JP3529589B2 - Ultrasonic motor control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an ultrasonic motor.

[0002]

2. Description of the Related Art Generally, an ultrasonic motor applies a high frequency voltage to a piezoelectric element provided in a stator to generate traveling wave vibration, and is rotatably arranged with respect to the stator based on the vibration. The rotor is rotated. Such an ultrasonic motor has a resonance frequency in order to obtain high output and high efficiency drive. By supplying a high frequency voltage equal to the resonance frequency to the piezoelectric element, the ultrasonic motor can be driven with high output and high efficiency.

However, in practice, when a high frequency voltage equal to the resonance frequency is supplied to the ultrasonic motor to drive the ultrasonic motor, the traveling wave vibration generated in the stator is disturbed due to over-amplitude and the like. Then, there is a problem that the disturbance of the vibration becomes a source of generation of abnormal noise of the ultrasonic motor.

Therefore, as one of the measures described above, the drive control of the ultrasonic motor is performed by the peak value control.
More specifically, the peak value control is to control the high frequency voltage applied to the piezoelectric element so that the positive and negative peak values are equal to the reference level (0 volt). That is, the waveform of the high frequency voltage applied to the piezoelectric element is controlled so as not to be disturbed. Therefore, if such a high frequency voltage is supplied to the ultrasonic motor, no abnormal noise is generated from the motor. Then, the ultrasonic motor compares the high frequency voltage applied to the piezoelectric element with the feedback voltage from the stator, and is controlled so as to approach the resonance frequency.

The ultrasonic motor controlled by the peak value control as described above is different from the ultrasonic motor without significantly impairing the original characteristics of the ultrasonic motor (low rotation, high torque, high rotation, low torque). Generation of sound is suppressed.

[0006]

A case where the above ultrasonic motor is mounted on a vehicle brake device 30 as shown in FIG. 11 will be described. That is, an ultrasonic motor (hereinafter, simply referred to as a motor) 31 is provided inside the actuator 32, and through the actuator 32,
The brake pad 34 is driven so as to abut or separate from a brake disc 33 fixed to an axle (not shown) in a flange shape.

More specifically, the motor 31 rotates normally when the driver steps on a brake pedal (not shown). By this normal rotation, the actuator 32 is operated in one direction to move the brake pad 34 in a direction in which it comes into contact with the brake disc 33. When the brake pad 34 comes into contact with the brake disc 33, the frictional forces act on each other to stop the rotation of the axle.

Further, the motor 31 rotates in the reverse direction when the driver returns the brake pedal. By this reverse rotation, the actuator 32 is operated in the other direction to move the brake pad 34 in the direction away from the brake disc 33. When the brake pad 34 separates from the brake disc 33, the axle becomes rotatable.

Here, the vehicle brake device 30 includes a brake pad 34 in order to shorten the braking distance of the brake.
Needs to be brought into contact with the brake disc 33 in a short time, and a high pressure contact force is required after the contact with the disc 33. In this case, the motor 31 is connected to the brake pad 3
High rotation is required so that 4 moves at high speed in the gap D with the brake disc 33, and high torque is required after the pad 34 contacts the disc 33.

However, if the motor 31 is simply used for the vehicle brake device 30 and the above-mentioned control of only the peak value control is performed on the motor 31, the motor 3 can be operated.
It is not possible to perform switching control for higher rotation or higher torque based on the usage state of No. 1. That is, the motor 3
The control suitable for the usage state of No. 1 could not be performed.
Therefore, by detecting the usage state of the motor 31, etc., high rotation,
Alternatively, it is necessary to determine which one of high torque is required and switch the characteristics of the motor based on the determination.

The present invention has been made to solve the above problems, and an object thereof is to switch an ultrasonic motor that is rotationally driven to either high rotational drive or high torque drive, and It is an object of the present invention to provide a control method of an ultrasonic motor capable of performing control suitable for the usage state of the motor.

[0012]

According to a first aspect of the present invention, there is provided an ultrasonic motor mounted on a vehicle brake device.
The method is to press the brake disc to rotate the axle.
Place the brake pad that stops rolling on the brake disc.
And move it in the direction of contact or the direction of separation.
Ultrasonic motor provided as a drive source for the actuator
Drive with high rotation or high torque.
Switch to one of the drive modes to change the motor
In the control method of the ultrasonic motor that performs suitable control,
The load torque applied to the ultrasonic motor is detected and detected.
The load torque value and the preset reference torque value.
When the load torque value at that time is less than the reference torque value
The brake pad against the brake disc
High speed drive for ultrasonic motor in a separated state
Motion is requested, and the motor is judged based on this judgment.
Is controlled at high speed, and the load torque value at that time is the reference torque.
If the brake value is exceeded, the brake pad will
The ultrasonic mode is in contact with the disk.
It is determined that high torque drive is required for the
The motor is controlled to a high torque based on
When the ultrasonic motor is controlled to rotate at high speed,
Rotate the rotation speed at the target rotation speed for high rotation and
When the motor is controlled with high torque, the rotation speed of the ultrasonic motor
The ultrasonic motor is rotated at the target rotation speed for high torque.
The number of rotations has hysteresis near the reference torque value.
The point is to have it .

The invention according to claim 2 is a vehicle brake.
A method for controlling an ultrasonic motor mounted on a device, comprising:
A brake that presses against the rake disc to stop axle rotation.
-Direction in which the brake pad contacts the brake disc
Or drive the actuator to move in the direction of separating
The ultrasonic motor provided as a source is driven to rotate.
High rotated at state or switching to either a high torque drive, Te control method smell of the ultrasonic motor to perform control suitable for the use state of the motor, it detects a load torque value applied to the ultrasonic motor, The detected load torque value,
It compares the reference torque value set in advance, when the load torque is below reference torque value at that time, the Burekipa
Is separated from the brake disc
What against the ultrasonic motor is determined that the high rotation drive is required, the motor and the high speed control on the basis of this determination, and,
<br/> when the load torque value at that time exceeds the reference torque value, the brake pad is brought to the brake disk
A contact state in contact against the ultrasonic motor is determined that the high torque driving is required, so a high torque controlling the motor based on the determination, Kokai said ultrasonic motor
When the rotation control is performed, the filter from the stator of the ultrasonic motor is
The feedback voltage is not the target feedback voltage for high rotation.
Rotate the ultrasonic motor so that the ultrasonic motor
When high torque control is performed, from the stator of the ultrasonic motor
Feedback voltage is target feedback for high torque
The ultrasonic motor is rotated so that the voltage becomes
The motor feedback voltage is near the reference torque value.
Then, the point is that it has hysteresis .

[0014]

According to a third aspect of the present invention, the frequency of the high frequency voltage applied to the stator of the ultrasonic motor in order to rotationally drive the ultrasonic motor is changed to drive the motor at high rotational speed or high torque. The point is to do so.

The invention according to claim 4 is characterized in that the voltage value of the high-frequency voltage is further changed when the ultrasonic motor is driven at high torque .

According to the first and second aspects of the invention, the load torque value applied to the ultrasonically driven ultrasonic motor is detected. Detected load torque value is compared with a predetermined reference torque value, determined in the case the load torque value is smaller than the reference torque value at that time, a high rotational drive to the ultrasonic motor has been requested, the determination Based on the above, high rotation control of the motor is performed. Further, when the load torque value at that time exceeds the reference torque value, it is determined that the high torque drive to the ultrasonic motor is requested, the motor on the basis of this determination is a high torque control is performed. That is, a request for either high rotation drive or high torque drive is determined based on the load torque value applied to the ultrasonic motor, and the motor is determined to be either high rotation drive or high torque drive based on the determination. Can be switched. Therefore,
The usage status of the ultrasonic motor can be easily detected,
The motor can always be driven in a suitable state.

[0018]

According to the third aspect of the invention, the ultrasonic motor is driven at a high rotation speed or a high speed by changing the frequency of the high frequency voltage applied to the stator of the motor to rotate the motor. Torque drive is performed. For example, the ultrasonic motor becomes high rotation (low torque) when the frequency of the high frequency voltage applied to the stator is close to the resonance frequency, and conversely becomes low rotation (high torque) when the frequency is moved away from the resonance frequency. That is, the frequency when the high rotational driving is required is controlled to approach the resonance frequency to the motor, a high torque drive is required
At this time , the frequency is controlled to move away from the resonance frequency in order to achieve low rotation. Therefore, it is possible to easily perform switching control for increasing the rotation speed or increasing the torque of the motor.

According to the fourth aspect of the invention, when the ultrasonic motor is driven at high torque, the voltage value of the high frequency voltage applied to the stator is further changed. Since the ultrasonic motor has a high torque when the voltage value of the high frequency voltage applied to the stator is increased, the voltage value of the high frequency voltage is increased when high torque driving is required for the motor. Therefore, it is possible to surely increase the torque of the motor.

[0021]

DETAILED DESCRIPTION OF THE INVENTION

(First Embodiment) A first embodiment in which the present invention is embodied in a control device for an ultrasonic motor mounted on a vehicle brake device will be described below with reference to FIGS. The vehicle brake device of the present embodiment has the same configuration as the vehicle brake device 30 shown in FIG. 11 described above, and is characterized by the control device for the ultrasonic motor 31. Therefore,
For convenience of explanation, the control device will be mainly described below.

FIG. 1 shows a control device for the ultrasonic motor 31. A rotor (not shown) rotatably arranged with respect to the stator 1 is in pressure contact with the ring-shaped stator 1 provided in the motor 31. The stator 1 is provided with arc-shaped first and second drive electrodes 1a and 1b in which a plurality of electrode plates (not shown) for driving the piezoelectric elements are alternately polarized. The first and second drive electrodes 1a and 1b are arranged so as to be separated from each other and displaced by a position corresponding to a quarter wavelength of the applied high frequency voltage. A feedback electrode 1c is formed between the first drive electrode 1a and the second drive electrode 1b. A motor drive circuit 2 is connected to the first and second drive electrodes 1a and 1b.

The motor drive circuit 2 comprises a reference signal generation circuit 3, a frequency transition circuit 4, a driving high voltage generation circuit 5, and a phase shift circuit 6. The circuits 3 to 6 of the motor drive circuit 2 are connected to the motor drive controller 7, respectively.

The reference signal generation circuit 3 generates a reference high frequency voltage E0 having a constant period and a constant voltage value as a reference for driving the piezoelectric element based on the voltage generation signal S1 from the controller 7 to generate a frequency transition circuit. Output to 4.

The frequency shift circuit 4 includes the controller 7
The frequency of the reference high frequency voltage E0 is changed on the basis of the frequency control signal S2 from the above and is output to the driving high voltage generating circuit 5 as the intermediate high frequency voltage E1. Incidentally, if this frequency is brought close to the resonance frequency, the motor 31 will rotate at high speed, and conversely, if the frequency is moved away from the resonance frequency, the motor 31 will rotate at low speed.

The driving high voltage generating circuit 5 changes the voltage value of the intermediate high frequency voltage E1 based on the voltage control signal S3 from the controller 7 and outputs it as the driving high frequency voltage E2 to the first driving electrode 1a. And outputs to the phase shift circuit 6. Incidentally, when the voltage value is increased, the motor 31 has a high torque, and conversely, when the voltage is decreased, the motor 31 has a low torque.

When the phase inversion signal S4 for normally rotating the motor 31 is inputted from the controller 7, the phase shift circuit 6 temporally phase-shifts the driving high frequency voltage E2 from the driving high voltage generating circuit 5 by 90 degrees. Is converted into a delayed voltage and output to the second drive electrode 1b. That is, the drive high frequency voltage E2 for normal rotation is applied to each drive electrode 1a, 1b of the stator 1.
Is applied, the traveling wave vibration is generated in the stator 1 in the direction in which the rotor is normally rotated.

When the phase inversion signal S4 for reversing the motor 31 is inputted from the controller 7, the phase shift circuit 6 outputs the driving high frequency voltage E2 from the driving high voltage generating circuit 5 by 90 degrees in time. The voltage is converted to a phase advanced voltage and output to the second drive electrode 1b. That is, the drive high-frequency voltage E for reverse rotation is applied to each drive electrode 1a, 1b of the stator 1.
2 is applied, and traveling wave vibration occurs in the stator 1 in the direction in which the rotor rotates in the reverse direction.

Therefore, when the ultrasonic motor 31 rotates forward,
The actuator 32 operates in a direction to bring the brake pad 34 into contact with the brake disc 33. When the ultrasonic motor 31 rotates in the reverse direction, the actuator 32 operates in the direction of separating the brake pad 34 from the brake disc 33.

A host controller 8 that controls the vehicle is connected to the motor drive controller 7. The host controller 8 includes a pedal depression sensor 9a for detecting depression of a brake pedal provided in a driver's seat.
Are connected. The pedal depression sensor 9a outputs an ON signal SON to the host controller 8 immediately when the brake is depressed from the released state. Host controller 8
Outputs an activation signal SST to the motor drive controller 7 based on the ON signal SON from the pedal depression sensor 9a.

Further, the host controller 8 is connected with a depression amount detection sensor 9b for detecting the depression amount F of the driver's brake pedal. The depression amount F is the magnitude of the braking force intended by the driver, and if the depression amount F is large, a large braking force is required.
The magnitude of the braking force depends on the brake disc 3
3 is proportional to the contact force of the brake pad 34. Therefore, increasing the braking force means increasing the contact force of the brake pad 34. Further, as the contact force increases, the load torque value T of the motor 31 increases proportionally.

The depression amount detection sensor 9b outputs a depression amount detection signal SF proportional to the depression amount F of the driver to the host controller 8. The host controller 8 detects the depression amount detection signal S from the depression amount detection sensor 9b at each time.
F, that is, the drive torque control signal SH corresponding to the depression amount F
Is output. Further, the host controller 8 sends to the motor drive controller 7 a forward / reverse command signal CCW for normally rotating the motor 31 based on the detection signal SF when the stepping amount F is increasing with time. When the depression amount F is decreasing with time, a forward / reverse command signal CCW for reversely rotating the motor 31 is output.

The motor drive controller 7 comprises a read-only memory (hereinafter referred to as ROM) 7a and a readable and rewritable memory (hereinafter referred to as RAM) 7b. The motor drive controller 7 uses the start signal SST, the drive torque control signal SH, and the forward / reverse command signal CC.
Enter W. Further, the drive controller 7 includes a motor 31
The load torque detection signal ST from the load torque detection sensor 10 for detecting the load torque value T related to is input. Further, the drive controller 7 inputs the rotation speed detection signal SN from the rotation detection sensor 11 which detects the rotation speed N of the motor 31. Furthermore, the drive controller 7 is the stator 1
Feedback voltage Vfb from the feedback electrode 1c of
Enter. Then, the drive controller 7 is a RAM 7
At b, the load torque value T and the rotation speed N based on the detection signals ST and SN and the feedback voltage Vfb are temporarily stored.

A brake control program for driving and controlling the motor 31 is stored in the ROM 7a of the drive controller 7. The drive controller 7 operates based on this control program.

More specifically, the drive controller 7 executes the brake control program in response to the activation signal SST, and outputs the voltage generation signal S1 for driving the reference signal generation circuit 3 to the generation circuit 3. It has become. Then, in the present embodiment, the drive controller 7 determines the load torque value (actual braking force) T of the motor 31 at that time based on the load torque detection signal ST from the load torque detection sensor 10 that detects the load torque value T. Is higher than the predetermined reference torque value T1, the "high rotation control mode" is executed, and when the reference torque value T1 is exceeded, the "high torque control mode" is executed. The reference torque value T1 is a value equal to the load torque value T applied to the motor 31 immediately after the brake pad 34 comes into contact with the brake disc 33 (or just before being separated).

Further, the motor drive controller 7 is adapted to calculate a target torque value of the motor 31 with respect to the amount F of depression of the brake pedal at that time based on the drive torque control signal SH. This calculation is performed based on the table of the target torque value of the motor 31 with respect to the depression amount F stored in the ROM 7a.

Here, FIG. 4 shows a table of the target torque values. When the load torque value T applied to the motor 31 is equal to or less than the reference torque value T1 (in the high rotation control mode), the drive controller 7 controls the motor 3 with respect to the depression amount F.
In order to achieve the target torque value of 1, the rotation speed N is rotated at the high rotation target rotation speed Nan. When the motor 31 rotates at the target rotation speed Nan for high rotation, it is driven at high rotation. Further, the drive controller 7 controls the load torque value T applied to the motor 31.
When the torque exceeds the reference torque value T1 (in the high torque control mode), the rotation speed N is rotated at the high torque target rotation speed Nat in order to obtain the target torque value of the motor 31 with respect to the depression amount F. Since this high torque target rotation speed Nat is set lower than the high rotation target rotation speed Nan,
When the motor 31 rotates at the high torque target rotation speed Nat, high torque drive is performed.

Note that the drive controller 7 increases the target torque value of the motor 31 with respect to the depression amount F, and when the load torque value T reaches the reference torque value T1, increases the motor 31 from the high rotation target rotation speed Nan to a higher value. Target speed for torque Nat
Drive at. On the contrary, the drive controller 7 reduces the target torque value of the motor 31 with respect to the depression amount F, and when the load torque value T reaches the reference torque value T1, changes the motor 31 from the high torque target rotation speed Nat to the high rotation speed. Drive at the target speed Nan. The rotation speed N of the motor 31 is
There is hysteresis near the reference torque value T1.

In the high rotation control mode, the drive controller 7 outputs the phase inversion signal S4 to the phase shift circuit 6 based on the forward / reverse rotation command signal CCW from the host controller 8 to control the motor 31 in the forward / reverse rotation. ing.

In this high rotation control mode, the drive controller 7 receives the forward / reverse command signal CCW for forward rotation and the start signal SST, and at the same time, based on the drive torque control signal SH. The target torque value of the motor 31 with respect to the depression amount F of the brake pedal is calculated. Then, the drive controller 7 outputs a frequency control signal S2 for setting the motor 31 to the target torque value to the frequency transition circuit 4 based on the target torque value.

Further, the forward / reverse command signal CCW for reverse rotation is input, and the load torque value T is decreased to decrease the reference torque value T1.
In the following, the drive controller 7 calculates the target torque value of the motor 31 with respect to the amount F of depression of the brake pedal at that time based on the drive torque control signal SH, as described above. Then, the drive controller 7 outputs the frequency control signal S2 for setting the motor 31 to the target torque value to the frequency transition circuit 4 based on the target torque value.

That is, the drive controller 7 determines that the brake pad 34 is separated from the brake disc 33 when the load torque value T is equal to or less than the reference torque value T1. Then, the drive controller 7 uses the motor 31
In order to increase the rotation speed of the motor 31, a high rotation control mode is executed, and in order to bring the motor 31 to a target torque value, the rotation frequency N is driven by the frequency transition circuit 4 so as to approach the high rotation target rotation speed Nan. It controls the frequency f of the voltage E2.

On the other hand, in the high torque control mode, the drive controller 7 outputs the phase inversion signal S4 to the phase shift circuit 6 based on the forward / reverse rotation command signal CCW from the host controller 8 to control the motor 31 in the forward / reverse rotation. It has become.

In this high torque control mode, the drive controller 7 uses the drive torque control signal SH to set the target torque value of the motor 31 with respect to the amount F of depression of the brake pedal at that time (in this mode, the braking force,
That is, the contact force of the brake pad 34) is calculated. The drive controller 7 uses the load torque detection signal ST from the load torque detection sensor 10 to determine the motor 31 at that time.
The load torque value (actual braking force) T of is calculated. Subsequently, the drive controller 7 sets the frequency control signal S2 and the voltage control signal S3 for setting the motor 31 to the target torque value based on the target torque value and the load torque value T, respectively. The voltage is output to the voltage generation circuit 5.

When the forward / reverse rotation command signal CCW for reverse rotation is input and the load torque value T decreases, the drive controller 7 causes the drive torque control signal SH to change as described above.
The target torque value of the motor 31 with respect to the amount F of depression of the brake pedal at that time (in this mode, the braking force, that is, the contact force of the brake pad 34) is calculated based on the above. The drive controller 7 determines the load torque value (actual braking force) T of the motor 31 at that time based on the load torque detection signal ST from the load torque detection sensor 10. Subsequently, the drive controller 7 sets the frequency control signal S2 and the voltage control signal S3 for setting the motor 31 to the target torque value based on the target torque value and the load torque value T, respectively. The voltage is output to the voltage generation circuit 5.

That is, the drive controller 7 determines that the brake pad 34 is in contact with the brake disc 33 when the load torque value T exceeds the reference torque value T1. The drive controller 7 then drives the motor 3
The high-torque control mode is executed to increase the torque of 1 and the frequency transition circuit 4 drives the motor 31 so that its rotation speed N approaches the high-torque target rotation speed Nat in order to achieve the target torque value. The frequency f of the high-frequency voltage E2 is controlled, and the driving high-voltage generation circuit 5 controls the voltage value Vin
Change.

Next, the operation of the control device for the ultrasonic motor configured as described above will be described with reference to FIGS.
For convenience of explanation, as shown in FIG. 2, the driver depresses the brake pedal (areas A1 and A2), returns the depressed pedal and depresses it again (areas A3 and A4), and further returns the pedal completely (area). A case of performing a series of pedal depression operations such as A5 and A6) will be described as an example. In the areas A1 and A6, the brake pad 34 is separated from the brake disc 33, and in the areas A2 to A5, the brake pad 34 is in contact with the brake disc 33. .
Further, FIG. 3 shows a torque judgment type control routine executed by the motor drive controller 7.

As an initial state, the brake pad 34 has a predetermined space D with respect to the brake disc 33. Further, the control routine shown in FIG. 3 is performed by the pedal depression sensor 9a when the driver starts to depress the brake pedal.
It starts based on the start signal SST from the host controller 8 based on the ON signal SON.

First, in the area A1 where the driver starts to depress the brake pedal, the pedal depression sensor 9a outputs an ON signal SON to the host controller 8, and the controller 8 outputs a start signal SST to the motor drive controller 7. . The motor drive controller 7 uses the start signal S
The control routine is started based on ST, and the voltage generation signal S1 is output to the reference signal generation circuit 3. The reference signal generation circuit 3 outputs a reference high frequency voltage E0 based on the voltage generation signal S1.

Further, the depression amount F increases as the brake pedal is depressed, and the depression amount detection sensor 9b outputs a depression amount detection signal SF proportional to the depression amount F to the host controller 8. The host controller 8 outputs a drive torque control signal SH corresponding to the stepping amount detection signal SF to the motor drive controller 7 and also outputs a forward / reverse rotation command signal CCW for rotating the motor 31 in the forward direction.

The motor drive controller 7 executes step 2
1, the frequency f of the driving high frequency voltage E2 applied to the driving electrodes 1a and 1b of the stator 1 and the initial value of the voltage value Vin are set. Since the load torque value T applied to the motor 31 is small at the initial stage of pedal depression, the motor drive controller 7 determines that the frequency f of the drive high frequency voltage E2 is f.
Is set to the maximum value by the frequency transition circuit 4, and the voltage value Vin is set to a predetermined value by the driving high voltage generation circuit 5. or,
The motor drive controller 7 causes the phase shift circuit 6 to drive the drive high frequency voltage E for forward rotation based on the forward / reverse rotation command signal CCW.
Output 2 Then, the motor 31 rotates in the normal direction, the rotation speed N thereof becomes maximum, and the load torque value T applied to the motor 31 gradually increases.

The motor drive controller 7 executes step 2
2, the brake pad 34 is the brake disc 3
3, the load torque value T applied to the motor 31 is less than or equal to the reference torque value T1. At this time, since the load torque value T is equal to or less than the reference torque value T1, the motor drive controller 7 determines in step 23
Then, the control is performed in the "high speed control mode".

The motor drive controller 7 executes step 2
3, it is determined whether the rotation speed N is the high rotation target rotation speed Nan shown in FIG. This step 23
When it is determined that the rotation speed N is the high rotation target rotation speed Nan, the process returns to step 22. On the other hand, this step 2
3, the rotation speed N of the motor 31 is the target rotation speed Nan for high rotation.
If not, the process proceeds to the next step 24. In step 24, a correction value .DELTA.f1 determined in advance so as to approach the target rotational speed Nan for high rotation is subtracted from or added to the frequency f of the drive high frequency voltage E2 just applied, and the process returns to step 22.

That is, the motor drive controller 7 proceeds to step 22 until the rotation speed N of the motor 31 reaches the target torque value of the motor 31 with respect to the brake pedal depression amount F calculated each time, in this case the high rotation target rotation speed Nan. ~
24 is repeated, and the frequency f of the driving high frequency voltage E2 is changed by the frequency transition circuit 4 to make the rotation of the motor 31 high. Then, based on the higher rotation of the motor 31, the brake pad 34 moves at a high speed in the direction of contacting the brake disc 33, and the gap D between the pad 34 and the disc 33 is sharply reduced. That is, the brake pad 3
It takes a short time for 4 to contact the brake disc 33.

Eventually, the brake pad 34 comes into contact with the brake disc 33, that is, the pad 34 and the disc 3
In the area A2 where the gap D with respect to 3 becomes "0", the load torque value T of the motor 31 becomes a value exceeding the reference torque value T1. Then, the motor drive controller 7 proceeds from step 22 to step 25, and switches its control from the "high rotation control mode" to the "high torque control mode".

The motor drive controller 7 executes step 2
5, it is determined whether or not the rotation speed N of the motor 31 is the high-torque target rotation speed Nat determined in advance by a test or the like as shown in FIG. If it is determined in step 25 that the rotation speed N is the high torque target rotation speed Nat, the routine returns to step 22. On the other hand, if it is determined in step 25 that the rotation speed N of the motor 31 is not the high torque target rotation speed Nat, the routine proceeds to the next step 26. In step 26, a predetermined correction value Δf2 is added or subtracted from the frequency f of the drive high frequency voltage E2 just applied to bring it closer to the high torque target rotational speed Nat, and the voltage Vin
Then, the correction value ΔV is added or subtracted, and the process returns to step 22.

That is, the motor drive controller 7 proceeds to step 2 until the rotation speed N of the motor 31 reaches the target torque value of the motor 31 with respect to the brake pedal depression amount F calculated each time, in this case the high torque target rotation speed Nat.
The frequency transition circuit 4 changes the frequency f of the driving high frequency voltage E2 by repeating steps 2, 25 and 26. Further, the motor drive controller 7 changes the voltage value Vin of the drive high frequency voltage E2 in the drive high voltage generation circuit 5 in step 26. Then, the torque of the motor 31 is increased. Then, as the torque of the motor 31 increases, the pressure contact force of the brake pad 34 with respect to the brake disc 33 increases.

Next, in the area A3 where the driver releases the brake pedal, the depression amount F changes from increasing to decreasing. At this time, the depression amount detection sensor 9b outputs a depression amount detection signal SF proportional to the depression amount F to the host controller 8
Output to. The host controller 8 outputs a drive torque control signal SH corresponding to the stepping amount detection signal SF to the motor drive controller 7 and also outputs a forward / reverse command signal CCW for reversely rotating the motor 31. The motor drive controller 7 controls the forward / reverse rotation command signal CC for reverse rotation.
Based on W, the phase shift circuit 6 outputs the driving high frequency voltage E2 for reverse rotation.

Further, the motor drive controller 7 causes the frequency control signal S2 and the voltage control signal S3 to correspond to the frequency transition signal S2 and the voltage control signal S3, respectively, in order to bring the motor 31 to the target torque value for the brake pedal depression amount F calculated each time.
And output to the driving high voltage generating circuit 5. Then, the motor 31 reversely rotates, the load torque value T of the motor 31 decreases in proportion to the depression amount F of the brake pedal, and the pressure contact force of the brake pad 34 to the brake disc 33 decreases.

Next, when the driver again enters the region A4 where the brake pedal is started to be depressed again, the depression amount F changes from a decrease to an increase. At this time, the depression amount detection sensor 9b
Outputs a depression amount detection signal SF proportional to the depression amount F to the host controller 8. The host controller 8 sends a stepping amount detection signal S to the motor drive controller 7.
A drive torque control signal SH corresponding to F is output, and a forward / reverse rotation command signal CCW for normally rotating the motor 31
Is output. The motor drive controller 7 causes the phase shift circuit 6 to output a drive high frequency voltage E2 for forward rotation based on the forward / reverse rotation command signal CCW for forward rotation.

Further, the motor drive controller 7 causes the frequency control signal S2 and the voltage control signal S3 to correspond to the frequency transition signal S2 and the voltage control signal S3, respectively, in order to bring the motor 31 to the target torque value with respect to the brake pedal depression amount F calculated each time.
And output to the driving high voltage generating circuit 5. Then, the motor 31 rotates normally, the load torque value T of the motor 31 increases in proportion to the depression amount F of the brake pedal, and the pressure contact force of the brake pad 34 to the brake disc 33 increases.

Next, when the driver stops depressing the brake pedal and enters the area A5 where the depression amount F changes from increasing to decreasing, the motor drive controller 7 reverses the motor 31 as in the area A3. Motor 31
The load torque value T of the brake disc 3 of the brake pad 34 decreases in proportion to the depression amount F of the brake pedal.
The pressure contact force for 3 decreases.

When the brake pad 34 reaches the area A6 where it is separated from the brake disc 33, the load torque value T of the motor 31 becomes less than the reference torque value T1.
Then, the motor drive controller 7 proceeds from step 22 to step 23, and switches its control from the "high torque control mode" to the "high rotation control mode". As described above, the motor drive controller 7 determines that the rotation speed N of the motor 31 corresponds to the stepping amount F of the brake pedal of the motor 31.
The frequency f of the drive high-frequency voltage E2 is changed by the frequency transition circuit 4 so that the target rotation speed Nan for high rotation such that the target torque value is obtained becomes. Then, based on the higher rotation of the motor 31, the brake pad 34 moves at a high speed in the direction of separating from the brake disc 33, and the gap D between the pad 34 and the disc 33 is rapidly widened. That is, the brake pad 34 secures a predetermined space D with respect to the brake disc 33 in a short time.

When the brake pedal is completely returned, the pedal depression sensor 9a stops outputting the ON signal SON to the host controller 8, and the controller 8 stops outputting the start signal SST to the motor drive controller 7.
Then, the motor drive controller 7 stops the output of the voltage generation signal S1 to the reference signal generation circuit 3 and stops the rotation of the motor 31. At the same time, the motor drive controller 7 ends the control routine.

As described above, this embodiment has the following features. (1) In the present embodiment, the usage state of the motor 31 is detected based on the load torque value T applied to the motor 31.
Based on this detection, it is determined whether the motor 31 is required to be driven at a high rotation speed or a high torque,
Based on the determination, the motor 31 is switched to either high rotation drive or high torque drive. Therefore,
The control suitable for the usage state of the ultrasonic motor 31 can be performed. Moreover, the usage state of the motor 31 is
Since the load torque value T is used for the detection, the detection can be facilitated.

(2) Further, an ultrasonic motor generally has a high rotation (low torque) when the frequency of the high frequency voltage is close to the resonance frequency, and a low rotation (high torque) when the frequency is far from the resonance frequency. Become. That is, when the motor 31 is required to rotate at high speed, the motor drive controller 7 controls the frequency f of the driving high frequency voltage E2 to approach the resonance frequency through the frequency shift circuit 4 (high rotation control mode). When high torque is required, the frequency f is controlled so as to move away from the resonance frequency in order to achieve low rotation (high torque control mode). Therefore, it is possible to easily perform switching control for increasing the rotation speed or increasing the torque of the motor 31.

(3) Further, in the high torque control mode, the motor drive controller 7 increases the voltage value Vin of the drive high frequency voltage E2 output from the drive high voltage generating circuit 5. Generally, the ultrasonic motor has high torque when the voltage value of the supplied high frequency voltage is increased. Therefore, it is possible to surely increase the torque of the motor 31.

(4) In the vehicle brake device 30 of this embodiment, the motor drive controller 7 drives the ultrasonic motor 31 to rotate at high speed when the brake pad 34 is separated from the brake disc 33. When the brake pad 34 is moved at high speed and the brake pad 34 is in contact with the brake disc 33, the motor drive controller 7 causes the ultrasonic motor 31 to move.
Is driven with a high torque to increase the pressure contact force of the brake pad 34. Therefore, the time until the brake pad 34 contacts the brake disc 33 becomes short, and the braking force becomes large after the pad 34 contacts the disc 33, so that the braking distance of the brake can be shortened. (Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, step 23 and step 25 in the flowchart of the first embodiment shown in FIG. 3 are replaced with step 23a and step 25a, respectively.

As shown in FIG. 5, in step 23a,
It is determined whether or not the feedback voltage Vfb from the stator 1 is the high rotation speed feedback voltage Vfbn which is determined in advance by a test or the like as shown in FIG. This step 23
If it is determined that the feedback voltage Vfb is the high speed target feedback voltage Vfbn in step a, the above step 2 is performed.
Return to 2. On the other hand, if it is determined in step 23 that the feedback voltage Vfb is not the high rotation target feedback voltage Vfbn, the process proceeds to the next step 24. Step two
In 4, the correction value Δf1 determined in advance so as to be closer to the high-speed target feedback voltage Vfbn is subtracted from or added to the frequency f of the drive high frequency voltage E2 just applied,
Return to step 22. Then, steps 22 to 24 are repeated until the feedback voltage Vfb from the stator 1 reaches the high-rotation target feedback voltage Vfbn.

Further, in step 25a, the feedback voltage Vfb from the stator 1 is the target feedback voltage for high torque Vfb for high torque which is determined in advance by a test as shown in FIG.
It is determined whether it is t. If it is determined in step 25a that the feedback voltage Vfb is the high torque target feedback voltage Vfbt, the process returns to step 22. On the other hand, when it is determined in step 25a that the feedback voltage Vfb is not the high torque target feedback voltage Vfbt, the process proceeds to the next step 26. Step 26
Then, a predetermined correction value Δf2 is added to or subtracted from the frequency f of the drive high-frequency voltage E2 just applied to the high torque target feedback voltage Vfbt, and a correction value ΔV is added to or added to the voltage Vin. The subtraction is performed and the process returns to step 22. Then, steps 22, 25 and 26 are executed until the feedback voltage Vfb from the stator 1 reaches the high torque target feedback voltage Vfbt.
Is repeated.

That is, since the feedback voltage Vfb from the stator 1 is a value corresponding to the rotation speed N of the motor 31, this feedback voltage Vfb is used in the present embodiment.
Is used as a substitute value for the rotation speed N of the motor 31.

In this way, in this embodiment, the rotation speed N of the motor 31 is not necessary, so that the rotation detection sensor 11 for detecting the rotation speed N can be omitted.
That is, in addition to the effect of the first embodiment described above, by omitting the rotation detection sensor 11, it is possible to contribute to cost reduction of the control device for the ultrasonic motor.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to FIGS. 7 and 8. In the present embodiment, the drive controller 7 determines the reference rotation speed N of the motor 31 at that time based on the rotation speed detection signal SN from the rotation detection sensor 11 that detects the rotation speed N of the motor 31. When the number N1 is exceeded, the "high speed control mode" is executed, and when the reference speed N1 or less, the "high torque control mode" is executed. The reference rotational speed N1 is set to a value equal to the rotational speed N of the motor 31 immediately after the brake pad 34 comes into contact with the brake disc 33 (or immediately before being separated).

As described above, the motor drive controller 7 calculates the target torque value of the motor 31 with respect to the amount F of depression of the brake pedal at that time based on the drive torque control signal SH. This operation is RO
The calculation is performed based on the table of the target torque value of the motor 31 with respect to the depression amount F stored in M7a.

Here, FIG. 8 shows a table of the target torque values. When the rotation speed N of the motor 31 exceeds the reference rotation speed N1 (in the high rotation control mode), the drive controller 7 increases the rotation speed N so as to set the target torque value of the motor 31 with respect to the depression amount F. Rotate at the target rotation speed Nan for rotation. When the motor 31 rotates at the target rotation speed Nan for high rotation, it is driven at high rotation. Further, when the rotation speed N of the motor 31 is equal to or lower than the reference rotation speed N1 (in the high torque control mode), the drive controller 7 increases the rotation speed N so as to obtain the target torque value of the motor 31 with respect to the depression amount F. Rotate at the target rotation speed Nat for torque. Since the high torque target rotation speed Nat is set lower than the high rotation target rotation speed Nan, the motor 31 is driven at high torque when rotated at the high torque target rotation speed Nat.

In the high rotation control mode, as in the first embodiment, the drive controller 7 sets the rotation speed N to the high rotation target rotation in order to set the target torque value of the motor 31 with respect to the depression amount F. The frequency transition circuit 4 controls the frequency f of the driving high frequency voltage E2 so as to approach the number Nan.

In the high torque control mode, as in the first embodiment, the drive controller 7 sets the rotation speed N of the motor 31 to the target torque for high torque in order to set the target torque value of the motor 31 to the depression amount F. The frequency transition circuit 4 controls the frequency f of the driving high frequency voltage E2 so as to approach the number Nat, and the driving high voltage generation circuit 5 controls the voltage value V.
change in.

Next, the operation of the control device for the ultrasonic motor configured as described above will be described with reference to FIG. Figure 7
It is a rotation speed determination type control routine executed by the motor drive controller 7. This control routine is performed by the pedal depression sensor 9 when the driver starts to depress the brake pedal.
It starts based on the start signal SST from the host controller 8 based on the ON signal SON of a. Incidentally, in the present embodiment, step 22 of the flowchart in the first embodiment shown in FIG. 3 is replaced with step 22a.

That is, in step 22a, it is determined whether the brake pad 34 is separated from the brake disc 33 as described above, that is, whether the rotation speed N of the motor 31 exceeds the reference rotation speed N1. When it is determined in step 22 that the reference rotation speed N1 is exceeded, that is, "YES", the motor drive controller 7 is in the "high rotation control mode".
Then, the process proceeds to step 23, and the same processing as that of the first embodiment is performed. On the other hand, when it is determined in step 22 that the rotation speed N is less than or equal to the reference rotation speed N1, that is, "NO", the motor drive controller 7 sets the "high torque control mode" and proceeds to the next step 25 to execute the first embodiment. Processing similar to is performed.

With this arrangement, in the present embodiment, the load torque value T is not required by using the rotation speed N of the motor 31 in place of the load torque value T of the motor 31, so that the load torque value T is unnecessary. The load torque detection sensor 10 that detects T can be omitted. That is, the above-mentioned first
In addition to the effects of the embodiment described above, the load torque detection sensor 1
By omitting 0, it is possible to contribute to cost reduction of the control device for the ultrasonic motor.

(Fourth Embodiment) A fourth embodiment of the present invention will be described below with reference to FIGS. 9 and 10. In the present embodiment, step 23 and step 25 of the flowchart in the third embodiment shown in FIG. 7 are replaced with step 23a and step 25a, respectively.
Was replaced with.

That is, as shown in FIG. 9, the motor drive controller 7 of the present embodiment is a rotation speed determination type controller that compares the rotation speed N of the motor 31 with the reference rotation speed N1 in step 22. As shown in FIG. 10, the feedback voltage Vfb from the stator 1 is used as a substitute value for the rotation speed N as in the second embodiment. By doing so, also in the present embodiment, the same effect as that of the third embodiment can be obtained.

The present invention is not limited to the above-mentioned embodiment, but may be carried out as follows without departing from the gist of the present invention. In each of the above-described embodiments, in the high torque control mode, the motor drive controller 7 increases the voltage value Vin of the driving high frequency voltage E2 output from the driving high voltage generation circuit 5, but especially the voltage Vin The value may not be changed, and only the frequency f may be lowered.

In each of the above embodiments, the stepping amount detection signal SF from the stepping amount detecting sensor 9b is input to the motor drive controller 7 via the host controller 8, but the host controller 8 is omitted and the motor drive controller 7 is omitted. You may input directly into.

In each of the above-described embodiments, switching between high rotation driving and high torque driving of the motor 31 is performed by changing the frequency f and the voltage value Vin of the driving high frequency voltage E2 applied to the stator 1 of the motor 31. However, the switching of the drive is not limited to this. For example, if the pressure contact force of the rotor with respect to the stator is increased, the rotation speed becomes low (high torque), and if the pressure contact force of the rotor with respect to the stator is decreased, the rotation speed becomes high (low torque). The driving may be switched.

In each of the above embodiments, the ultrasonic motor 3 is used.
Although the usage state of No. 1 is detected based on the load torque detection sensor 10 or the rotation detection sensor 11, other detection means may be used as long as the usage state of the motor 31 can be detected.

In each of the above embodiments, the ultrasonic motor 3 is used.
Although the control device of No. 1 is applied to the vehicle brake device, the control device is not limited to this, and the ultrasonic motor can be controlled by switching between high rotation drive and high torque drive according to the use state. Any device will do.

The technical ideas other than the claims that can be understood from the above-described embodiments will be described below along with their effects. (A) A brake pad (34) that is brought into pressure contact with the brake disc (33) to stop the rotation of the axle, and the brake pad (34) is moved in a direction to come into contact with or separate from the brake disc (33). The ultrasonic motor (3 provided as a drive source of the actuator (32)
1), a drive means (2) for rotating the motor (31) by applying a high frequency voltage (E2) to the stator (1) of the ultrasonic motor (31), and a brake pedal of a vehicle. The depression amount detecting means (9b) for detecting the depression amount (F) and the pressure contact force of the brake pad (34) with respect to the brake disc (33) proportional to the depression amount (F) of the brake pedal are used. A vehicle brake device comprising: a control means (7) for outputting a control signal (S2, S3) for controlling the rotational force or rotational direction of an ultrasonic motor (31) to the drive means (2). ,
Load torque value (T) applied to the ultrasonic motor (31)
The load torque detection means (10) for detecting the load torque value (T) is compared, and the control means (7) compares the load torque value (T) with a preset reference torque value (T1) to determine the load torque value (T) at that time. When T) is less than or equal to the reference torque value (T1), the brake pad (34) moves to the brake disc (3).
3) When the load torque value (T) at that time is greater than the reference torque value (T1), the brake pad (34) is disengaged from the brake disc (33). And a contact portion that determines that the brake pad is in contact with the brake disc (33) or when the brake pad (34) is separated from the brake disc (33). In order to move at high speed in the contact direction, the ultrasonic motor (3
Control signal (S2, S3) to drive 1) high rotation
Is output to the drive means (2), and when it is determined that the contact state is established, the brake pad (3
4) Drive control for outputting control signals (S2, S3) for driving the ultrasonic motor (31) with high torque to the drive means (2) in order to increase the pressure contact force to the brake disc (33). A brake device for a vehicle, comprising: a part (7).

According to this structure, the load torque detecting means detects the load torque value applied to the ultrasonic motor.
The determination unit provided in the control means compares the load torque value with a preset reference torque value, and when the load torque value at that time is equal to or less than the reference torque value, the brake pad is separated from the brake disc. When the load torque value at that time exceeds the reference torque value, it is determined that the brake pad is in contact with the brake disc. When it is determined that the brake pad is in the separated state, the drive control unit provided in the control means drives the ultrasonic motor at a high rotation speed in order to move the brake pad at a high speed in a direction in which the brake pad is separated from or in contact with the brake disc. A control signal for driving the ultrasonic motor is driven to a high torque in order to increase the pressure contact force of the brake pad to the brake disc when it is determined to be in the contact state. Output to the means. Then, in the separated state, the ultrasonic motor is driven to rotate at a high speed, and the brake pad is moved at a high speed in the direction of separating from or in contact with the brake disc. Further, in the contact state, the ultrasonic motor is driven with a high torque to increase the pressure contact force of the brake pad with the brake disc. As a result, the time until the brake pad contacts the brake disc becomes short, and the braking force becomes large after the brake pad contacts the brake disc, so that the braking distance of the brake can be shortened.

(B) Brake pad (34) that presses against the brake disc (33) to stop the rotation of the axle.
An ultrasonic motor (31) provided as a drive source for an actuator (32) that moves the brake pad (34) in the direction of abutting or separating from the brake disc (33), and the ultrasonic motor (31). Drive means (2) for applying a high frequency voltage (E2) to the stator (1) of (31) to drive the motor (31) to rotate, and stepping for detecting the amount of depression (F) of the brake pedal provided in the vehicle. The amount detecting means (9b) and the pressure contact force of the brake pad (34) with respect to the brake disc (33) proportional to the depression amount (F) of the brake pedal,
A vehicle brake device comprising: a control means (7) for outputting a control signal (S2, S3) for controlling a rotational force or a rotational direction of the ultrasonic motor (31) to the drive means (2). A rotation detecting means (11) for detecting the rotation speed (N) of the ultrasonic motor (31), and the control means (7) controls the rotation speed (N) and a preset reference rotation speed ( N1), and when the rotation speed (N) at that time exceeds the reference rotation speed (N1), it is determined that the brake pad (34) is in a separated state in which it is separated from the brake disc (33). In addition, when the rotational speed (N) at that time is equal to or lower than the reference rotational speed (N1), the brake pad (34) is moved to the brake disc (33).
A determination unit (7) that determines that the brake disc is in contact with the brake disc (3), and a determination unit (7) that determines that the brake pad (34) is in the separated state.
3) A control signal (S2, S3) for driving the ultrasonic motor (31) to rotate at a high speed is output to the drive means (2) in order to move the ultrasonic motor (31) at a high speed in a direction away from or in contact with the drive means (2). In addition, when it is determined that the contact state is established, control for driving the ultrasonic motor (31) with high torque in order to increase the pressure contact force of the brake pad (34) with respect to the brake disc (33). A vehicle brake device comprising: a drive control section (7) for outputting signals (S2, S3) to the drive means (2).

According to this structure, the rotation detecting means is
The rotation speed of the ultrasonic motor is detected. The determination unit provided in the control means compares the rotation speed with a preset reference rotation speed, and when the rotation speed at that time exceeds the reference rotation speed, the brake pad is separated from the brake disc. When the rotation speed at that time is equal to or lower than the reference rotation speed, it is determined that the brake pad is in contact with the brake disc. When it is determined that the brake pad is in the separated state, the drive control unit provided in the control means drives the ultrasonic motor at a high rotation speed in order to move the brake pad at a high speed in a direction in which the brake pad is separated from or in contact with the brake disc. A control signal for driving the ultrasonic motor is driven to a high torque in order to increase the pressure contact force of the brake pad to the brake disc when it is determined to be in the contact state. Output to the means. Then, in the separated state, the ultrasonic motor drives at high rotation,
The brake pad is moved at a high speed in a direction in which it is separated from or in contact with the brake disc. Further, in the contact state, the ultrasonic motor is driven with a high torque to increase the pressure contact force of the brake pad with the brake disc.
As a result, similarly to the invention described in (a) above, the time until the brake pad comes into contact with the brake disc becomes short, and the braking force becomes large after the brake pad comes into contact with the brake disc. The braking distance can be shortened.

(C) The drive control section (7) provided in the control means (7) changes the frequency (f) of the high frequency voltage (E2) via the drive means (2) to change the ultrasonic wave. The vehicle brake device as described in (a) or (b) above, wherein the motor (31) is driven to rotate at a high speed or a high torque.

According to this structure, the drive control section provided in the control means changes the frequency of the high frequency voltage via the drive means to drive the ultrasonic motor at high rotation or high torque. That is, the ultrasonic motor becomes high rotation (low torque) when the frequency of the high-frequency voltage applied to the stator approaches the resonance frequency, and conversely becomes low rotation (high torque) when the frequency is moved away from the resonance frequency. That is, the frequency is controlled to approach the resonance frequency when the motor is requested to drive at high rotation, and the frequency is controlled to move away from the resonance frequency to achieve low rotation when requested to drive high torque. Therefore, the high rotation of the motor,
Alternatively, the switching control for increasing the torque can be easily performed.

(D) When the ultrasonic motor (31) is driven at high torque, the drive control section (7) provided in the control means (7) further applies a high frequency voltage () through the drive means (2). The vehicle brake device according to (c) above, wherein the voltage value (Vin) of E2) is changed.

According to this structure, the drive control section provided in the control means further changes the voltage value of the high frequency voltage via the drive means when the ultrasonic motor is driven at high torque. That is, the ultrasonic motor has high torque when the voltage value of the high frequency voltage applied to the stator is increased.
That is, when high torque driving is required for the motor, the frequency of the high frequency voltage is controlled so as to move away from the resonance frequency and the voltage value is increased. Therefore, it is possible to surely increase the torque of the motor.

[0096]

As described in detail above, according to the present invention,
It is possible to provide a control method of an ultrasonic motor capable of performing control suitable for the usage state of the motor by switching the rotationally driven ultrasonic motor to either high rotation driving or high torque driving.

[Brief description of drawings]

FIG. 1 is an electrical configuration diagram of an ultrasonic motor according to a first embodiment.

FIG. 2 is an explanatory diagram showing a change in each numerical value based on an operation of a brake pedal.

FIG. 3 is a flowchart showing a torque determination type control routine.

FIG. 4 is a characteristic diagram showing a relationship between torque and rotation speed.

FIG. 5 is a flowchart showing a torque determination type control routine according to a second embodiment.

FIG. 6 is a characteristic diagram showing the relationship between torque and feedback voltage.

FIG. 7 is a flowchart showing a rotation speed determination type control routine according to a third embodiment.

FIG. 8 is a characteristic diagram showing a relationship between torque and rotation speed.

FIG. 9 is a flowchart showing a rotation speed determination type control routine according to a fourth embodiment.

FIG. 10 is a characteristic diagram showing the relationship between torque and feedback voltage.

FIG. 11 is a schematic configuration diagram showing a vehicle brake device.

[Explanation of symbols]

1 ... Stator, 31 ... Ultrasonic motor, E2 ... Driving high frequency voltage as high frequency voltage, F ... Depression amount, f ... Frequency,
N ... rotation speed, N1 ... reference rotation speed, T ... load torque value, T
1 ... Reference torque value, Vin ... Voltage value.

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02N 2/00 F16D 65/18

Claims (4)

(57) [Claims] 1. A vehicle brake device (30) mounted on a vehicle.
A method for controlling an ultrasonic motor, comprising: a brake disc
A brake pad that presses against (33) to stop the rotation of the axle.
Abut (34) on the brake disc (33)
Actuator that moves in the direction of moving or separating
Ultrasonic motor provided as a drive source for the motor (32)
(31) is rotated at high speed,
Is switched to one of high torque drive, and the motor (3
Control of the ultrasonic motor that performs control suitable for the usage condition of 1)
Method, load torque value (T) applied to the ultrasonic motor (31)
Is detected, and the detected load torque value (T) and the preset reference torque
Compared with the torque value (T1), the load torque value (T) at that time is less than the reference torque value (T1).
When down, the brake pad (34) brakes
If it is in a separated state separated from the disc (33),
It was determined that high rotation drive was required for the sonic motor (31).
Based on this determination, the motor (31) is controlled to a high rotation speed.
Also, the load torque value (T) at that time is the reference torque value.
When (T1) is exceeded, the brake pad (3
4) abutment against brake disc (33)
High torque drive for ultrasonic motor (31)
Is determined to have been requested, and based on this determination, the motor
(31) is controlled by high torque, and when the ultrasonic motor (31) is controlled by high rotation,
The rotation speed (N) of the sound wave motor (31) is set to the target rotation for high rotation.
The number (N an,) is rotated by, Couto an ultrasonic motor (31)
The number of rotations of the ultrasonic motor (31) when the torque is controlled
(N) is rotated at the target rotation speed (N at ) for high torque, and the rotation speed (N ) of the ultrasonic motor (31) is the reference value.
A method for controlling an ultrasonic motor, characterized in that hysteresis is provided near the torque value (T1) . 2. Mounted on a vehicle brake device (30)
A method for controlling an ultrasonic motor, comprising: a brake disc
A brake pad that presses against (33) to stop the rotation of the axle.
Abut (34) on the brake disc (33)
Actuator that moves in the direction of moving or separating
The chromatography data ultrasonic motor provided as a drive source (32) (31), a high rotational drive in the state of being rotated, or by switching to either a high torque drive, the motor (3
Performing control suitable for the state of use of 1) Te control method smell of the ultrasonic motor, the ultrasonic load torque applied to the motor (31) (T)
Is detected, the detected load torque value (T) is compared with a preset reference torque value (T1), and when the load torque value (T) at that time is equal to or less than the reference torque value (T1), The brake pad (34) is a brake
A separated state of being separated to the disk (33) against the ultrasonic motor (31) determines that the high rotation drive is required, the motor (31) and high-rotation control based on the determination, and , when the load torque value at that time (T) has exceeded the reference torque value (T1), said brake pad (3
4) abutment against brake disc (33)
A state against the ultrasonic motor (31) determines that a high torque driving is required, so a high torque controlling the motor (31) based on the determination, the high ultrasonic motor (31) When the rotation is controlled, it is super
Feed bar from stator (1) of sonic motor (31)
The target voltage for high rotation is the feedback voltage (V fb )
Rotate the ultrasonic motor (31) so that (V fbn ).
When the ultrasonic motor (31) is under high torque control
The stator (1) of the ultrasonic motor (31) is
The feedback voltage (V fb ) is the target feedback for high torque.
The ultrasonic motor (31) so that the voltage becomes V fbt
When the ultrasonic motor (31) is rotated, the feedback voltage (V f
b ) is the hysteresis near the reference torque value (T1).
A method of controlling an ultrasonic motor, which is characterized by having a space. 3. The ultrasonic motor (31) is rotationally driven.
Applied to the stator (1) of the motor (31) to
By changing the frequency (f) of the high frequency voltage (E 2 ) generated,
The motor (31) is driven with high rotation or high torque.
Claim, characterized in that the the cause 1 or claim 2
A method for controlling an ultrasonic motor according to item 1. 4. A high torque drive of the ultrasonic motor (31)
During operation, the voltage value (V in ) of the high frequency voltage (E 2 )
Claims 1 to 3, characterized in that so as to vary the
The method for controlling an ultrasonic motor according to any one of 1.