JP6304123B2 - Electric braking device for vehicle - Google Patents

Description

The present invention relates to an electric brake system of a vehicle including the motor control equipment in the vehicle for controlling a motor having three-phase coils.

  Patent Document 1 describes a motor that functions as a power source for an electric vehicle such as a hybrid vehicle, and a motor control device for a vehicle that controls the motor. The motor controlled by the motor control device is a brushless motor having a three-phase coil. The motor control device includes an inverter circuit that generates an alternating current and outputs the alternating current to each coil, and a control unit that controls the inverter circuit. And in such a motor control apparatus, the excessive temperature rise of the switching element is suppressed by switching the control method of a motor according to the temperature of the switching element of an inverter circuit.

  Note that a motor having a three-phase coil, for example, as a power source of an electric braking device including a rotating body that rotates integrally with a wheel and a friction member that applies a braking force to the wheel by being pressed against the rotating body. It can also be adopted. In this case, by adjusting the rotation amount of the motor, the force for pressing the friction member against the rotating body, that is, the braking force applied to the wheel can be controlled.

JP 2010-246207 A

  By the way, in the above-described electric braking device, the rotation angle of the motor may be held when the braking force applied to the wheel is held. In this case, the value of the current flowing through each coil of the motor is also maintained so that the rotation angle of the motor does not change.

  Incidentally, the phases of the currents flowing through the coils of the motor are 120 ° different from each other. Therefore, depending on the rotation angle of the motor, the absolute value of the current flowing in one coil (hereinafter also referred to as “specific coil”) of each coil becomes substantially equal to the maximum value, while the current flowing in the other coils. The absolute value of may be relatively small. If a state in which a large current flows only in a specific coil is continued in this way, the temperature of the specific coil becomes too higher than the temperature of the other coil, so that the change over time in the characteristics of the specific coil is different. There is a risk of proceeding more than the other coil.

An object of the present invention, the aging of the characteristics of one of the coils of the three-phase coils of the motor to provide a braking control apparatus for vehicles which is Ru can be suppressed that would more advanced than the other coil It is in.

An electric braking device for a vehicle for solving the above problem includes a motor control device that adjusts the rotation angle of a motor having a three-phase coil by individually controlling an alternating current supplied to each coil. The state of the motor when the absolute value of the current flowing through one coil of each coil is larger than the absolute value of the current flowing through the other coil, and the absolute value of the current flowing through the same coil is equal to or greater than the peak judgment value. Assume that the specific state is a coil in which the absolute value of the flowing current is equal to or greater than the peak determination value when the motor is in the specific state. In this case, the vehicle motor control device includes a control unit that performs a continuation canceling process for changing the rotation angle of the motor when it is detected that the motor is in a specific state.

  When the absolute value of the alternating current flowing through one of the three-phase coils of the motor is equal to or greater than the peak determination value, the absolute value of the alternating current flowing through another coil other than the one coil is less than the peak determination value. . Therefore, the temperature of the one coil tends to be higher than the temperature of the other coil.

  In the above configuration, when it is detected that the motor is in the specific state, the value of the current flowing through the specific coil changes by changing the rotation angle of the motor by performing the continuation cancellation process. Is done. Thereby, it is suppressed that the state where the absolute value of the current flowing through the specific coil is equal to or higher than the peak determination value is suppressed, and the temperature of the specific coil is suppressed from being excessively higher than the temperatures of the other coils. Can do. Therefore, it becomes possible to suppress the secular change of the characteristics of one of the three-phase coils of the motor from proceeding more than the other coils.

Also, control section is a continuation resolving process, variation permitted angle including a rotation angle of the motor, both when the motor and the rotation angle which is not the specific state, the motor is continued to be the specific state It is preferable to vibrate the rotation angle of the motor within the range.

  According to the above configuration, it is possible to suppress the absolute value of the current flowing through the specific coil from continuing to be equal to or higher than the peak determination value by vibrating the rotation angle of the motor within the variation allowable angle range. In addition, since the value of the current flowing in other coils other than the specific coil also fluctuates when the rotation angle of the motor is vibrated, the temperature divergence between the coils is smaller than when the motor rotation angle is not vibrated. Can be suppressed.

  Furthermore, the variation permission angle range is a range including the rotation angle when the motor is continuously in the specific state. Therefore, when the rotation angle of the motor is vibrated by the execution of the continuation canceling process, it is possible to suppress an increase in the deviation of the rotation angle of the motor from the rotation angle when the motor is held.

Also, if the motors is a reference rotational angle the rotation angle of the motor when it is being continued to be the specific state, the lower limit of the variation allowed angle range, by subtracting the prescribed rotational angle from a reference rotational angle It is a difference, and the upper limit value of the variation allowable angle range is preferably a sum obtained by adding a specified rotation angle to a reference rotation angle.

  According to the above configuration, when the rotation angle of the motor is vibrated by performing the continuation cancellation process, the rotation angle of the motor vibrates around the reference rotation angle. Therefore, compared to the case where the rotation angle that is the center of the variation allowable angle range is not the reference rotation angle, the rotation angle when the rotation angle of the motor is held when the rotation angle of the motor is vibrated by performing the continuous cancellation process It is possible to further suppress an increase in the deviation of the rotation angle of the motor from the reference rotation angle.

Also, control section is a continuation cancellation processing changes the rotation angle of the motor rotation angle absolute value of the current flowing through the particular coil is smaller than the peak determination value, it is preferable to keep the same rotation angle.

  According to the above configuration, the absolute value of the current flowing through the specific coil can be made smaller than the peak determination value by changing the rotation angle of the motor by performing the continuation cancellation process. Therefore, it can suppress that the temperature of a specific coil becomes high too much.

Further, the vehicle motor control device vibrates the rotation angle of the motor when detecting that the state where the rotation angle of the motor is maintained is continued in a state where current flows through each coil. You may provide the control part which performs a continuous cancellation process.

  When the state in which the rotation angle of the motor is maintained is maintained, the value of the current flowing through each coil of the motor is maintained, so that the state where the absolute value of the current flowing through each coil is different may be continued. . For this reason, when the state in which the rotation angle of the motor is maintained is continued, a temperature divergence between the coils tends to occur. According to the above configuration, the absolute value of the current flowing through each coil is changed by vibrating the rotation angle of the motor within the allowable change angle range. For this reason, it is difficult for the absolute value of the current flowing in some of the coils to be larger than the absolute value of the current flowing in the other coils, and as a result, the temperature divergence between the coils can be suppressed. it can. In this way, it is possible to prevent the secular change in the characteristics of one of the three-phase coils of the motor from proceeding more than the other coils.

  Further, as an electric braking device for a vehicle, a rotating body that rotates integrally with a wheel, a friction member that applies a braking force to the wheel by being pressed against the rotating body, a motor having a three-phase coil, and driving of the motor There is a device provided with a motor control device that controls a force that presses the friction member against the rotating body by controlling. The vehicle motor control device can be employed as the motor control device for the electric braking device for the vehicle.

  In such an electric braking device for a vehicle, in order to continuously apply a constant braking force to the wheels, the state of maintaining the rotation angle of the motor may be continued. That is, the motor may continue to be in a specific state.

  Therefore, in the electric braking device for a vehicle described above, the control unit changes the rotation angle of the motor to a rotation angle at which the absolute value of the current flowing through the specific coil is smaller than the peak determination value as the continuation cancellation process. And a second continuation cancellation process that vibrates the rotation angle of the motor within a range of allowable change angles including a rotation angle at which the motor does not enter a specific state. Also good.

  When the second continuation elimination process is performed, the rotation angle of the motor is vibrated, so that the braking force applied to the wheels is likely to vibrate, but it is easy to suppress variations in the temperature rise mode of each coil of the motor. . On the other hand, when the first continuation cancellation process is being performed, only the rotation angle of the motor is changed, so that the braking force applied to the wheels is unlikely to change. That is, in the first continuation cancellation process, the uncomfortable feeling given to the driver is small because the braking force applied to the wheels is less likely to change than in the second continuation cancellation process.

  Therefore, when the control unit detects that the motor is continuously in a specific state under a situation where the braking force is applied to the wheels, the control unit performs the first continuation cancellation process when the vehicle is not stopped. When the vehicle is stopped, the second continuation cancellation process may be performed.

  According to this configuration, when the vehicle is not stopped, by performing the first continuation canceling process, after suppressing the difference between the temperature of the specific coil and the temperature of other coils other than the specific coil to some extent, A decrease in drivability can be suppressed. On the other hand, when the vehicle is stopped, by performing the second continuation elimination process, it is possible to suppress variations in the temperature increase mode of each coil.

  Further, in the electric braking device for a vehicle as described above, when the braking force applied to the wheels is large, the rotation amount of the motor is larger than when the braking force is small. For this reason, when the braking force applied to the wheels is large, even if the rotation angle of the motor is changed within a certain range, the rate of change of the braking force is small, and the uncomfortable feeling given to the driver tends to be small. On the other hand, when the braking force applied to the wheels is small, if the rotation angle of the motor is changed within a certain range, the rate of change of the braking force increases, and the driver feels uncomfortable.

  Therefore, in the electric braking device for a vehicle including the motor control device for a vehicle as the motor control device, the control unit permits the execution of the continuation canceling process when the braking force applied to the wheels is equal to or greater than the braking force determination value. When the braking force applied to the wheel is less than the braking force determination value under the condition that the vehicle is not stopped, the continuation canceling process may be prohibited.

  According to the above configuration, under the situation where the braking force applied to the wheel is equal to or greater than the braking force determination value, it can be determined that the rate of fluctuation of the braking force with respect to the wheel due to the execution of the continuation cancellation process is difficult to increase. Therefore, when it is detected that the motor is in a specific state, the continuation elimination process is performed to prevent the temperature of one coil from becoming too high than the temperature of the other coil. can do. On the other hand, when the braking force applied to the wheel is less than the braking force determination value when the vehicle is not stopped, the rate of fluctuation in the braking force applied to the wheel tends to increase when the continuation elimination process is performed. Therefore, it can be determined that the uncomfortable feeling given to the driver increases. Therefore, under these circumstances, the continuation cancellation process is not performed even when the motor is continuously in the specific state. Therefore, it is possible to suppress a decrease in drivability associated with the execution of the continuous cancellation process.

The block diagram which shows the outline of one Embodiment of the electric braking device of a vehicle. FIG. 3 is a circuit diagram showing an electrical configuration of a vehicle motor control device provided in the electric braking device of the vehicle and a motor controlled by the motor control device. The graph which shows an example of the change aspect of the rotation angle in the 1st continuation cancellation process which the motor control apparatus of the vehicle implements. The graph which shows an example of the vibration aspect of the rotation angle in the 2nd continuation cancellation process which the motor control apparatus of the vehicle implements. The flowchart explaining the process routine which a control part implements when giving braking force according to the amount of brake operations to a wheel. The flowchart explaining the process routine which a control part implements in order to suppress the deviation with the temperature of one coil and the temperature of another coil among each coil which comprises a motor. It is a timing chart at the time of giving braking force to a wheel, (a) shows change of vehicle body speed of vehicles, (b) shows change of braking force to a wheel, and (c) shows rotation angle of a motor. (D) shows the transition of the value of the current flowing through each coil of the motor. 7 is a flowchart for explaining a part of a processing routine executed by a control unit when a braking force corresponding to a brake operation amount is applied to a wheel in an electric braking device for a vehicle according to another embodiment. The block diagram which shows the outline of the electric braking device of the vehicle of other another embodiment.

Hereinafter, an embodiment in which a vehicle motor control device and a vehicle electric braking device are embodied will be described with reference to the drawings.
As shown in FIG. 1, the electric braking device 10 for a vehicle includes an electric brake actuator 12 provided for each wheel 11 and a control device 13 for controlling the brake actuator 12. For example, the electric braking device 10 applied to a vehicle having four wheels 11 includes a total of four brake actuators 12.

  The brake actuator 12 is a disc-type electric actuator, and includes a brake disc 20 that is an example of a rotating body that rotates integrally with the wheel 11, and a brake caliper 21 that is supported by the vehicle body. The brake caliper 21 supports a pair of brake pads 22 arranged on both sides of the brake disc 20 in the vehicle width direction, which is also the left-right direction in the figure. These brake pads 22 correspond to an example of a “friction member”. The brake pad 22 is movable in a direction toward and away from the brake disk 20, and a greater braking force is applied to the wheel 11 as the force pressing the brake pad 22 against the brake disk 20 is larger.

  In addition, as a brake actuator applied to the electric braking device 10, a drum type electric actuator can be cited in addition to the disk type. In this case, the brake drum corresponds to an example of a “rotating body”, and the brake shoe corresponds to an example of a “friction member”.

  The brake caliper 21 is provided with a motor 23 and a transmission mechanism 24 that transmits the output from the motor 23 to the brake pad 22. When the motor 23 is driven, the output from the motor 23 is transmitted to the brake pad 22 through the transmission mechanism 24. As a result, the brake pad 22 is pressed against the brake disc 20 or the pressing of the brake pad 22 against the brake disc 20 is eliminated.

  In the present specification, the driving of the motor 23 for bringing the brake pad 22 close to the brake disc 20 or increasing the force pressing the brake pad 22 against the brake disc 20 is also referred to as positive drive. The driving of the motor 23 for reducing the force pressing the brake pad 22 against the brake disk 20 or separating the brake pad 22 from the brake disk 20 is also referred to as reverse driving. Further, the rotation direction of the output shaft 231 of the motor 23 when the motor 23 is normally driven is opposite to the rotation direction of the output shaft 231 when the motor 23 is reversely driven.

  The transmission mechanism 24 includes a speed reducer 25 that decelerates and outputs the rotational speed of the output shaft 231 of the motor 23, and a shaft member 26 connected to the output side of the speed reducer 25. The shaft member 26 rotates when the output torque from the motor 23 is transmitted through the speed reducer 25. At this time, the shaft member 26 rotates in a direction according to the rotation direction of the output shaft 231 of the motor 23. In the present embodiment, the reduction ratio of the speed reducer 25 is such that even if the braking force applied to the wheel 11 changes by one rotation of the motor 23, the driver of the vehicle hardly feels the change in the braking force. The ratio is set.

  Further, the transmission mechanism 24 is provided with a screw member 27 connected to the tip of the shaft member 26 and a piston 28 that supports the brake pad 22. The screw member 27 is located inside the piston 28, and the peripheral surface of the screw member 27 is subjected to male screw processing. That is, the peripheral surface of the screw member 27 is a male screw portion.

  Internal thread processing is given to the inner peripheral surface of the piston 28. That is, the inner peripheral surface of the piston 28 is a female screw portion into which the male screw portion of the screw member 27 is screwed. Therefore, the rotational movement of the screw member 27 is converted into a linear movement and input to the piston 28. That is, the screw member 27 and the piston 28 constitute an example of a “converter” that converts the rotational motion of the output shaft 231 of the motor 23 into a linear motion and outputs the linear motion to the brake pad 22.

  Of the plurality of brake actuators 12 provided in the vehicle, some brake actuators 12 are provided with a lock mechanism 30 for holding a braking force applied to the wheels 11 as shown in FIG. ing. For example, the brake actuator 12 having the lock mechanism 30 can include a brake actuator for a rear wheel.

  The lock mechanism 30 is fixed to the output shaft 231 of the motor 23, a ratchet gear 31 that rotates integrally with the output shaft 231, a claw member 32 that moves forward and backward in a direction toward and away from the ratchet gear 31, and a claw member 32 has a solenoid 33 as a power source. The ratchet gear 31 rotates based on the drive of the motor 23.

  As shown in FIG. 1, the control device 13 includes a rotation angle detection sensor 101 that detects the rotation angle of the output shaft 231 of the motor 23, that is, the ratchet gear 31, and a pushing force that detects the force with which the piston 28 pushes the brake pad 22. The pressure sensor 102 is electrically connected. The pressing force detected by the pressing force sensor 102 correlates with the force pressing the brake pad 22 against the brake disc 20. Therefore, the control device 13 can estimate the force pressing the brake pad 22 against the brake disc 20 based on the pressing force detected by the pressing force sensor 102.

  The control device 13 is electrically connected to a stroke sensor 103 that detects a brake operation amount of the brake pedal 200. Based on the amount of brake operation detected by the stroke sensor 103, the control device 13 calculates the required braking force requested by the driver. And the control apparatus 13 controls the drive of the motor 23 according to the calculated request | requirement braking force. For example, the control device 13 drives the motor 23 forward when the required braking force is large, and reversely drives the motor 23 when the required braking force is small. Further, the control device 13 does not change the rotation angle of the output shaft 231 of the motor 23 when the required braking force is held.

  A parking switch 111 is electrically connected to the control device 13. When the parking switch 111 is turned on while the vehicle is stopped, the control device 13 positively drives the motor 23 to apply the braking force necessary for stopping the vehicle to the wheel 11, and this state To drive the motor 23 and the solenoid 33. Then, after confirming that the braking force applied to the wheel 11 is held by the lock mechanism 30, the control device 13 stops driving the motor 23 and the solenoid 33.

  Further, a wheel speed sensor 104 that detects the wheel speed of the wheel 11 is electrically connected to the control device 13. The control device 13 calculates the vehicle body speed based on at least one wheel speed (for example, the largest wheel speed) among the wheel speeds for each wheel 11.

Next, the motor 23 and the control device 13 will be described in detail with reference to FIG.
As shown in FIG. 2, the motor 23 is a three-phase AC brushless motor having a u-phase coil 23u, a v-phase coil 23v, and a w-phase coil 23w. The rotation angle of the output shaft 231 of the motor 23 is simply referred to as “rotation angle θ of the motor 23”, and the rotation of the output shaft 231 of the motor 23 is simply referred to as “the motor 23 rotates”.

  The control device 13 includes a motor control device 40 that adjusts the rotation of the motor 23 by individually controlling the alternating current supplied to the coils 23u, 23v, and 23w. The motor control device 40 is provided with an inverter circuit 41 that switches a current flowing through the motor 23, a control unit 42 that controls the inverter circuit 41, and a battery 43 as a DC power source.

A battery 43 is connected to the input side of the inverter circuit 41, and the motor 23 is connected to the output side of the inverter circuit 41.
The inverter circuit 41 includes a power line EL1 connected to the anode side of the battery 43, a power line EL2 connected to the cathode side of the battery 43, a u-phase upper and lower arm ELu corresponding to the u-phase coil 23u, and a v-phase coil 23v. A corresponding v-phase upper and lower arm ELv and a w-phase upper and lower arm ELw corresponding to the w-phase coil 23w are provided. The inverter circuit 41 includes a smoothing capacitor C connected to the power lines EL1 and EL2 in parallel with the battery 43, a current sensor 411 that detects the value of the current flowing through the u-phase coil 23u of the motor 23, and a w-phase coil 23w. And a current sensor 412 for detecting the value of the flowing current.

  One end of the u-phase upper and lower arm ELu is connected to the power line EL1, and the other end of the u-phase upper and lower arm ELu is connected to the power line EL2. The u-phase upper and lower arms ELu are provided with switching elements Q1u and Q2u connected in series between the power lines EL1 and EL2, and freewheeling diodes D1u and D2u connected in parallel to the switching elements Q1u and Q2u. . And the connection part of switching element Q1u and switching element Q2u in u phase upper and lower arm ELu is connected with u phase coil 23u.

  One end of the v-phase upper and lower arm ELv is connected to the power line EL1, and the other end of the v-phase upper and lower arm ELv is connected to the power line EL2. The v-phase upper and lower arms ELv are provided with switching elements Q1v and Q2v connected in series between the power lines EL1 and EL2, and freewheeling diodes D1v and D2v connected in parallel to the switching elements Q1v and Q2v. . And the connection site | part of switching element Q1v and switching element Q2v in v phase upper and lower arm ELv is connected with v phase coil 23v.

  One end of the w-phase upper and lower arm ELw is connected to the power line EL1, and the other end of the w-phase upper and lower arm ELw is connected to the power line EL2. The w-phase upper and lower arms ELw are provided with switching elements Q1w and Q2w connected in series between the power lines EL1 and EL2, and freewheeling diodes D1w and D2w connected in parallel to the switching elements Q1w and Q2w. . And the connection part of switching element Q1w and switching element Q2w in w phase upper and lower arm ELw is connected with w phase coil 23w.

  In the example shown in FIG. 2, IGBTs (insulated gate bipolar transistors) are used as the switching elements Q1u to Q1w and Q2u to Q2w. However, elements other than IGBTs, such as power MOSFETs, may be employed as the switching elements Q1u to Q1w and Q2u to Q2w as long as they can be switched on and off quickly.

  A control unit 42 is electrically connected to the gates of the switching elements Q1u to Q1w and Q2u to Q2w. The switching elements Q1u to Q1w and Q2u to Q2w are turned on / off when a drive signal having a predetermined pulse width is input from the control unit 42 to the gate. For example, by appropriately controlling on / off of the switching elements Q1u to Q1w and Q2u to Q2w, the inverter circuit 41 generates an alternating current based on the direct current input from the battery 43, and the alternating current is supplied to the motor 23. Output to.

  Specifically, when a positive current is passed through u-phase coil 23u, switching element Q1u is turned on and switching element Q2u is turned off. At this time, the longer the period during which switching element Q1u is on, the greater the positive current flowing through u-phase coil 23u. On the other hand, when a negative current is passed through u-phase coil 23u, switching element Q1u is turned off and switching element Q2u is turned on. At this time, the longer the period during which switching element Q2u is on, the greater the negative current flowing through u-phase coil 23u.

  Further, when a positive current is supplied to the v-phase coil 23v, the switching element Q1v is turned on and the switching element Q2v is turned off. When a negative current is supplied to the v-phase coil 23v, the switching element Q1v is turned off. At the same time, the switching element Q2v is turned on. Further, when a positive current is passed through the w-phase coil 23w, the switching element Q1w is turned on and the switching element Q2w is turned off. When a negative current is passed through the w-phase coil 23w, the switching element Q1w is turned off. At the same time, the switching element Q2w is turned on.

  Thus, the rotation angle of the motor 23 is adjusted by changing the current flowing through the coils 23u, 23v, and 23w of the motor 23. Therefore, in this embodiment, the switching elements Q1u, Q1v, and Q1w constitute an example of a “positive current generator” for outputting a positive current to the coils 23u, 23v, and 23w, and the switching elements Q2u, Q2v, and Q2w Thus, an example of a “negative current generation unit” for outputting a negative current to the coils 23u, 23v, and 23w is configured. That is, the inverter circuit 41 has a configuration in which a positive current generator and a negative current generator are provided for each of the coils 23u, 23v, and 23w of the motor 23.

  Current sensors 411 and 412 are electrically connected to the control unit 42. Therefore, the control unit 42 can acquire the value of the current flowing through the u-phase coil 23u and the value of the current flowing through the w-phase coil 23w based on the current values detected by the current sensors 411 and 412. Further, the control unit 42 can calculate the value of the current flowing through the v-phase coil 23v based on the value of the current flowing through the u-phase coil 23u and the value of the current flowing through the w-phase coil 23w.

  In the following description of the present specification, the current flowing through the u-phase coil 23u is referred to as “current Iu”, the current flowing through the v-phase coil 23v is referred to as “current Iv”, and the current flowing through the w-phase coil 23w is referred to as “current Iw”. "

  Next, the relationship between the currents Iu, Iv, Iw flowing through the coils 23u, 23v, 23w of the motor 23 and the rotation angle θ of the motor 23 will be described with reference to FIGS. 3 and 4, the current Iu flowing through the u-phase coil 23u is indicated by a solid line, the current Iv flowing through the v-phase coil 23v is indicated by a broken line, and the current Iw flowing through the w-phase coil 23w is indicated by a two-dot chain line. Yes.

  As shown in FIGS. 3 and 4, since the motor 23 is a three-phase AC motor, the rotation angle of the motor 23 is changed by periodically changing the currents Iu, Iv, Iw flowing through the coils 23u, 23v, 23w. θ can be changed. Thus, the phases of the currents Iu, Iv, and Iw flowing through the coils 23u, 23v, and 23w are different from each other by “120 °”. However, the fluctuation ranges of the currents Iu, Iv, and Iw are equal to each other, and the maximum values Im of the currents Iu, Iv, and Iw are equal to each other. That is, the currents Iu, Iv, and Iw vary between the lower limit value “−Im” and the upper limit value “+ Im”.

  In the vehicle electric braking apparatus 10 of the present embodiment, the braking force applied to the wheels 11 can be controlled by controlling the rotation of the motor 23. That is, the braking force applied to the wheel 11 is increased by increasing the rotation angle θ of the motor 23. On the other hand, when the braking force applied to the wheel 11 is held, the rotation angle θ of the motor 23 is held. When the rotation angle θ of the motor 23 is maintained in this way, the values of the currents Iu, Iv, and Iw that are passed through the coils 23u, 23v, and 23w of the motor 23 so that the rotation angle θ of the motor 23 does not change are also determined. Retained.

  Therefore, depending on the rotation angle θ of the motor 23 when the braking force applied to the wheel 11 is held in this way, the absolute value of the current flowing through one of the coils 23u, 23v, 23w is the maximum value. While it is substantially equal to Im, the absolute value of the current flowing through the other coils may be smaller than the maximum value Im. Thus, the state of the motor 23 when the absolute value of the current flowing through one coil is substantially equal to the maximum value Im is referred to as a “specific state”, and is flowing when the motor 23 is in the specific state. A coil whose absolute value of current is substantially equal to the maximum value Im is referred to as a “specific coil”.

  Specifically, the absolute value of the current flowing through one coil among the coils 23u, 23v, and 23w is larger than the absolute value of the current flowing through the other coil, and the absolute value of the current flowing through the one coil is determined as a peak. When the value is equal to or greater than the value IpTh, it can be determined that the motor 23 is in the specific state. Further, when the motor 23 is in the specific state, a coil whose absolute value of the flowing current is equal to or greater than the peak determination value IpTh corresponds to the specific coil.

  For example, as shown in FIG. 3, when the rotation angle θ of the motor 23 is “90 °”, the absolute value of the current Iu flowing through the u-phase coil 23u is the absolute value of the current Iv flowing through the v-phase coil 23v and the w-phase. The absolute value of the current Iu flowing through the u-phase coil 23u is greater than the absolute value of the current Iw flowing through the coil 23w, and is greater than or equal to the peak determination value IpTh. Therefore, in such a case, it can be determined that the motor 23 is in the specific state, and the u-phase coil 23u corresponds to the specific coil.

The peak determination value IpTh is set to a value that satisfies the following conditions.
(Condition 1-1) When the absolute value of the current flowing through one of the coils 23u, 23v, and 23w is equal to or greater than the peak determination value IpTh, the absolute value of the current flowing through the other coil is the peak determination value IpTh. No more than that.

  (Condition 1-2) When the absolute value of the current flowing through one of the coils 23u, 23v, and 23w is “0 (zero)”, the peak determination value IpTh is the absolute value of the current flowing through the other coil. Bigger than. For example, when the rotation angle θ is “60 °”, the value of the current Iv flowing through the v-phase coil 23v is “0 (zero)”, the absolute value of the current Iu flowing through the u-phase coil 23u, and the w-phase coil 23w. The absolute value of the current Iw flowing through the current is a relatively large value. The peak determination value IpTh is set to a value larger than the absolute value of the current Iu flowing through the u-phase coil 23u and the absolute value of the current Iw flowing through the w-phase coil 23w.

  When the motor 23 is in the specific state as described above, the absolute value of the current flowing through the specific coil among the coils 23u, 23v, and 23w is large, but the absolute value of the current flowing through the other coils is relatively high. small. Therefore, if the motor 23 continues to be in the specific state, the temperature of the specific coil becomes higher than the temperature of the other coil, and the secular change of the characteristic of the specific coil may progress more than the other coil. is there.

  As an example, as shown in FIG. 3, when the rotation angle θ of the motor 23 is maintained at “90 °”, the absolute value of the current Iu flowing through the u-phase coil 23u is equal to the maximum value Im, while the v-phase coil The absolute values of the currents Iu and Iw flowing through the 23v and w-phase coils 23w are about half of the maximum value Im. In this case, the motor 23 is in a specific state, the u-phase coil 23u corresponds to a specific coil, and the v-phase coil 23v and the w-phase coil 23w correspond to other coils. In this case, the temperature of the u-phase coil 23u is higher than the temperatures of the v-phase coil 23v and the w-phase coil 23w.

  Therefore, in this embodiment, when it is detected that the motor 23 is in the specific state, the rotation angle θ of the motor 23 is changed, and the continuation cancellation that changes the value of the current flowing through the specific coil is eliminated. Processing was carried out. By carrying out the continuation elimination process in this way, a state where the absolute value of the current flowing through the specific coil is larger than the absolute value of the current flowing through the other coil is continued, or the temperature of the specific coil and the other coil It is suppressed that the deviation from the temperature becomes too large.

  That is, the continuation cancellation process performed by the control unit 42 is a first continuation cancellation in which the rotation angle θ of the motor 23 is changed to a rotation angle at which the absolute value of the current flowing in the specific coil becomes small and the rotation angle θ is maintained. And a second continuation canceling process for oscillating the rotation angle θ of the motor 23 within an angle range including the rotation angle at which the absolute value of the current flowing through the specific coil is reduced. And the control part 42 implements a 1st continuation cancellation process, or implements a 2nd continuation cancellation process according to a condition.

Next, the first continuation cancellation process will be described with reference to FIG.
As shown in FIG. 3, in the first continuation cancellation process, when it is detected that the motor 23 is in the specific state, the absolute value of the current flowing through the specific coil is determined from the peak determination value IpTh. The rotation angle θ of the motor 23 is changed so as to decrease, and the rotation angle θ is maintained. In this case, the rotation angle θ of the motor 23 to be held is changed to a rotation angle at which the absolute value of the current flowing through one of the two other coils other than the specific coil is “0 (zero)”. Is done. For example, when it is detected that the rotation angle θ of the motor 23 is maintained at “90 °” as indicated by a solid arrow in FIG. 3, the rotation angle θ of the motor 23 is set to “60”. By changing to “°”, the absolute value of the current Iu flowing through the u-phase coil 23u, which is a specific coil, is reduced. As a result, the absolute value of the current Iv flowing through the v-phase coil 23v becomes “0 (zero)”.

  At this time, in the first continuation elimination process, the absolute value of the current Iu flowing through the u-phase coil 23u, which is a specific coil, is reduced by changing the rotation angle θ of the motor 23 to “120 °”. Also good. As a result, the absolute value of the current Iw flowing through the w-phase coil 23w becomes “0 (zero)”.

  In the first continuation cancellation process, the absolute value of the current flowing through any one of the coils 23u, 23v, and 23w is changed to “0 (zero)” by changing the rotation angle θ of the motor 23. If possible, the change amount of the rotation angle θ may be a value different from “30 °”. For example, the rotation angle θ of the motor 23 may be changed by “90 °”. In this case, the absolute value of the current flowing through the specific coil can be set to “0 (zero)”. Further, the rotation angle θ of the motor 23 may be changed by “150 °”. In this case, the absolute value of the current flowing through one of the two other coils different from the specific coil can be set to “0 (zero)”.

Next, the second continuation elimination process will be described with reference to FIG.
As shown in FIG. 4, in the second continuation cancellation process, when it is detected that the motor 23 is in the specific state, the rotation angle θ of the motor 23 is oscillated within the variation allowable angle range Rθ. Let The variation allowable angle range Rθ at this time is set so as to satisfy the following conditions.

  (Condition 2-1) The motor 23 includes a rotation angle that is not in a specific state. For example, when the second continuation elimination process is performed due to the state in which the rotation angle θ of the motor 23 is maintained at “90 °”, the current flowing through the u-phase coil 23u that is a specific coil Including the rotation angle θ at which the absolute value of is less than the peak determination value IpTh.

  (Condition 2-2) The rotation angle θ at which the absolute value of the current flowing through the coils 23u, 23v, 23w other than the specific coil is “0 (zero)” is included. For example, when the second continuation elimination process is performed due to the state in which the rotation angle θ of the motor 23 is maintained at “90 °”, the current flowing through the v-phase coil 23v, which is another coil, is performed. The rotation angle at which the absolute value of Iv is “0 (zero)” and the rotation angle at which the absolute value of the current Iw flowing through the w-phase coil 23w, which is another coil, is “0 (zero)”.

(Condition 2-3) The rotation angle at which the absolute value of the current flowing through the specific coil is “0 (zero)” is included.
(Condition 2-4) The reference rotation angle θb, which is the rotation angle θ when the motor 23 is continuously in the specific state, is included. More specifically, the lower limit value θl of the allowable variation angle range is a difference obtained by subtracting the specified rotation angle θd from the reference rotation angle θb, and the upper limit value θh of the allowable change angle range is the difference between the specified rotation angle θd and the reference rotation angle θb. It must be the sum of additions.

  In the present embodiment, the specified rotation angle θd is set to “90 °” in order for the variation allowable angle range Rθ to satisfy all of the above (Condition 2-1) to (Condition 2-4). As a result, as shown in FIG. 4, when it is detected that the state in which the rotation angle θ of the motor 23 is held at “90 °” is continued, the lower limit value θl of the variation allowable angle range is “0”. (Zero) ° ”and the upper limit value θh of the variation allowable angle range is set to“ 180 ° ”. Therefore, the rotation angle θ is oscillated between “0 (zero) °” and “180 °” by performing the second continuation elimination process. Of course, if the variation allowable angle range Rθ satisfies all of the above (condition 2-1) to (condition 2-4), the specified rotation angle θd may be set to a value larger than “90 °”. .

  In the second continuation elimination process, the variation allowable angle range Rθ may be appropriately changed as long as (Condition 2-1) is included. For example, the change permission angle range Rθ may be set so that the reference rotation angle θb becomes the lower limit value θl, or the change permission angle range Rθ may be set so that the reference rotation angle θb becomes the upper limit value θh. . Further, if the reference rotation angle θb is included, the variation allowable angle range Rθ may be set so as not to include an angle at which the absolute value of the current flowing through the specific coil is “0 (zero)”. For example, when the reference rotation angle θb is “90 °” and the specific coil is the u-phase coil 23u, the variation allowable angle range Rθ is set so as not to include “0 (zero) °” and “180 °”. May be. If the reference rotation angle θb is included, the variation allowable angle range Rθ is set so as not to include an angle at which the absolute value of the current flowing in other coils other than the specific coil is “0 (zero)”. May be. For example, when the reference rotation angle θb is “90 °” and the specific coil is the u-phase coil 23u, the variation allowable angle range Rθ may be set so as not to include “60 °” and “120 °”. Good.

  Furthermore, the variation allowable angle range Rθ may be set so as not to include the reference rotation angle θb. For example, when the reference rotation angle θb is “90 °” and the specific coil is the u-phase coil 23u, the variation is permitted so that “120 °” becomes the lower limit value θl and “270 °” becomes the upper limit value θh. The angle range Rθ may be set.

  By the way, in the present embodiment, when the first continuation cancellation process and the second continuation cancellation process are performed when the braking force is applied to the wheel 11, the driver requests a certain braking force. Even in this case, the braking force applied to the wheel 11 may change.

  Here, when the second continuation canceling process is performed, the rotation angle θ of the motor 23 is vibrated, so that the braking force applied to the wheel 11 is likely to vibrate, but each coil 23u, It is easy to suppress variations in the temperature rise mode of 23v and 23w. On the other hand, when the first continuation cancellation process is being performed, only the rotation angle θ of the motor 23 is changed, so that the braking force applied to the wheels 11 is unlikely to change.

  Therefore, in the present embodiment, the first continuation cancellation process is performed when the vehicle is not stopped, that is, while the vehicle is decelerating, while the second continuation cancellation process is performed when the vehicle is stopped. I have to.

  Next, a processing routine executed by the control unit 42 of the vehicle motor control device 40 in a situation where the brake operation is performed will be described with reference to a flowchart shown in FIG. This processing routine is a processing routine that is executed every preset control cycle. This processing routine is based on the premise that the driver is performing a brake operation, but may be executed during vehicle braking without a brake operation by the driver, such as an automatic brake. However, in this case, each process of steps S11 and S12 is omitted.

  As shown in FIG. 5, in this processing routine, the control unit 42 acquires the brake operation amount BO detected by the stroke sensor 103 (step S11), and the brake operation amount BO is less than “0 (zero)”. It is determined whether it is larger (step S12). When the brake operation amount BO is “0 (zero)” (step S12: NO), since it can be determined that the brake operation is not performed, the control unit 42 sets “0 (zero)” to the specific state duration TC. (Step S13), and then this processing routine is temporarily terminated. The specific state continuation period TC is a value indicating a period during which the motor 23 is continuously in the specific state.

  In step S12, when the brake operation amount BO is larger than “0 (zero)” (step S12: YES), the control unit 42 calculates the required braking force BPT for each wheel 11 based on the brake operation amount BO ( In step S14, the inverter circuit 41 is driven based on the required braking force BPT (step S15). Specifically, the control unit 42 determines a force for pressing the brake pad 22 against the brake disc 20 so that the braking force BP applied to the wheel 11 becomes the required braking force BPT, and the brake pad 22 is applied to the brake disc 20 with the force. The amount of rotation of the motor 23 required for pressing the motor 23 is determined. In this way, the control unit 42 controls the inverter circuit 41 so that the rotation amount of the motor 23 becomes the determined rotation amount.

  Then, the control unit 42 acquires the value of the current Iu flowing through the u-phase coil 23u and the value of the current Iw flowing through the w-phase coil 23w detected by the current sensors 411 and 412, and based on the values of both the currents Iu and Iw. Then, the value of the current Iv flowing through the v-phase coil 23v is acquired (step S16). Subsequently, the control unit 42 determines whether or not the motor 23 is in a specific state (step S17). In step S17, when there is a coil having an absolute current value equal to or greater than the peak determination value IpTh among the coils 23u, 23v, and 23w, it can be determined that the motor 23 is in the specific state. On the other hand, when the absolute values of the currents flowing through all the coils 23u, 23v, and 23w are less than the peak determination value IpTh, it can be determined that the motor 23 is not in the specific state.

  In step S17, when the motor 23 is not in the specific state (step S17: NO), the control unit 42 shifts the process to step S13. On the other hand, when the motor 23 is in the specific state (step S17: YES), the control unit 42 updates the specific state duration TC (step S18). That is, the control unit 42 integrates a value corresponding to the control cycle of this processing routine in the specific state duration TC.

  Subsequently, the control unit 42 determines whether or not the specific state continuation period TC is greater than or equal to the period determination value TCTh (step S19). The period determination value TCTh is a determination value for determining whether or not to perform the continuation cancellation process according to the specific state continuation period TC. That is, the control unit 42 can detect that the motor 23 is continuously in the specific state when the specific state continuation period TC is equal to or greater than the period determination value TCTh. When the specific state continuation period TC is less than the period determination value TCTh (step S19: NO), the control unit 42 once ends this processing routine. On the other hand, when the specific state continuation period TC is equal to or greater than the period determination value TCTh (step S19: YES), the control unit 42 performs a continuation cancellation process described later with reference to FIG. 6 (step S20), and then performs this process. The routine is temporarily terminated.

Next, with reference to the flowchart shown in FIG. 6, the continuation cancellation process (continuation cancellation process routine) of step S20 performed by the control unit 42 will be described.
As shown in FIG. 6, in this processing routine, the control unit 42 acquires the vehicle body speed VS based on the wheel speed detected by the wheel speed sensor 104 (step S31), and the vehicle is detected based on the vehicle body speed VS. It is determined whether or not it is stopped (step S32). When the vehicle is not stopped (step S32: NO), since the vehicle can be determined to be decelerating, the control unit 42 performs the first continuation cancellation process (step S33), and the process will be described later. The process proceeds to S35. On the other hand, when the vehicle is stopped (step S32: YES), the control unit 42 performs the second continuation elimination process (step S34), and the process proceeds to the next step S35.

  In step S <b> 35, the control unit 42 acquires the brake operation amount BO detected by the stroke sensor 103. Subsequently, the control unit 42 calculates the required braking force BPT based on the acquired brake operation amount BO (step S36), and determines whether or not the required braking force BPT has changed (step S37). If the required braking force BPT has not changed, it can be determined that there is no need to change the rotation angle θ of the motor 23, so the first continuation cancellation process and the second continuation cancellation process are continued. It is desirable to make it. However, when the required braking force BPT is changing, it is necessary to change the braking force applied to the wheel 11, and therefore the first continuation cancellation process and the second continuation cancellation process may be terminated. desirable.

  Therefore, when the required braking force BPT has not changed in step S37 (step S37: NO), the control unit 42 shifts the process to the previous step S31. On the other hand, when the required braking force BPT has changed (step S37: YES), the control unit 42 ends the present processing routine and ends the execution of the first continuation cancellation process and the second continuation cancellation process.

  Next, an example of a method for controlling the motor 23 when the brake operation is performed while the vehicle is running and the required braking force BPT is held constant will be described with reference to the timing chart shown in FIG. In FIG. 7, as in FIGS. 3 and 4, the current Iu flowing through the u-phase coil 23u is indicated by a solid line, the current Iv flowing through the v-phase coil 23v is indicated by a broken line, and the current Iw flowing through the w-phase coil 23w is It is indicated by a two-dot chain line. In the present embodiment, as described above, the specified rotation angle θd in the second continuation cancellation process is “90 °”.

  As shown in FIGS. 7A, 7B, 7C, and 7D, when the requested braking force BPT is held at the first timing t11, the braking force BP applied to the wheel 11 is requested. In order to maintain the power BPT, the rotation angle θ of the motor 23 is maintained. In this case, the values of the currents Iu, Iv, Iw flowing through the coils 23u, 23v, 23w of the motor 23 are held. Further, at the rotation angle θ of the motor 23 at the first timing t11, since the absolute value of the current Iu flowing through the u-phase coil 23u is equal to or greater than the peak determination value IpTh, the motor 23 is in a specific state, and the u-phase coil 23u It can be determined that the coil is a specific coil.

  In the example shown in FIG. 7, for easy understanding of the explanation, the rotational angle θ of the motor 23 when the motor 23 is in a specific state is the absolute value of the current Iu flowing through the u-phase coil 23u. It is assumed that the rotation angle θ (90 °) is the maximum value Im. In this case, the rotation angle θ corresponds to the reference rotation angle θb.

  After the first timing t11, since the motor 23 is continuously in the specific state, the specific state continuation period TC gradually increases. Then, at the second timing t12, the specific state continuation period TC reaches the period determination value TCTh. Since the vehicle is decelerating between the second timing t12 and the third timing t13, the first continuation cancellation process is performed. Then, the rotation angle θ of the motor 23 is changed so that the absolute value of the current Iu flowing through the u-phase coil 23u, which is a specific coil, becomes smaller than the peak determination value IpTh by performing the first continuation cancellation process. . As a result, the absolute value of the current Iu flowing through the u-phase coil 23u for a period longer than the period determination value TCTh is suppressed from being greater than or equal to the peak determination value IpTh.

  In the first continuation cancellation process, not only the current Iu flowing through the u-phase coil 23u but also the current Iv flowing through the v-phase coil 23v and the current flowing through the w-phase coil 23w in order to change the rotation angle θ of the motor 23. Iw is also changed. In the first continuation cancellation process shown in FIG. 7, when the rotation angle θ (90 °) immediately before the start of the first continuation cancellation process is the reference rotation angle θb, the rotation angle θ of the motor 23 is changed to the reference rotation angle θb. The angle obtained by subtracting “30 °” from (60 °). As a result, the absolute value of the current Iv flowing through the v-phase coil 23v becomes “0 (zero) °”, while the absolute value of the current Iu flowing through the u-phase coil 23u and the absolute value of the current Iw flowing through the w-phase coil 23w. Are equal to each other. Note that the actual braking force applied to the wheels 11 (hereinafter also referred to as “actual braking force BPR”) is slightly changed by changing the rotation angle θ of the motor 23 through the execution of the first continuation cancellation process. To decrease. However, the actual braking force BPR is hardly noticed by the driver of the vehicle.

  Then, at the third timing t13, the vehicle stops under a situation where the required braking force BPT is held. Therefore, after the third timing t13, the second continuation elimination process is performed, so that the rotation angle θ of the motor 23 is vibrated at a high speed within the variation allowable angle range Rθ. In FIG. 7, for convenience of understanding the description, the current flowing through the coils 23u, 23v, and 23w during the execution of the second continuation cancellation process is depicted as oscillating relatively slowly.

  In the example shown in FIG. 7, the lower limit value θl of the variation permission angle range Rθ is a rotation angle (0 °) obtained by subtracting the specified rotation angle θd (90 °) from the reference rotation angle θb (90 °). The upper limit value θh of the angle range Rθ is a rotation angle (180 °) obtained by adding the specified rotation angle θd (90 °) to the reference rotation angle θb (90 °).

  In other words, in the period from the third timing t13 to the fourth timing t14, the rotation angle θ of the motor 23 is gradually decreased until it reaches the lower limit value θl (0 °) of the variation allowable angle range.

  In the period from the fourth timing t14 to the fifth timing t15, the rotation angle θ of the motor 23 is gradually increased until it reaches the upper limit value θh (180 °) of the variation allowable angle range. Subsequently, in the period from the fifth timing t15 to the sixth timing t16, the rotation angle θ of the motor 23 is gradually decreased until it reaches the lower limit value θl of the variation allowable angle range. And while the execution conditions of the 2nd continuation cancellation process are satisfied, such vibration of the rotation angle θ of the motor 23 is continued.

  The implementation period of the second continuation elimination process includes a period in which the absolute value of the current Iu flowing through the u-phase coil 23u that is the specific coil is less than the peak determination value IpTh. Therefore, it is suppressed that the temperature of u phase coil 23u becomes higher than the temperature of v phase coil 23v and w phase coil 23w.

  In addition, during the execution period of the second continuation cancellation process, the rotation angle θ at which the value of the current Iu flowing through the u-phase coil 23u of the specific coil becomes “0 (zero)” and the current Iv flowing through the v-phase coil 23v A rotation angle θ at which the value is “0 (zero)” and a rotation angle θ at which the value of the current Iw flowing through the w-phase coil 23 w is “0 (zero)” are included. Further, during the implementation period, the rotation angle θ at which the absolute value of the current Iu flowing through the u-phase coil 23u of the specific coil becomes the maximum value Im and the rotation at which the value of the current Iv flowing through the v-phase coil 23v becomes the maximum value Im. The angle θ and the rotation angle θ at which the value of the current Iw flowing through the w-phase coil 23w becomes the maximum value Im are included. For this reason, when the rotation angle θ of the motor 23 is vibrated by performing the second continuation elimination process, variations in the temperature rise of the coils 23u, 23v, 23w are suppressed, and the coils 23u, 23v, The deviation of the temperature rise amount between 23 w is suppressed.

  Further, during the period from the fourth timing t14 to the sixth timing t16, the rotation angle of the motor 23 when the absolute value of the current Iu flowing through the u-phase coil 23u, which is a specific coil, is equal to or greater than the peak determination value IpTh. θ is included. More specifically, the variation allowable angle range Rθ is set so that the reference rotation angle θb is the center. For this reason, when the rotation angle θ of the motor 23 is vibrated by the execution of the second continuation cancellation process, the deviation amount of the rotation angle θ from the reference rotation angle θb becomes small.

  Note that the actual braking force BPR applied to the wheel 11 is also vibrated by performing the second continuation elimination process. However, in the example shown in FIG. 7, the second continuation elimination process is performed while the vehicle is stopped. For this reason, the change in vehicle behavior that accompanies the execution of the second continuation cancellation process does not occur, so that a reduction in drivability can be suppressed.

The above embodiment may be changed to another embodiment as described below.
In the electric braking device 10 for a vehicle, when the braking force BP applied to the wheel 11 is large, the rotation angle θ of the motor 23 is larger than when the braking force BP is small. For this reason, when the braking force BP applied to the wheel 11 is large, even if the rotation angle θ of the motor 23 is changed within a certain range, the rate of change of the braking force BP is small, and the uncomfortable feeling given to the driver is reduced. Cheap. On the other hand, when the braking force BP to be applied to the wheels 11 is small, if the rotation angle θ of the motor 23 is changed within a certain range, the rate of change of the braking force BP increases and the driver feels uncomfortable. .

  Therefore, when it can be determined that the braking force BP applied to the wheel 11 is large, the continuation canceling process may be performed when it is detected that the motor 23 is in the specific state. On the other hand, if it can be determined that the braking force BP applied to the wheel 11 is small, the continuation cancellation process may not be performed even if it is detected that the motor 23 is in the specific state.

  That is, as shown in FIG. 8, when the specific state duration TC is equal to or greater than the period determination value TCTh (step S19: YES), the control unit 42 determines whether or not the required braking force BPT is equal to or greater than the braking force determination value BPTh. Is determined (step S41). When the required braking force BPT is less than the braking force determination value BPTh (step S41: NO), the control unit 42 once ends this processing routine. In this case, the first continuation cancellation process and the second continuation cancellation process are not performed.

  On the other hand, when the required braking force BPT is equal to or greater than the braking force determination value BPTh (step S41: YES), the control unit 42 executes a continuation cancellation process (a first continuation cancellation process or a second continuation cancellation process) ( Step S42) After that, this processing routine is once ended. The braking force determination value BPTh is a determination value for determining whether or not to execute the continuation cancellation process, and is preferably determined as appropriate.

  According to the above configuration, in a situation where the braking force BP applied to the wheel 11 is greater than or equal to the braking force determination value BPTh, it is determined that the rate of fluctuation of the braking force BP with respect to the wheel 11 due to the execution of the continuation cancellation process is unlikely to increase. can do. Therefore, when it is detected that the motor 23 is in the specific state, the continuation canceling process is performed, so that the temperature of one coil becomes too higher than the temperature of the other coil. Can be suppressed.

  On the other hand, under the situation where the braking force BP to be applied to the wheel 11 is less than the braking force determination value BPTh, if the continuation elimination process is performed, the rate of fluctuation of the braking force BP to be applied to the wheel 11 is likely to increase, It can be judged that the sense of incongruity increases. Therefore, under such circumstances, even if the motor 23 continues to be in the specific state, the continuation cancellation process is not performed. Therefore, during vehicle braking, it is possible to suppress the occurrence of an event in which drivability is reduced due to the execution of the continuation cancellation process.

  In the example shown in FIG. 8, under the situation where the braking force BP applied to the wheel 11 is less than the braking force determination value BPTh, the execution of the continuation canceling process is prohibited regardless of whether or not the vehicle is stopped. ing. However, when the vehicle is stopped, drivability is hardly deteriorated even if the braking force BP applied to the wheels 11 varies due to the execution of the continuation cancellation process. Therefore, in a situation where the braking force BP applied to the wheel 11 is less than the braking force determination value BPTh, the execution of the continuation cancellation process may be prohibited only when the vehicle is not stopped. That is, even when the braking force BP applied to the wheel 11 is less than the braking force determination value BPTh, it is detected that the motor 23 is in a specific state when the vehicle is stopped. When it is done, the continuation cancellation process may be performed.

  When a positive current is supplied to the coil, the switching elements Q1u, Q1v, Q1w are turned on in the inverter circuit 41. Therefore, the current flows through the switching elements Q1u, Q1v, Q1w, so that the switching elements Q1u, Q1v, Q1w Temperature tends to rise. On the other hand, when a positive current flows through the coil, the switching elements Q2u, Q2v, Q2w of the inverter circuit 41 are turned off, so that no current flows through the switching elements Q2u, Q2v, Q2w, and the switching elements Q2u, Q2v, The temperature of Q2w is hard to rise. Similarly, when a negative current flows through the coil, current flows through the switching elements Q2u, Q2v, Q2w, and no current flows through the switching elements Q1u, Q1v, Q1w. Therefore, the temperature of the switching elements Q2u, Q2v, Q2w is The temperature of the switching elements Q1u, Q1v, Q1w is difficult to rise. Therefore, when one of the positive current and the negative current continues to flow through the coil, the temperature of the switching element that is turned on to flow the one current through the coil becomes excessively high. There is a fear.

  Therefore, the variation allowable angle range Rθ may be set to include both the rotation angle θ in which a positive current flows in a specific coil and the rotation angle θ in which a negative current flows in the specific coil. According to this, when the rotation angle θ of the motor 23 is vibrated by performing the second continuation cancellation process, a positive current is caused to flow through a specific coil, thereby forming a switching that constitutes an example of the negative current generation unit. A period in which the temperature rise of the element can be suppressed can be created. Moreover, the period which can suppress the temperature rise of the switching element which comprises an example of a positive current production | generation part can be created by sending a negative electric current through a specific coil.

  For example, when the u-phase coil 23u is a specific coil, a period in which the temperature rise of the switching element Q2u can be suppressed by flowing a positive current through the u-phase coil 23u, and a negative current is passed through the u-phase coil 23u. Thus, it is possible to create a period during which the temperature rise of the switching element Q1u can be suppressed. Therefore, it is possible to prevent an excessively large temperature difference between the two switching elements Q1u and Q2u that change the direction of the current Iu flowing through the u-phase coil 23u, which is a specific coil, during the execution of the second continuation elimination process. can do.

  When such a second continuation elimination process is performed, for example, the variation permission angle range Rθ may be set to “360 °”. In this case, the rotation angle θ of the motor 23 is vibrated by performing the second continuation cancellation process, so that the switching elements Q1u to Q1w and Q2u to Q2w of the coils 23u, 23v, and 23w are caused to vibrate in one cycle of the vibration. The period during which the power is turned on can be made equal. That is, it is possible to suppress an increase in temperature difference between the switching elements Q1u to Q1w and Q2u to Q2w of the coils 23u, 23v, and 23w.

  As an electric braking device for a vehicle, as long as the braking force BP to be applied to the wheel 11 can be adjusted by controlling the rotation angle θ of the motor 23, a device other than the electric braking device 10 is used. May be adopted. An example of such another electric braking device is shown in FIG.

  In addition, the electric braking device 10A for a vehicle shown in FIG. 9 is different from the above embodiment in the configuration for displacing the brake pad 22. Therefore, in the following description, parts different from the above embodiment will be mainly described, and the same members as those in the above embodiment will be denoted by the same reference numerals and redundant description will be omitted.

  As shown in FIG. 9, an electric braking device 10A for a vehicle includes a braking mechanism 12A provided for each wheel 11, a first actuator 51 that adjusts a braking force BP applied to the wheel 11 by the braking mechanism 12A, and A second actuator 52 and a control device 13A that controls the first actuator 51 and the second actuator 52 are provided.

  The brake mechanism 12A is provided with a brake disc 20, a brake pad 22, and a wheel cylinder 29 to which brake fluid is supplied from the first actuator 51 and the second actuator 52. The brake pad 22 approaches the brake disc 20 when the WC pressure, which is the hydraulic pressure in the wheel cylinder 29, is increased, and moves away from the brake disc 20 when the WC pressure is decreased. When the brake pad 22 is in contact with the brake disc 20, the higher the WC pressure, the greater the force pressing the brake pad 22 against the brake disc 20, and the braking force BP applied to the wheel 11 by the braking mechanism 12A is increased. growing.

  The first actuator 51 includes a first hydraulic pressure generation device 511, a first hydraulic pressure passage 512 for supplying brake fluid from the first hydraulic pressure generation device 511 to the wheel cylinder 29, and a first hydraulic pressure passage. And a shutoff valve 513 provided at 512. The first hydraulic pressure generator 511 is provided with a master cylinder 514 that generates an MC pressure that is a hydraulic pressure corresponding to the brake operation amount BO.

  In the first actuator 51, when the shutoff valve 513 is open, an amount of brake fluid corresponding to the MC pressure in the master cylinder 514 is supplied into the wheel cylinder 29 of the braking mechanism 12A. That is, the higher the MC pressure, the higher the WC pressure. On the other hand, when the shut-off valve 513 is closed, the brake fluid is restricted from being supplied from the master cylinder 514 to the wheel cylinder 29 regardless of the brake operation amount BO. The shut-off valve 513 is closed, for example, when a second actuator 52 described below is operating normally, and opened when the second actuator 52 is not operating normally.

  The second actuator 52 includes a second hydraulic pressure generator 521, a motor 23, a transmission mechanism 24A that transmits the output of the motor 23 to the second hydraulic pressure generator 521, a second hydraulic pressure path 522, It has. The second hydraulic pressure generator 521 is provided with a slave cylinder 523 that generates an SC pressure that is a hydraulic pressure corresponding to the rotation amount of the motor 23 driven according to the brake operation amount BO. The SC pressure is increased by increasing the rotation angle θ of the motor 23, and can be decreased by decreasing the rotation angle θ. In the second actuator 52, an amount of brake fluid corresponding to the SC pressure in the slave cylinder 523 is supplied into the wheel cylinder 29 of the braking mechanism 12A. That is, the higher the SC pressure, the higher the WC pressure.

  Even in such an electric braking device 10A for a vehicle, the rotation angle θ of the motor 23 may be held in order to hold the braking force BP applied to the vehicle, as in the above embodiment. Therefore, even in the vehicle control device 13A of the electric braking device 10A for such a vehicle, the motor control device 40 in the above embodiment may be provided.

  In the timing chart shown in FIG. 7, the rotation angle θ of the motor 23 is changed stepwise at the second timing t12, but the rotation angle θ of the motor 23 may be changed gradually. According to this, it is possible to suppress a sudden change in the braking force BP applied to the wheel 11 and suppress a decrease in drivability.

  The amount of change in the rotation angle θ of the motor 23 in the first continuation cancellation process and the change permission angle range Rθ in the second continuation cancellation process depend on the characteristics of the electric braking device 10 such as the reduction ratio of the speed reducer 25. It is preferable to determine appropriately. For example, when the speed reduction ratio of the speed reducer 25 is small, the change amount and the variation allowable angle range Rθ may be made smaller than when the speed reduction ratio is large. According to this, when implementing the 1st continuation cancellation process and the 2nd continuation cancellation process, it suppresses that braking force BP given to wheel 11 changes greatly, and suppresses a fall in drivability. Can do.

  As shown in FIGS. 3 and 4, there is a correlation between the rotation angle θ of the motor 23 and the values of the currents Iu, Iv, Iw flowing through the coils 23u, 23v, 23w. Therefore, the angle range of the rotation angle θ of the motor 23 when the absolute values of the currents Iu, Iv, Iw flowing through the coils 23u, 23v, 23w are equal to or greater than the peak determination value IpTh is obtained in advance. It may be determined whether the motor 23 is in a specific state by determining whether the rotation angle θ is included in the angle range (step S17).

  In the flowchart shown in FIG. 6, step S33 may be omitted. That is, when the vehicle is not stopped, the first continuation cancellation process may not be performed. In the flowchart shown in FIG. 6, step S34 may be omitted. That is, when the vehicle is stopped, the second continuation cancellation process may not be performed.

  In the flowchart shown in FIG. 6, steps S32 and S33 may be omitted. That is, the second continuation cancellation process may be performed regardless of whether or not the vehicle is stopped. In the flowchart shown in FIG. 6, steps S32 and S34 may be omitted. That is, the first continuation cancellation process may be performed regardless of whether or not the vehicle is stopped.

  The required braking force BPT may not be calculated based on the brake operation amount BO detected by the stroke sensor 103. For example, a sensor that detects the pedaling force applied to the brake pedal 200 by the driver may be provided, and the required braking force BPT may be calculated based on the pedaling force detected by the sensor.

  When the state in which the rotation angle θ of the motor 23 is held is continued, the values of the currents Iu, Iv, Iw flowing through the coils 23u, 23v, 23w of the motor 23 are held. A state where absolute values of currents Iu, Iv, and Iw flowing through 23u, 23v, and 23w are different may be continued. For this reason, when the state where the rotation angle θ of the motor 23 is maintained is continued, a temperature divergence is likely to occur between the coils 23u, 23v, and 23w.

  For example, when the rotation angle θ of the motor 23 is “60 °”, the absolute value of the current Iu flowing through the u-phase coil 23u and the absolute value of the current Iw flowing through the w-phase coil 23w are currents flowing through the v-phase coil 23v. It becomes larger than the absolute value of Iv, and the temperature of the u-phase coil 23u and the w-phase coil 23w tends to be higher than the temperature of the v-phase coil 23v. When the rotation angle θ of the motor 23 is “90 °”, the absolute value of the current Iu flowing through the u-phase coil 23u flows through the absolute value of the current Iv flowing through the v-phase coil 23v and the w-phase coil 23w. It becomes larger than the absolute value of the current Iw, and the temperature of the u-phase coil 23u tends to be higher than the temperatures of the v-phase coil 23v and the w-phase coil 23w.

  Therefore, in such a case, a continuation elimination process (second continuation elimination process) for vibrating the rotation angle θ of the motor 23 may be performed. According to this, by oscillating the rotation angle θ of the motor 23, the absolute values of the currents Iu, Iv, Iw flowing through the coils 23u, 23v, 23w can be varied. For this reason, it is difficult for the absolute values of the currents flowing in some of the coils 23u, 23v, and 23w to be greater than the absolute values of the currents flowing in the other coils, and as a result, the coils 23u, 23v, The temperature divergence between 23 w can be suppressed. In this way, it is possible to prevent the secular change in the characteristics of one of the three-phase coils 23u, 23v, and 23w of the motor 23 from proceeding more than the other coils. In this case, the vibration range of the rotation angle θ of the motor 23 may be the variation allowable angle range Rθ of the above embodiment.

  The vehicle motor control device 40 may be applied to other in-vehicle devices other than the vehicle electric braking device. For example, in an electric power steering apparatus that assists steering using the rotational force of the motor 23, the rotational angle θ of the motor 23 may be held in order to keep the steering angle constant. Accordingly, the vehicle motor control device 40 may be employed in such an electric power steering device.

  DESCRIPTION OF SYMBOLS 10,10A ... Electric brake device, 11 ... Wheel, 13, 13A ... Vehicle control device, 20 ... Brake disk (an example of a rotating body), 22 ... Brake pad (an example of a friction member), 23 ... Motor, 23u ... u Phase coil, 23v ... v phase coil, 23w ... w phase coil, 40 ... vehicle motor control device, 41 ... inverter circuit, 42 ... control unit, BP ... braking force, BPTh ... braking force judgment value, Iu ... u phase coil , Current flowing in Iv ... v phase coil, current flowing in Iw ... w phase coil, IpTh ... peak determination value, Im ... maximum value, Q1u, Q1v, Q1w ... switching element (an example of a positive current generator), Q2u, Q2v, Q2w: switching element (an example of a negative current generation unit), Rθ: variation permission angle range, θ: rotation angle, θb: reference rotation angle, θd: specified rotation angle, θl: variation permission Lower limit value of angle range, θh: upper limit value of fluctuation allowable angle range.

Claims (1)

A rotating body that rotates integrally with the wheel;
A friction member that applies a braking force to the wheel by being pressed against the rotating body;
A motor having a three-phase coil;
A motor control device that controls the force of pressing the friction member against the rotating body by adjusting the rotation of the motor by individually controlling the alternating current supplied to each coil ; and
The absolute value of the current flowing in one coil among the coils is larger than the absolute value of the current flowing in the other coil, and the absolute value of the current flowing in the one coil is equal to or greater than the peak determination value. Make the state a specific state,
When the motor is in a specific state, the absolute value of the flowing current is equal to or greater than the peak determination value, and the coil is a specific coil,
The motor control device includes a control unit that performs a continuation canceling process for changing a rotation angle of the motor when it is detected that the motor is continuously in the specific state.
The controller is
As the continuation cancellation process,
A first continuation canceling process for changing the rotation angle of the motor to a rotation angle at which an absolute value of a current flowing through the specific coil is smaller than the peak determination value, and maintaining the rotation angle;
And a second continuation elimination process for vibrating the rotation angle of the motor within a variation permission angle range including a rotation angle at which the motor does not enter the specific state,
When it is detected that the motor is in the specific state under a situation where braking force is applied to the wheel,
The electric braking device for a vehicle, wherein when the vehicle is not stopped, the first continuation cancellation process is performed, and when the vehicle is stopped, the second continuation cancellation process is performed.