl, VMr is switched from non-energized to energized. As a result, the electromagnetic valve VSM is changed from the closed position to the open position, and the electromagnetic valves VMl and VMr are 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.

  An example in which inertia compensation control and sudden stop control are executed will be described with reference to the time chart of FIG.

<Inertia compensation control>
The influence of the inertia moment (inertia) of the electric motor MTR and the like is compensated by the inertia compensation control executed by the inertia compensation control block KHS shown in FIG. The torque necessary for accelerating the electric motor MTR is proportional to the rotational angular acceleration of the electric motor MTR. Further, the output torque of the electric motor MTR is proportional to the amount of energization applied. Therefore, the inertia compensation energization amounts (target values) Ijt and Ikt are set to values obtained by differentiating the target rotation angle (displacement) of the electric motor MTR twice (target values of angular acceleration) and the torque constant of the electric motor MTR. To be determined. Here, the target value Ijt is calculated to increase the energization amount, and the target value Ikt is determined to decrease the energization amount.

  At time t0, the driver suddenly operated the BP. For this reason, execution of inertia compensation control is started at time t1, the inertia compensation energization amount Ijt is increased with respect to the target energization amount Ist, and the final target energization amount Imt is determined. At time t2, the inertia compensation control is terminated.

<Sudden stop control>
With the sudden stop control executed in the sudden stop control block QTC shown in FIG. 2, the hydraulic pressure response at the start of the anti-skid control can be ensured. The sudden stop control is a control for suddenly decelerating at the maximum capacity of the electric motor MTR and urgently stopping the rotational motion. Therefore, in the sudden stop control block QTC, the maximum amount (energization limit value) imm that can be energized in the reverse direction Rvs of the electric motor is set as a step value as the target value (abrupt stop energization amount) Iqt of the sudden stop control. (Discontinuous from previous Imt, stepwise, and instantaneously).

  After the inertia compensation control is ended (after time t2), the wheel slip state amount Slp (at least one of the wheel slip speed Vslp and the wheel acceleration dVw) calculated based on the wheel speed Vwa starts to increase. . At time t3, the wheel slip state amount Slp exceeds the control threshold value, and execution of the anti-skid control is started. Since the rotational speed dMka of the electric motor MTR at this time point t3 exceeds the predetermined value dmk1, the sudden stop control is executed simultaneously with the start of execution of the anti-skid control. Here, the rotation speed dMka is calculated based on the rotation angle Mka acquired by the rotation angle acquisition means (rotation angle sensor) MKA (Mka is first-order differentiated and dMka is calculated). With the execution of the sudden stop control, Imt is reduced stepwise to the energization limit value imm (<0). As a result, the electric motor MTR rapidly decelerates and rotates in the reverse rotation direction Rvs. As a result, the overshoot of the brake fluid pressure is suppressed, and the pressure reduction can be started immediately. The sudden stop control is terminated when the rotational speed dMka of the electric motor MTR becomes equal to or less than a predetermined value dmk2 (<dmk1) (time t4).

<Priority order of inertia compensation control and sudden stop control>
Since the sudden stop control has priority over the inertia compensation control, when the sudden stop energization amount Iqt is input simultaneously with the inertia compensation energization amounts Ijt and Ikt, the inertia compensation energization amounts Ijt and Ikt are set to zero. The sudden stop energization amount Iqt is output. When the start of the sudden stop control is determined at time t5 during the execution of the inertia compensation control, the inertia compensation control is immediately terminated and the sudden stop control is started. For this reason, the depressurization response of the brake fluid pressure immediately after the start of the anti-skid control can be ensured.

<Pressure control mechanism CLK>
The details of the pressure regulating mechanism CLK (particularly corresponding to the left front wheel WHl) disposed on the front wheel of the vehicle will be described with reference to the configuration diagram of FIG.

  As in the case of the other figures, the suffixes attached to the end of various symbols are represented such that the suffix “l” corresponds to the left wheel and the suffix “r” corresponds to the right wheel. For example, “CP1” is associated with the brake caliper for the left front wheel, and “CPr” is associated with the brake caliper for the right front wheel. Since the one corresponding to the right front wheel WHr (CPr and the like) is the same as the one corresponding to the left front wheel WHl (CP1 and the like), only the one corresponding to the left front wheel WHl will be described. In addition, what corresponds to the left front wheel WHr can be described by replacing “left” with “right” and replacing the suffix “l” at the end of the symbol with the suffix “r” in the description. Furthermore, although the thing corresponding to a front wheel is demonstrated here, you may correspond to a rear wheel.

  The pressure regulating mechanism CLK is connected to a pipe HWl between the electromagnetic valve VMl and the wheel cylinder WCl, and is driven by an electric motor MTR. The pressure regulation mechanism CLK is configured by a reduction gear GSK, a rotation / linear motion conversion mechanism (screw member) NJB, a control piston PSC, a control cylinder SCL, and a return spring SPR.

  The reduction gear GSK is composed of a small diameter gear SKH and a large diameter gear DKH. The number of teeth Zo of the large diameter gear DKH is larger than the number of teeth Zi of the small diameter gear SKH (Zo> Zi). Therefore, the pitch circle diameter of the large-diameter gear DKH is larger than the pitch circle diameter of the small-diameter gear SKH. That is, the rotational power of the electric motor MTR is decelerated by the reduction gear GSK and transmitted to the screw member NJB. Specifically, the small diameter gear SKH is fixed to the output shaft Jmt of the electric motor MTR. The large-diameter gear DKH and the bolt member BLT are fixed so that the large-diameter gear DKH is engaged with the small-diameter gear SKH, and the rotation axis Jdk of the large-diameter gear DKH is aligned with the rotation axis of the bolt member BLT of the screw member NJB. The That is, in the reduction gear GSK, the rotational power Tq from the electric motor MTR is input to the small diameter gear SKH, which is decelerated and output from the large diameter gear DKH to the screw member NJB.

  The input speed from the electric motor MTR to the small-diameter gear SKH of the reduction gear GSK is the input rotational speed Ni. Further, the output speed from the large-diameter gear DKH of the reduction gear GSK to the screw member NJB (for example, BLT) is set as the output rotation speed No. Here, the “number of rotations” is the number of rotations per unit time and correlates with the angular velocity around the rotation axis. A value obtained by dividing the input rotational speed Ni of the speed reducer GSK by the output rotational speed No of the speed reducer GSK is defined as a speed transmission ratio (so-called speed reduction ratio of the speed reducer GSK) Hs (= Ni / No). . The speed transmission ratio Hs is also a value obtained by dividing the number of teeth Zo of the output gear (large diameter gear DKH) of the reduction gear GSK by the number of teeth Zi of the input gear (small diameter gear SKH) of the reduction gear GSK (that is, Hs = Zo / Zi). The rotational power To output from the reduction gear GSK is a value obtained by multiplying the rotational output (output torque) Tq of the electric motor MTR by the speed transmission ratio Hs (To = Tq × Hs).

  The rotational power To (= Tq × Hs) of the reduction gear GSK is converted into the linear power Fs of the control piston PSC by the screw member NJB. Specifically, the bolt member BLT of the screw member NJB is fixed coaxially with the large-diameter gear DKH, the nut member NUT screwed with the bolt member BLT is moved, and the control piston PSC is pushed by the nut member NUT. As a result, the linear power Fs of the control piston PSC is converted. Here, since the rotational movement of the nut member NUT is restrained by the key member KYB, the nut member NUT is moved in the direction of the rotational axis of the large-diameter gear DKH and presses the control piston PSC.

  As the screw member NJB, a “sliding screw” such as a trapezoidal screw is employed. Further, as the screw member NJB, a “rolling screw” such as a ball screw can be employed.

  The control piston PSC is moved by the nut member NUT constituting the screw member NJB. The control piston PSC is inserted into the inner hole of the control cylinder SCL to form a piston / cylinder combination. Specifically, the control piston PSC is provided with a cup seal GSC, and sealing is performed between the inner hole (inner wall) of the control cylinder SCL, and the fluid chamber is defined by the control cylinder SCL and the control piston PSC. Rsc is formed. The fluid chamber Rsc of the control cylinder SCL is connected to the fluid pipe HWl via the port HSC. As the control piston PSC is moved in the axial direction (center axis Jsc), the volume of the fluid chamber Rsc changes. At this time, since the electromagnetic valve VMl is in the closed position, the brake fluid BFL is not moved in the direction of the master cylinder MCL, but is moved relative to the wheel cylinder WCl. Note that the cross-sectional area in the inner hole of the control cylinder SCL (referred to as the cross-sectional area of the control cylinder SCL) is Asc. The cross-sectional area Asc of the control cylinder SCL matches the pressure receiving area of the control piston PSC.

  The pressure regulating mechanism CLK is provided with a return spring (elastic body) SPR. When the energization of the electric motor MTR is stopped by the return spring SPR, the control piston PSC is returned to the initial position (position corresponding to zero braking hydraulic pressure).

  The brake caliper CPI is a floating type, and a wheel cylinder WCl is provided here. A wheel piston PWC is inserted into the inner hole of the wheel cylinder WCl to form a piston / cylinder combination. A cup seal GWC is provided on the outer periphery of the wheel piston PWC, and a sealing property is exhibited between the cup seal GWC and the inner hole (inner wall) of the wheel cylinder WCl. That is, the fluid chamber Rwc defined by the wheel cylinder WCl and the wheel piston PWC is formed by the wheel cylinder cup seal GWC. The wheel piston PWC is connected to the friction member MSB and configured to press the MSB. The sectional area of the inner hole of the wheel cylinder WCl (referred to as the sectional area of WCl) is Awc. The cross-sectional area Awc of the wheel cylinder WCl matches the pressure receiving area of the wheel piston PWC.

  The fluid chamber Rwc formed by the combination of the wheel piston PWC and the wheel cylinder WCl is filled with the brake fluid BFL. Moreover, it is connected to the fluid piping HWl via the fluid chamber Rwc and the port HWC. Therefore, when the control piston PSC is reciprocated in the direction of the central axis Jsc by the electric motor MTR and the volume of the fluid chamber Rsc is increased or decreased, the flow of the brake fluid BFL into or out of the fluid chamber Rwc causes the fluid chamber Rwc to enter the fluid chamber Rwc. The hydraulic pressure changes. As a result, the force with which the friction member (for example, brake pad) MSB presses the rotating member (for example, brake disc) KTl is adjusted, and the braking torque of the wheel WHl is controlled.

  Specifically, when the electric motor MTR is rotationally driven in the forward rotation direction Fwd, the control piston PSC is moved so as to reduce the volume of the fluid chamber Rsc (moving leftward in the figure), and the brake fluid BFL is It is moved from the control cylinder SCL to the wheel cylinder WCl. As a result, the volume of the fluid chamber Rwc is increased, the pressing force of the friction member MSB against the rotating member KTl is increased, and the braking torque of the wheel WHl is increased. On the other hand, when the electric motor MTR is rotationally driven in the reverse rotation direction Rvs, the control piston PSC is moved so as to increase the volume of Rsc (moving in the right direction in the figure), and the brake fluid BFL is transferred from the wheel cylinder WCl to the control cylinder. SCL moved. As a result, the volume of the fluid chamber Rwc is reduced, the pressing force of the friction member MSB against the rotating member KTl is reduced, and the braking torque of the wheel WHl is reduced.

  Deceleration so that the speed transmission ratio Hs (= Ni / No) is larger than the area ratio Ha (= Awc / Asc), which is a value obtained by dividing the sectional area Awc of the wheel cylinder WCl by the sectional area Asc of the control cylinder SCL. The specifications of the machine GSK, the control cylinder SCL, and the wheel cylinder WCl are determined. Specifically, in the gear transmission mechanism, since the speed transmission ratio (reduction ratio) is determined by the number of teeth of the gear, in the relationship between the number of teeth Zi of the small diameter gear SKH and the number of teeth Zo of the large diameter gear DKH, Hs = The relationship Zo / Zi is established.

  Responsiveness due to driving of the electric motor MTR depends on the moment of inertia. Since the inertia moment is affected by the speed transmission ratio Hs of the reduction gear GSK, the equivalent inertia moment is adopted when the influence of the inertia moment is taken into consideration. Here, the equivalent inertia moment is a value converted into an inertia moment around the output shaft Jmt (that is, Jsk) of the electric motor MTR in consideration of the speed transmission ratio Hs. Specifically, the equivalent moment of inertia is calculated by multiplying the original moment of inertia by the square of the reciprocal of the speed transmission ratio Hs (ie, 1 / Hs ^ 2). That is, the inertia moment Io (ie, the original moment of inertia) around the output shaft Jdk of the speed reducer GSK is divided by the square of the speed transmission ratio Hs, thereby obtaining an equivalent around the motor rotation axis Jmt (ie, Jsk). The moment of inertia Ko is determined (Ko = Io / Hs ^ 2). As is clear from this relationship, the equivalent inertia moment Ko is set to a smaller value as the speed transmission ratio Hs is larger.

  The output torque of the electric motor MTR is increased by the reduction gear GSK. For this reason, the member (for example, DKH) on the output shaft of the speed reducer GSK has high strength (for example, the tooth thickness is increased) in order to transmit a large torque. Furthermore, in the reduction gear GSK, the diameter of the large diameter gear DKH is relatively larger than the diameter of the small diameter gear SKH. For this reason, the inertia moment Io around the output shaft Jdk of the reduction gear GSK including the large-diameter gear DKH is relatively large.

  The value “1 / Hs ^ 2” converges to “0 (zero)” sequentially as the speed transmission ratio Hs increases. For this reason, in the region where the speed transmission ratio Hs is larger than a certain value (predetermined value), the value “1 / Hs ^ 2” is sufficiently small. Based on such knowledge, the specifications of the pressure regulating mechanism CLK and the wheel cylinder WCl are determined and configured so that the speed transmission ratio Hs is larger than the area ratio Ha. In the relationship between the speed transmission ratio Hs and the area ratio Ha, when the speed transmission ratio Hs is set relatively large, the equivalent inertia moment Ko around the output shaft Jdk of the reduction gear GSK is reduced. In control, sufficient responsiveness of the brake fluid pressure can be ensured. Specifically, the reversal of the electric motor MTR (change in the rotation direction from Fwd to Rvs) immediately after the start of the anti-skid control can be performed instantaneously.

  Further, the equivalent inertia moment Ko of the entire member existing around the output shaft of the reduction gear GSK can be set smaller than the inertia moment Im of the electric motor MTR. For this reason, in the equivalent inertia moment around Jmt, the ratio of the equivalent inertia moment Ko is made relatively small with respect to the inertia moment Im of the electric motor alone. As a result, the influence of the moment of inertia around the output shaft of the reduction gear GSK (DKH moment of inertia, etc.) is reduced, so that the response of braking fluid pressure in anti-skid control (particularly, the pressure reduction response at the start of anti-skid control) Can be improved.

  By the way, the speed transmission ratio (reduction ratio) Hs and the area ratio Ha correspond to the “lever ratio (lever ratio)” in the “lever”. That is, the reduction gear GSK increases the force (torque) from the electric motor MTR by Hs times, and decreases the displacement by “1 / Hs” times. Similarly, in Pascal's principle, the pressing force of the control piston PSC of the control cylinder SCL is amplified Ha times and transmitted as the pressing force of the wheel piston PWC of the wheel cylinder WCl. Further, the displacement of the control piston PSC of the control cylinder SCL is reduced by a factor of “1 / Ha” and transmitted as the displacement of the wheel piston PWC of the wheel cylinder WCl. That is, the output of the electric motor MTR is increased “Hs × Ha” times by the speed transmission ratio Hs and the area ratio Ha, and the displacement is decreased by “1 / (Hs × Ha)” times. It is transmitted to WCl (that is, friction member MSB).

  In the power transmission path from the output of the electric motor MTR to the pressing force of the wheel piston PWC (that is, the hydraulic pressure of WCl), the value corresponding to the lever ratio (= Hs × Ha, referred to as lever ratio equivalent value) is Based on the maximum required hydraulic pressure in the wheel cylinder WCl and the output characteristics of the electric motor MTR, the value is substantially constant. Therefore, when the speed transmission ratio Hs is set relatively large, the area ratio Ha needs to be relatively small. Conversely, when the speed transmission ratio Hs is set to a relatively small value, the area ratio Ha is set to a relatively large value.

  The size of the area ratio Ha is adjusted by the lead of the screw member NJB (the distance traveled by the PSC when the NJB is rotated once). When the area ratio Ha is set relatively small, the lead of the screw member NJB needs to be small. However, if the lead of the screw member NJB is set too small, its manufacture may be difficult. For this reason, in the relationship between CLK and WCl, the area ratio Ha is determined to be larger than “1”. That is, the specifications of the wheel cylinder WCl and the control cylinder SCL are set so that the cross-sectional area Awc of the wheel cylinder WCl is larger than the cross-sectional area Asc of the control cylinder SCL. As a result, there is no need to minimize the lead of the rotation / linear motion conversion mechanism (also referred to as a screw member) NJB, and its feasibility can be ensured.

  As described above, when the configuration of the pressure regulating mechanism CLK is summarized, the area ratio Ha is set larger than “1” and the speed transmission ratio Hs is set larger than the area ratio Ha. That is, the relationship between the area ratio Ha and the speed transmission ratio Hs is determined by “1 <Ha <Hs”. An area ratio Ha (= Awc / Asc), which is a value obtained by dividing the cross-sectional area Awc of the wheel cylinders WCl and WCr by the cross-sectional area Asc of the control cylinder SCL, is set to be larger than “1” (that is, the cross-sectional area Awc is Therefore, the formation of the lead of the rotation / linear motion conversion mechanism (screw member) NJB (for example, ease of processing) can be ensured. Further, since the speed transmission ratio Hs (= Ni / No) is set to be larger than the area ratio Ha (= Awc / Asc), the equivalent inertia moment Ko of the member (such as DKH) around the output shaft Jdk of the reduction gear GSK. However, it is set as small as possible, and sufficient anti-skid control can ensure sufficient response of the brake fluid pressure.

  In the configuration of the screw member (rotation / linear motion conversion mechanism) NJB, the relationship between the bolt member BLT and the nut member NUT can be replaced. That is, a configuration in which the nut member NUT is coaxially fixed to the large-diameter gear DKH and the bolt member BLT is moved in the axial direction to press the control piston PSC can be employed.

  In the reduction gear GSK, a wrapping transmission mechanism may be employed instead of the gear transmission mechanism. The winding transmission mechanism is at least one of “by pulley and belt”, “by sprocket and chain”, and “by rope car and rope”.

<Driving means DRV (example of a three-phase brushless motor)>
FIG. 5 is an example of drive means (drive circuit) DRV when the electric motor MTR is a brushless motor. The driving means DRV is an electric circuit that drives the electric motor MTR, and is a pulse width modulation block PWM that performs pulse width modulation (PWM) based on the six switching elements S1 to S6 and the target energization amount Imt. The switching control block SWT controls the energized / non-energized states of S1 to S6 based on the duty ratio Dut determined by the PWM.

  The six switching elements S1 to S6 are elements that can turn on / off a part of the electric circuit, and for example, MOS-FETs can be used. In the brushless motor, the position acquisition means MKA acquires the rotor position (rotation angle) Mka of the electric motor MTR. Then, by controlling the switching elements S1 to S6, the direction of the coil energization amount of the U phase (Tu terminal), V phase (Tv terminal), and W phase (Tw terminal) (that is, the excitation direction) is Based on the rotation angle Mka, the electric motor MTR is rotationally driven by sequentially switching. That is, the rotation direction of the brushless motor (forward rotation direction Fwd or reverse rotation direction Rvs) is determined by the relationship between the rotor and the excitation position. Here, the forward rotation direction Fwd of the electric motor MTR is a rotation direction corresponding to an increase in braking fluid pressure, and the reverse rotation direction Rvs of the electric motor MTR is a rotation direction corresponding to a decrease in braking fluid pressure.

  In the pulse width modulation block PWM, the duty ratio of the pulse width (ratio of ON time to one cycle) is determined based on the magnitude of the target energization amount Imt, and is based on the sign (positive sign or negative sign) of Imt. Thus, the rotation direction of the electric motor MTR is determined. For example, the rotation direction of the electric motor MTR is set such that the forward rotation direction Fwd is a positive (plus) value and the reverse rotation direction Rvs is a negative (minus) value. Since the final output voltage is determined by the input voltage (battery BAT voltage) and the duty ratio Dut, the rotation direction and output torque of the electric motor MTR are controlled.

  In the switching control block SWT, a signal indicating whether each switching element is turned on (energized) or turned off (non-energized) is transmitted to S1 to S6. By this signal, the switching elements S1 to S6 are controlled, and the rotation direction and output torque (rotational power) of the electric motor MTR are controlled.

<Other embodiment of reduction gear GSK (multistage reduction)>
Another embodiment of the reduction gear GSK will be described with reference to the configuration diagram of FIG. In the pressure regulating mechanism CLK shown in FIG. 4, the speed reducer GSK is one-stage deceleration (deceleration by one set of SKH and DKH), but multistage deceleration can be adopted as GSK. For example, a two-stage speed reducer GSK shown in FIG. 6 may be employed.

  As in the case of the one-speed reduction gear GSK, the small-diameter gear SKH is fixed to a rotary shaft Jsk that is coaxial with the output shaft Jmt of the electric motor MTR, and rotates integrally with the rotor of the electric motor MTR. The small diameter gear SKH is meshed with the large diameter intermediate gear DKC. The number of teeth Zcd of the large diameter intermediate gear DKC is larger than the number of teeth Zi of the small diameter gear SKH, and the pitch diameter of the large diameter intermediate gear DKC is larger than the pitch diameter of the small diameter gear SKH. The small-diameter intermediate gear SKC is fixed to the large-diameter intermediate gear DKC by a coaxial Jck, and is driven to rotate integrally with the large-diameter intermediate gear DKC. Further, the small diameter intermediate gear SKC is meshed with the large diameter gear DKH. The number of teeth Zo of the large-diameter gear DKH is larger than the number of teeth Zcs of the small-diameter intermediate gear SKC, and the pitch circle diameter of the large-diameter gear DKH is larger than the pitch circle diameter of the small-diameter intermediate gear SKC. Furthermore, the large-diameter gear DKH is coaxial with the screw member NJB (for example, BLT), is fixed to the output shaft Jdk of the reduction gear GSK, and rotates integrally with the screw member NJB.

  In the first reduction stage formed by the small-diameter gear SKH and the large-diameter intermediate gear DKC, the first speed transmission ratio (reduction ratio) Hs1 is a value “Ni / Nc obtained by dividing the rotational speed Ni by the rotational speed Nc. Is represented. In the second reduction gear stage formed by the small-diameter intermediate gear SKC and the large-diameter gear DKH, the second speed transmission ratio (reduction ratio) Hs2 is a value “Nc” obtained by dividing the rotational speed Nc by the rotational speed No. / No ". The speed transmission ratio (reduction ratio) Hs of the entire reduction gear GSK is represented by a value “Ni / No” obtained by dividing the rotational speed Ni by the rotational speed No. This relationship can be calculated as Hs = Hs1 × Hs2 = (Ni / Nc) × (Nc / No) = Ni / No. In terms of the number of teeth, Hs1 = Zcd / Zi and Hs2 = Zo / Zcs.

  Also in the case of two-stage deceleration, the speed transmission ratio Hs is set to be larger than the area ratio Ha, as in the case of the one-stage deceleration shown in FIG. Here, the speed transmission ratio (so-called reduction ratio) Hs is a value obtained by dividing the input rotational speed Ni from the electric motor MTR to the reduction gear GSK by the output rotational speed No of the reduction gear GSK (Hs = Ni / No). It is. The area ratio Ha is a value obtained by dividing the cross-sectional area Awc of the wheel cylinders WCl and WCr by the cross-sectional area Asc of the control cylinder SCL (Ha = Awc / Asc).

  Further, a value Ko (= Io / Hs ^ 2) obtained by dividing the inertia moment Io around the output shaft Jdk of the reduction gear GSK by the square of the speed transmission ratio Hs is made smaller than the inertia moment Im of the electric motor MTR. It is configured as follows. That is, the inertia moment Io around the output shaft Jdk of the reduction gear GSK is converted into the equivalent inertia moment Ko around the input shaft Jsk of the reduction gear GSK in consideration of the speed transmission ratio Hs. The equivalent inertia moment Ko is configured to be smaller than the inertia moment Im of the electric motor MTR (that is, Ko <Im). With this configuration, even in the case of multi-stage deceleration (for example, two-stage deceleration), the same effect as in the case of one-stage deceleration (FIG. 4) is obtained.

<Operation and effect of the present invention>
The brake fluid pressure is increased / decreased by forward / reverse rotation of the electric motor MTR, so that the brake control device that exhibits the control brake function in addition to the service brake function has the most severe operating state in the response of the brake fluid pressure. One is a situation in which anti-skid control is started immediately after sudden braking is performed. Specifically, in the state where the electric motor MTR is rapidly accelerated in the forward rotation direction Fwd in order to rapidly increase the brake fluid pressure, the wheel slip Slp increases and the brake fluid pressure is rapidly decreased. In order for this operation to be properly executed, the moment of inertia of the braking control device needs to be reduced.

  Here, the moment of inertia is a function of the speed transmission ratio (also referred to as a reduction ratio) Hs. Therefore, in order to evaluate the response of the entire braking control apparatus driven by the electric motor MTR, each member (DKH Etc.) needs to be converted into an inertia moment around the output shaft Jmt of the electric motor MTR (that is, the input shaft Jsk of the reduction gear GSK) and discussed. Therefore, the equivalent moment of inertia Ko converted from the moment of inertia Io around the output shaft Jdk of the reduction gear GSK to the moment of inertia around the output shaft Jmt of the electric motor MTR (that is, the input shaft Jsk of the reduction gear GSK) is adopted. . Specifically, the equivalent moment of inertia Ko around the rotation axis Jmt (ie, Jsk) is equal to the square of the reciprocal of the speed transmission ratio Hs (ie, “1/1”) to the moment of inertia Io around the output shaft Jdk of the reduction gear GSK. Hs ^ 2 ") is multiplied. The speed transmission ratio Hs is “a value obtained by dividing the input rotational speed (input speed) Ni of the reduction gear GSK by the output rotational speed (output speed) No of the reduction gear GSK (value“ Ni / No ”)”, or , “Value obtained by dividing the number of teeth Zo of the output gear (large diameter gear DKH) of the reduction gear GSK by the number of teeth Zi of the input gear (small diameter gear SKH) of the reduction gear GSK (value“ Zo / Zi ”)” Is done.

  The characteristic diagram of FIG. 7 shows the relationship of the equivalent moment of inertia Ko to the speed transmission ratio Hs. The operation and effect of the present invention will be described with reference to FIG.

  The output torque of the electric motor MTR is increased by the reduction gear GSK. For this reason, a member (for example, DKH) on the output shaft Jdk of the reduction gear GSK needs high strength in order to be able to transmit a large torque, and the moment of inertia (the inherent moment of inertia of the member) is relative. Become bigger. However, since the equivalent inertia moment Ko is proportional to the square of the reciprocal of the speed transmission ratio Hs (ie, “1 / Hs ^ 2”), if the speed transmission ratio Hs is large, a member on the output shaft of the reduction gear GSK. The equivalent moment of inertia becomes smaller. Further, since the value “1 / Hs ^ 2” converges to “0 (zero)” as the speed transmission ratio Hs increases, a region where the speed transmission ratio Hs is larger than a certain value (predetermined value) ( In the range), the value “1 / Hs ^ 2” is sufficiently small. As a result, in this region, the equivalent moment of inertia can be set to a sufficiently small value. For example, as shown in FIG. 7, when the area ratio Ha is a relatively small value hs1, the equivalent moment of inertia Ko is a relatively large value ko1. On the other hand, when the speed transmission ratio Hs is a relatively large value hs2, the equivalent inertia moment Ko is a relatively small value ko2.

  In the present invention, based on such knowledge, in the specifications and specifications of the pressure regulating mechanism CLK (particularly GSK, SCL, and PSC) and the wheel cylinders WCl, WCr, the speed transmission ratio Hs is the area ratio. It is configured to be larger than Ha (Hs> Ha). Here, the speed transmission ratio Hs is a value obtained by dividing the input rotational speed (input speed) Ni from the electric motor MTR to the reduction gear GSK by the output rotational speed (output speed) No of the reduction gear GSK (that is, Hs). = Ni / No). The area ratio Ha is a value obtained by dividing the cross-sectional area Awc of the wheel cylinders WCl and WCr by the cross-sectional area Asc of the control cylinder SCL (that is, Ha = Awc / Asc).

  Although the response due to the driving of the electric motor MTR depends on the moment of inertia, “Hs> Ha” is set, so the equivalent inertia moment Ko of the entire member existing around the output shaft of the reduction gear GSK is relatively reduced. The Therefore, in a state where the electric motor MTR is rapidly rotated in the forward rotation direction Fwd, the wheel slip state amount Slp exceeds a predetermined value, the anti-skid control is started, and the electric motor MTR is suddenly reversed in the reverse rotation direction Rvs ( Responsiveness when the rotation direction is changed from Fwd to Rvs) can be ensured. As a result, in anti-skid control, sufficient braking fluid pressure responsiveness (particularly, time-responsiveness of pressure reduction by anti-skid control) can be ensured.

  In the present invention, a value Ko (= Io / Hs ^ 2) obtained by dividing the inertia moment Io around the output shaft Jdk of the reduction gear GSK by the square of the speed transmission ratio Hs is a single inertia moment of the electric motor MTR. It is configured to be smaller than Im. Here, the value Ko is an equivalent moment of inertia around the output shaft Jdk of the reduction gear GSK.

  The equivalent inertia moment Ko of the entire member existing around the output shaft Jdk of the reduction gear GSK is made smaller than the inertia moment Im (single unit) of the electric motor MTR. For this reason, the degree (degree) to which the equivalent inertia moment Ko contributes to the inertia moment around the motor rotation axis Jmt is made smaller than the inertia moment Im of the MTR alone. That is, since the influence of the inertia moment around the output shaft Jdk of the reduction gear GSK (DKH inertia moment, etc.) is reduced, the response of the brake fluid pressure in the anti-skid control (particularly, the pressure reduction response at the start of the anti-skid control) ) Can be improved.

  Furthermore, in the present invention, the sectional area Awc of one wheel cylinder WCl is configured to be larger than the sectional area Asc of one control cylinder SCL. That is, the wheel cylinder WCl, and the area ratio Ha, which is “a value obtained by dividing the cross-sectional area Awc of one wheel cylinder WCl by the cross-sectional area Asc of one control cylinder SCL”, is larger than “1”. Specifications (dimensions) of the control cylinder SCL are set.

  In the braking control device, the speed transmission ratio (reduction ratio) Hs and the area ratio Ha correspond to the “lever ratio (lever ratio)” in the “lever”. Here, a value obtained by multiplying the speed transmission ratio Hs and the area ratio Ha is referred to as a “lever ratio equivalent value”. In the vehicle, the lever ratio equivalent value (= Hs × Ha) is determined by the required maximum hydraulic pressure in the wheel cylinder WCl and the output characteristics (lock torque, maximum rotation speed) of the electric motor MTR. For this reason, in a general vehicle (a vehicle in which a general electric motor MTR is employed and a general braking performance is required), the lever ratio equivalent value is a substantially constant value. Therefore, when the speed transmission ratio Hs is set to be large, the area ratio Ha is reduced. Conversely, when the speed transmission ratio Hs is set to a small value, the area ratio Ha needs to be set to a large value. is there.

  The size of the area ratio Ha is adjusted by the lead of the screw member NJB. Here, the lead of the screw member NJB is the displacement of the control piston PSC corresponding to one rotation of the screw member NJB. When the lead of the screw member NJB is reduced, the amount of the brake fluid BFL discharged from the control cylinder SCL is relatively small with respect to the output rotational speed of the reduction gear GSK. For this reason, when the area ratio Ha is set to be very small, the lead of the screw member NJB needs to be minimized. However, if the lead of the screw member NJB is set too small, it may be difficult to manufacture the screw member NJB. By setting “Ha> 1,” the formation of the lead of the rotation / linear motion conversion mechanism (screw member) NJB is secured, and the area ratio Ha is set to the minimum necessary value, and the speed transmission ratio Hs can be a sufficiently large value.

  In summary, the area ratio Ha is set larger than “1” and the speed transmission ratio Hs is set larger than the area ratio Ha. That is, the area ratio Ha and the speed transmission ratio Hs are set with a relationship of “1 <Ha <Hs”. Since the speed transmission ratio Hs (= Ni / No) is set larger than the area ratio Ha (= Awc / Asc), the equivalent inertia moment Ko of a member (such as DKH) around the output shaft Jdk of the speed reducer GSK is It is set as small as necessary, and sufficient anti-skid control can ensure sufficient braking fluid pressure response. Furthermore, since the area ratio Ha (= Awc / Asc) is set to be larger than “1” (that is, the cross-sectional area Awc is set to be larger than the cross-sectional area Asc), the feasibility of the lead of the screw member NJB ( For example, the workability of the screw member NJB) can be ensured.

  ECU: Electronic control unit, MTR: Electric motor, CLK: Pressure adjusting mechanism, SCL: Control cylinder, WCl, WCr: Wheel cylinder, GSK: Reducer, NJB: Rotation / linear motion conversion mechanism (screw member), VWA: Wheel Speed acquisition means, CTL ... control means, MKA ... rotation angle acquisition means, BPA ... operation amount acquisition means

Claims (3)

A wheel cylinder provided on a vehicle wheel;
An operation amount obtaining means for obtaining an operation amount of the braking operation member of the vehicle;
An electric motor controlled based on the operation amount;
A pressure regulating mechanism that is driven by the electric motor and adjusts the pressure of the brake fluid in the wheel cylinder;
A vehicle braking control apparatus comprising:
Wheel speed acquisition means for acquiring the rotational speed of the wheel;
Control means for performing anti-skid control for preventing locking of the wheel based on the rotational speed by adjusting the rotational power of the electric motor;
With
The pressure regulating mechanism is
A speed reducer that decelerates the rotational power;
A rotation / linear motion conversion mechanism that is connected to the speed reducer and converts the rotational power into linear power of a control piston;
A control cylinder which is combined with the control piston and moves the brake fluid to and from the wheel cylinder by a reciprocating motion of the control piston;
Comprising
A speed transmission ratio that is a value obtained by dividing the input rotational speed from the electric motor to the speed reducer by the output speed of the speed reducer,
A vehicle braking control device configured to be larger than an area ratio that is a value obtained by dividing a cross-sectional area of the wheel cylinder by a cross-sectional area of the control cylinder. In the vehicle braking control device according to claim 1,
A braking control device for a vehicle configured to make a value obtained by dividing an inertia moment around an output shaft of the reduction gear by a square of the speed transmission ratio smaller than an inertia moment of the electric motor. In the vehicle braking control device according to any one of claims 1 and 2,
A braking control device for a vehicle configured to make a cross-sectional area of the wheel cylinder larger than a cross-sectional area of the control cylinder.

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