JP2015040029A - Vehicular electric brake apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular electric brake apparatus allowing easy bending of a power line that interconnects a vehicular body side and a wheel side electrically.SOLUTION: An electric brake apparatus, for use in generating braking torque in a wheel by pressing a friction member onto a rotary member fixed to the wheel by using drive torque of a motor MTR, includes: a vehicular body power source BBD for use in supplying power to the motor that is fixed to a vehicle body; and a wheel power source BWH for use in supplying power to the motor that is fixed to the wheel. The vehicular body power source BBD supplies the wheel power source BWH with power via a first electric path (PBD+PWH), while the wheel power source BWH supplies the motor MTR with power via a second electric path (PWH). In the case of generating braking torque in a wheel, the motor MTR is driven normally by using the wheel power source BWH.

Description

  The present invention relates to an electric braking device for a vehicle.

  Patent Document 1 states that “it is mounted on a vehicle body for the purpose of providing a vehicle power supply device capable of supplying required electric power to each in-vehicle electrical device even when one power source fails”. A first system for supplying the first electrical energy to the first predetermined vehicle-mounted electrical device from the one power source that has been connected, and a second power source mounted on the vehicle body to the second predetermined vehicle-mounted electrical device. A second system for supplying the second electrical energy, and conversion supply means for converting the second electrical energy into the first electrical energy and supplying the first electrical energy to the first system ”. ing.

  Further, in Patent Document 1, “the remaining energy detecting means for detecting the remaining electric energy of each of the one power source and the other power source, and the one power source or the above based on the remaining electric energy of each power source, And a power supply selection unit that selects any one of the conversion supply units and connects to the first system ”.

  In Patent Document 2, “communication circuit, control circuit, and motor are driven” for the purpose of “reducing the cost of the power line for electrically connecting the vehicle body side and the wheel side and providing an inexpensive brake device”. A drive control device equipped with a drive circuit is installed on the wheel side, and power is supplied from the vehicle body side to the drive control device via two power lines to drive a motor mounted on the wheel to generate a braking force. Is described.

  In a vehicle having a plurality of power sources exemplified in Patent Document 1, when the electric braking device exemplified in Patent Document 2 is adopted, two power lines are required for the device. Even when power corresponding to the maximum output of the device is supplied via the power line, a power line that is somewhat thick (having a large cross-sectional area) is required to minimize the voltage drop across the power line. It becomes. If the power line is thick, the power line is difficult to bend. The wheel is displaced relative to the vehicle body via the suspension. Therefore, in the electric braking device, a configuration in which a power line that electrically connects the vehicle body side and the wheel side is easily bent is desired.

JP 2000-31444 A Japanese Patent No. 4154833

  The present invention has been made to cope with the above problem, and an object thereof is to provide an electric braking device in which a power line that electrically connects the vehicle body side and the wheel side is easily bent.

  An electric braking device for a vehicle according to the present invention includes a rotating member (KTB) fixed to a vehicle wheel (WHL), an electric motor (MTR) provided on the wheel (WHL) side, and the electric motor (MTR). ) And the friction member (MSB) for generating braking torque on the wheel (WHL) by pressing the rotating member (KTB) using the driving torque of the vehicle, and the vehicle body provided on the vehicle body (BDY) side of the vehicle Based on a power source (BBD), a wheel power source (BWH) provided on the wheel (WHL) side, a braking operation by a driver of the vehicle, the vehicle body power source (BBD), and the wheel power source (BWH) Control means (CTL, DCC, SWb) for driving the electric motor (MTR) using at least one of them.

  In this apparatus, a power source for supplying electric power to the electric motor MTR is provided not only on the vehicle body side but also on the wheel side. The electric motor is provided on the wheel side. Accordingly, when power is supplied from the vehicle power supply BBD to the electric motor MTR, it is necessary to pass through the “power line that electrically connects the vehicle body side and the wheel side”, while power is supplied from the wheel power supply BWH to the electric motor MTR. When supplying, it is not necessary to go through the power line. As a result, by appropriately using the power source for supplying power to the electric motor, the burden on the power line is reduced as compared with the case where the power source for supplying power to the electric motor MTR is provided only on the vehicle body side. That is, a thinner wiring (a conducting wire having a small cross-sectional area) can be adopted as the power line. As a result, the flexibility of the power line (wiring) can be further ensured.

  In this device, the vehicle body power supply (BBD) supplies power to the wheel power supply (BWH) via a first electric path (PBD + PWH), and the wheel power supply (BWH) is supplied to a second electric path (PWH). ) To supply electric power to the electric motor (MTR), and the control means (CTL, DCC, SWb) uses the wheel power source (BWH) when generating braking torque on the wheel (WHL). The electric motor (MTR) is preferably configured to be driven.

  According to this, when braking is not requested (when the driver is not performing a braking operation, for example, when Bpa = 0), the wheel power supply BWH is connected to the first electric path (vehicle power line) from the vehicle power supply BBD. The battery can be gradually charged by receiving power supply via the PBD and the wheel power line PWH). Typically, the wheel power supply BWH can be slowly charged over a time longer than the time required for normal vehicle deceleration operation (time required for braking from normal vehicle deceleration start to end). At the time of a braking request (when the driver is performing a braking operation, for example, when Bpa> 0), the electric motor MTR passes from the wheel power source BWH via the second electric path (wheel power line PWH). Driven by receiving power supply. In other words, the electric power supplied from the vehicle body power supply BBD is temporarily stored in the wheel power supply BWH. The electric power stored in the wheel power source BWH is supplied from the wheel power source BWH to the electric motor MTR as necessary (in response to a braking request).

  For this reason, as a “power line that electrically connects the vehicle body side and the wheel side”, that is, as a wiring (first electrical path) from the vehicle body power supply BBD to the wheel power supply BWH, a thin wiring (conductive wire having a small cross-sectional area) is Adopted. As a result, the flexibility of the power line (wiring) PBD can be ensured. Furthermore, when the wheel power source BWH is configured to be adjacent to the electric motor MTR, the wheel power source BWH can be connected to a drive circuit of the electric motor by a bus bar. Since the electric resistance of the bus bar is small, the voltage drop at the bus bar itself is small. Therefore, in this case, the electric motor can be driven efficiently. Here, the bus bar is a metal bar that functions as a conductor. Since the bus bar does not require an insulation coating, the heat dissipation is high. Therefore, it is easy to deal with the problem of heat dissipation when a large current passes through the bus bar.

  In this device, a state of charge acquisition means (JDA) for acquiring a state of charge (Jda) of the wheel power supply (BWH), and power for supplying electric power from the vehicle body power supply (BBD) to the electric motor (MTR) And a switching means (SWb) for connecting / blocking the third electrical path (PBD), the control means (CTL, DCC, SWb) has the charge state quantity (Jda) set to a first predetermined value ( jdx) or more, the third electric path (PBD) is cut off, the electric motor (MTR) is driven using only the wheel power source (BWH), and the state of charge (Jda) is When it is less than the first predetermined value (jdx), the third electric path (PBD) is connected, and the electric motor (MTR) is driven using the wheel power supply (BWH) and the vehicle body power supply (BBD). Like It is preferable to be made.

  According to this, when the state of charge Jda of the wheel power source BWH is appropriate (Jda ≧ jdx), the power supply source to the electric motor MTR is the wheel power source alone, and the state of charge Jda of the wheel power source BWH is Is reduced (Jda <jdx), the power supply source to the electric motor MTR is changed from the wheel power source alone to the wheel power source and the vehicle body power source. As a result, the occurrence of a situation where the electric power supplied to the electric motor MTR is insufficient during braking can be suppressed in advance. As the charge state quantity Jda, for example, the voltage of the wheel power supply BWH can be acquired.

  In this case, when the state of charge (Jda) is less than a second predetermined value (jdy, ≦ jdx) less than or equal to the first predetermined value, the first electric path (PBD + PWH) is cut off. It is preferable.

  According to this, when the state of charge Jda of the wheel power source BWH further decreases, the electrical path between the vehicle body power source BBD and the wheel power source BWH is interrupted. Therefore, the electric power supplied from the vehicle power supply BBD is not consumed for charging the wheel power supply BWH, but can be consumed exclusively for driving the electric motor MTR. As a result, the electric motor MTR can be driven efficiently, and the occurrence of a situation where the electric power supplied to the electric motor MTR is insufficient can be further suppressed.

1 is an overall configuration diagram of an electric braking device for a vehicle according to an embodiment of the present invention. FIG. 2 is an overall configuration diagram of an electronic control unit, a vehicle body power supply, and braking means illustrated in FIG. 1. It is a functional block diagram of a drive means in case a motor with a brush is adopted, and an electric circuit diagram. It is a figure for demonstrating supply of the electric power to an electric motor.

  Hereinafter, an electric braking device for a vehicle according to an embodiment of the present invention will be described with reference to the drawings.

<Overall Configuration of Electric Brake Device for Vehicle according to Embodiment of the Present Invention>
FIG. 1 shows a state where an electric braking device according to an embodiment of the present invention is mounted on a vehicle. The electric braking device generates a braking force on the wheel by applying a braking torque to the wheel according to an operation amount of a braking operation member (for example, a brake pedal) by the driver, and decelerates the traveling vehicle.

  A vehicle body power supply (first power supply) BBD is provided (fixed) to the vehicle body BDY. The vehicle body power supply (storage battery) BBD supplies electric power to the electronic control unit ECU and the braking means (brake actuator) BRK. Further, an alternator ALT is provided on the vehicle body BDY. The vehicle body power supply BBD is charged by the alternator ALT.

  An electronic control unit ECU is provided (fixed) on the vehicle body BDY. In the electronic control unit ECU, the drive signal of the electric motor MTR is calculated based on the braking operation amount Bpa, and the drive means (electric circuit for driving the MTR) in the BRK via the signal line (for example, serial communication bus) SCB. Sent to DRV. Electric power for driving the electric motor MTR is supplied from the vehicle body power supply BBD to the DRV via the ECU and the vehicle body power line (first power line) PBD.

  Driving means DRV is provided (fixed) in the caliper CPR. The drive means DRV is a drive circuit (electric circuit) for driving the electric motor MTR, and includes a control means CTL, a bridge circuit HBR composed of switching elements (for example, MOS-FET), a noise reduction circuit NIZ, and And wheel power source BWH. In the control means CTL programmed in the DRV, the switching element is driven based on the MTR drive signal (for example, the target pressing force Fbt) transmitted from the ECU, and the rotational direction and rotational power of the MTR are controlled. The

  At the time of normal braking request (when the wheel power supply BWH is functioning properly), the power for driving the electric motor MTR is supplied from the wheel power supply (second power supply) BWH to the wheel power line (second power line) PWH. To the HBR (that is, the MTR via the switching element).

  The wheel power source (second power source) BWH is charged during normal running (when braking is not required) by energization from the vehicle body power source (first power source) BBD. This charging (power feeding from BBD to BWH) is performed via the ECU and the vehicle body power line (first power line) PBD. The signal line (for example, serial communication bus) SCB and the vehicle body power line PBD are collectively referred to as “wiring (wire harness)”.

  Power line communication in which the vehicle body power line PBD is also used as a signal line (communication line) SCB may be employed. In this case, the SCB is integrated into the PBD (that is, the SCB is omitted), and the electric motor drive signal is superimposed on the PBD and transmitted to the DRV. Here, the power line communication is also referred to as power line carrier communication (PLC, Power Line Communication). By adopting power line communication, a communication system that performs high-speed data communication using the power supply wiring PBD can be obtained.

  One side of the suspension arm (for example, the upper arm UAM, the lower arm LAM) is attached to the vehicle body BDY of the vehicle, and the other side is attached to the knuckle NKL. The coil spring SPR and the shock absorber SHA are attached to a suspension arm or a knuckle NKL. The wheel WHL is suspended from the vehicle body BDY by the coil spring SPR and the shock absorber SHA. The suspension arm, SPR, NKL, and SHA are members constituting a known suspension device.

  The hub bearing unit HBU is fixed to the knuckle NKL. The wheel WHL is supported by a hub bearing in the hub bearing unit HBU. A rotating member (brake disc) KTB is fixed to the wheel WHL, and the KTB is rotated integrally with the WHL (that is, the rotating shaft of the KTB and the rotating shaft of the WHL are coaxial).

  The mounting bracket MTB is fixed to the knuckle NKL by fastening members (for example, bolts) TK1 and TK2 (not shown). A caliper CPR is attached to the MTB via slide pins GD1, GD2 (not shown). The brake caliper CPR is a floating caliper and is configured to sandwich a rotating member (brake disk) KTB via two friction members (brake pads) MSB. Specifically, the slide pins GD1 and GD2 are fixed to the mounting bracket MTB, and the pressing member (piston) PSN in the caliper CRP is slid by the electric motor MTR along the GD1 and GD2 toward the rotating member KTB. .

<Whole structure of electronic control unit ECU, vehicle body power supply BBD, and braking means BRK>
As shown in FIG. 2, a vehicle including this electric braking device includes a braking operation member BP, an electronic control unit ECU, a vehicle body power supply (storage battery, etc.) BBD, and a braking means (brake actuator) BRK. Here, the ECU and BRK are connected by a signal line (signal line) SCB and a vehicle body power line (power line) PBD via an ECU side connector CNB and a BRK side connector CNC. The BRK is supplied with an MTR drive signal and electric power from the ECU.

  The braking operation member (for example, brake pedal) BP is a member that the driver operates to decelerate the vehicle. Based on the operation amount of BP, the braking means (brake actuator) BRK adjusts the braking torque of the wheel WHL, the braking force is generated on the wheel WHL, and the running vehicle is decelerated.

  The braking operation member BP is provided with a braking operation amount acquisition means BPA. The operation amount (braking operation amount) Bpa of the braking operation member BP by the driver is acquired (detected) by the braking operation amount acquisition means BPA. As a braking operation amount acquisition means BPA, a sensor (pressure sensor) for detecting the pressure of a master cylinder (not shown), an operation force of the braking operation member BP, and / or a sensor for detecting a displacement amount (a brake pedal depression force sensor, Brake pedal stroke sensor) is adopted.

  Accordingly, the braking operation amount Bpa is calculated based on at least one of the master cylinder pressure, the brake pedal depression force, and the brake pedal stroke. The braking operation amount Bpa is input to the electronic control unit ECU. Bpa is calculated or acquired by another electronic control unit, and the calculated value (signal) can be transmitted to the ECU via the communication bus.

  The vehicle body power supply (first power supply) BBD is a power supply fixed to the vehicle body BDY. The vehicle body power supply BBD supplies power to the electronic control unit ECU provided on the vehicle body side. As the vehicle power source BBD, a rechargeable secondary battery (also referred to as a storage battery or a rechargeable battery) may be employed. Here, the secondary battery is one of batteries (chemical battery) that converts chemical energy of a substance into direct-current power by a chemical reaction, and can store electricity by charging and can be used repeatedly.

  Specifically, in the secondary battery, the internal chemical energy is converted into electrical energy during the discharge process, and the current is passed in the opposite direction to that during discharge, thereby converting the electrical energy into chemical energy and storing the energy. Is done. The body power supply BBD is charged by an alternator (generator) ALT when the amount of stored electricity (accumulated energy) decreases.

  The electronic control unit ECU outputs a target value (drive signal) Fbt for driving the electric motor MTR to the drive means DRV. In addition, electric power for driving the MTR is supplied to the DRV via the ECU. Specifically, the ECU is provided with a connector CNB, and the serial communication bus SCB and the vehicle body power line PBD are connected to the driving means DRV via the CNB. Then, a target value (target pressing force) Fbt is calculated by target calculation means TRG programmed in the electronic control unit ECU, and Fbt is transmitted to the DRV through the SCB. Further, electric power (current) from the vehicle body power supply BBD is supplied to the drive means DRV and the like through the vehicle body power line PBD via the ECU.

[Target calculation means TRG]
Target calculation means TRG (control algorithm) for calculating the target value (target pressing force) Fbt of the braking means BRK is programmed in the electronic control unit ECU.

  The target calculation means TRG is a control algorithm and includes an instruction pressing force calculation block FBS, an anti-skid control block ABS, a traction control block TCS, a vehicle stabilization control block ESC, and a target pressing force calculation block FBT. .

  In the command pressure calculation block FBS, the command pressure Fbs of each wheel WHL is calculated based on the braking operation amount Bpa and the command pressure calculation characteristic (calculation map) CHfb set in advance. Fbs is a target value of a pressing force that is a force with which the friction member (brake pad) MSB presses the rotating member (brake disc) KTB in the electric braking means BRK.

  In the anti-skid control block ABS, a target pressing force Fabs for executing known anti-skid control (Anti-Skid Control) is calculated based on an acquisition result (wheel speed) of a wheel speed acquisition means (not shown). The That is, the anti-skid control target pressing force Fabs is a target value of the pressing force for preventing wheel lock.

  In the traction control block TCS, a target pressing force Ftcs for executing known traction control (Traction Control) is calculated based on an acquisition result (wheel speed) of a wheel speed acquisition means (not shown). That is, the traction control target pressing force Ftcs is a target value of the pressing force for suppressing wheel spin (overspeed).

  In the vehicle stabilization control block ESC, based on the acquisition result (yaw rate) of the vehicle behavior acquisition means (for example, yaw rate sensor, not shown), a target push for executing the well-known vehicle stabilization control (Vehicle Stability Control) is performed. The pressure Fesc is calculated. That is, the vehicle stabilization control target pressing force Fesc is a target value of the pressing force for suppressing excessive vehicle understeer and / or oversteer.

  In the target pressing force calculation block FBT, the final target pressing force Fbs, the anti-skid control target pressing force Fabs, the traction control target pressing force Ftcs, and the vehicle stabilization control target pressing force Fesc are used. The pressure Fbt is calculated. Specifically, one of Fabs, Ftcs, and Fesc is selected, Fbs is corrected by the selected one, and Fbt is calculated. The selection order of Fabs, Ftcs, and Fesc is determined based on the running state of the vehicle and the state of the wheels. Note that Ftsc is not calculated when the corresponding wheel is not a drive wheel (when not connected to the drive train).

  The target pressing force (signal) Fbt calculated by the target calculating means TRG is applied to the braking means BRK (specifically, driving) fixed to the wheel via the ECU side connector CNB and the signal line (serial communication bus) SCB. Circuit DRV).

[Brake means BRK]
The braking means (brake actuator) BRK includes a brake caliper (floating caliper) CPR, a pressing member (brake piston) PSN, an electric motor (brush motor or brushless motor) MTR, a position detection means MKA, a reduction gear GSK, and a shaft member. The SFT includes a screw member NJB, a pressing force acquisition unit FBA, and a driving unit (MTR driving circuit) DRV.

  The brake caliper CPR is a floating caliper and is configured to sandwich a rotating member (brake disk) KTB via two friction members (brake pads) MSB. Within the caliper CPR, the pressing member PSN is slid and moved forward or backward toward the rotating member KTB. In the caliper CPR, the keyway KYM is formed so as to extend in the direction of the rotation axis (shaft axis Jsf) of the shaft member SFT.

  The pressing member (brake piston) PSN presses the friction member MSB against the rotating member KTB to generate a frictional force. The key member KYA is fixed to the pressing member PSN. When the key member KYA is fitted into the key groove KYM, the pressing member PSN is restricted from rotating around the shaft axis, but linear movement in the direction of the shaft axis (longitudinal direction of the key groove KYM) is allowed. Is done.

  The electric motor MTR generates power for pressing the friction member MSB against the rotating member KTB. That is, the electric motor MTR drives the pressing member PSN. Specifically, the output of the electric motor MTR (rotational power around the motor shaft Jmt) is transmitted to the shaft member SFT via the reduction gear GSK, and the rotational power of the SFT (torque around the shaft axis Jsf) It is converted into linear power (thrust in the direction of the pressing shaft Jps) by the conversion member (for example, screw member) NJB and transmitted to the pressing member PSN. Then, the pressing member (brake piston) PSN is advanced or retracted toward the rotating member (brake disc) KTB. By the movement of the PSN, the force (pressing force) Fba that the friction member (brake pad) MSB presses the rotating member KTB is adjusted. Since the rotating member KTB is fixed to the wheel WHL, a frictional force is generated between the friction member MSB and the rotating member KTB, and the braking force is adjusted to the wheel WHL, for example, the traveling vehicle is decelerated. As the electric motor MTR, a motor with a brush or a brushless motor is employed.

  In the rotation direction of the electric motor MTR, the forward rotation direction corresponds to the direction in which the friction member MSB approaches the rotation member KTB (the direction in which the pressing force increases and the braking torque increases), and the reverse rotation direction corresponds to the friction member MSB. Corresponds to the direction away from the rotating member KTB (the direction in which the pressing force decreases and the braking torque decreases). The output of the electric motor MTR is determined based on the target energization amount Imt calculated by the target calculation means TRG. Specifically, when the sign of the target energization amount Imt is a positive sign (Imt> 0), the electric motor MTR is driven in the forward rotation direction, and the sign of Imt is a negative sign (Imt <0). The electric motor MTR is driven in the reverse direction. Further, the rotational power of the electric motor MTR is determined based on the magnitude (absolute value) of the target energization amount Imt. That is, the larger the absolute value of the target energization amount Imt, the larger the output torque of the electric motor MTR, and the smaller the absolute value of the target energization amount Imt, the smaller the output torque.

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

The reduction gear GSK reduces the rotational speed of the power of the electric motor MTR and outputs it to the shaft member SFT. That is, the rotational output (torque) of the MTR is increased according to the reduction ratio of the reduction gear GSK, and the rotational force (torque) of the shaft member SFT is obtained. For example, the GSK is composed of a small diameter gear SKH and a large diameter gear DKH. As GSK, instead of the gear transmission mechanism, a winding transmission mechanism such as a belt or a chain, or a friction transmission mechanism may be employed.
The shaft member SFT is a rotating shaft member and transmits the rotational power transmitted from the reduction gear GSK to the screw member NJB. The end of the shaft member SFT is processed into a spherical shape and functions as a universal joint. This universal joint compensates for the influence of the swing (swinging motion) of the pressing member PSN that occurs when the friction member MSB slides.

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

  The screw member NJB is configured by a sliding screw (such as a trapezoidal screw) that transmits power by “sliding”. In this case, the nut member NUT is provided with a female screw (inner screw) MNJ. The bolt member BLT is provided with a male screw (outer screw) ONJ and is screwed to the MNJ of the NUT. The rotational power (torque) transmitted from the shaft member SFT is transmitted as linear power (thrust) of the pressing member PSN via the screw member NJB (ONJ and MNJ).

  Further, instead of the above-described sliding screw, a rolling screw (such as a ball screw) in which power is transmitted by “rolling” may be employed for the screw member NJB. In this case, a ball groove is provided in the nut member and the bolt member. Power is transmitted through a ball (steel ball) fitted in the ball groove. In place of the screw member NJB, a conversion mechanism such as a ball ramp member, a rotary wedge member, a rack and pinion member, or the like may be employed as a power conversion member for converting a rotational motion into a linear motion.

  The pressing force acquisition means FBA acquires (detects) the reaction force (reaction) of the force (pressing force) Fba that the pressing member PSN presses the friction member MSB. A strain generating body is formed in the FBA, and the strain is detected by a strain detection element, and Fba is acquired. For example, as a strain detection element, a device using a change in electrical resistance (strain gauge), a device using ultrasonic waves, or the like can be used. The FBA is provided between the shaft member SFT and the caliper CPR, and is fixed to the caliper CRP. The detected pressing force Fba is input to the driving means DRV.

  The driving means DRV is fixed in the caliper CPR, and drives and controls the electric motor MTR based on the target pressing force Fbt. The DRV is composed of a control means CTL, a wheel power supply BWH, a bridge circuit HBR, and the like. Details of DRV will be described later.

[Connectors CNB, CNC, and wiring SCB, PBD]
A connector CNC is provided on the surface of the caliper CPR. From here, the drive power of the electric motor MTR and the drive signal (target pressing force Fbt) of the MTR are taken into the drive means DRV. The target signal Fbt is supplied to the BRK side connector (wheel side connector) CNC by the signal line SCB and the electric power by the vehicle body power line PBD, respectively.

  Similar to the drive means DRV, the connector CNB is provided in the electronic control unit ECU. The signal line SCB and the power line PBD are connected to the ECU via the ECU side connector (vehicle body side connector) CNB. That is, the electronic control unit ECU (vehicle body BDY is connected to the vehicle body BDY) via wiring (signal line SCB and power line PBD) relayed by the ECU side connector (vehicle body side connector) CNB and the BRK side connector (wheel side connector) CNC. Arrangement) and the drive circuit DRV (arranged on the wheel WHL) are connected. In other words, the signal line SCB transmits the target pressing force Fbt from the ECU to the DRV via the connectors CNB and CNC. Further, the power line PBD supplies power for driving the electric motor MTR from the ECU to the DRV through the connectors CNB and CNC at normal times. As the PBD, a twisted pair cable (Twisted Pair Cable) formed by twisting two electric wires may be employed.

<Driving means DRV>
Next, details of the driving means (driving circuit) DRV will be described with reference to FIG. Based on the target pressing force Fbt, the driving unit DRV controls the energization state of the electric motor MTR and adjusts the output of the MTR (that is, the braking torque generated by the braking unit BRK). FIG. 3 shows an example of drive means DRV in the case where a motor with a brush (also simply referred to as a brush motor) is employed as the electric motor MTR. The driving means DRV includes a wheel power source BWH, a control means CTL, a bridge circuit HBR formed by a plurality of switching elements (power transistors) S1 to S4, a noise reduction circuit NIZ, an energization amount acquisition means IMA, and a connector CNC. The

  As the electric motor MTR, a motor with a brush (also simply referred to as a brush motor) is employed. A motor with a brush is also called a commutator motor. In the electric motor, a current flowing through an armature (electromagnet by winding) is rotated by a mechanical commutator (commutator) CMT and a brush BLC. It is switched according to the phase. That is, the commutator CMT and the brush BLC constitute a mechanical rotation switch, and the current to the winding circuit is alternately inverted. In a motor with a brush, the stator (stator) side is constituted by a permanent magnet, and the rotor (rotor) side is constituted by a winding circuit (electromagnet). The brush BLC is in contact with the commutator CMT so that electric power is supplied to the winding circuit (rotor). The brush BLC is pressed against the commutator CMT by a spring (elastic body), and a current is commutated by rotating the CMT.

[Wheel power supply BWH]
The driving means DRV is provided with a wheel power source (second power source) BWH. That is, the wheel power source BWH is a power source provided on the wheel side (inside the braking means BRK) separately from the vehicle body power source (first power source) BBD. The wheel power supply BWH is connected to the bridge circuit HBR (that is, the electric motor MTR) by the wheel power line PWH. Since BWH and HBR are adjacent to each other, a bus bar (Bus Bar, a metal bar that functions as a conductor) is adopted as the wheel power line PWH. For this reason, the voltage drop by wiring resistance is slight, and the electric motor MTR can be driven efficiently. Further, since the bus bar does not require an insulating coating, the heat dissipation is high and it is possible to easily cope with a large current.

  The wheel power source (second power source) BWH has an electric capacity corresponding to a plurality of braking operations. For example, the electric capacity is limited to a necessary and sufficient level for repeating the vehicle from the maximum speed to the stop 2-3 times. The wheel power supply BWH supplies electric power to the electric motor MTR except when there is a possibility of insufficient power supply (when the BWH is malfunctioning or when sudden braking is requested). The BWH is charged by the vehicle body power supply BBD (or the alternator ALT of the vehicle) at the time of non-braking request (when the braking operation member BP is not operated by the driver). Since the BWH is a power source provided on the wheel, an energy capacity (storage capacity) smaller than that of the BBD can be adopted.

  As the wheel power supply BWH, an electric double layer capacitor (also referred to as an ultra capacitor or a super capacitor) may be employed. In an electric double-layer capacitor (EDLC), when an electric potential is applied to a system in which charged particles move relatively freely, the charged particles are generated according to the electric field. As a result of the movement, a pair of positive and negative charged particles forming a pair at the interface is used. An electric double layer capacitor is suitable for BWH because its internal resistance is small and charging and discharging are performed rapidly.

[Control means CTL]
The control means CTL controls the actual energization amount (finally the magnitude and direction of the current) to the electric motor MTR based on the target pressing force (target value) Fbt. Part of the control means CTL is a control algorithm, which is programmed into a CPU (Central Processing Unit) in the DRV. The CTL includes an instruction energization amount calculation block IST, a pressing force feedback control block IFT, an energization amount adjustment calculation block IMT, a pulse width modulation block PWM, a switching control block SWT, and power management means DGK.

  The command energization amount calculation block IST calculates the command energization amount Ist based on the target pressing force Fbt (transmitted from TRG) and preset command energization amount calculation characteristics (calculation maps) CHs1 and CHs2. Ist is a target value of the energization amount to the electric motor MTR for the electric braking means BRK to achieve the target pressing force Fbt. The calculation map of Ist is composed of two characteristics CHs1 and CHs2 in consideration of the hysteresis of the electric braking means BRK. The characteristic CHs1 corresponds to the case where the pressing force is increased, and the characteristic CHs2 corresponds to the case where the pressing force is decreased. Therefore, compared with the characteristic CHs2, the characteristic CHs1 is set to output a relatively large command energization amount Ist.

  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 substantially proportional to the current, the current target value of the electric motor MTR can be used as the target value of the energization amount. Further, if the supply voltage to the electric motor MTR is increased, the current is increased as a result, so that the supply voltage value can be used as the target energization amount. Furthermore, since the supply voltage value can be adjusted by the duty ratio in pulse width modulation (PWM), this duty ratio can be used as the energization amount.

  The pressing force feedback control block IFT calculates the pressing force feedback energization amount Ift based on the target pressing force (target value) Fbt and the actual pressing force (actual value) Fba. The command energization amount Ist is calculated as a value corresponding to the target pressing force Fbt, but an error (steady error) occurs between the target pressing force Fbt and the actual pressing force Fba due to the efficiency variation of the electric braking means BRK. There is. The pressing force feedback energization amount Ift is calculated based on a deviation (pressing force deviation) ΔFb between the target pressing force Fbt and the actual pressing force Fba and a preset calculation characteristic (calculation map) CHp, and the above error is calculated. Decided to decrease. The actual pressing force Fba is acquired (detected) by a pressing force acquisition unit FBA described later.

  The inertia compensation energization amount calculation block IKT calculates an inertia compensation energization amount (target value) Ikt for compensating for the influence of inertia (inertia) of the braking means BRK (particularly, the electric motor MTR) based on the target pressing force Fbt. To do. Here, the inertia is an inertia moment in a rotational motion or an inertia mass in a linear motion. Specifically, the inertia compensation energization amount Ikt is determined when the electric motor is stopped or is moving at a low speed, when the movement (rotational movement) is accelerated, and when the electric motor is moved (rotational movement). It is calculated when the vehicle decelerates suddenly and stops. With Ikt, when MTR is accelerated, the responsiveness of the generation of the pressing force is improved, and when MTR is decelerated, the overshoot of the pressing force is suppressed, and the convergence can be improved.

  In the inertia compensation energization amount calculation block IKT, the inertia compensation energization amount Ikt is calculated based on the second-order differential value of the target pressing force Fbt. Fbt is proportional to the rotation angle Mka of the MTR, and the torque for starting the MTR is proportional to the second-order differential value of Mka. In addition, Ikt can be calculated based on the amount of time variation of Fbt and a preset calculation map. Ikt is calculated so as to increase the energization amount when the MTR is accelerated and decrease the energization amount when the MTR is decelerated.

  The energization amount adjustment calculation block IMT calculates a target energization amount Imt that is a final target value for the electric motor MTR. In the IMT, the command energization amount Ist is adjusted by the pressing force feedback energization amount Ift and the inertia compensation energization amount Ikt, and the target energization amount Imt is calculated. Specifically, when the MTR is accelerated, the feedback energization amount Ift and the inertia compensation energization amount Ikt are added to the command energization amount Ist, and this is calculated as the final target energization amount Imt (Imt = Ist + Ift + Ikt). On the other hand, when the MTR is decelerated, the feedback energization amount Ift is added to the command energization amount Ist, the inertia compensation energization amount Ikt is subtracted, and the final target energization amount Imt is calculated (Imt = Ist + Ift). -Ikt). Then, based on the sign (value sign) of the target energization amount Imt, the rotation direction of the electric motor MTR (forward rotation direction in which the pressing force increases or reverse rotation direction in which the pressing force decreases) is determined, and the target energization amount Imt. The output (rotational power) of the electric motor MTR is controlled based on the size of the motor.

  The pulse width modulation block PWM calculates an instruction value (target value) for performing pulse width modulation (PWM) based on the target energization amount Imt (normally). Specifically, the pulse width modulation block PWM determines the pulse width duty ratio Dut (ON / OFF time ratio) based on the target energization amount Imt and a preset characteristic (computation map). . In addition, the PWM determines the rotation direction of the MTR based on the sign of Imt (positive sign or negative sign). For example, the rotation direction of the electric motor MTR is set such that the forward rotation direction is a positive (plus) value and the reverse rotation direction is a negative (minus) value. Since the final output voltage is determined by the input voltage (power supply voltage) and the duty ratio Dut, the rotation direction of the MTR and the energization amount to the MTR (that is, the output of the MTR) are determined in PWM.

  In the pulse width modulation block PWM, so-called current feedback control can be executed. In this case, a detection value (actual current supply amount to the electric motor MTR, for example, an actual current value) Ima of the current supply amount acquisition unit IMA is input to the PWM. Then, the duty ratio Dut is corrected (finely adjusted) based on the deviation ΔIm between the target energization amount Imt and the actual energization amount Ima. With this current feedback control, highly accurate motor control can be achieved.

  The switching control block SWT outputs a drive signal to the switching elements (S1 to S4) constituting the bridge circuit HBR based on the duty ratio (target value) Dut. This drive signal indicates whether each switching element is energized or not energized. Specifically, when the electric motor MTR is driven in the forward rotation direction based on the duty ratio Dut, S1 and S4 are energized (ON state), and S2 and S3 are de-energized (OFF state) ) And the energization / non-energization states of S1 and S4 are switched in the energization time (energization cycle) corresponding to Dut. Similarly, when the MTR is driven in the reverse direction, S1 and S4 are controlled to be in a non-energized state (OFF state), and S2 and S3 are controlled to be in an energized state (ON state), and the energized state of S2 and S3 ( ON / OFF switching cycle) is adjusted based on the duty ratio Dut. As the Dut increases, the energization time per unit time is lengthened, and a larger current flows through the MTR. For example, when Dut = 100% is instructed, the corresponding switching element is always energized, and when Dut = 0% is instructed, it is in a non-energized state.

  The power management means DGK manages the power supply state to the electric motor MTR, monitors the state of the wheel power source BWH, and properly maintains the state of charge. The power management means DGK includes switching means (switch group) SWX, charge state quantity acquisition means JDA, and determination calculation block HNT. The switching means SWX (a part of the electric circuit) includes a plurality of switches (such as SWc) for switching the connection state in the electric circuit. The charge state amount acquisition unit JDA acquires (detects) an actual value Jda (for example, an actual voltage value) of the charge state of the BWH. The determination operation block HNT (control algorithm) controls the power supply state to the bridge circuit HBR and manages the charging state of the BWH by adjusting the connection state of the SWX based on various state quantities (Imt, Jda, etc.). .

  Based on the target energization amount Imt, the determination calculation block HNT switches the switching unit SWX to adjust the power supply source (that is, the MTR power supply source) to the bridge circuit HBR. Specifically, when the wheel power source BWH functions properly by the HNT, the power supply from the vehicle body power source BBD is interrupted, and the power supply to the MTR is performed mainly by the BWH (for example, BWH alone). . Since the BWH is a power source provided on the wheel, the energy capacity (storage capacity) is smaller than that of the BBD. For this reason, the power supply capability of the BWH is limited. When the BWH has a reduced capacity (such as a reduced charge state), power is supplied from the BBD. Depending on the situation, there are cases where power is supplied by BBD and BWH (combined power supply) and power is supplied only by BBD (single power supply for BBD).

  The power management means DGK monitors the power storage state of the wheel power supply BWH by the charge state amount acquisition means JDA, and charges the wheel power supply BWH when the power storage state decreases. For example, when JDA detects the voltage Jda of BWH and Jda falls below a voltage threshold value (a predetermined value set in advance), charging to BWH is started. As a condition for starting charging, “the braking operation member BP is not operated (the non-braking state is affirmed)” is added as a condition. This condition is determined based on “the braking operation amount Bpa is less than the predetermined value bpx”. Alternatively, a stop switch STP (ON / OFF switch) is provided in the braking operation member BP, and determination can be made based on the signal Stp (by indicating that the Stp is in the ON state). The wheel power supply BWH is charged by the BBD (or the alternator ALT of the vehicle) at the time of non-braking request. The time of non-braking request | requirement is a case where the braking torque provision to a wheel is not requested | required, for example, when the braking operation member BP is not operated by the driver | operator.

[Bridge circuit HBR and noise reduction circuit NIZ]
The switching elements S1 to S4 are elements that can turn on (energize) / off (non-energize) a part of the electric circuit. For example, a MOS-FET or IGBT is used as the switching element. A switching circuit S1 to S4 constitutes a bridge circuit HBR. Here, the bridge circuit does not require a bi-directional power supply, the energization direction to the electric motor is changed with a single power supply, and the rotation direction (forward rotation direction or reverse rotation direction) of the electric motor is controlled. A circuit that can be made. This bridge circuit is also referred to as an H bridge circuit or a full bridge circuit. The switching elements S1 to S4 are driven by the control means CTL (signal from the switching control block SWT). By switching the energization / non-energization state of each switching element, the rotation direction (forward rotation direction, reverse rotation direction) and output torque (magnification amount) of the electric motor MTR are adjusted. Here, the forward rotation direction of the MTR is a rotation direction in which the friction member MSB is brought closer to the rotation member KTB, the braking torque is increased, and the deceleration of the running vehicle is increased. The reverse rotation direction of the MTR is MSB In the rotational direction in which the braking torque is reduced and the deceleration of the running vehicle is reduced.

  When a large output is required for the electric motor MTR, a large current is passed through the switching elements S1 to S4. At this time, since heat is generated in the switching elements S1 to S4, a heat radiating plate (heat sink) can be provided in S1 to S4. Specifically, a metal plate (for example, an aluminum plate) with good thermal conductivity can be fixed to S1 to S4.

  The drive circuit DRV is provided with a noise reduction circuit (stabilization circuit) NIZ for stabilizing supply power (that is, reducing voltage fluctuation). The noise reduction circuit NIZ is a so-called LC circuit (also referred to as an LC filter), and includes a combination of at least one inductor (coil) IND and at least one capacitor (capacitor) CND. For example, as the NIZ, the first and second capacitors CND1, CND2 and the inductor IND are combined to form a low-pass filter (π-type filter). Specifically, the π-type low-pass filter is a so-called Chebyshev low-pass LC filter, which is a filter including two capacitors CND1 and CND2 parallel to the line and one series inductor. In general, an inductor is more expensive than a capacitor (capacitor). Therefore, by adopting a π-type filter, component costs are suppressed, and good performance can be obtained. Further, as the noise reduction filter NIZ, a T-type low-pass filter (configured by two series inductors and one parallel capacitor) may be employed instead of the π-type low-pass filter.

  The drive circuit DRV is provided with energization amount acquisition means (for example, a current sensor) IMA. The energization amount acquisition means IMA acquires (detects) an actual energization amount (for example, current that actually flows through the electric motor MTR) Ima to the electric motor MTR.

[Electric motor MTR]
As the electric motor MTR, a brushless motor may be employed instead of the brush motor. The brushless motor is also referred to as a non-commutator motor (brushless direct current motor). In the electric motor, current is commutated by an electronic circuit instead of the mechanical commutator CMT of the brushed motor. . In the brushless motor, the rotor (rotor) is a permanent magnet, and the stator (stator) is a winding circuit (electromagnet). The rotor rotation position Mka is detected, and the switching element is switched according to Mka. As a result, the supply current is commutated. The rotor position Mka is detected by position acquisition means MKA provided inside the electric motor MTR.

  When a brushless motor is employed, the bridge circuit HBR of the driving unit DRV is configured by six switching elements. As in the case of the motor with brush, the energization state / non-energization state of the switching elements constituting the bridge circuit HBR is controlled based on the duty ratio (target value) Dut determined by the pulse width modulation block PWM.

  In the brushless motor, the position acquisition means MKA acquires the rotor position (rotation angle) Mka of the electric motor MTR. In the switching control block SWT, the six switching elements constituting the three-phase bridge circuit are controlled based on the actual position Mka. The switching elements sequentially switch the direction of the energization amount of the U-phase, V-phase, and W-phase coils of the bridge circuit (that is, the excitation direction) to drive the MTR. The rotation direction (forward rotation or reverse rotation) of the brushless motor is determined by the relationship between the rotor and the excitation position.

<First Embodiment of Power Management Unit DGK>
Next, referring to FIG. 4, the electrical connection between the vehicle power supply BBD and the wheel power supply BWH and the first embodiment of the power management means DGK (part of CTL) for managing the power supplies BBD and BWH. explain.

  A vehicle body power supply (first power supply) BBD is provided in the vehicle body BDY. Further, the BDY is provided with an alternator ALT that generates electric power and charges the BBD. The alternator ALT is a generator and is driven by a power source such as an engine. When the power storage amount (charge amount) of the vehicle body power supply BBD decreases, the power generated by ALT is supplied to the BBD via the diode Da, and the BBD is charged. The power (current) from ALT and BBD is supplied to the drive circuit DRV via the diode Db. Therefore, the alternator ALT is a part of the vehicle body power supply. When the alternator ALT is generating electric power, this electric power is also supplied to the DRV. Therefore, the BBD and the ALT serve as a supply source (vehicle power source) of electric power (current) to the DRV.

  Power is supplied from the vehicle body power supply BBD or the like to the drive means DRV through the vehicle body power line PBD. Here, as the power line PBD, a twisted pair cable (a twisted pair cable, an electric wire twisted in two pairs) may be employed. The PBD is connected to the drive means DRV via a connector (vehicle body side connector) CNB provided in the ECU.

  Driving means (driving circuit) DRV is provided in a caliper CPR fixed to the wheel WHL. The drive means DRV is provided with a connector (wheel side connector) CNC, and electric power (current) is introduced into the DRV via the CNC. The drive means DRV is programmed with a control means CTL, a noise reduction circuit NIZ, a bridge circuit HBR (S1 to S4), a wheel power supply BWH, a DC-DC converter (also simply referred to as a converter) DCC, and Power management means DGK (a part of CTL) for management is provided. All of these are provided in the CPR (fixed on the wheel side).

  The wheel power supply BWH receives power supply from the vehicle body power supply BBD or the like via the vehicle body power line PBD and the wheel power line PWH. Here, the vehicle body power line PBD and the wheel power line PWH correspond to the first electric path. Wheel power supply BWH supplies electric power to electric motor MTR via wheel power line PWH (corresponding to the second electric path). For example, an electric double layer capacitor (also simply referred to as a capacitor) is employed as the BWH. Since the capacitor has a lower internal resistance than a secondary battery (storage battery), it can be charged and discharged in a short time. A bus bar can be adopted as the wheel power line PWH, which is a power supply path from the BWH to the MTR. The use of a bus bar eliminates the need for complicated terminal processing, facilitates assembly, and is suitable for supplying a large current.

  The DC-DC converter DCC controls a direct current voltage, and converts a direct current of a certain voltage into a direct current of a different voltage (steps up or down). That is, the output voltage of the wheel power supply BWH is changed to a voltage suitable for driving the electric motor MTR by the converter (voltage conversion means) DCC. As the DC-DC converter DCC, any one of a chopper control type, a switching control type, and a series regulator type may be employed.

  The power management means DGK controls (switches) the connection state between each power supply (BBD, ALT, and BWH) and the bridge circuit HBR. The power management means DGK includes switching means SWX (a general term for switches SWb and SWc), a determination calculation block HNT, and a charge state amount acquisition means JDA.

  The switching means SWX (SWb, SWc) switches the connection state in the electric circuit based on the calculation result (signals Csb, Csc) in the determination calculation block HNT. Specifically, the switching means SWb and SWc are ON / OFF switches having two positions, a closed position (energized state) and an open position (non-energized state). The switching means SWX (SWb, SWc) is selected from one of two positions (open position, closed position) based on the drive signals Csb, Csc.

  The connection state between the vehicle body power supply BBD and the electric motor MTR is switched by the switching means (switch) SWb. When the closed position of SWb is selected, BBD and MTR are connected, and when the open position is selected, BBD and MTR are disconnected. When non-braking is requested (when generation of braking torque is not required), the connection state between the vehicle power supply BBD and the wheel power supply BWH is switched by the switching means SWb and SWc for charging the wheel power supply BWH. Note that the switch SWc is selected to be in the closed position when the wheel power source BWH is charged, but in other cases, the open position is selected. When the BWH capacity drop (for example, a voltage drop) occurs, the switching unit SWb is set to the closed position and the switching unit SWc is set to the open position, so that the minimum power supply to the MTR is reduced to the BBD (and / or , ALT). Although energization from BBD to BWH can occur due to the voltage difference, the open position of SWc is selected, and energization from BBD to BWH can be interrupted by diode Dc. Even when the capacity of the BWH is reduced, the minimum energization amount can be secured to the MTR by the power supply from the BBD.

  When a braking request is made (for example, when a braking operation is being performed by the driver and Bpa> 0), the switching means SWb is in the open position (non-energized state), and the vehicle body side power supply source Power supply from (at least one of the vehicle body power supply BBD and the alternator ALT) is cut off. Therefore, power is supplied to the bridge circuit HBR (a circuit that supplies power to the MTR) only by the wheel power source BWH (current path is in the order of BWH → DCC → PWH → Dc → HBR → MTR). Here, “whether or not braking is requested” can be determined based on the braking operation amount Bpa. For example, when Bpa ≧ bpx (threshold value), “when braking is requested” is determined, and when Bpa <bpx, “when non-braking is requested” is determined.

  When non-braking is requested (for example, when a braking operation is not performed by the driver and Bpa = 0) and BWH needs to be charged, the switching means SWb and SWc are closed ( A power supply source (at least one of the vehicle power supply BBD and the alternator ALT) is supplied to the wheel power supply BWH, and the BWH is charged (the current path is BBD). → PBD → SWb → SWc → PWH → DCC → BWH).

  The state-of-charge obtaining unit JDA obtains (detects) a state amount (charge state amount) Jda representing the state of charge (power storage state) of the wheel power source BWH. For example, the state of charge acquisition means JDA acquires the voltage of the wheel power source BWH as the state of charge Jda. Furthermore, JDA acquires the temperature of BWH as Jda. Further, the elapsed time from the time when charging is started can be acquired as Jda.

  The power management means DGK charges the wheel power source BWH based on the charge state amount Jda. The amount of electricity stored in the BWH is lost over time due to self-discharge. Therefore, the determination calculation block HNT (a part of DGK) has a current from BBD (or ALT) to BWH when the driver is not operating the braking operation member BP (for example, determined by the condition of Bpa <bpx). And charge is stored (charged) in the BWH. Specifically, the switches SWb and SWc are closed by the drive signals Csb and Csc from the HNT, and the wheel power source BWH, the vehicle body power source BBD, and the alternator ALT are connected. And HNT complete | finishes charge, when it will be in the state (full charge) in which the electric charge was fully stored in BWH. That is, the SWC is switched from the closed position to the open position by the HNT, so that the connection between the BWH and the BBD and ALT is cut off.

  The timing of the end of charging (full charge) is determined based on the state of charge Jda of the wheel power source BWH. For example, as the state of charge Jda, the voltage of BWH is detected, and the fully charged state can be detected based on the change in the voltage of BWH. Further, based on the capacity of BWH and the charge / discharge time, full charge can be determined by calculation processing programmed in the determination calculation block HNT. Furthermore, in the power supply management means DGK, as the charging method, at least one of -ΔV method charging, temperature control method charging, dT / dt control method, pulse charging, and trickle charging can be adopted. In the −ΔV system charging, a phenomenon in which the voltage of the battery slightly decreases when the battery is charged exceeding the fully charged state is charged based on this voltage change. In the temperature control method, the temperature of the wheel battery BWH is detected as the charge state quantity Jda, and charging is performed based on the temperature rise of the battery. In dT / dt control type charging, a differential value (time variation dJda of Jda) of the temperature (increase) of the battery BWH is detected, and charging is performed based on dJda. In the pulse charging method, after reaching a predetermined voltage by constant current charging, charging is continued by a pulse current. In the pulse charging, the cell voltage is allowed to exceed a predetermined voltage for a very short time, and the cell voltage is closely monitored, so that overcharging can be suppressed and rapid charging can be performed. In the trickle charging method, a fully charged state is maintained by constantly supplying a weak current that does not affect or affect the battery characteristics.

  When a large current is supplied from the vehicle body power supply BBD to the electric motor MTR provided on the wheel, it is important to set the electrical resistance of the vehicle body power line PBD (part of the first electrical path) low. That is, it is required to use a thick lead wire (large cross-sectional area) as the PBD. However, since there is relative motion between the vehicle body and the wheels, the flexibility (bending fatigue) can be a problem when a thick conductor is employed. The wheel power source BWH is charged at the time of non-braking request, and the MWH is supplied with power from the BWH at the time of braking request. Specifically, at the time of non-braking request, power is gradually (slowly and time consuming) supplied from the vehicle body power supply BBD, and the wheel power supply BWH is charged. When a braking request is made, a large current is supplied from the wheel power source BWH to the electric motor MTR via the wheel power line (second electric path, for example, bus bar) PWH. Therefore, the vehicle body power line (for example, twisted pair cable) PBD is not required to flow a large current corresponding to sudden braking. As a result, a thin (small cross-sectional area) conductor can be adopted as the vehicle body power line PBD, and the flexibility thereof can be improved.

  In the determination calculation block HNT, the drive signal Csb of SWb and the drive signal Csc of SWc are output based on the state quantity (braking state quantity) Bja indicating the necessity of braking, and the connection state of the switches SWb and SWc is changed. Be controlled. That is, the position of each switching means (switch) is selected based on the instruction signals Csb and Csc transmitted from the HNT. Here, at least one of the state quantities calculated based on the braking operation amount Bpa is employed as the state quantity Bja indicating whether or not braking is necessary. Further, since the traction control and the vehicle stabilization control operate even when the driver is not performing a braking operation, at least one of the state quantities calculated based on these control amounts Ftcs and Fesc is The braking state quantity Bja can be employed. Therefore, in the calculation process, at least one state quantity from the braking operation quantity Bpa to the target duty ratio Dut (for example, Fbt, Imt) can be adopted as the braking state quantity Bja. Further, a stop switch STP for acquiring the presence or absence of a braking operation is provided in the braking operation member BP, and Bja can be calculated based on the STP signal Stp (ON signal or OFF signal).

  When the braking state quantity Bja is equal to or greater than a threshold value bj0 (a predetermined value that is set in advance and greater than “0”) (Bja ≧ bj0), “requires braking (braking request)” Is determined. For example, the “braking request” can be determined when the target energization amount Imt transmitted from the IMT is equal to or greater than the threshold value im0. When braking is requested, the open position of SWb and the open position of SWc are selected. When braking is required, the power supply from the vehicle body power supply BBD is cut off, and the electric motor MTR is supplied with power only by the wheel power supply BWH. The power supply path at this time is “BWH → DCC → PWH → Dc → HBR → MTR”. Here, the wheel power line PWH corresponds to a second electric path (path that electrically connects the wheel power supply BWH and the electric motor MTR). In this case, the power supply from the vehicle body power supply BBD to the bridge circuit HBR can be cut off by the open position of the switch SWb.

  When the braking state quantity Bja is less than the threshold value bj0 (for example, when Bja is “0”), it is determined that “braking is not necessary (non-braking request)”. For example, the non-braking request can be determined when the target energization amount Imt is less than the threshold value im0. In addition, when the BWH needs to be charged (that is, when non-braking is requested and when the BWH is charged), the closed position of SWb and the closed position of SWc are selected. In this case, the power supply path from the BBD to the BWH is “BBD (or ALT) → Db → PBD → SWb → SWc → PWH → DCC → BWH”. Here, PBD and PWH correspond to the first electric path (path that electrically connects the vehicle power source BBD and the wheel power source BWH).

  When non-braking is required and charging of BWH is not required, the closed position of SWb and the closed position of SWc are selected. In anticipation of the situation in which braking is started, HBR, BBD, and BWH are connected to each other so that power can be supplied from at least one of BBD and BWH. As a result, even if the function of the BWH is reduced, power can be supplied from at least the BBD.

[Responding to braking requests when charging the BWH and when the capacity of the BWH is reduced]
There may be a case where braking is required while the wheel power supply BWH is being charged. In this case, the determination calculation block HNT determines “whether or not power can be supplied from the BWH” based on the state of charge Jda. For example, “power supply is possible” is determined when the state of charge Jda is greater than or equal to a predetermined value jdx, and “power supply is not possible” is determined when Jda is less than the predetermined value jdx.

  When the charged amount of the wheel power source BWH is sufficient and power can be supplied to the MTR (when it is determined that “power can be supplied”), the SWb is changed from the closed position to the open position, and “BWH → DCC → PWH → Power is supplied through a route of “Dc → HBR → MTR”. On the other hand, when the power storage amount of the wheel power source BWH is insufficient and power supply is not possible (when it is determined that “power supply is impossible”), the closed position of SWb is maintained and SWc is changed from the closed position to the open position. Is done. Therefore, power is supplied through a route “BBD → Db → PBD → SWb → HBR → MTR”. Furthermore, since the BWH and the HBR are disconnected from each other depending on the open position of the diode Dc and the switch SWc, the energization from the BBD to the BWH can be prevented, and the minimum energization to the MTR can be ensured. Here, the vehicle body power line PBD corresponds to a third electric path (path that electrically connects the vehicle body power supply BBD and the electric motor MTR).

  Although the BWH capability (for example, voltage drop) occurs and braking is required, there may be a case where power cannot be supplied from the BWH. In this case, the closed position of SWb and the open position of SWc are selected. Here, the decrease in the capacity of the BWH can be determined based on the voltage of the BWH. Moreover, since a capability fall may be due to a shortage of the amount of electricity stored in the BWH, the capability fall can be determined based on the state of charge Jda.

  Specifically, when the voltage EBWH of BWH is less than a predetermined value eb0, or when the state of charge Jda is less than a predetermined value jd0, a decrease in capacity is determined. When it is determined that the capacity of the BWH is lowered, the power supply path from the BBD to the MTR is “BBD (or ALT) → Db → PBD → SWb → HBR → MTR”. When loss of function occurs in the BWH, power is supplied to the MTR from the BBD. The electrical connection between BWH and HBR is cut off by the open position of SWc and diode Dc. Due to the potential difference, energization from the BBD may flow into the BWH. However, since the SWc open position (non-energization) is selected and the energization direction is limited by the diode Dc, energization to the BWH side is performed. Can be prevented. As a result, even when the BWH has a reduced capacity, the power supply from the BBD can ensure the minimum energization of the MTR.

<Second Embodiment of Power Management Unit DGK>
As described above, in the first embodiment of the power management means DGK described above, the switch SWb is provided to block power supply from the BBD and / or ALT to the MTR, but the SWb may be omitted. Specifically, the voltage conversion means (converter) DCC adjusts the voltage of the wheel power supply BWH to an appropriate value, so that power supply from the BBD or the like to the MTR can be blocked without using SWb.

  RPBD is the resistance value of the wiring from the vehicle body power supply BBD to the electric motor MTR (particularly the resistance value of the vehicle body power line PBD), RWHL is the resistance value of the wiring (wheel power line, bus bar) from the converter DCC to the MTR, and RMTR is the electric motor MTR. , EBBD is the BBD voltage value, and EDCC is the DCC output voltage value, the current iBBD supplied from the BBD to the MTR is the current iBWH supplied from the BWH to the MTR, and finally the electric motor A current value iMTR energized in the MTR is expressed by the following equation.

iBBD = {(RWHL + RMTR) · EBDD−RMTR · EDCC}

/ (RPBD · RWHL + RWHL · RMTR + RMTR · RPBD)
... Formula (1)
iBWH = {− RMTR · EBDD + (RPBD + RMTR) · EDCC}

/ (RPBD · RWHL + RWHL · RMTR + RMTR · RPBD)
... Formula (2)
iMTR = iBBD + iBWH = (RWHL / EBBD + RPBD / EDCC)

/ (RPBD · RWHL + RWHL · RMTR + RMTR · RPBD)
... Formula (3)

  In the equation (3), when the resistance value RWHL is very small with respect to the resistance value RPBD and is substantially “0” (RWHL << RPBD), the bridge circuit HBR (that is, the electric motor MTR) The power supply from the vehicle body power supply BBD is blocked (blocked), and power can be supplied from the converter DCC (ie, the wheel power supply BWH). For example, RPBD (resistance of conductor PBD, contact resistance of connectors CNB, CNC, etc.) is 200 mΩ, RWHL is 10 mΩ (resistance of bus bar PWH), RMTR is 250 mΩ (winding resistance of electric motor, contact resistance of brush BLC, S1 Assume that the MTR does not rotate and the pressing force is maintained (that is, no back electromotive force is generated). When the vehicle body power supply BBD of the power supply voltage EBBD = 12V is connected to the MTR and the wheel power supply BWH is not connected to the MTR, a current of 26.7 A is supplied from the BBD to the MTR. Under this condition, when the wheel power supply BWH voltage-adjusted to EDCC = 12V is connected, the current iBBD supplied from the BBD to the MTR is 2.2A, the current iBWH supplied from the BWH to the MTR is 44.0A, and the final Thus, the current value iMTR energized to the electric motor MTR is 46.2A. Therefore, power supply from the BBD is suppressed to 4.8%, and a current of 95.2% from the BWH is supplied to the MTR.

  Furthermore, when the output voltage of converter DCC is increased, current tends to flow from DCC to BBD due to a potential difference between DCC and BBD. However, current cannot flow from the DCC side to the BBD side by the diode Db. Therefore, energization from BBD to MTR can be completely cut off. The DCC output voltage value (cutoff voltage) E0 when the energization from the BBD can be completely cut off is obtained based on the above resistance values (RMTR, etc.) and the BBD voltage value EBBD. Specifically, the cutoff voltage E0 is obtained as the value of EDCC when iBBD = 0 is satisfied by substituting each resistance value (known) and the BBD voltage value (known) into the above equation. By the voltage conversion means DCC, the voltage EBWH of the wheel power supply BWH is boosted to a voltage higher than the cutoff voltage E0, the current supply from the vehicle body power supply BBD to the electric motor MTR is completely cut off, and the BTR alone can supply power to the MTR. .

  Similarly, in the second embodiment, when BWH is charged, SWc is set to the closed position. When there is a braking request during charging, SWc is changed from the closed position to the open position. At this time, the DCC adjusts the voltage of BWH to be higher than the voltage of BBD. When the charged amount of BWH is sufficient and power supply is possible, power supply is performed from the BWH side via Dc due to a potential difference. On the other hand, when the amount of electricity stored in BWH is insufficient and power supply is not possible, BWH and HBR are disconnected from each other depending on the open position of Dc and SWc. Is prevented.

  Similarly, when a BWH capacity decrease (for example, a voltage decrease) occurs, power is supplied from the BBD side to the HBR side due to a potential difference. Specifically, since the output voltage of the DCC decreases, the current from the BBD tends to flow to the DCC side, but this flow is blocked by the open positions of the diodes Dc and SWc. As a result, since all the electric power from the BBD side is supplied to the HBR, the minimum energization to the MTR can be ensured.

  Similarly, in the second embodiment, when braking is requested (when braking is requested), electric power is supplied from the wheel power source BWH to the electric motor MTR. In order to supply power more effectively, the output voltage EDCC of the converter (voltage conversion means) DCC can be adjusted to be larger than the voltage EBBD of the vehicle body power supply BBD. In other words, the voltage EBWH of the wheel power supply BWH is boosted to a value (EDCC) greater than the voltage EBBD of the vehicle body power supply BBD. The BWH is gradually charged over time from the vehicle body power supply BBD when braking is not required (when non-braking is requested). Therefore, a large current corresponding to sudden braking is not applied to the vehicle body power line (first electric path, for example, twisted pair cable) PBD. When a braking request is made, a large current is supplied from the wheel power source BWH to the electric motor MTR via the wheel power line (second electric path, for example, bus bar) PWH, so that the body power line PBD is thin (small cross-sectional area). Can be employed.

  MSB ... friction member, KTB ... rotating member, MTR ... electric motor, BBD ... vehicle body power supply, BWH ... wheel power supply, CTL ... control means, JDA ... charge state quantity acquisition means, SWb ... switching means, Jda ... charge state quantity, PBD + PWH ... 1st electric path, PWH ... 2nd electric path, PBD ... 3rd electric path

Claims (4)

A rotating member fixed to a vehicle wheel;
An electric motor provided on the wheel side of the vehicle;
A friction member that presses the rotating member using a driving torque of the electric motor to generate a braking torque on the wheel;
A vehicle body power supply provided on the vehicle body side of the vehicle;
A wheel power source provided on the wheel side of the vehicle;
Control means for driving the electric motor using at least one of the vehicle body power supply and the wheel power supply based on a braking operation by a driver of the vehicle;
An electric braking device for a vehicle, comprising: The electric braking device for a vehicle according to claim 1,
The vehicle body power supply supplies power to the wheel power supply via a first electrical path,
The wheel power supply supplies power to the electric motor via a second electrical path;
The control means includes
An electric braking device for a vehicle configured to drive the electric motor using the wheel power source when generating braking torque on the wheel. An electric braking device for a vehicle according to claim 2,
A charging state amount acquisition means for acquiring a charging state amount of the wheel power supply;
The control means includes
A switching means for connecting / blocking a third electric path for supplying electric power from the vehicle body power source to the electric motor;
The control means includes
When the state-of-charge amount is greater than or equal to a first predetermined value, the third electric path is interrupted and the electric motor is driven using only the wheel power source
The vehicle is configured to connect the third electric path and drive the electric motor using the wheel power source and the vehicle body power source when the state of charge is less than the first predetermined value. Electric braking device. The electric braking device for a vehicle according to claim 3,
The control means includes
An electric braking device for a vehicle configured to block the first electric path when the state of charge is less than a second predetermined value which is equal to or less than the first predetermined value.

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