WO2019022148A1

WO2019022148A1 - Electric brake device

Info

Publication number: WO2019022148A1
Application number: PCT/JP2018/027924
Authority: WO
Inventors: 唯増田
Original assignee: Ntn株式会社
Priority date: 2017-07-27
Filing date: 2018-07-25
Publication date: 2019-01-31
Also published as: JP2019025990A; JP6952528B2

Abstract

Provided is an electric brake device with which a switch power supply can be reliably charged and caused to operate rapidly when a brake operation next occurs, and with which no-load noise and vibration can be improved. The electric brake device is provided with a switch means (21) such as a half bridge circuit for controlling a state of connection between a coil end of an electric motor (6) and a power supply device (3). The electric brake device is provided with a switch power supply (22) having an electric power storing function, comprising a capacitor or the like for switching the switch means (21). The electric brake device is provided with a charging means (24) such as a charging circuit which causes the switch means (22) to store electric power, in a predetermined switching pattern of the switch means (21). The electric brake device is provided with a brake standby function unit (16) with which, when it has been determined that a transition to a brake released state is complete, at least the electric motor (6) in a stationary state is not driven spontaneously, and the switch means (21) is maintained in a predetermined switching pattern capable of being caused to store electric power in the switch means (22) by means of the charging means (24).

Description

Electric brake device

Related application

This application claims the priority of Japanese Patent Application No. 201-145232 filed on Jul. 27, 2017, which is incorporated by reference in its entirety.

The present invention relates to an electric brake device used for vehicles such as automobiles and various devices.

BACKGROUND Conventionally, an actuator for an electric brake provided with an electric motor, a linear motion mechanism, and a reduction gear has been proposed (Patent Document 1). In addition, an electric actuator provided with a planetary roller mechanism and an electric motor has been proposed (Patent Document 2).

Japanese Patent Application Publication No. 06-327190 JP, 2006-194356, A

For example, in an electric brake device using an electric linear actuator as in the

documents

1 and 2, a half bridge circuit which converts DC power of a battery into AC power is used as a motor driver. The half bridge circuit is composed of an H arm switch that performs connection with the positive side of the battery and an L arm switch that performs connection with the negative side. Also, in order to drive the motor driver at low cost, when the L arm switch is turned on as a switching potential source of the H arm switch, charges are accumulated from a predetermined potential source and the H arm switch is turned on. In some cases, a charge circuit using a bootstrap capacitor that functions as a potential source applied to the gate is provided.

However, when the braking force is released to put the electric brake device in the standby state when the brake operation is released, if the boot strap capacitor for driving the half bridge circuit is discharged, the switch element on the H arm side can be turned on. Since it loses, when a brake operation is input next, it can not drive a motor promptly, and there is a possibility that a response of a brake may be overdue. The above problem is more likely to occur, particularly when traveling on a freeway, etc., where the brake can not be pressed for a long time. As measures against the above problems, increasing the capacitance of the bootstrap capacitor and providing an insulating structure for preventing discharge may cause problems in cost and an increase in mounting space.

In addition, in the above-mentioned electric brake device, a digital arithmetic unit (microcomputer etc.) is generally used to mount complicated calculations at low cost, but when controlling the electric motor to a predetermined angle, it is used for resolution and sampling. There may be a minute oscillation caused by this. In particular, in the no-load state at the time of releasing the brake as described above, deterioration of NHV (noise harshness vibration) due to the peristalsis may be a problem due to the influence of backlash or the like of the mechanical joint. As a countermeasure against the above-mentioned problems, for example, when using an arithmetic unit with extremely small resolution and sampling, or an analog element which does not require sampling or the like, cost may be a problem. Or when it is set as a structure without backlash in a mechanical coupling part, manufacturing cost may become a problem.

Alternatively, when the motor control is completely stopped as a countermeasure for the NHV, there is a problem that the discharge of the bootstrap capacitor tends to occur. In addition, when the electric motor is rotated by external force such as vibration due to the unevenness of the road surface, the position changes from the original brake standby state, and the gap between the friction material in the brake standby state and the brake rotor is reduced. Unintended drag torque may occur or may be expanded to cause a response delay at the time of the next brake operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric brake system capable of reliably charging a switch power supply, operating promptly at the next braking operation, and improving noise and vibration at no load.

Hereinafter, the present invention will be described with reference to the reference numerals of the embodiments for the sake of convenience to facilitate understanding.

The electric brake device according to the present invention comprises a brake rotor 31, a friction member 32 for generating a braking force by coming into contact with the brake rotor 31, and a friction member operating means for operating the friction member 32 by driving the electric motor 6. And a control device 5 for controlling the output of the electric motor 6 to follow a given brake command value, and a DC power supply device 3 for applying electric power to the electric motor 6). ,
The control device 5
Switch means 21 for controlling the connection state between the coil end of the electric motor 6 and the power supply device 3;
A switch power supply 22 having a storage function and functioning as a power supply for switching at least a part of the switch means 21;
Charge means 24 for storing power in the switch power supply 22 in a predetermined switching pattern of the switch means 21;
A brake release request determination function unit 14 that determines that an operation for requesting a brake release has been performed when at least one of the brake force command value and its derivative value becomes smaller than a predetermined value;
When it is determined that the operation for requesting the brake release has been performed, the friction material operating means (2) is driven to a predetermined brake release state, and the angle of the electric motor 6 at this time and its differential value At least one of a release completion determination function unit 15 that determines that the transition to the brake release state is completed;
When it is determined that the transition to the release state is completed, at least the stationary electric motor 6 is not driven spontaneously and the switch means 21 is stored by the charge means 24 or the switch power supply 22. And a brake standby function unit 16 for maintaining a predetermined switching pattern that can be stored in the switch power supply 22.

According to this configuration, when it is determined that the transition to the release state is completed, the brake standby function unit 16 does not spontaneously drive the electric motor 6 at least in the stationary state, and the switch unit 21 Are maintained in a predetermined switching pattern that can be stored in the switch power supply 22 by the charging means 24. Therefore, the switch power supply 22 is surely charged, and can be operated promptly at the next braking operation. Further, since the voltage condition is not driven spontaneously, noise and vibration at no load, so-called NHV can be improved. The "predetermined value" is provided for each of the braking force command value and its differential value. Further, the above "predetermined value" and each of the following "predetermined value" and the "predetermined" values referred to in this specification are values appropriately determined by a test or a design.

In the electric brake device of this configuration,
The switch means 21 is a switch circuit provided with a pair of L-arm switch circuit 21L and H-arm switch circuit 21H for each coil end of the electric motor 6,
The L arm switch circuit 21L includes a first input / output terminal 25La connected to the coil end of the electric motor 6, a second input / output terminal 25Lb connected to the negative side of the power supply 3, and The negative side of the power supply device 3 and the above-mentioned power supply device 3 are provided by a transistor element 25 having a switching terminal 25Lc to which both the input / output terminals 25La and 25Lb are connected by inputting a positive potential to the second input / output terminal 25Lb. It is a switch circuit unit that controls the connection state with the coil end of the electric motor 6,
The H arm switch circuit 21H includes a first input / output terminal 25Ha connected to the positive side of the power supply device 3, a second input / output terminal 25Hb connected to a coil end of the electric motor 6, and The positive side of the power supply device 3 and the electric motor are provided by a transistor element 25H having a switching terminal 25Hc connecting the two input / output terminals 25Ha and 25Hb by inputting a positive potential to the two input / output terminals 25Hb. It is a switch circuit unit that controls the connection with the coil end of the motor 6,
The switch power supply 22 is a capacitor connected to the second input / output terminal 25Hb of the transistor element 25H in the H arm switch circuit 21H as an electrical reference potential,
The charge means 24 is a charge circuit for storing charge in the switch power supply 22 composed of the capacitor when the L arm switch circuit 21L is in a connected state,
The brake standby function unit 16 keeps all the L arm switches 21 L always connected and keeps all the H arm switches 21 H disconnected.
You may do so.

In the case of this configuration, since all the

switch circuits

21H and 21L of the switch means 21 are kept in a constant state of on or off, the switching loss can be reduced and power consumption reduction can be expected. Specifically, when the brake is released, the L arm switch circuit 21L turns on and the H arm switch circuit 21H turns off for the state of the switch means 21 consisting of a half bridge circuit in the motor driver 13 of the electric brake device. Maintaining a constant state, the switch power supply 22 consisting of a bootstrap capacitor used as a voltage for switching the H arm switch circuit 21H is maintained in a charged state. The brake release request judgment function unit 14 determines the brake release request from the brake command of the command means (brake pedal etc.) 4 and its variation amount, and the electric brake device stands by from the motor angle and motor angular velocity at that time. The brake release completion determination function unit 15 determines whether the position has been shifted to the position, and in this state, the brake standby function unit 16 causes the brake standby function unit 16 to maintain the state of the switch means 21 composed of the half bridge circuit. .

By keeping the L arm switch circuit 21 L on and the H arm switch circuit 21 H off as described above, the switch power supply 22 consisting of a bootstrap capacitor is always charged and a request to apply a brake is given, It can be made to respond promptly. Switching is not performed by always turning on all L arm switch circuits 21L and always turning off H arm switch circuits 21H, so that switching losses may occur due to stray capacitance of

transistor elements

25H and 25L such as FET. The standby power can be reduced. Since the motor terminal voltages u, v, w are all the same voltage, the electric motor 6 is not driven spontaneously, and minute chattering or the like due to sensor resolution or sampling does not occur. Quietness can be achieved. When the electric motor 6 is turned from the outside due to vibration or the like, regenerative torque due to power generation is generated in the electric motor 6 and the electric motor 6 can be prevented from separating rapidly from the standby position. It is easy to return to the standby position.

In the electric brake device according to the present invention, the release completion determination function unit 14 is configured to detect a deviation of the motor angle with respect to a motor angle target value at which a predetermined gap may be generated between the friction material 32 and the brake rotor 31. It may be determined that the release of the brake is completed in a state where the absolute value is equal to or less than the predetermined value and the absolute value of the motor angular velocity is equal to or less than the predetermined value.

Further, in the electric brake device according to the present invention, the release completion determination function unit 14 sets a motor angle relative to a motor angle target value at which a predetermined gap can be generated between the friction member 32 and the brake rotor 31. A counter 14a may be provided to measure the duration of the state in which the absolute value of the deviation is less than or equal to a predetermined value, and when the value of the counter 14a exceeds the predetermined value, it may be determined that the brake release is completed.

In the electric brake device according to the present invention, the brake standby function unit 16 releases the brake standby function to shift the friction state to a predetermined brake release state when the fluctuation of the motor angle becomes larger than a predetermined amount during execution. The material 32 may be driven. With this configuration, when the gap amount at the time of standby changes due to the influence of vibration or the like, occurrence of unintended drag torque and response delay can be prevented by appropriately correcting and maintaining the gap amount.

In the electric brake system according to the present invention, the control device 5 is an angle estimation means (9) for estimating the angle of the electric motor 6, a cogging torque estimation function unit 11a for estimating cogging torque from the estimated angle, and a brake When transitioning from the state to the brake release state, it may have a standby position adjusting function unit 11b that uses a motor angle at which the estimated cogging torque becomes substantially zero as an angle command value. If the function of the brake standby function unit 16 is executed at a phase where a relatively large cogging torque is generated, the motor is rotated by the cogging torque. However, when the cogging torque estimation function unit 11a and the standby position adjustment function unit 11b are provided, the motor is prevented from being rotated by the cogging torque by setting the cogging torque to stand by at a motor angle which is zero or sufficiently small in advance. can do.

Any combination of the at least two configurations disclosed in the claims and / or the description and / or the drawings is included in the invention. In particular, any combination of two or more of the claims is included in the invention.

The invention will be more clearly understood from the following description of the preferred embodiments with reference to the accompanying drawings. However, the embodiments and the drawings are for the purpose of illustration and description only and are not to be taken as limiting the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same reference numerals in multiple drawings indicate the same or corresponding parts.

FIG. 1 is a block diagram showing a conceptual configuration of an electric brake device according to a first embodiment of the present invention. It is an enlarged view of the upper part of FIG. It is an enlarged view of the lower part of FIG. It is a flowchart which shows the control operation example of the same electric brake device. It is sectional drawing which shows the specific example of the friction brake mechanism of the same electric brake device, and a direct-acting actuator. It is a block diagram which shows the conceptual structure of the electrically-driven brake device which concerns on other embodiment of this invention.

A first embodiment of the present invention will be described in conjunction with FIGS. 2 and 3 show the upper and lower portions of FIG. 1 in an enlarged manner, respectively. In FIG. 1, the electric brake device includes a friction brake mechanism 1, a direct acting actuator 2 which is a friction material operating means, a power supply device 3, and a direct acting actuator so as to follow command values given from a command means 4. And a control device 5 for controlling the output of the electric motor 6.

<< Friction brake mechanism 1 >>
For example, as shown in FIG. 5, the friction brake mechanism 1 comprises a brake rotor 31 and a friction material 32 which is brought into contact with the brake rotor 31 to generate a braking force. The friction brake mechanism 1 may be, for example, a disk brake device using a brake disk and a caliper as the brake rotor 31 and the friction material 32, or may be a drum brake device using a drum and a lining. In this embodiment, the linear actuator 2 is used as the friction material operation means for operating the friction material 32. However, the friction material operation means may operate the friction material 32 along an arc locus, for example. The friction material 32 may be in contact with the brake rotor 31 in operation.

<< Linear actuator 2 >>
The linear motion actuator 2 includes an electric motor 6 and a linear motion mechanism 7 for converting the rotational output of the electric motor 6 into a linear reciprocating motion. In the example of FIG. 5, the linear actuator 2 is provided with a reduction gear 33 consisting of a gear train or the like of a spur gear that decelerates the output of the electric motor 6, and the linear movement mechanism 7 reciprocates the rotational output of the reduction gear 33. Convert to Besides, the reduction gear 33 may be a worm gear, a planetary gear, or the like, and may not necessarily be provided.

As shown in FIG. 1, in addition to the above, the linear actuator 2 also has a load sensor 8 for detecting an axial load of the linear motion mechanism 7 and an angle sensor for detecting a motor angle (rotational angle of the rotor) of the electric motor 6. And 9. Further, various sensors (not shown) such as a thermistor may be separately provided as necessary.

The electric motor 6 is preferably a permanent magnet synchronous motor, which can save space and increase torque, which is considered to be preferable. For example, a DC motor using a brush, a reluctance motor not using a permanent magnet, or an induction motor etc. Can also be applied.

The linear motion mechanism 7 may use various types of screw mechanisms such as a planetary roller screw and a ball screw, and various mechanisms that convert rotational motion into linear motion by a circumferentially inclined portion formed on the rotary shaft, such as a ball lamp. it can.

The angle sensor 9 is, for example, a resolver or a magnetic encoder, which is considered to be suitable with high accuracy and high reliability and suitable, but various sensors such as an optical encoder can also be applied. Alternatively, instead of using the angle sensor 9 as the angle estimation means, for example, an angle sensorless estimation (not shown) in which the motor angle is estimated from the relationship between voltage and current in the control device 5 can be used.

The load sensor 8 can use, for example, a magnetic sensor that detects displacement or deformation, a strain sensor, a pressure sensor, or the like. Alternatively, without providing the load sensor 8 as load estimation, load sensorless estimation may be used in the control device 5 based on motor angle and motor brake device stiffness, motor current, linear actuator efficiency, and the like. Alternatively, various sensors outside the electromotive brake device may be used, such as, for example, the wheel torque of the wheel on which the electromotive brake device is mounted, and a sensor that detects the longitudinal force of the vehicle equipped with the electromotive brake device.

<< Power supply device 3 and command means 4 >>
The power supply device 3 has a function of storing DC power by storing electricity, such as a battery, and may be a device serving as a power supply of the whole vehicle or a device serving as a dedicated power supply of the electric brake device. . The command means 4 is a means for performing a request for brake on and brake release such as a brake pedal, and outputs a command from, for example, a pedal stroke sensor or the like provided on the brake pedal. The command of the command means 4 may be given to the control device 5 of the electric brake device via a host ECU [Electronic Control Unit] such as VCU [Vehicle Control Unit] (not shown). The command means 4 may be part of an automatic driving function unit in a vehicle having a function of performing automatic driving.

<< Configuration of Control Device 5 >>
The control device 5 has, as a basic configuration, a main brake control function unit 11, a switching pattern determination function unit 12, and a motor driver 13, and in addition, a brake release request determination function unit 14 and a brake release completion determination function unit And a brake standby function unit 16. Each of the

functional units

11, 12, 14, 15, 16 having the control device 5 is constituted by an arithmetic unit such as a microcomputer, an FPGA, an ASIC or the like and a peripheral circuit, for example.

<Main brake control function unit 11>
The main brake control function unit 11 performs control calculation to control the electric motor 6 so that the estimated braking force estimated by the load sensor 8 or the like follows the braking force command value requested by the command means 4 . The control calculation may use, for example, feedback control that directly uses a braking force command value and an estimated value, or may convert the braking force into another physical quantity such as an angle to perform the control calculation. Further, the feedback control calculation may be a calculation structure in which a plurality of minor feedback loops are provided, for example, to provide a motor current control loop in a braking force control loop, and the motor operation amount is calculated in a single feedback loop. It may be a structure. In addition, feed forward control etc. can be used or used together suitably.

Further, the main brake control function unit 11, in addition to the function of following control of the braking force in order to reduce drag torque at the time of releasing the brake, when releasing the braking force, the friction material of the friction brake mechanism 1 It is preferable to provide the function of controlling the linear actuator 2 at a position where a predetermined clearance is provided between the brake rotor 32 and the brake rotor 31 (see FIG. 3). The above function may be, for example, a function of estimating the position of the linear actuator 2 from the motor angle and the equivalent lead of the linear actuator 2, etc. Although this is considered to be low cost and suitable, A position sensor (not shown) for detecting the position may be additionally provided.

<Switching Pattern Determination Function Unit 12>
The switching pattern determination function unit 12 is a connection / disconnection pattern (or switching pattern) between the coil end of the electric motor 6 and the power supply device 3 in the motor driver 13 mainly based on the motor operation amount calculated in the main brake control function unit 11 Have a function of determining For example, in the case of using the power supply device 3 whose DC voltage is Vdc (plus side: + Vdc, minus side: GND), when the voltage of a predetermined motor terminal is Vn, the ratio is approximately Vn / Vdc within a predetermined time. The time may be connected to the positive side (+ Vdc), and a pulse signal may be generated to connect the time when the ratio is approximately (1−Vn / Vdc) to the negative side (GND).

<Motor driver 13>
The motor driver 13 has a switch means 21 for controlling the connection between the coil end of the electric motor 6 and the power supply device 3 and a switch having a storage function and functioning as a power source for switching at least a part of the switch means 21. Power is supplied to the switch power supply 21 in a predetermined switching pattern of the switch means 21. The switch control circuit 23 applies switch control signals to the power supply 22 and the

transistor elements

25H and 25L which are switch elements constituting the switch means 21. And charging means 24 for accumulating. The switch control circuit 23 applies switch control signals to the

transistor elements

25H and 25L in accordance with the switching pattern output from the switch pattern determination function unit 12.

<Switching means 21>
Specifically, the switch means 21 is a switch circuit provided with a pair of L-arm switch circuit 21L and H-arm switch circuit 21H at coil ends u, v, w of the electric motor 6, respectively. The form is a half bridge circuit.

The L arm switch circuit 21L is a switch circuit unit that controls the connection state between the negative side of the power supply device 3 and the coil ends u, v, w of the electric motor 6 by a transistor element 25L such as an FET. The transistor element 25L includes a first input / output terminal 25La connected to coil ends u, v, w of the electric motor 6, a second input / output terminal 25Lb connected to the negative side of the power supply 3, and It has switching terminal 25Lc which connects both input / output terminal 25La and 25Lb by inputting positive potential to the 2nd input / output terminal 25Lb.

The H arm switch circuit 21H is a switch circuit unit that controls the connection between the positive side of the power supply 3 and the coil ends u, v, w of the electric motor 6 by a transistor element 25H such as an FET. The transistor element 25H includes a first input / output terminal 25Ha connected to the positive side of the power supply 3 and a second input / output terminal 25Hb connected to coil ends u, v, w of the electric motor 6. It has switching terminal 25Hc which connects both input / output terminals 25Ha and 25Hb by inputting positive potential to the second input / output terminal 25Hb.

<Switch power supply 22 and charge means 24>
The switch power supply 22 is a so-called bootstrap capacitor which is connected as the electric reference potential to the second input / output terminal 25Hb of the transistor element 25H in the H arm switch circuit 21H. The charge means 24 is a charge circuit for storing charge in the switch power supply 22 composed of the capacitor when the L arm switch circuit 21L is in a connected state, and is used as a potential source (not shown) of a predetermined potential V2. It comprises a circuit connected to the switch power supply 22 via the diode 24a. The potential V2 may be a potential sufficient to connect at least the terminals 25La and 25Lb and 25Ha and 25Hb of the transistor elements to at least the switching terminals 25Lc and 25Hc of the

transistor elements

25L and 25H. The potential V2 may be, for example, a potential equal to V1 applied from the power supply device 3 common to the potential V1 or, for example, when the power supply device 3 is a general vehicle low voltage power supply 12V, a circuit such as a microcomputer It may be a potential lower than V1, such as +5 V or +3.3 V, which has been stepped down.

<Brake Release Request Determination Function Unit 14>
The brake release request determination function unit 14 determines that “an operation for requesting release of the brake has been performed” when the magnitude of at least one of the brake force command value and the derivative thereof becomes smaller than a predetermined value. It is. For example, when the brake force command value falls below a predetermined value, or when the decrease change amount of the brake force command value falls below a predetermined value, the brake release request determination function unit 14 performs the brake based on a predetermined condition using both of them. It may be possible to have a function of determining whether or not cancellation of is required. Alternatively, for example, as with a VCU in a vehicle, a host ECU for generating a braking force command value is provided, and the host ECU separately transmits a brake release request signal, and a request for releasing the brake upon reception of the brake release request. It can also be configured to judge.

<Cancel Completion Determination Function Unit 15>
When it is determined that the brake release is requested, the release completion determination function unit 15 drives the linear motion actuator 2 which is the friction material operating means to a predetermined brake release state, and the electric motor 6 at this time is From the angle and / or its derivative value, it is determined that the transition to the brake release state is completed.

The release completion determination function unit 15 has a predetermined position, for example, a position where a predetermined clearance can be provided between the friction material 32 of the friction brake mechanism 1 and the brake rotor 31 when, for example, the brake release is requested. It has a function to determine whether the brake release state has been achieved. For example, in the case where the motor angle is controlled to a position where a predetermined gap (clearance amount) can be obtained, the above determination is made when the magnitude of the deviation between the angle command value and the estimated motor angle falls below a predetermined value. May be determined on the basis of a predetermined condition in which these are used in combination or when the value of .beta. The motor angular velocity may be estimated by, for example, a state estimation observer (not shown) or the like, and the transition of the motor angle within a predetermined time may be used as a physical quantity substantially equivalent to the angular velocity.

As a specific example, the release completion determination function unit 14 determines the absolute value of the motor angle deviation with respect to the motor angle target value at which a predetermined gap can be generated between the friction material 32 and the brake rotor 31. It may be determined that the brake release is completed in a state where the value is equal to or less than the predetermined value and the absolute value of the motor angular velocity is equal to or less than the predetermined value.

In addition to the above, the cancellation completion determination function unit 14 is configured such that the absolute value of the deviation of the motor angle is a predetermined value with respect to the motor angle target value at which a predetermined gap can occur between the friction material 32 and the brake rotor 31. A counter 14a (see FIG. 2) for measuring the duration of the following state may be provided, and when the value of the counter 14a exceeds a predetermined value, it may be determined that the brake release is completed.

<Brake standby function unit 16>
When it is determined that the transition to the release state is completed, the brake standby function unit 16 does not drive the electric motor 6 at least in a standstill state spontaneously, and the switch means 21 is not operated by the charge means 24. A predetermined switching pattern that can be stored in the switch power supply 22 is maintained. Specifically, when the brake release request function unit 14 determines that the brake release request is requested and the brake release completion determination function unit 15 determines that the brake release is completed. The switching pattern determination function unit 12 can be configured to have a function of generating a predetermined switching pattern.

The brake standby function unit 16 releases the brake standby function and drives the friction material 32 to a predetermined brake release state when the fluctuation of the motor angle becomes larger than a predetermined amount during execution. It is also good. With this configuration, when the gap amount at the time of standby changes due to the influence of vibration or the like, occurrence of unintended drag torque and response delay can be prevented by appropriately correcting and maintaining the gap amount.

<< Outline of the operation of the above configuration >>
When the brake is released, the state of the switch means 21 consisting of a half bridge circuit in the motor driver 13 of the electric brake device is maintained in a constant state in which the L arm switch circuit 21L is on and the H arm switch circuit 21H is off. The switch power supply 22 consisting of a bootstrap capacitor used as a voltage for switching the H arm switch 21H is maintained in a charged state. The brake release request determination function unit 14 determines the brake release request from the brake command of the command means (brake pedal etc.) 4 and its change amount by the brake release request determination function unit 14, and the motor brake device determines a predetermined standby position based on the motor angle and angular velocity at that time. The brake release completion judging function unit 15 judges whether or not the state has been shifted to and the state maintenance of the switch means 21 composed of the above-mentioned half bridge circuit is executed by the brake standby function unit 16 in this state to make the brake standby state.

<< Operation of the above configuration and details of the configuration of each part >>
The motor driver 13 is configured to have the switch means 21 composed of a half bridge circuit using the

transistor elements

25H and 25L such as FET as switch elements as described above, and PWM which determines the motor applied voltage by a predetermined duty ratio, for example. The configuration is to control. This is considered to be suitable because of its low cost and high performance. Alternatively, a transformer circuit or the like may be provided to perform PAM control. The switching pattern determination function unit 12 performs a switching pattern for performing the PWM control and the PAM control.

The L arm switch circuit 21L is turned on as a switching potential source of the transistor element 25H of the H arm switch circuit 21H which connects to the positive side of the power supply device 3 among the half bridge circuits constituting the switch means 21. Charge means is a charge circuit using a switch power supply 22 consisting of a bootstrap capacitor that functions as a potential source to be applied to the gate when electric charge is accumulated from a predetermined potential source when turning on the H arm switch circuit 21H. 24 is preferable because the motor driver 13 can be driven at low cost.

At this time, if the motor driver 13 is not switched or the on-time of the L-arm switch 21L continues to be short, the charge state of the switch power supply 22 consisting of the bootstrap capacitor becomes insufficient and the H-arm switch circuit 21H is turned on. There may be problems that can not be Therefore, the switching pattern determination function unit 12 performs switching such that the on time of the L arm switch circuit 21L is sufficiently long such that the charge state of the switch power supply 22 consisting of a bootstrap capacitor is sufficient for control of the H arm switch circuit 21H. It is preferable to set the pattern. In particular, when the L-arm switch circuit 21 is always on and the H-arm switch circuit 21H is always off, the switch power supply 22 composed of the bootstrap capacitor can be reliably maintained in a good charge state and accompanied by switching. It is considered particularly suitable because no loss occurs. Further, at this time, since the electric motor 6 is not driven spontaneously, the operation noise due to the motor oscillation does not occur, and the NHV can be improved. In particular, for example, when the linear actuator 2 has a mechanical joint such as a reduction gear 33 (see FIG. 3) made of parallel gears or the like, slight vibration may occur due to the influence of backlash or the like in the unloaded state where the brake is released. On the other hand, NHV may be greatly improved because a relatively large operation noise is generated.

When an external force is applied to the electric motor 6 due to, for example, vibration of a vehicle equipped with an electric brake when the constant switching pattern is in the above-mentioned state, the electric motor 6 generates power and generates load torque. The electric motor 6 is less likely to be turned by an external force as compared with the case where it does. Therefore, for example, the motor can be prevented from deviating from the predetermined motor standby angle due to the motor external force or the like, and even if it is temporarily separated, it can be returned to the original standby position relatively easily.

<< Operation flow example of brake standby function unit 16 etc. >>
FIG. 4 shows an example when the brake standby function unit 16 etc. execute in the example of FIG. In step S1, for example, when the braking force command value falls below a predetermined value, or when the decreasing change amount of the braking force command value falls below a predetermined value, or the release of the brake is requested based on a predetermined condition using both of them. The brake release request determination function unit 14 determines whether it is present. If the release of the brake is not required, the process proceeds to step S5, the execution of the brake control is continued, and the determination of step S1 is performed again.

In step S2, for example, when the magnitude of the deviation between the angle command value and the estimated motor angle falls below a predetermined value, or when the magnitude of the motor angular velocity falls below a predetermined value, or based on a predetermined condition using both of them. The brake release determination function unit 15 determines whether the release is completed.

If it is determined in step S2 that the brake release is completed, the process proceeds to step S3. In step S3, when the brake release is requested and the brake release is completed, all the H arm switch circuits 21H are turned off and all the L arm switch circuits 21L are turned on for the switching pattern of the motor driver 13. Set to state. The switching pattern may be a switching pattern capable of sufficiently charging at least the switch power supply 22 composed of the bootstrap capacitor of the motor driver 13 of FIG. 1, but if it is as shown in this figure, each of the

swing circuit

21H and 21L is turned on. Since the off operation is not performed, the loss associated with switching can be reduced, which is considered preferable. At this time, if the electric motor 6 is rotated by an external force such as vibration of the vehicle equipped with the electric brake device, for example, during the process of step S3, then in step S2 of the subsequent control cycle, the brake release is not completed. The electric motor is controlled to follow the control to the target angle promptly again in step S4.

According to the electric brake device of this embodiment, the switch power supply 22 consisting of a bootstrap capacitor is always charged by keeping the L arm switch circuit 21 L on and the H arm switch circuit 21 H off in this manner. When a request to apply a brake is made, it is possible to promptly respond. Switching is not performed by always turning on all L arm switch circuits 21L and always turning off H arm switch circuits 21H, so that switching losses associated with stray capacitances of

transistor elements

25H and 25L such as FETs do not occur. The standby power can be reduced. Since all the motor terminal voltages become the same voltage, the electric motor 6 is not driven spontaneously, and minute chattering or the like due to sensor resolution or sampling does not occur, so that the operation noise can be suppressed. When the electric motor 6 is turned from the outside due to vibration or the like, regenerative torque due to power generation is generated in the electric motor 6 and the electric motor 6 can be prevented from separating rapidly from the standby position. It is easy to return to the standby position.

<< Other Embodiments >>
FIG. 6 shows another embodiment of the present invention. This embodiment is the same as the first embodiment shown in FIGS. 1 to 5 except for the matters described particularly. This embodiment shows an example of adjusting the brake standby position in accordance with the cogging torque of the electric motor 6 in addition to the configuration of the first embodiment. In this embodiment, the control device 5 includes a cogging torque estimation function unit 11a that estimates the value of cogging torque from the angle estimated by the angle estimation means including the angle sensor 9 and the like, and from the brake state to the brake release state. A standby position adjusting function unit 11 is provided which uses a motor angle at which the estimated cogging torque becomes substantially zero when making a transition, as an angle command value.

When the electric brake device enters the standby state by the function of the brake standby function unit 16, the electric motor 6 rotates when an external force is applied. That is, when the brake standby state is established in a state where there is a rotational force in a predetermined direction by the cogging torque, the electric motor 6 may be rotated by a predetermined amount by the cogging torque. At that time, for example, according to the flow of FIG. 4, the case where the brake standby function is executed (step S3) and the case where it is not so (step S4) may be repeated, which may result in unnecessary swing.

Therefore, the cogging torque of the electric motor 6 is estimated, and the motor position at which the cogging torque becomes zero is set in advance as the standby position by the standby position adjustment function unit 11b, whereby the control of the brake standby function unit 16 is performed. Can be maintained without the electric motor 6 being turned even if the controller 1 is executed. The cogging torque may be estimated in advance by using an estimation LUT (look-up table) (not shown) or the like based on design or measurement, or from motor operation or the like when torque is zeroed. A method may be used.

As described above, although the preferred embodiments have been described with reference to the drawings, various additions, modifications, and deletions can be made without departing from the spirit of the present invention. Therefore, such is also included in the scope of the present invention.

1 ... Friction brake mechanism 2 ... Linear actuator (friction material operating means)
3 Power supply device 4 Command means 5 Control device 6 Electric motor 8 Load sensor 9 Angle sensor (angle estimation means)
11a ... cogging torque estimation function unit 11b ... standby position adjustment function unit 12 ... switching pattern determination function unit 13 ... motor driver 14 ... brake release request determination function unit 14a ... counter 15 ... release completion determination function unit 16 ... brake standby function unit 21 ... switch 21 L ... L arm switch circuit 21 H ... H arm switch circuit 22 ... switch power supply 24 ...

charge

25 H, 25 L ... transistor element 25 Ha ... first input / output terminal 25 Hb ... second input / output terminal 25 Hc ... switching terminal 25 La ... second First input / output terminal 25Lb Second input / output terminal 25Lc Switching terminal 31 Brake rotor 32 Friction material

Claims

The electric motor so as to follow a brake rotor, a friction material which contacts the brake rotor to generate a braking force, a friction material operating means which operates the friction material by driving an electric motor, and a given brake command value. An electric brake apparatus comprising: a control device that controls an output of a motor; and a direct current power supply device that applies electric power to the electric motor,
The controller
Switch means for controlling the connection between the coil end of the electric motor and the power supply device;
A switch power supply having a storage function and functioning as a power supply for switching at least a part of the switch means;
Charge means for storing power in the switch power supply in a predetermined switching pattern of the switch means;
A brake release request determination function unit that determines that an operation for requesting a brake release has been performed when at least one of the brake force command value and its derivative value becomes smaller than a predetermined value;
When it is determined that the operation for requesting the brake release has been performed, the friction material operating means is driven to a predetermined brake release state, and at least one of the angle of the electric motor and the derivative thereof at this time. A release completion determination function unit that determines that the transition to the brake release state is completed;
When it is determined that the transition to the release state is completed, at least the stationary state electric motor is not driven spontaneously and predetermined switching may be performed to charge the switch means by the charge means by the charge means. And a brake standby function to maintain a pattern;
Electric brake device.
In the electric brake device according to claim 1,
The switch means is a switch circuit provided with a pair of L-arm switch and H-arm switch for each coil end of the electric motor,
The L arm switch includes a first input / output terminal connected to the coil end of the electric motor, a second input / output terminal connected to the negative side of the power supply device, and the second input / output terminal. Switch circuit for controlling the connection state between the negative side of the power supply and the coil end of the electric motor by a transistor element having a switching terminal for connecting the input / output terminals by inputting a positive potential. Is a department,
The H arm switch includes a first input / output terminal connected to the positive side of the power supply device, a second input / output terminal connected to a coil end of the electric motor, and the second input / output terminal. Switch circuit for controlling the connection state between the positive side of the power supply device and the coil end of the electric motor by a transistor element having a switching terminal for connecting the two input / output terminals when a positive potential is input. Is a department,
The switch power supply is a capacitor connected to the second input / output terminal of the H arm switch as an electrical reference potential,
The charge means is a charge circuit that stores charge in a switch power supply composed of the capacitor when the L arm switch is in a connected state,
The brake standby function unit always keeps all the L arm switches connected and always keeps all the H arm switches disconnected.
Electric brake device.
The electric brake device according to claim 1 or 2, wherein the release completion determination function unit sets a motor with respect to a motor angle target value at which a predetermined gap can be generated between the friction material and the brake rotor. An electric brake device that determines that the brake release is completed in a state where the absolute value of the deviation of the angle is equal to or less than a predetermined value and the absolute value of the motor angular velocity is equal to or less than a predetermined value.
The electric brake device according to claim 1 or 2, wherein the release completion determination function unit sets a motor with respect to a motor angle target value at which a predetermined gap can be generated between the friction material and the brake rotor. An electric brake device comprising: a counter that measures a duration of a state in which the absolute value of the deviation of the angle is equal to or less than a predetermined value, and judging that the brake release is completed when the value of the counter exceeds the predetermined value.
The electric brake device according to any one of claims 1 to 4, wherein the brake standby function unit releases the brake standby function when the variation of the motor angle becomes larger than a predetermined amount during execution. And an electric brake device for driving the friction material to a predetermined brake release state.
The electric brake system according to any one of claims 1 to 4, wherein the control device is an angle estimating means for estimating an angle of the electric motor, and a cogging torque for estimating a cogging torque from the estimated angle. An electric brake apparatus comprising: an estimation function unit; and a standby position adjustment function unit that sets a motor angle at which the estimated cogging torque becomes substantially zero when the brake state is shifted to the brake release state.