JP2017128283A - Electric braking device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately dispose a circuit board for driving an electric motor and reduce the size of a device in the electric braking device for decelerating rotating power of the electric motor and pressing a friction member on a rotating member so as to apply braking torque to a wheel.SOLUTION: An electric braking device generates braking torque of a wheel WHL by pressing a friction member MSB on a rotating member KTB fixed to the wheel WHL of a vehicle via an electric motor MTR. The electric braking device includes: a circuit board KBN mounted with a processor and a bridge circuit to drive the electric motor MTR; a decelerator GSK for decelerating rotating power output by the electric motor MTR; and a power conversion mechanism HNK for converting the rotating power output by the decelerator GSK to linear power to move a pressing member PSN for pressing the friction member MSB on the rotating member KTB. Viewed in the direction vertical to a rotation axis Jmt of the electric motor MTR, the circuit board KBN is located between the electric motor MTR and the decelerator GSK.SELECTED DRAWING: Figure 1

Description

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

  Patent Document 1 states that “in the case of an integrated structure with an electric circuit portion, an electric brake device having an improved countermeasure against heat of the drive circuit is provided with an electric motor sandwiched between a brake pad and a motor. It is described that a circuit unit is provided, a power module is provided so that a heat radiating surface faces an inner surface of a metal outer case of the electric circuit unit, and a control circuit board is arranged on the motor side with respect to the power module.

  Patent Document 2 describes a configuration in which a gear train is arranged between an electric motor and a circuit board for an electromechanically driven disc brake.

  The devices described in Patent Documents 1 and 2 are mounted on the wheel side. In such an electric braking device, it is assumed that the electric motor and the circuit board are electrically connected by a pin (an electric conductor that is not flexibly bent) instead of a bendable covered wire. As described in Patent Documents 1 and 2, in a configuration in which a power transmission mechanism such as a speed reducer is disposed between the electric motor and the circuit board, the pins must be routed around the power transmission mechanism. I must. For this reason, the arrangement of the pins becomes a limiting condition, and it becomes difficult to reduce the size of the electric braking device and improve the mounting property on the wheel side.

JP 2007-278311 A International Publication No. 2010/060725

  An object of the present invention is to appropriately provide a circuit board for driving an electric motor in an electric braking device for a vehicle that applies a braking torque to a wheel by pressing a friction member against the rotating member by decelerating the rotational power of the electric motor. It is to provide something that can be arranged and downsized.

  The electric braking device for a vehicle according to the present invention presses the friction member (MSB) to the rotating member (KTB) fixed to the wheel (WHL) of the vehicle via the electric motor (MTR), thereby the wheel (WHL). An electric braking device for a vehicle that generates a braking torque of a microprocessor (MPR) and a circuit board (KBN) on which a bridge circuit (BRG) is mounted so as to drive the electric motor (MTR); A reduction gear (GSK) that decelerates the rotational power output by the electric motor (MTR), and the rotational power output by the reduction gear (GSK) is converted into linear power, and the friction member (MSB) is converted into the rotational member ( A power conversion mechanism (HNK) that moves a pressing member (PSN) that presses against KTB.

  In the electric braking device for a vehicle according to the present invention, when viewed in a direction perpendicular to the rotation axis (Jmt) of the electric motor (MTR), the circuit board (KBN) includes the electric motor (MTR) and the speed reducer ( GSK).

  Since the circuit board KBN is provided between the electric motor MTR and the reduction gear GSK when viewed in the vertical direction of the rotation axis Jmt of the electric motor MTR (because the electric motor MTR, the circuit board KBN, and the reduction gear GSK are arranged in this order). ), And the positional relationship in which the circuit board KBN and the electric motor MTR are brought close to each other. For this reason, the pin PMT of the electric motor MTR and the pin PMK of the rotation angle sensor MKA can be directly joined to the circuit board KBN without going around the outer periphery of the speed reducer GSK. As a result, the electrical connection is simplified, and the electric braking device DSS (particularly, the braking means BRK) can be reduced in size.

  The electric braking device for a vehicle according to the present invention presses the friction member (MSB) to the rotating member (KTB) fixed to the wheel (WHL) of the vehicle via the electric motor (MTR), thereby the wheel (WHL). A braking force sensor (FBA) that detects a pressing force (Fba) that is a force that presses the friction member (MSB) against the rotating member (KTB). A circuit board (KBN) on which a microprocessor (MPR) and a bridge circuit (BRG) are mounted to drive the electric motor (MTR) based on the pressing force (Fba), and the electric motor (MTR) A speed reducer (GSK) that decelerates the rotational power to be output, and the rotational power output by the speed reducer (GSK) are converted into linear power, and the friction member (MSB) is converted to the rotational member (KTB). Comprising power conversion mechanism for moving the pressing member (PSN) for pressing the (HNK), to.

  In the electric braking device for a vehicle according to the present invention, the circuit board (KBN) includes the pressing force sensor (FBA) and the deceleration when viewed in a direction perpendicular to the rotation axis (Jps) of the power conversion mechanism (HNK). It is located between the machine (GSK).

  Since the circuit board KBN is provided between the pressing force sensor FBA and the reduction gear GSK in the vertical direction of the rotation axis Jps of the power conversion mechanism HNK, the positional relationship in which the circuit board KBN and the pressing force sensor FBA are close to each other. It is said. For this reason, the pin PFB of the pressing force sensor FBA can be directly joined to the circuit board KBN without going around the outer peripheral portion of the reduction gear GSK. As a result, the electrical connection is simplified, and the electric braking device DSS (particularly, the braking means BRK) can be reduced in size.

1 is an overall configuration diagram of an electric braking device for a vehicle according to an embodiment of the present invention. It is a schematic diagram for demonstrating 1st Embodiment of a drive circuit board | substrate. It is a schematic diagram for demonstrating 2nd Embodiment of a drive circuit board | substrate. It is a fragmentary sectional view for demonstrating the positional relationship of a drive circuit board and a reduction gear in the perpendicular direction view with respect to the rotating shaft line of an electric motor. FIG. 5 is a layout diagram for explaining a positional relationship between a drive circuit board and a speed reducer when viewed in a direction parallel to the rotation axis of the 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>
An electric braking device DSS according to an embodiment of the present invention will be described with reference to the overall configuration diagram of FIG. The vehicle includes an electric braking device DSS, a braking operation member BP, an operation amount acquisition unit BPA, a rotating member (for example, a brake disc, a brake drum) KTB, and a friction member (for example, a brake pad, a brake shoe) MSB. . The electric braking device DSS is composed of an electronic control unit ECU, a communication line SGL, a power line PWL, and a braking means BRK.

  The braking operation member (for example, brake pedal) BP is a member that the driver operates to decelerate the vehicle. The braking torque of the wheel WHL is adjusted by the braking means BRK in accordance with the operation of the braking operation member BP. As a result, braking force is generated on the wheels WHL, and the traveling vehicle is decelerated.

  The braking operation member BP is provided with an operation amount acquisition means BPA. An operation amount (braking operation amount) Bpa of the braking operation member BP is acquired (detected) by the operation amount acquisition means BPA. As the operation amount acquisition means BPA, a sensor (pressure sensor) for detecting the pressure of the master cylinder, a sensor (stepping force sensor) for detecting the operation force of the braking operation member BP, and a sensor for detecting the operation displacement of the braking operation member BP ( At least one of the stroke sensors) is employed. 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 detected braking operation amount Bpa is input to the electronic control unit ECU.

≪Electronic control unit ECU≫
The electronic control unit ECU includes a target pressing force calculation block FBT, a vehicle body side communication unit CMB, and a connector CNC. The electronic control unit ECU corresponds to a part of the control means (controller) CTL.

  In the target pressing force calculation block FBT, a target value (target pressing force) Fbt related to the force (pressing force) by which the friction member MSB presses the rotating member KTB is calculated. Specifically, the target pressing force Fbt is monotonically increased from zero as the braking operation amount Bpa increases based on the braking operation amount Bpa and the preset calculation map CHfb. Calculated.

  The target pressing force Fbt is input to the vehicle body side communication unit CMB. A signal (Fbt or the like) is transmitted from the vehicle body side communication unit CMB to the circuit board KBN (particularly, the wheel side communication unit CMW) in the braking means BRK via the communication line SGL and the connector CNC. The communication line SGL connected by the connector CNC is a communication unit between the electronic control unit ECU fixed to the vehicle body and the braking unit BRK fixed to the wheel. As the signal line SGL, a serial communication bus (for example, CAN bus) can be adopted. The power line PWL is connected to the connector CNC. Electric power is supplied from the electronic control unit ECU to the braking means BRK through the power line PWL.

≪Braking means (brake actuator) BRK≫
The braking means BRK is provided on the wheel WHL, applies braking torque to the wheel WHL, and generates braking force. The running vehicle is decelerated by the braking means BRK. A configuration of a so-called disc type braking device (disc brake) is exemplified as the braking means BRK. In this case, the friction member MSB is a brake pad, and the rotating member KTB is a brake disk. The braking means BRK may be a drum type braking device (drum brake). In the case of a drum brake, the friction member MSB is a brake shoe, and the rotating member KTB is a brake drum.

  The braking means BRK (brake actuator) includes a brake caliper CRP, a pressing member PSN, an electric motor MTR, a rotation angle sensor MKA, a reduction gear GSK, an input member SFI, an output member SFO, a power conversion mechanism HNK, a pressing force sensor FBA, and The drive circuit board KBN is used. Each member (PSN or the like) is housed in the brake caliper CRP.

  A floating caliper may be employed as a brake caliper (also simply referred to as a caliper) CRP. The caliper CRP is configured to sandwich a rotating member (brake disc) KTB via two friction members (brake pads) MSB. Within the caliper CRP, the pressing member (brake piston) PSN is moved (advanced or retracted) with respect to the rotating member KTB. By the movement of the pressing member PSN, the friction member MSB is pressed against the rotating member KTB, and a frictional force is generated. A part of the caliper CRP has a box-type structure. Specifically, the caliper CRP has a space inside, and various members (circuit board KBN and the like) are accommodated therein.

  The movement of the pressing member PSN is performed by the power of the electric motor MTR. Specifically, the output of the electric motor MTR (rotational power around the motor shaft) is transmitted from the input member (input shaft) SFI to the output member (output shaft) SFO via the reduction gear GSK. Then, the rotational power (torque) of the output member SFO is converted into linear power (axial thrust of the pressing member PSN) by the power conversion mechanism HNK and transmitted to the pressing member PSN. As a result, the pressing member PSN is moved with respect to the rotating member KTB. By the movement of the pressing member PSN, the force (pressing force) by which the friction member MSB presses the rotating member KTB is adjusted. Since rotating member KTB is fixed to wheel WHL, a frictional force is generated between friction member MSB and rotating member KTB, and the braking force of wheel WHL is adjusted.

  The electric motor MTR is a power source for driving (moving) the pressing member (piston) PSN. For example, a motor with a brush or a brushless motor can be employed as the electric motor MTR. 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 rotation angle sensor MKA acquires (detects) the position (rotation angle) Mka of the rotor (rotor) of the electric motor MTR. The detected rotation angle Mka is input to the circuit board KBN via the rotation angle pin PMK.

  The pressing force sensor FBA acquires (detects) a force (pressing force) Fba that the pressing member PSN presses the friction member MSB. The detected actual pressing force Fba is input to the circuit board KBN via the pressing force pin PFB. For example, the pressing force sensor FBA is provided between the power conversion mechanism HNK and the caliper CRP in the output member SFO.

  The drive circuit board (also simply referred to as a circuit board) KBN is an electric circuit that drives the electric motor MTR. The circuit board KBN is composed of hardware such as a microprocessor (an arithmetic processing unit, also simply referred to as a processor) MPR, a bridge circuit BRG, and the like, and a control algorithm (software) programmed in the microprocessor MPR. The electric motor MTR and the circuit board KBN are electrically connected via the motor pin PMT. The circuit board KBN is fixed to the caliper CRP, and is disposed between the electric motor MTR and the speed reducer GSK when viewed from a direction orthogonal to the motor rotation axis Jmt. The circuit board KBN corresponds to a part of the control means (controller) CTL.

  A connector CNC is fixed to the circuit board KBN. Based on the target pressing force Fbt transmitted from the electronic control unit ECU via the signal line SGL, the output torque (rotational power) of the electric motor MTR is controlled. Further, electric power transmitted from the electronic control unit ECU via the power line PWL is input to the circuit board KBN via the connector CNC. This electric power is a power source for the electric motor MTR and a power source for the rotation angle sensor MKA and the pressing force sensor FBA.

<First Embodiment of Drive Circuit Board KBN>
A first embodiment of a drive circuit board (also simply referred to as a circuit board) KBN will be described with reference to the schematic diagram of FIG. This is an example in which a brush motor (simply referred to as a brush motor) is employed as the electric motor MTR. The electric motor MTR is driven by the circuit board KBN.

  The electric motor (brush motor) MTR is electrically connected to the circuit board KBN by motor pins PMT. The circuit board KBN is provided with through holes (through holes) Ts and Tb for the motor pins PMT, and the two motor pins PMT are press-fitted into the two through holes Ts and Tb to form an electrically connected state. Specifically, a press-fit connector (press-fit terminal) is employed as the terminal of the motor pin PMT.

  An acquisition result (motor rotation angle) Mka of the rotation angle sensor MKA is input to the circuit board KBN by the rotation angle pin PMK. The circuit board KBN is provided with a through hole Tm for the rotation angle pin PMK, and the rotation angle pin PMK is press-fitted into the through hole Tm to form an electrical connection state. Specifically, a press-fit connector is employed as the terminal of the rotation angle pin PMK.

  Similarly, an acquisition result (actual pressing force) Fba of the pressing force sensor FBA is input to the circuit board KBN by the pressing force pin PFB. The circuit board KBN is provided with a through hole (through hole) Tf for the pressing force pin PFB, and the pressing force pin PFB is press-fitted into the through hole Tf to form an electrical connection state. Specifically, a press-fit connector is employed as the terminal of the pressing force pin PFB.

  Here, the “press-fit connector (press-fit terminal)” is an electrical connection that does not use solder. Pin terminals (press-fit portions) are inserted into through holes (through holes) formed in the circuit board (printed circuit board) KBN. And electricity supply is performed because the outer periphery of a press fit terminal and the inner periphery of a through hole contact each other. That is, the terminal portion (press fit portion) of the pin is press-fitted into the printed circuit board, and contact energization is performed by an elastic force generated by elastic deformation at that time. For this reason, the compliant shape which gives elasticity to a pin terminal is required, For example, the shape which a notch part is formed in a pin terminal and a notch part bends may be employ | adopted.

  The circuit board KBN includes a connector CNC, a wheel side communication unit CMW, a motor control calculation unit CMT, a bridge circuit BRG, and a noise reduction filter (also referred to as a noise reduction circuit) LPF. The circuit board KBN is fixed to the caliper CRP.

  A connector CNC is fixed to the circuit board (electric circuit board for driving the motor) KBN. The connector CNC connects the power line PWL and the signal line SGL between the electronic control unit ECU and the braking means BRK. Electric power is supplied to the circuit board KBN from the storage battery BAT and the generator ALT fixed to the vehicle body side through the power line PWL. Further, the target pressing force Fbt is inputted to the circuit board KBN (particularly, the wheel side communication unit CMW) from the vehicle body side electronic control unit ECU (particularly, the vehicle body side communication unit CMB) through the signal line (communication bus) SGL. The

  The wheel side communication unit CMW of the circuit board KBN receives the target value Fbt of the pressing force from the vehicle body side communication unit CMB of the electronic control unit ECU via the signal line SGL. The wheel side communication unit CMW is a communication protocol and is incorporated in a microprocessor (also simply referred to as a processor) MPR mounted on the circuit board KBN.

≪Motor control calculation unit CMT≫
In the motor control calculation unit CMT, in order to drive the electric motor MTR, the energization amount to the electric motor MTR (that is, the output torque of the electric motor MTR) and the energization direction (that is, the rotation direction of the electric motor MTR) are controlled. The The motor control calculation unit CMT includes an instruction energization amount calculation block IST, a pressing force feedback control block FBC, a target energization amount calculation block IMT, a pulse width modulation block PWM, and a switching control block SWT. The motor control calculation unit CMT is a control algorithm and is programmed in the processor MPR mounted on the circuit board KBN.

  The command energization amount calculation block IST calculates the command energization amount Ist based on the target pressing force Fbt and preset calculation characteristics (calculation maps) CHs1 and CHs2. The command energization amount Ist is a target value of the energization amount to the electric motor MTR for achieving the target pressing force Fbt. Specifically, the instruction energization amount Ist is calculated so as to monotonously increase as the target pressing force Fbt increases. Here, the calculation map of the command energization amount Ist is composed of two characteristics CHs1 and CHs2 in consideration of the hysteresis of the braking means BRK.

  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 the pulse width modulation, this duty ratio can be used as the energization amount.

  The pressing force feedback control block FBC calculates a pressing force feedback energization amount (also simply referred to as feedback energizing amount) Ibt based on the target pressing force (target value) Fbt and the actual pressing force (actual value) Fba. First, in the pressing force feedback control block FBC, a deviation (pressing force deviation) eFb (= Fbt−Fba) between the target pressing force Fbt and the actual pressing force Fba is calculated. In the feedback energizing amount calculation block IBT in the pressing force feedback control block FBC, the pressing force feedback energizing amount Ibt is calculated based on the pressing force deviation eFb so that the target value Fbt of the pressing force matches the actual value Fba. Is done.

  Specifically, a proportional term of the feedback energization amount Ibt is determined by multiplying the pressing force deviation eFb by a proportional gain (predetermined value) Kp. A differential value of the pressing force deviation eFb is calculated, and this is multiplied by a differential gain (predetermined value) Kd to calculate a differential term of the feedback energization amount Ibt. Further, an integral value of the pressing force deviation eFb is calculated, and this is multiplied by an integral gain (predetermined value) Ki, and an integral term of the feedback energization amount Ibt is calculated. Then, the proportional, differential, and integral terms of the feedback energization amount Ibt are added to determine the final feedback energization amount Ibt. That is, in the pressing force feedback control block FBC, the feedback energization amount Ibt is determined based on so-called feedback control based on pressing force (PID control).

  In the target energization amount calculation block IMT, a target energization amount Imt that is a final target value for the electric motor MTR is calculated. Although the command energization amount Ist is calculated as a value corresponding to the target pressing force Fbt, there may be an error between the target pressing force Fbt and the actual pressing force Fba due to fluctuations in the efficiency of the power transmission member of the braking means BRK. Therefore, the command energization amount Ist is adjusted by the feedback energization amount Ibt, and the target energization amount Imt is determined so as to reduce the error. Specifically, the feedback energization amount Ibt is added to the command energization amount Ist, and the target energization amount Imt is calculated.

  The direction of rotation of the electric motor MTR is determined based on the sign (the sign of the value) of the target energization amount Imt, and the output (rotational power) of the electric motor MTR is controlled based on the magnitude of the target energization amount Imt. For example, when the sign of the target energization amount Imt is a positive sign (Imt> 0), the electric motor MTR is driven in the normal rotation direction (increase direction of the pressing force), and the sign of the target energization amount Imt is a negative sign. In some cases (Imt <0), the electric motor MTR is driven in the reverse direction (in the pressing force decreasing direction). In addition, the output torque of the electric motor MTR is controlled to increase as the absolute value of the target energization amount Imt increases, and the output torque is controlled to decrease as the absolute value of the target energization amount Imt decreases.

  In the pulse width modulation block PWM, an instruction value (target value) Dut for performing pulse width modulation is calculated based on the target energization amount Imt. Specifically, in the pulse width modulation block PWM, based on the target energization amount Imt and a preset characteristic (computation map), the duty ratio Dut of the pulse width (in the periodic pulse wave, the on-state for the period is set. The proportion of the state) is determined. In addition, in the pulse width modulation block PWM, 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. 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, in the pulse width modulation block PWM, the rotation direction of the electric motor MTR and the energization amount to the electric motor MTR (that is, the electric motor MTR). MTR output) is determined.

  Furthermore, so-called current feedback control is executed in the pulse width modulation block PWM. A detection value (for example, actual current value) Ima of the energization amount acquisition means IMA is input to the pulse width modulation block PWM, and is based on a deviation (energization amount deviation) eIm between the target energization amount Imt and the actual energization amount Ima. Thus, the duty ratio Dut is corrected (finely adjusted). By this current feedback control, the target value Imt and the actual value Ima are controlled to coincide with each other, and high-precision motor control can be achieved.

  In the switching control block SWT, signals (drive signals) Sw1 to Sw4 for driving the switching elements SW1 to SW4 constituting the bridge circuit BRG are determined based on the duty ratio (target value) Dut. The drive signals Sw1 to Sw4 are determined so that the energization time per unit time is increased as the duty ratio Dut is increased, and a larger current is passed through the electric motor MTR. By these drive signals Sw1 to Sw4, energization / non-energization and switching time per unit time in the switching elements SW1 to SW4 are controlled. That is, the rotation direction and output torque of the electric motor MTR are controlled by the drive signals Sw1 to Sw4. The motor control calculation unit CMT has been described above.

  The bridge circuit BRG can change the energization direction of the electric motor with a single power source without requiring a bidirectional power source, and can control the rotation direction (forward rotation direction or reverse rotation direction) of the electric motor. Circuit. The bridge circuit BRG includes switching elements SW1 to SW4 and is mounted on the circuit board KBN. The switching elements SW1 to SW4 are elements that can switch a part of the electric circuit to ON (energized) or OFF (non-energized). For example, MOS-FETs and IGBTs are used as the switching elements SW1 to SW4.

  When the electric motor MTR is driven in the forward rotation direction, the switching elements SW1 and SW4 are turned on (on state), and the switching elements SW2 and SW3 are turned off (off state). On the other hand, when the electric motor MTR is driven in the reverse direction, the switching elements SW1 and SW4 are turned off (off state), and the switching elements SW2 and SW3 are turned on (on state). That is, in the reverse drive of the electric motor MTR, a current flows in the opposite direction to the normal drive.

  The bridge circuit BRG is provided with energization amount acquisition means (for example, a current sensor) IMA for the electric motor. The energization amount acquisition means IMA acquires the energization amount (actual value) Ima of the electric motor MTR. For example, the current value that actually flows through the electric motor MTR can be detected as the actual energization amount Ima by the motor current sensor IMA.

A noise reduction filter (also referred to as a noise reduction circuit) LPF is mounted on the circuit board KBN in order to stabilize the supplied power. The noise reduction circuit LPF is configured by a combination of at least one capacitor (capacitor) and at least one inductor (coil). The noise reduction circuit LPF is a stabilization circuit for reducing voltage fluctuation or the like, and is a so-called LC circuit (also referred to as an LC filter).
<Second Embodiment of Drive Circuit Board KBN>
A second embodiment of the drive circuit board KBN will be described with reference to the schematic diagram of FIG. This is an example in which a brushless DC motor (three-phase brushless motor, simply referred to as a brushless motor) is employed as the electric motor MTR. In this case, the bridge circuit BRG is configured by six switching elements ZW1 to ZW6. Here, the wheel side communication unit CMW and the motor control calculation unit CMT are the same as those in the case of the brush motor, and thus the description thereof is omitted.

  In the brushless motor MTR, current is commutated by an electric circuit instead of the mechanical commutator of the brushed motor. In the structure of the brushless motor MTR, the rotor (rotor) is a permanent magnet and the stator (stator) is a winding circuit (electromagnet). Then, the rotation position (rotation angle) Mka of the rotor is detected, and the switching elements ZW1 to ZW6 are switched according to the rotation angle Mka, so that the supply current is commutated. The rotor position (rotation angle) Mka of the brushless motor MTR is detected by a rotation angle sensor MKA. The bridge circuit BRG configured by the switching elements ZW1 to ZW6 is mounted on the drive circuit board KBN fixed to the caliper CRP.

  A connector CNC is fixed to the circuit board KBN. The signal Fbt and power supplied by the signal line SGL and the power line PWL are input to the circuit board KBN from the electronic control unit ECU provided on the vehicle body side via the connector CNC.

  As in the case of the brush motor, in the pulse width modulation block PWM, the duty ratio (target value) Dut is calculated so as to perform pulse width modulation based on the target value Imt of the energization amount and the actual value Ima. Further, in the pulse width modulation block PWM, the duty ratio Dut of the pulse width is determined based on the magnitude (absolute value) of the target energization amount Imt, and the electric current is determined based on the sign (value positive / negative) of the target energization amount Imt. The rotation direction of the motor MTR is determined.

  Then, in the switching control block SWT, drive signals Zw1 to Zw6 for controlling the energization / non-energization states of the switching elements ZW1 to ZW6 are calculated based on the duty ratio Dut. Here, in the brushless motor, the rotor position (rotation angle) Mka of the electric motor MTR is acquired by the rotation angle sensor MKA, and based on this, the six switching elements ZW1 to ZW6 constituting the three-phase bridge circuit BRG are driven. Signals Zw1 to Zw6 to be determined are determined. The switching elements ZW1 to ZW6 sequentially switch the direction of the coil energization amount (that is, the excitation direction) of the U-phase, V-phase, and W-phase of the electric motor MTR to drive the electric motor MTR. The rotation direction (forward rotation or reverse rotation) of the brushless motor MTR is determined by the relationship between the rotor and the excitation position.

  Similarly, in the rotation direction of the electric motor MTR, the forward rotation direction is a rotation direction in which the friction member MSB and the rotation member KTB are brought closer, the braking torque is increased, and the deceleration of the traveling vehicle is increased. The reverse rotation direction is a rotation direction in which the friction member MSB is separated from the rotating member KTB, the braking torque is reduced, and the deceleration of the traveling vehicle is reduced.

  The U-phase, V-phase, and W-phase coils of the brushless motor MTR are electrically connected to the circuit board KBN (particularly, through holes Tu, Tv, Tw), respectively, by three motor pins PMT. The rotation angle sensor MKA is also electrically connected to the circuit board KBN (particularly, the through hole Tm) by the rotation angle pin PMK. Here, the terminals of the pins PMT and PMK are press-fit connectors.

  The circuit board KBN includes a filter circuit (LC circuit) for reducing noise (reducing power fluctuations) by combining at least one capacitor (capacitor) and at least one inductor (coil) in order to stabilize supply power. And also referred to as an LC filter).

  For example, the capacitor CND and the first and second inductors IND1 and IND2 are mounted on the circuit board KBN. These are combined to form a low-pass filter (T-type filter) LPF, and noise reduction can be performed. Specifically, the T-type noise reduction circuit LPF is composed of two series inductors IND1, IND2 and one parallel capacitor CND, and the harmonic attenuation performance (attenuation amount in the attenuation band) is improved. obtain.

  Further, as illustrated in the balloon of X part, the first and second capacitors CND1, CND2 and the inductor IND are mounted on the circuit board KBN, and a π-type low-pass filter (noise reduction filter) LPF is formed. obtain. Specifically, the π-type low-pass filter LPF includes two capacitors CND1 and CND2 parallel to the line and one series inductor. In general, since a capacitor (capacitor) is cheaper than an inductor, the use of a π-type noise reduction circuit LPF suppresses component costs and provides a good noise reduction effect.

<Positional relationship between the drive circuit board KBN and the speed reducer GSK (viewed in a direction perpendicular to the rotation axis Jmt of the electric motor)>
With reference to the partial cross-sectional view of FIG. 4, the positional relationship between the drive circuit board KBN and the reduction gear GSK (particularly, the direction perpendicular to the rotation axis Jmt of the electric motor MTR) will be described. Specifically, the arrangement of the electric motor MTR, the circuit board KBN, and the speed reducer GSK will be described.

  The rotation axis Jmt of the electric motor MTR and the rotation axis Jps of the power conversion mechanism HNK are not coaxial but are parallel and separated by a predetermined distance djk. That is, the braking means BRK employs a so-called two-axis configuration in the reduction gear GSK, which has two rotation axes, that is, the rotation axis Jmt of the input shaft and the rotation axis Jps of the output shaft.

  The caliper CRP is configured by being divided into each member of the substrate case CKB, the sealing member CMP, the partition member CSK, and the pressing case CPS. The board case CKB is a member for housing the circuit board KBN and the speed reducer GSK. The circuit board KBN is fixed inside the board case CKB, and the speed reducer GSK is supported in a rotatable state. Yes. By the sealing member CMP, the substrate case CKB is covered with a sealing member (not shown) and is sealed for waterproofing and dustproofing. The partition member CSK is a partition wall for dividing (dividing) the space formed by the substrate case CKB and the sealing member CMP into two. The pressing case CPS is a member for housing the power conversion mechanism HNK, the pressing member PSN, and the like.

  Of the space divided into two by the partition member CSK, the circuit board KBN is fixed to one side space that is closer to the electric motor MTR. Since the circuit board KBN is accommodated in this one side space, this space is referred to as a “substrate chamber Hkb”. Further, the speed reducer GSK is provided in the other side space on the side opposite to the side on the electric motor MTR (the side far from the electric motor MTR) relative to the partition member CSK. Since the reduction gear GSK is accommodated in the other side space, this space is referred to as “deceleration chamber Hgs”. In other words, the partition member CSK is a member that partitions the substrate chamber Hkb and the deceleration chamber Hgs. A lubricant such as grease is applied to the reduction gear GSK for lubrication, but the circuit board KBN is surrounded by the partition member CSK so that the lubricant does not touch the circuit board KBN.

  The electric motor MTR is fixed to the substrate case CKB of the caliper CRP via a seal member (not shown). The input shaft SFI is fixed to the output shaft of the electric motor MTR so as to rotate integrally with the rotor of the electric motor MTR.

  A single circuit board KBN is fixed to the board case CKB via a fixing member KBK. Here, the surface of the circuit board KBN (the plane on which the processor MPR, the bridge circuit BRG, and the like are mounted) is fixed perpendicular to the rotation axis Jmt of the electric motor MTR. The board case CKB is provided with a through hole for the motor pin PMT and a through hole for the input shaft SFI. The motor pin PMT passes through this hole and is electrically connected to the circuit board KBN. Further, the input shaft SFI also penetrates the through hole of the substrate case CKB. A rotation angle sensor MKA is fixed to the input shaft SFI, and the pin PMK of the rotation angle sensor MKA is electrically connected to the circuit board KBN in the same manner as the pin PMT.

  The motor pin PMT supplies power to the electric motor MTR from the circuit board KBN (particularly, the bridge circuit BRG) so as to rotationally drive the electric motor MTR. For example, the motor pin PMT has a press-fit terminal (a terminal provided with a gap at the tip so as to be easily elastically deformed), and is press-fitted into the circuit board KBN to perform contact energization. The rotation angle Mka of the electric motor MTR is detected by the rotation angle sensor MKA provided in the electric motor MTR or in the input shaft SFI in the substrate chamber Hkb. The rotation angle Mka is joined to the circuit board KBN via the rotation angle pin PMK. The rotation angle pin PMT supplies electric power to the rotation angle sensor MKA and transmits a detection signal (rotation angle) Mka of the rotation angle sensor MKA to the circuit board KBN (particularly, the processor MPR). Similar to the motor pin PMT, the rotation angle pin PMK has a press-fit terminal, is press-fitted into the circuit board KBN, and performs contact energization.

  The input shaft SFI further extends through the circuit board KBN and the partition member CSK and extends into the deceleration chamber Hgs. The first small-diameter gear SK1 is fixed to the input shaft SFI inside the deceleration chamber Hgs. That is, the axis of rotation of the electric motor MTR and the input shaft of the reduction gear GSK are the same (coaxial). The first small diameter gear SK1 is meshed with the first large diameter gear DK1. Here, the number of teeth of the first large-diameter gear DK1 is larger than the number of teeth of the first small-diameter gear SK1. Therefore, the combination of the first small diameter gear SK1 and the first large diameter gear DK1 reduces the rotational movement of the input shaft SFI and increases the torque of the input shaft SFI.

  The first large diameter gear DK1 is fixed to the intermediate shaft SFC. A second small diameter gear SK2 is fixed to the intermediate shaft SFC. That is, the first large-diameter gear DK1 and the second small-diameter gear SK2 rotate together. A second large-diameter gear DK2 is meshed with the second small-diameter gear SK2. Here, the number of teeth of the second large diameter gear DK2 is larger than the number of teeth of the second small diameter gear SK2. Therefore, the rotational movement of the intermediate shaft SFC is decelerated and the torque of the intermediate shaft SFC is increased by the combination of the second small diameter gear SK2 and the second large diameter gear DK2.

  The second large diameter gear DK2 is fixed to the output shaft SFO. The output shaft SFO rotates integrally with the second large-diameter gear DK2, and transmits the rotational power to the power conversion mechanism HNK. Therefore, the output shaft of the reduction gear GSK and the input of the power conversion mechanism HNK have the same axis (coaxial). The reduction gear GSK includes a first small diameter gear SK1, a first large diameter gear DK1, a second small diameter gear SK2, and a second large diameter gear DK2. In other words, the reduction gear GSK performs two-stage deceleration. The rotational power of the electric motor MTR is decelerated by the reduction gear GSK (that is, the torque of the input shaft SFI, which is the output torque of the electric motor MTR), and is transmitted to the output shaft SFO. This rotational power is transmitted from the output shaft SFO to the power conversion mechanism HNK.

  The pressing case CPS and the substrate case CKB are fixed via a seal member (not shown). Further, since the friction member MSB detects a pressing force Fba that is a force pressing the rotating member KTB, the pressing force sensor FBA is sandwiched between the pressing case CPS and a power conversion mechanism (for example, a screw mechanism) HNK. Installed. The pressing case CPS and the substrate case CKB are provided with a through hole for the pin PFB of the pressing force sensor FBA and a through hole for the output shaft SFO. The pressing force pin PFB passes through this hole and is press-fitted into the circuit board KBN to be electrically connected. The output shaft SFO also passes through the through holes of the pressing case CPS and the substrate case CKB, and is connected to the power conversion mechanism HNK.

  The pressing force sensor FBA is joined to the circuit board KBN via the pressing force pin PFB. The pressing force pin PFB supplies power to the pressing force sensor FBA and transmits a detection signal (pressing force) Fba of the pressing force sensor FBA to the circuit board KBN (particularly, the processor MPR). Similar to the rotation angle pin PMK, the pressing force pin PFB has a press-fit terminal, is press-fitted into the circuit board KBN, and contact energization is performed.

  As described above, when viewed from the direction perpendicular to the rotation axis Jmt of the electric motor MTR (as viewed from the direction perpendicular to the rotation axis Jmt), the arrangement of the electric motor MTR, the circuit board KBN, and the speed reducer GSK is as follows. The circuit board KBN is provided between the electric motor MTR and the speed reducer GSK. That is, the circuit board KBN and the electric motor MTR are arranged close to each other. Further, when viewed from the direction perpendicular to the rotation axis Jps (parallel to Jmt) of the power conversion mechanism HNK (as viewed in the direction perpendicular to the rotation axis Jps), the power conversion mechanism HNK (specifically, the power conversion mechanism HNK and In the arrangement of the pressing force sensor FBA sandwiched between the caliper CRP), the circuit board KBN, and the reduction gear GSK, the circuit board KBN is placed between the power conversion mechanism HNK (the pressing force sensor FBA) and the reduction gear GSK. Provided. In other words, the power conversion mechanism HNK, the pressing force sensor FBA, the circuit board KBN, and the speed reducer GSK are arranged in this order. Therefore, the circuit board KBN and the pressing force sensor FBA are arranged close to each other. For this reason, the pin PMT of the electric motor MTR, the pin PMK of the rotation angle sensor MKA, and the pin PFB of the pressing force sensor FBA can be directly joined to the circuit board KBN without going around the outer periphery of the reduction gear GSK. For example, a straight pin (a pin whose longitudinal shape is a straight line) may be employed as at least one of the motor pin PMT, the rotation angle pin PMK, and the pressing force pin PFB. By arranging each member as described above, the electrical connection is simplified, and the electric braking device DSS (particularly, the braking means BRK) can be reduced in size.

<Position relationship between drive circuit board KBN and reduction gear GSK (viewed in parallel direction with respect to rotation axis Jmt of electric motor)>
With reference to the layout diagram of FIG. 5, the positional relationship between the drive circuit board KBN and the speed reducer GSK (particularly in the direction parallel to the rotation axis Jmt of the electric motor MTR) will be described. Specifically, the shape of the circuit board KBN, such as electronic components mounted on the circuit board KBN, and the positional relationship between the circuit board KBN and the speed reducer GSK will be described. Here, the circuit board KBN is a single printed board, and its four corners are fixed to the caliper CRP by the fixing members KBK.

  First, electronic components and the like mounted on the circuit board KBN which is one printed board will be described. A connector CNC is fixed to the circuit board KBN. Signals are exchanged with the ECU on the vehicle body and electric power is supplied via the connector CNC. The circuit board KBN includes a microprocessor MPR for executing various arithmetic processes, a bridge circuit BRG (aggregation of switching elements) for driving the electric motor MTR, and noise reduction for stabilizing the power supply voltage. A circuit LPF and another electronic component DEN are mounted (see FIGS. 2 and 3).

  Furthermore, the circuit board KBN is provided with a through hole (through hole) Akn, and the pin PMT of the electric motor MTR, the pin PMK of the rotation angle sensor MKA, and the pin PFB of the pressing force sensor FBA are formed through holes (press fit). Through hole) Akn. That is, the joints of the pins PMT, PMK, and PFB with the circuit board KBN are terminals for press-fit connection. Here, the press-fit connection means that a contact load is generated between the pins PMT, PMK, PFB and the through-hole Akn by press-fitting a terminal slightly wider than the through-hole of the circuit board KBN, and the electric To get a good connection. Therefore, the through-hole insertion part of the press-fit terminal of the pins PMT, PMK, PFB has an elastic structure (for example, a structure having a notch part Krk) (a motor pin in a balloon indicated by a one-dot chain line illustrated in the Y part) See PMT example).

  Next, the shape of the circuit board KBN will be described. As described above, the circuit board KBN is disposed between the electric motor MTR, the power conversion mechanism HNK, and the reduction gear GSK. Therefore, the circuit board KBN has a shape through which an input shaft SFI for transmitting power from the electric motor MTR to the reduction gear GSK and an output shaft SFO for transmitting power from the reduction gear GSK to the power conversion mechanism HNK can pass. is necessary. Therefore, the circuit board KBN is provided with, for example, a cutout shape (U-shaped cutout) as shown in the A portion or a hole shape (circular hole) as shown in the B portion. As a specific example, the input shaft SFI penetrates the circuit board KBN through a U-shaped notch Ukr, and connects the electric motor MTR and the first small-diameter gear SK1. The output shaft SFO passes through the circular hole Enk and connects the second large-diameter gear DK2 and the power conversion mechanism HNK. That is, the circuit board KBN is provided with at least one of a hole (not limited to a circular shape) and a notch (not limited to a U shape), and the electric power of the electric motor MTR is supplied to the circuit board KBN. Is transmitted to the reduction gear GSK. Then, this power again passes through the circuit board KBN and is transmitted from the reduction gear GSK to the power conversion mechanism HNK.

  Finally, the relationship between the circuit board KBN and the speed reducer GSK (particularly when the speed reducer GSK is viewed from the direction perpendicular to the circuit board KBN) will be described. With respect to the circuit board KBN and the speed reducer GSK, the above-described arrangement is employed to reduce the size of the electric braking device DSS. For this reason, when the reduction gear GSK is projected onto the circuit board KBN (that is, when the reduction gear GSK is viewed from a direction parallel to the rotation axis Jmt and perpendicular to the surface of the circuit board KBN), The entire speed reducer GSK is substantially projected onto the circuit board KBN. For example, the speed reducer GSK is projected onto the drive circuit board KBN, which is one printed board, with an area of 70% or more. With such a configuration, the electric braking device DSS can be reduced in size, and an improvement in mountability on a vehicle can be achieved.

<Action and effect>
As described above, the rotation output of the electric motor MTR is decelerated by the reduction gear GSK and output to the power conversion mechanism HNK. Therefore, the output torque of the electric motor MTR is increased and transmitted to the power conversion mechanism HNK. The input shaft of the reduction gear GSK (matching the rotation axis of the electric motor MTR) SFI and the output shaft of the reduction gear GSK (matching the input shaft of the power conversion mechanism HNK) SFO are parallel to the rotation axis Jps. In addition, they are separated by a distance (predetermined distance djk) (there is two rotation axes, so it is referred to as “two-axis configuration”). When viewed from the direction perpendicular to the rotation axes Jmt and Jps, the circuit board KBN (one printed board) is positioned between the “electric motor MTR” and the “reduction gear GSK”. Furthermore, when viewed from the direction perpendicular to the rotation axes Jmt and Jps, the circuit board KBN is positioned between the “power conversion mechanism HNK (ie, the pressing force sensor FBA)” and the “reduction gear GSK”. . The mounting surface of the circuit board KBN (the plane on which the processor MPR, the bridge circuit BRG, the noise reduction circuit LPF, and the like are mounted) is made parallel to the rotation axes Jmt and Jps. In this arrangement, at least one of the input shaft SFI and the output shaft SFO penetrates the circuit board KBN.

  Since the electric motor MTR, the speed reducer GSK, the circuit board KBN, the power conversion mechanism HNK, and the pressing force sensor FBA are arranged close to the circuit board KBN as described above, the electric motor MTR, the rotation angle sensor MKA, In addition, the distance between the pressing force sensor FBA and the circuit board KBN is shortened. As a result, the electrical connection between the electric motor MTR, the rotation angle sensor MKA, the pressing force sensor FBA, and the circuit board KBN can be simplified. Specifically, pins (for example, straight pins) PMT, PMK, and PFB can be used without using a bendable electrical wiring covered with vinyl or the like, and the size of the braking means BRK can be reduced. obtain. And since a press fit terminal can be employ | adopted as a terminal of pins PMT, PMK, and PFB, the assembly | attachment property of the braking means BRK is also improved.

<Other arrangements such as circuit board KBN>
The case where the reduction gear GSK has two rotation axes and the braking means BRK has a two-axis configuration has been described above. However, the input / output rotation axes of the reduction gear GSK are the same (that is, one rotation axis). A certain “single-axis configuration” braking means BRK may be employed. Specifically, as the speed reducer GSK, a planetary gear mechanism, a wave gear mechanism, or the like in which the input rotation shaft (input shaft) SFI and the output rotation shaft (output shaft) SFO are the same axis line is employed. In the arrangement of the circuit board KBN and the like in this one-axis configuration, the circuit board KBN (one printed board) is positioned between the “electric motor MTR” and the “reduction gear GSK, the power conversion mechanism HNK”. As in the case of the two-axis configuration, the input shaft SFI penetrates the circuit board KBN and is connected to the speed reducer GSK. The circuit board KBN is fixed to the caliper CRP perpendicular to the rotation axis Jmt of the input shaft SFI.

  Even in the 1-axis configuration, the same effects as in the 2-axis configuration are achieved. That is, the electric motor MTR, the rotation angle sensor MKA, and the circuit board KBN are brought close to each other, and the distance between them is shortened. For this reason, the electrical connection between the electric motor MTR and the rotation angle sensor MKA and the circuit board KBN is simplified. A straight pin can be employed at least for the motor pin PMT and the rotation angle pin PMK, and downsizing of the braking means BRK can be achieved. Further, press-fit terminals are adopted as the terminals of the pins PMT and PMK, and the assembling property of the braking means BRK can be improved.

BP ... braking operation member, BRK ... brake actuator, CRP ... brake caliper, MTR ... electric motor, MKA ... rotation angle sensor, FBA ... pressing force sensor, HNK ... power conversion mechanism, GSK ... speed reducer, KBN ... drive circuit board, MPR ... Microprocessor, BRG ... Bridge circuit, PMT ... Electric motor pin (motor pin), PMK ... Rotation angle sensor pin (rotation angle pin), PFB ... Push pressure sensor pin (pressing force pin)

Claims (2)

An electric braking device for a vehicle that presses a friction member to a rotating member fixed to a wheel of the vehicle via an electric motor to generate a braking torque of the wheel,
A circuit board on which a microprocessor and a bridge circuit are mounted to drive the electric motor;
A speed reducer that decelerates the rotational power output by the electric motor;
A power conversion mechanism that converts rotational power output from the speed reducer into linear power and moves a pressing member that presses the friction member against the rotating member;
With
When viewed in the direction perpendicular to the rotation axis of the electric motor, the circuit board is located between the electric motor and the speed reducer. An electric braking device for a vehicle that presses a friction member to a rotating member fixed to a wheel of the vehicle via an electric motor to generate a braking torque of the wheel,
A pressing force sensor that detects a pressing force that is a force pressing the friction member against the rotating member;
A circuit board on which a microprocessor and a bridge circuit are mounted so as to drive the electric motor based on the pressing force;
A speed reducer that decelerates the rotational power output by the electric motor;
A power conversion mechanism that converts rotational power output from the speed reducer into linear power and moves a pressing member that presses the friction member against the rotating member;
With
When viewed in the direction perpendicular to the rotation axis of the power conversion mechanism, the circuit board is an electric braking device for a vehicle that is located between the pressing force sensor and the speed reducer.