JP2008207679A - Electric braking device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric braking device capable of withstanding steady energization while making the device smaller and reducing cost of the components. <P>SOLUTION: The electric braking device comprises a three-phase brushless motor 1311 for generating rotation torque, a rotation-linear motion converting mechanism for converting rotation motions of the three-phase brushless motor 1311 to linear motions, a piston moved by the linear motions of the rotation-linear motion converting mechanism, a brake pad for pressing a disk rotor made to rotate together with wheels by the piston, switching circuits 1601-1606 for driving the three-phase brushless motor 1311, a three-phase inverter 1517 having inter-phase short circuit switches 1607, 1608 for performing an inter-phase short circuit, a control circuit for controlling the switching circuits 1601-1606 and the inter-phase short circuit switches 1607, 1608 of the three-phase inverter 1517. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric brake device for an automobile and a control method thereof.

  There is known an electric brake device in which the rotational motion of the rotor of the electric motor is converted into the forward / backward movement of the piston by the rotation / linear motion conversion mechanism, and the brake pad is pressed against the disk rotor by the piston to generate the braking force. (For example, refer to Patent Document 1). In this electric brake, a brake pedal depression force (or displacement amount) by a driver is detected by a sensor, and the rotation of the electric motor is controlled by a controller in accordance with the detected depression force and displacement amount to obtain a desired braking force.

JP-A-60-206766

  For example, when the vehicle stops at an intersection according to a red light or when there is a traffic jam, the brake pedal remains depressed for a long time. In the meantime, in order to maintain the braking force, it is necessary to continuously energize a current sufficient to maintain the braking force commanded to the electric brake device.

  In order to allow the current to flow continuously, the design of the withstand voltage and heat dissipation of the control circuit drive element should be expanded to the steady region instead of the instantaneous time region, and the design should be such that the function of the device is satisfied by steady energization. Is customary. However, a design that can withstand steady energization leads to an increase in the surface area of the heat dissipation mechanism, and thus an increase in volume, an element withstand voltage, an increase in power consumption, and the like, leading to an increase in the size and cost of the electric brake device itself.

  In view of the above, an object of the present invention is to provide an electric brake device that can withstand steady energization while reducing the size of the device and reducing component costs, and a control method thereof.

  A three-phase brushless motor that generates rotational torque, a rotation / linear motion conversion mechanism that converts the rotational motion of the three-phase brushless motor into linear motion, a piston that moves by the linear motion of the rotation / linear motion conversion mechanism, and a piston that rotates with the wheels An electric brake device having a brake pad for pressing a disk rotor to be driven and a three-phase inverter having a switching circuit for driving a three-phase brushless motor is provided with means for generating a short circuit between the phases of the three-phase inverter.

  It is possible to provide an electric brake device that can withstand steady energization and a control method thereof while reducing the size of the device and reducing component costs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a schematic configuration diagram of a vehicle on which the electric brake device according to the first embodiment of the present invention is mounted. A description of the driving mechanism for traveling is omitted.

  The first electric brake device 1201 is mounted near the axle 1221 on the right front wheel 1211 side. The second electric brake device 1202 is mounted close to the axle 1221 on the left front wheel 1212 side. The third electric brake device 1203 is mounted on the right rear wheel 1213 side in the vicinity of the axle 1222. The fourth brake device 1204 is mounted near the axle 1222 on the left rear wheel 1214 side.

  Although the electric brake devices 1201 to 1204 have the same basic structure, the first electric brake device 1201 and the second electric brake device 1202 corresponding to the front wheel side are the same as the third brake device 1203 and the rear wheel side, respectively. It is preferable to be configured to generate a braking force larger than that of the fourth electric brake 1204.

  The front wheel axle 1221 and the rear wheel axle 1222 are provided with disk rotors 1231 to 1234 fixed to the respective axles. Although not shown in FIG. 2, the mechanism units 1241 to 1244 of each electric brake device include a pair of brake pads that face each surface side of the disk rotors 1231 to 1234. Furthermore, the electric motors provided in the mechanism units 1241 to 1244 generate rotational torque, and generate braking force by pressing the disc rotors 1231 to 1234 with the brake pads based on the rotational torque.

  In each of the electric brake devices 1201 to 1204, the electric circuit units 1251 to 1254 for controlling the current for driving the electric motors have an integrated structure that is fixed to the respective mechanism units 1241 to 1244. The electric circuit portions 1251 to 1254 are attached to the surface opposite to the brake pads provided in the mechanism portions 1241 to 1244 in the axle direction.

Electric power is supplied from the first battery 1261 through the first power supply line 1271 to the first electric brake device 1201 and the second electric brake device 1202 on the front wheel side. Electric power is supplied from the second battery 1262 through the second power supply line 1272 to the third electric brake device 1203 and the fourth electric brake device 1204 on the rear wheel side.

Electric power is supplied from the first battery 1261 to the first electric brake device 1201 for the right front wheel and the fourth electric brake device 1204 for the left rear wheel, and the second electric brake device 1202 for the left front wheel and the third electric brake device 1202 for the right rear wheel. The electric brake device 1203 may be supplied with electric power from the second battery 1262. By using two power supply lines, even if an abnormality occurs in one power supply line, braking by the other power supply line is possible, and safety is improved.

  In the vehicle brake system shown in FIG. 2, information regarding the stroke of the brake pedal 1281 or the pedal effort is detected by the pedal operation amount detector 1282 and input to the control circuit 1299 via the data signal line 1290. The control circuit 1299 is disposed, for example, in the passenger compartment, and performs upper control processing as a brake system for the electric circuit portion of each electric brake (hereinafter referred to as “upper control circuit”).

  The upper control circuit 1299 is connected to the states of the first to fourth electric brake devices 1201 to 1204 from the first to fourth electric brake devices 1201 to 1204 via the data signal lines 1291 to 1294, respectively, for example, the current value of the pressing force. , Receive information on the current value of the operation mode. Further, while monitoring the state of the electric motor, a control signal corresponding to information on the stroke of the brake pedal 1281 or the pedal depression force is transmitted to the electric brake devices 1201 to 1204 via the data signal lines 1291 to 1294, and The devices 1201 to 1204 are controlled. Note that the host controller 1299 is disposed in the passenger compartment.

  As described above, the electric brake device can acquire a brake command to be generated as an electric signal, and can control the braking force in accordance with the change in the signal. This electrical signal can be realized in any form such as an analog signal or a communication signal.

The host control circuit 1299 controls each of the electric brake devices 1201 to 1204 independently, or the first electric brake device 1201 and the second brake device 1202 on the front wheel side are grouped and a third on the rear wheel side. The electric brake device 1203 and the fourth brake device 1204 are set as other groups to control each group, or the front wheel side first electric brake device 1201 and the rear wheel side fourth electric brake device 1204 are grouped together. Each group may be controlled with the second electric brake device 1202 on the front wheel side and the third electric brake device 1203 on the rear wheel side as other groups. By performing control in groups, effects such as improved control responsiveness, reduced processing load on the control circuit, and increased fail-safe processing functions can be obtained.

  The electric brake devices 1201 to 1204 for automobiles having such a structure are easily affected by vibration because they are directly attached to the vehicle body without using a suspension or the like, for example, and moisture penetrates into the interior by running in rainy weather. It will be used in an environment where it is easy.

  In this embodiment, the electric brake devices 1201 to 1204 are configured by integrating the electric circuit portions 1251 to 1254 including the control circuit with the mechanism portions 1241 to 1244 as described above, and the control circuit includes a large number of semiconductor devices. Is provided. Since the semiconductor device has a property that its characteristics change due to heat, high-temperature frictional heat generated by the pressure of the brake pads in the mechanism parts 1241 to 1244 against the disk rotors 1231 to 1232 rotating with the wheels is generated in the electric circuit part 1251. It is necessary to suppress the conduction to 1254 as much as possible, and it is also necessary to efficiently dissipate the heat generated by the semiconductor device itself.

  FIG. 3 shows a conceptual diagram of the electric brake device of FIG. Hereinafter, the first electric brake device 1201 will be described as a representative example.

  The electric brake device 1201 includes a pair of brake pads 1306 and 1307 arranged to face each other. A part of the disk rotor 1231 that rotates as the axle rotates is disposed between the brake pads 1306 and 1307.

  The electric brake device 1201 is configured by integrating a mechanism portion 1241 and an electric circuit portion 1251 with each other. Since the mechanism portion 1241 and the electric circuit portion 1251 are separated in terms of regions, the mechanism portion 1241 and the electric circuit portion 1251 can be structurally separated.

  In the caliper 1301, the mechanism unit 1241 linearly moves, for example, a three-phase brushless motor 1311, a speed reducer 1321 that decelerates the rotation of the three-phase brushless motor 1311, and a three-phase brushless motor 1311 decelerated by the speed reducer 1321. A rotation / linear motion mechanism 1326 that converts the motion into motion and moves the piston 1331 back and forth is provided.

  The brake pad 1307 is attached to the piston 1331 and presses the disk rotor 1231 from one surface side by the thrust of the piston 1331. At this time, the electric brake device 1201 moves in the direction of arrow α in the figure using the pressing force from one surface side of the disk rotor 1231 as a reaction force, so that the brake pad 1306 presses the disk rotor 1231 from the other surface side. To do.

  The mechanism unit 1241 includes a parking brake (PKB) mechanism 1341. The parking brake mechanism 1341 stops the rotation of the three-phase brushless motor 1311 while the piston 1331 is supplying thrust to the disk rotor 1231, thereby supplying braking force without supplying power to the three-phase brushless motor 1311. Can be held.

In the vicinity of the three-phase brushless motor 1311, there are a rotation angle detection sensor 1351 for detecting the rotation angle of the three-phase brushless motor 1311, a thrust sensor 1353 for detecting a thrust generated by driving the three-phase brushless motor 1311, and a three-phase brushless motor 1311. A temperature sensor 1355 for detecting the temperature of is arranged. Output signals of the rotation angle detection sensor 1351, the thrust sensor 1353, and the temperature sensor 1355 are output to a lower control circuit 1399 disposed in the electric circuit unit 1251.

  The electric circuit unit 1251 receives power supply from a battery 1261 disposed on the vehicle body side. Further, various control signals are sent via a CAN (Controller Area Network) to which an engine control unit 1381, an AT control unit 1383, a pedal operation amount detector 1282 and the like are connected, or from the CAN via a host control circuit 1299. get.

The electric circuit unit 1251 includes an inverter circuit 1391 and a lower control device 1399. The inverter circuit 1391 is a circuit for controlling the voltage applied to the three-phase brushless motor 1311. The lower control circuit 1399 obtains a control signal via CAN, and further obtains output information signals such as the rotation angle detection sensor 1351, the thrust sensor 1353, and the temperature sensor 1355 from the mechanism unit 1241 side, and based on these signals. The inverter circuit 1391 is controlled.

  The three-phase brushless motor 1311 acquires the output from the inverter circuit 1391 and generates a rotational torque so that the piston 1331 generates a predetermined thrust. In the figure, reference numeral 1395 denotes a vehicle-side structure.

  FIG. 4 shows a cross-sectional view of the electric brake device of FIG.

  A line segment XX in FIG. 4 indicates a boundary between the mechanism unit 1241 and the electric circuit unit 1251, and a left side of the line segment XX in the drawing indicates the mechanism unit 1241, and a right side in the drawing indicates the electric circuit unit 1251.

  The caliper 1301 is integrally coupled to a claw portion 1302 formed in a substantially C shape by a bolt (not shown). The claw portion 1302 is formed across the disk rotor 1231. The brake pad 1307 is provided between the disc rotor 1231 that rotates with the wheel and the caliper 1301. Further, the brake pad 1306 is provided between the disk rotor 1231 and the tip of the claw portion 1302.

  The carrier 1303 fixed to the vehicle body side supports the electric brake device 1201 by a slide pin (not shown) attached to the carrier 1303 so as to be slidable along the rotation axis direction of the disk rotor 1231. The carrier 1303 receives a braking torque generated by contact between the brake pad 1306 and the disk rotor 1231.

  The caliper 1301 includes a stator of a three-phase brushless motor 1311, a rotor 1342 of the three-phase brushless motor 1311, a differential reduction mechanism 1321, a ball ramp mechanism 1326, a pad wear compensation mechanism 1304, a parking brake mechanism 1341 (lock mechanism). ).

  The rotor 1342 of the electric motor is rotated by the drive voltage from the inverter circuit 1391, and the rotation position is detected by the rotation angle detection sensor 1351. The stator is disposed so as to be in contact with the metal caliper 1301 so that heat can be efficiently radiated when the stator itself generates heat.

  The differential reduction mechanism 1321 reduces the rotation of the rotor 1342 of the electric motor.

  In the ball ramp mechanism 1326, the ball 1329 is inserted between the ball grooves (inclined grooves) formed in the rotating disk 1327 and the linearly moving disk 1328, and when the rotating disk 1327 rotates, the ball 1329 rolls in the groove. Thus, the linear motion disk 1328 moves along the axial direction in accordance with the rotation angle. As a result, the ball ramp mechanism 1326 converts the rotational motion of the rotor 1342 decelerated by the differential deceleration mechanism 1321 into a linear motion, and moves the piston 1331 in contact with the brake pad 1307 back and forth.

  A return spring 1343 is built in the base of the ball ramp mechanism 1326. The return spring 1343 rotates the ball ramp mechanism 1326 with a spring force in a direction in which the thrust decreases when the energization to the electric motor is interrupted and no torque is generated when the caliper generates thrust. It has a function of mechanically releasing the thrust of the brake pad 1306. Thereby, it is possible to prevent an unintended braking force from being generated on the vehicle, such as a failure of the electric brake device, and not to impair the stability of vehicle travel.

  The pad wear compensation mechanism 1304 transmits the rotation of the rotor 1342 of the electric motor to the linear motion disk 1328 via a one-way clutch and a spring, whereby the rotary disk 1327 and the linear motion disk 1328 are rotated together, and the piston 1331 is rotated. Move forward. Accordingly, when the brake pad 1307 is worn and a gap is formed between the brake 1307 and the piston 1331, the wear of the brake pad 1307 can be adjusted.

  The parking brake mechanism 1341 includes a claw wheel integrally provided on the outer peripheral portion of the rotor 1342 of the electric motor, and a lock unit having an engaging claw that engages with the claw wheel. Then, the lock unit locks the rotation of the rotor 1342 by engaging the engaging claw with the claw wheel by an actuator or the like (for example, a solenoid) according to the command signal. In a state where the brake pads 1306 and 1307 and the disk rotor 1231 are in contact with each other, the braking force can be mechanically held without supplying electric power.

  The thrust plate 1421 is disposed on the electric circuit portion 1251 side in the mechanism portion 1241 and has a function of receiving the thrust of the piston 1331 as a reaction force. A thrust sensor 1353 is disposed at the center of the thrust plate 1241.

  The thrust plate 1421 is disposed at a position slightly recessed toward the brake pad portion side with respect to the end surface of the caliper 1301 of the mechanism portion 1241 (part indicated by a line XX in the drawing). A gap (space) is formed between the constituent members of the mechanism part 1241 excluding the caliper 1301 and the electric circuit part 1251. On the other hand, the thrust sensor 1353 slightly protrudes toward the electric circuit portion 1251 beyond the end surface of the caliper 1301 (the portion of the line segment XX in the figure). However, the interface module 200 provided in the electric circuit unit 1251 is formed with a recess so as to avoid interference with the thrust sensor 1353.

  Since most of the constituent members of the mechanism portion 1241 including the caliper 1301 are made of metal, heat conduction efficiency is high. Therefore, heat from the brake pad portion (brake pads 1306 and 1307 and its peripheral portion) is transmitted to the peripheral mechanism portion 1241 and easily radiated to the outside via the caliper 1301.

  Further, since the electric circuit portion 1251 is formed on the surface opposite to the brake pad portion with the mechanism portion 1241 in between, heat transfer to the electric circuit portion 1251 is minimized. Further, since the above-described gap (space) is formed between the structural member of the mechanism unit 1241 and the electric circuit unit 1251, heat conduction from the mechanism unit 1241 to the electric circuit unit 1251 is further reduced.

  FIG. 5 is a circuit configuration diagram of the electric circuit unit 1251 of FIG.

  In the figure, a thick line frame 1251 corresponds to the electric circuit portion 1251 shown in FIG. 3, and a one-dot chain line frame 1391 corresponds to the inverter circuit 1391 shown in FIG. A dotted line frame 1503 in the drawing corresponds to a circuit in the mechanism unit 1241.

  Although not shown in the figure, the internal circuit 1241 and the electric circuit unit shown in FIG. 5 are protected from a cause of external injury such as a stepping stone because they are covered with a metal casing. In addition, by using a metal housing having high heat conductivity, heat generated from each circuit can be radiated. Furthermore, the shielding effect with respect to electromagnetic waves etc. is provided by using the metal housing | casing with high shielding property.

  First, in the circuit of the electric circuit unit 1251, power supplied via a power supply line in the vehicle is supplied to the power supply circuit 1511. The power (Vcc, Vdd) stabilized by the power supply circuit 1511 is supplied to a central control circuit (CPU) 1599. The power supply (Vcc) from the power supply circuit 1511 is detected by the VCC high voltage detection circuit 1513. When the VCC high voltage detection circuit 1513 detects a high voltage, the fail safe circuit 1515 is operated.

  The fail safe circuit 1515 operates a relay 1519 that switches power supplied to a three-phase motor inverter 1517 described later. When a high voltage is detected by the VCC high voltage detection circuit 1513, the power supply is turned off.

  The filter circuit 1521 removes noise from the power supplied into the electric circuit unit 1251 through the relay 1519 and supplies the power from which the noise has been removed to the three-phase motor inverter 1517.

The central control circuit 1599 acquires a control signal from the host control circuit 1299 via the CAN communication interface circuit 1523, and from the thrust sensor 1353, the rotation angle detection sensor 1351, and the temperature sensor 1355 arranged on the mechanism unit 1241 side. Are obtained via a thrust sensor interface circuit 1525, a rotation angle detection sensor interface circuit 1527, and a temperature sensor interface circuit 1529, respectively. Information on the current state of the three-phase brushless motor 1311 is acquired, and feedback control is performed based on a control signal from the host control circuit 1299, thereby causing the three-phase brushless motor 1311 to generate appropriate rotational torque. That is, the central control circuit 1599 causes the three-phase motor pre-driver circuit 1531 to output an appropriate signal based on the control signal from the host control circuit 1299 and the detection value of each sensor. In addition, the central control circuit 1599 acquires the voltage value of the power supply line 1570 as an analog signal via the interface 1571, and performs control correction due to fluctuations in the power supply voltage.

The three-phase motor inverter 1517 includes a phase current monitor circuit 1533 and phase voltage monitor circuits 1535U, 1535V, and 1535W. Phase current monitor circuit 1535U,
1535 V, 1535 W and phase voltage monitor circuit 1535 monitor the phase current and the phase voltage, respectively, and output the monitoring results to central control circuit 1599. The central control circuit 1599 operates the three-phase motor pre-driver circuit 1531 appropriately according to the monitoring result. Note that the three-phase motor inverter 1517 controls a current and voltage for driving the three-phase brushless motor 1311, and therefore incorporates a semiconductor device having a relatively large output.

  The central control circuit 1599 also receives a PKB solenoid in the mechanism unit 1241 via a parking brake (hereinafter, PKB) solenoid driver circuit 1537 based on a control signal from the host control circuit 1299, detection values of each sensor, and the like. 1342 is operated to activate the parking brake. PKB solenoid driver circuit 1537 is supplied with part of the power supplied to three-phase motor inverter 1517.

  In addition, the electric circuit unit 1251 includes a monitoring control circuit 1539 that transmits and receives signals to and from the central control circuit 1599, for example, a storage circuit 1541 that includes an EEPROM that stores failure information and the like.

The electrical circuit unit 1251 has many connections with the mechanism unit 1241, but there are very few connections with circuits other than the mechanism unit 1241 (battery 1261, host controller 1299). As a result, in the manufacturing process of the electric brake device 1201 having an integrated structure of the mechanism portion 1241 and the electric circuit portion 1251, complicated connection between the mechanism portion 1241 and the electric circuit portion 1251 is performed, and the electric brake device 1201 is completed. After that, when the electric brake device 1201 is attached to the vehicle body, the connection with the battery 1261 or the host control device 1299 can be performed very easily.

  In such an electric disc brake device, various sensors are used to detect vehicle conditions such as the rotational speed of each wheel, vehicle speed, vehicle acceleration, steering angle, vehicle lateral acceleration, and the like, and the controller performs electric power based on these detections. By controlling the rotation of the motor, boost control, anti-lock control, traction control and vehicle stabilization control can be obtained.

  FIG. 1 shows a circuit diagram of a three-phase motor inverter in an electric brake device according to Embodiment 1 of the present invention.

  The three-phase motor inverter 1517 has upper arm switching elements 1601, 1602, 1603 corresponding to the UVW phase, and lower arm switching elements 1604, 1605, 1606. In the present embodiment, interphase short-circuit switches 1607 and 1608 are provided. These interphase short-circuit switches 1607 and 1608 are opened and closed by a control signal from the CPU 1599 via the three-phase motor pre-driver in FIG.

  Here, a short circuit between phases will be described. In the three-phase brushless motor, a rotating magnetic field is generated by a stator, and rotation in synchronization with the rotating magnetic field is generated in the rotor by the rotating magnetic field and the attractive force of a permanent magnet embedded in the rotor. Here, when a rotational torque due to an external force is generated in the rotor with a short-circuit between two predetermined phases of the three phases, the magnetic field lines of the rotor intersect with the stator coil, and relative movement is caused by the rotation of the rotor. And a current is generated in the short circuit according to Fleming's left-hand rule. Along with this, a counter electromotive force is generated by the inductance component of the stator coil on the short circuit, and a current opposite to the short circuit current generated by the Fleming left-hand rule is generated by the counter electromotive force. This reverse current generates a torque (lock torque) opposite to the torque due to the external force, and locks the rotation of the rotor.

  In the present embodiment, an interphase short circuit is generated by operating the interphase short circuit switches 1607 and 1608, and the motor that propels the piston of the electric brake is locked by the generated lock torque. The braking force generated in the

  6 shows a flowchart of the lock torque control in the example of FIG. 1, and FIG. 7 shows a time chart by the control of FIG. This shows an operation in the case where the thrust is held in a brake operation operated by the driver on the vehicle side.

  In step 601 of FIG. 6, it is determined whether or not the state in which the brake pedal operation amount exceeds the predetermined value S0 has continued for a predetermined time. This process is executed by a hardware interrupt process triggered by detecting a momentary low voltage constantly or continuously by the CPU 112 at a constant time interval. The brake pedal operation amount may be obtained by the electric brake device through the host control device 1299 and the in-vehicle network, and information indicating that the state where the brake pedal operation amount exceeds the predetermined value S0 has continued for a predetermined time. The host controller may give the electric brake device. The same is true when it is determined that a brake pedal operation amount described below has fallen below a predetermined value S0. If the state where the brake pedal operation amount exceeds the predetermined value S0 does not continue for a predetermined time, this routine is terminated and the normal brake control is resumed.

Here, for example, it is assumed that the state in which the brake pedal operation amount exceeds the predetermined value S0 continues from time t1 to time t2 in FIG. Then, in 601 of FIG. 6, it is determined that the state where the brake pedal operation amount exceeds the predetermined value S0 has continued for a predetermined time, and the process proceeds to step 602.

  In step 602, the control of the inverter is stopped, and in step 603, the inter-phase short-circuit switches 1607 and 1608 are operated by the lock torque control signal to generate the inter-phase short circuit, thereby generating the lock torque in the motor. When the control of the inverter is stopped, no torque is generated in the motor, and the motor tries to rotate in the direction in which the thrust is released by the action of the return spring 1343 incorporated in the caliper 1301. However, in the process 603, the lock torque control signal becomes the lock side, each phase of the electric motor 9 is short-circuited, the lock torque is generated, the position of the piston 1331 in the caliper 1301 is held, and the generated thrust is held. .

  Here, it is preferable that the design is made in consideration of the coil length, the coil diameter, and the number of coil turns of the motor so that the generated lock torque overcomes the maximum spring force of the return spring 1343.

  Next, in step 604, the brake pedal operation amount is monitored. If the brake pedal operation amount falls below the predetermined value S0 at time t3, the lock torque control signal is released in step 605, and inverter control is returned in step 606. Resume normal brake control.

  According to this embodiment, in response to a braking force holding command output from the vehicle side, it becomes possible to hold the braking force only with electric power that maintains the interphase short-circuit switches 1607 and 1608 ON, and the electric power of the drive circuit Therefore, it is not necessary to increase the heat dissipation capacity, and the cost, weight, size, and power consumption of the apparatus can be reduced.

  FIG. 8 shows a flowchart of lock torque control in the electric brake device according to the second embodiment of the present invention, and FIG. 9 shows a time chart by the control of FIG. This shows the operation in the case where the thrust control generated due to the instantaneous drop in the power supply voltage cannot be maintained.

  In step 801 of FIG. 8, it is determined whether or not an instantaneous drop in the power supply voltage supplied to the electric brake device has occurred. This process is executed by a hardware interrupt process triggered by detecting a momentary low voltage constantly or continuously by the CPU 112 at a constant time interval. If no instantaneous drop in the power supply voltage has occurred, this routine ends and the normal brake control is resumed.

  Here, for example, from the state where the thrust is generated according to the thrust command from time 0 to time t4 in FIG. 9, there is an instantaneous low voltage state where the power supply voltage falls below V0 which is the lowest operating voltage of the device at time t4. Suppose that it occurred. Then, in 801 in FIG. 8, it is determined that an instantaneous drop in the power supply voltage has occurred, and the process proceeds to step 802.

  In step 802, control of the inverter is stopped, and in step 803, the interphase short-circuit switches 1607 and 1608 are operated by the lock torque control signal to generate an inter-phase short circuit, thereby generating a lock torque in the motor. When the control of the inverter is stopped, no torque is generated in the motor, and the motor tries to rotate in the direction in which the thrust is released by the action of the return spring 1343 incorporated in the caliper 1301. However, in process 803, the lock torque control signal becomes the lock side, each phase of the electric motor 9 is short-circuited, a lock torque is generated, the position of the piston 1331 in the caliper 1301 is held, and the generated thrust is held. .

  Next, in process 804, the power supply voltage is monitored. If the power supply voltage returns to the minimum operating voltage or higher at time t5, the lock torque control signal is released in process 805, inverter control is returned in process 806, and thrust control is performed. To resume.

  According to the present embodiment, since the generated thrust of the electric brake can be maintained with little use of energy from the power source, the brake force is completely released when the power source is momentarily reduced. It is possible to avoid it. Further, it is possible to avoid a situation in which the thrust is released by the low voltage generated instantaneously and the vehicle moves backward on a slope.

  FIG. 10 shows a circuit diagram of a three-phase motor inverter in the electric brake device according to Embodiment 3 of the present invention.

  In FIG. 1, the inter-phase short circuit is generated by the inter-phase short circuit switches 1607 and 1608. However, in this embodiment, the inter-phase short circuit switches 1607 and 1608 are eliminated, and instead, all the upper arm switching elements 1601, 1602 and 1603 of the inverter circuit are turned on. A short circuit between phases is generated by a method or a method of turning on the lower arm switching elements 1604, 1605, and 1606. Other configurations are the same as those of the first embodiment. Moreover, you may combine with Example 2. FIG.

  According to the present embodiment, the interphase short-circuit switches 1607 and 1608 are not required, and the braking force can be maintained by the control without preparing a new inverter, and the apparatus can be provided at a lower cost.

The circuit diagram of the three-phase motor inverter in the electric brake device which makes Example 1 of this invention is shown. 1 is a schematic configuration diagram of a vehicle equipped with an electric brake device that constitutes Embodiment 1 of the present invention. FIG. The conceptual diagram of the electric brake device of FIG. 2 is shown. Sectional drawing of the electric brake device of FIG. 2 is shown. The circuit block diagram of the electric circuit part 1251 of FIG. 3 is shown. The flowchart of the lock torque control in the example of FIG. 1 is shown. 7 shows a time chart according to the control of FIG. The flowchart of the lock torque control in the electric brake device which makes Example 2 of this invention is shown. 9 is a time chart according to the control of FIG. The circuit diagram of the three-phase motor inverter in the electric brake device which makes Example 3 of this invention is shown.

Explanation of symbols

1311 Three-phase brushless motor 1517 Three-phase motor inverters 1601 to 1603 Upper arm switching circuits 1604 to 1606 Lower arm switching circuits 1607 and 1608 Interphase short-circuit switch

Claims (20)

A three-phase brushless motor that generates rotational torque;
A rotation / linear motion conversion mechanism for converting the rotational motion of the three-phase brushless motor into linear motion;
A piston that moves by a linear motion of the rotation / linear motion conversion mechanism;
A brake pad that presses a disk rotor that rotates with the wheel by the piston;
A three-phase inverter having a switching circuit for driving the three-phase brushless motor, and an inter-phase short-circuit switch for inter-phase short circuit;
A control circuit for controlling the switching circuit of the three-phase inverter and the inter-phase short-circuit switch;
Electric brake device having The electric brake device according to claim 1,
The control circuit is an electric brake device that operates the interphase short-circuit switch when a state in which a brake pedal operation amount exceeds a predetermined value continues for a predetermined time. The electric brake device according to claim 2,
The said control circuit is an electric brake device which cancels | releases the said phase short circuit switch, when the said brake pedal operation amount falls below the said predetermined value after operating the said phase short circuit switch. The electric brake device according to claim 1,
The control circuit is an electric brake device that operates the phase-to-phase short-circuit switch when an instantaneous low voltage state occurs such that a power supply voltage is lower than a minimum operating voltage of the device. The electric brake device according to claim 4,
The said control circuit is an electric brake device which cancels | releases the said phase short circuit switch, when the said power supply voltage returns to the said minimum operating voltage after operating the said phase short circuit switch. A three-phase brushless motor that generates rotational torque;
A rotation / linear motion conversion mechanism for converting the rotational motion of the three-phase brushless motor into linear motion;
A piston that moves by a linear motion of the rotation / linear motion conversion mechanism;
A brake pad that presses a disk rotor that rotates with the wheel by the piston;
A three-phase inverter having a switching circuit for driving the three-phase brushless motor;
A control circuit that operates a switching circuit of the three-phase inverter to generate a short circuit between phases when a predetermined condition is satisfied;
Electric brake device having The electric brake device according to claim 6,
The control circuit is an electric brake device that operates a switching circuit of the three-phase inverter to generate a short circuit between phases when a state where a brake pedal operation amount exceeds a predetermined value continues for a predetermined time. The electric brake device according to claim 7,
The said control circuit is an electric brake device which cancels | releases the said phase short circuit, when the said brake pedal operation amount falls below the said predetermined value after generating the said phase short circuit. The electric brake device according to claim 6,
The control circuit is an electric brake device that operates a switching circuit of the three-phase inverter to generate a short circuit between phases when an instantaneous low voltage state occurs such that a power supply voltage falls below a minimum operating voltage of the device. The electric brake device according to claim 9, wherein
The said control circuit is an electric brake device which cancels | releases the said phase short circuit, when the said power supply voltage returns to the said minimum operating voltage after generating the said phase short circuit. A three-phase brushless motor that generates rotational torque;
A rotation / linear motion conversion mechanism for converting the rotational motion of the three-phase brushless motor into linear motion;
A piston that moves by a linear motion of the rotation / linear motion conversion mechanism;
A brake pad that presses a disk rotor that rotates with the wheel by the piston;
A control method for an electric brake device having a switching circuit for driving the three-phase brushless motor and a three-phase inverter having an inter-phase short-circuit switch for short-circuiting between phases,
A control method for an electric brake device that operates an inter-phase short-circuit switch when a predetermined condition is satisfied. It is a control method of the electric brake equipment according to claim 11,
The control method of the electric brake device which operates the said short circuit switch between phases, when the state in which the brake pedal operation amount exceeded the predetermined value continued for the predetermined time. A control method for an electric brake device according to claim 12,
A control method for an electric brake device that releases the inter-phase short-circuit switch when the operation amount of the brake pedal falls below the predetermined value after operating the inter-phase short-circuit switch. It is a control method of the electric brake equipment according to claim 11,
A control method for an electric brake device that operates an inter-phase short-circuit switch when an instantaneous low voltage state occurs such that a power supply voltage falls below a minimum operating voltage of the device. It is a control method of the electric brake equipment according to claim 14,
A control method for an electric brake device that releases the inter-phase short-circuit switch when the power supply voltage returns to the minimum operating voltage after operating the inter-phase short-circuit switch. A three-phase brushless motor that generates rotational torque;
A rotation / linear motion conversion mechanism for converting the rotational motion of the three-phase brushless motor into linear motion;
A piston that moves by a linear motion of the rotation / linear motion conversion mechanism;
A brake pad that presses a disk rotor that rotates with the wheel by the piston;
A control method of an electric brake device having a three-phase inverter having a switching circuit for driving the three-phase brushless motor,
A control method for an electric brake device in which a short circuit between phases is generated by operating a switching circuit of the three-phase inverter when a predetermined condition is satisfied. It is a control method of the electric brake equipment according to claim 16,
A control method for an electric brake device in which a short circuit between phases is generated by operating a switching circuit of the three-phase inverter when a state where a brake pedal operation amount exceeds a predetermined value continues for a predetermined time. A control method for an electric brake device according to claim 17,
A control method for an electric brake device that releases the inter-phase short circuit when the operation amount of the brake pedal falls below the predetermined value after the inter-phase short circuit is generated. It is a control method of the electric brake equipment according to claim 16,
An electric brake device that operates a switching circuit of the three-phase inverter to generate a short circuit between phases when a momentary low voltage state occurs such that a power supply voltage falls below a minimum operating voltage of the device. A control method for an electric brake device according to claim 19,
A control method of an electric brake device that releases the short circuit between phases when the power supply voltage returns to the minimum operating voltage after the short circuit between phases is generated.

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