JP2022101866A - Controller of vibration type actuator and vibration type driving device having the same - Google Patents

Abstract

To provide a controller of a vibration type actuator that can prevent an increase in temperature of an inverter (bridge circuit), and a vibration type driving device having the same.SOLUTION: A controller of an oscillatory wave motor has: a selection unit that selects a plurality of types of AC signals applied to a plurality of electrode groups or a plurality of types of PWM signals on which the plurality of types of AC signals applied to the plurality of electrode groups are based; and an indication unit that indicates the plurality of types of AC signals or the plurality of types of PWM signals selected by the selection unit. The indication unit indicates to the selection unit to select the plurality of types of AC signals or the plurality of types of PWM signals, for one electrode or a plurality of electrodes adjacent to each other, in the order of a first voltage phase and a first polarity, a second voltage phase and the first polarity, the first voltage phase and a second polarity, and the second voltage phase and the second polarity.SELECTED DRAWING: Figure 6

Description

The present invention relates to a drive device for a vibration type actuator and a vibration type drive device having the same.

A rotation drive device using a vibration wave motor (vibration type actuator) is superior in quietness and positioning accuracy as compared with the case of using a general electromagnetic motor, and is used for driving a lens of a single-lens reflex camera or the like.

An annulus-shaped vibrating body is used to rotate the rotary drive device using the vibrating actuator. When a two-phase frequency signal is applied to an electric-mechanical energy conversion element (hereinafter referred to as a drive piezoelectric element) arranged on the vibrating body, the vibrating body vibrates and contacts according to the vibration of the vibrating body. The body rotates.

Patent Document 1 describes a method using a flexible substrate having an annular shape when applying an electric signal to a vibrating body. According to this method, a drive piezoelectric element, an application electrode, and wiring from an external power source are integrally formed on a flexible substrate, mechanical energy for rotation is supplied (input) to the vibrating body, and the vibrating body is placed on the vibrating body. It is possible to generate (generate) a traveling wave.

Japanese Unexamined Patent Publication No. 11-187677

Since the vibration type actuator described in Patent Document 1 is driven by using an AC signal, it is necessary to convert a DC signal by an inverter. Since the bridge circuit used for the inverter uses a switching element to generate an AC signal, an electrical loss always occurs during driving.

However, as the drive frequency is increased, the frequency of switching increases and the temperature of the bridge circuit rises. Therefore, when the drive is continued for a long time, a device for cooling the bridge circuit is required.

Therefore, an object of the present invention is to provide a control device for a vibration type actuator capable of suppressing the temperature rise of an inverter (bridge circuit) and a vibration type drive device having the control device.

The control device for a vibration wave motor according to the present invention has at least a voltage phase with each other in each of a plurality of electrode groups formed in a vibrating body, each having only one electrode or a plurality of electrodes conducting with each other. And by applying any of a plurality of types of AC signals having different polarities to generate a traveling wave in the vibrating body, the contact body in contact with the vibrating body is made relative to the vibrating body. A control device for a moving vibration wave motor, which is based on the plurality of types of AC signals applied to each of the plurality of electrode groups or the plurality of types of AC signals applied to each of the plurality of electrode groups. It has a selection unit for selecting a type of PWM signal and an instruction unit for instructing the plurality of types of AC signals or the plurality of types of PWM signals selected by the selection unit, and the instruction unit has one. Alternatively, for each of the plurality of electrodes adjacent to each other, the first voltage phase and the first polarity, the second voltage phase and the first polarity, the first voltage phase and the second polarity, and the first. It is characterized in that the selection unit is instructed to select the plurality of types of AC signals or the plurality of types of PWM signals in the order of the voltage phase 2 and the second polarity.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a control device for a vibration type actuator capable of suppressing the temperature rise of an inverter (bridge circuit) and a vibration type drive device having the control device.

It is an overall view (block diagram) of the vibration type drive device which concerns on 1st Embodiment of this invention. It is a schematic diagram of the vibration type actuator which concerns on 1st Embodiment of this invention. It is sectional drawing of the vibration type actuator which concerns on 1st Embodiment of this invention. It is a figure for demonstrating the mode of the deformation of the drive vibration excited to the surface of a vibrating body which concerns on 1st Embodiment of this invention. It is a layout drawing of wiring and electrode on a flexible substrate which concerns on 1st Embodiment of this invention. It is a circuit diagram of the control device of the vibration type actuator when the 8th order drive order is instructed which concerns on 1st Embodiment of this invention. It is a circuit diagram of the control device of the vibration type actuator when the 4th order drive order is instructed which concerns on 1st Embodiment of this invention. It is an overall view (block diagram) of the vibration type drive device which concerns on 2nd Embodiment of this invention. It is a circuit diagram of the control device of the vibration type actuator when the 8th order drive order is instructed which concerns on 2nd Embodiment of this invention. It is a circuit diagram of the control device of the vibration type actuator when the 4th order drive order is instructed which concerns on 2nd Embodiment of this invention. It is an overall view (block diagram) of the vibration type drive device which concerns on a comparative form. It is a layout drawing of wiring and electrode on a flexible substrate which concerns on a comparative form. It is a circuit diagram in the case of driving with the 8th order drive order which concerns on the comparative form.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the configurations described in the following embodiments are merely examples, and the scope of the present invention is not limited by the configurations described in the embodiments.

[First Embodiment]
FIG. 1A is an overall view (block diagram) of the vibration type drive device according to the first embodiment of the present invention. The driving device of the vibration type actuator of the present embodiment includes a control unit 200, an inverter 400, a transformer and a smoothing circuit 500, and a conversion circuit 700 (selection unit).

The PWM signals A1 and B1, which are multi-phase (2-phase) pulse width modulation signals (PWM signals) generated inside the control unit 200 using a microcomputer, are converted into 2-phase AC signals (AC voltage) by the inverter 400. Is converted into AC signals A2 and B2. Further, the AC signals A2 and B2 are transformed and smoothed by the transformer and the smoothing circuit 500, and converted into AC signals A and B which are two-phase AC signals. Note that FIG. 1B is a circuit diagram of a transformer and a smoothing circuit 500 according to the first embodiment of the present invention. The three sine curves shown in FIG. 1 (b) schematically represent the phase of the current flowing in the place where the sine curve is shown.

In the selection unit 700, the AC signals A and B, which are multi-phase (two-phase) AC signals, and the AC signals A and B are 180 degrees out of phase with each other from the transformer and the smoothing circuit 500. Multiple (4) AC signals of XA and XB are supplied (input). Hereinafter, the AC signals A, B, XA and XB are collectively referred to as a plurality of types of AC signals.

The amplitude of the signal (AC signal A and XA) of the A phase (first voltage phase) and the amplitude of the signal (AC signal B and XB) of the B phase (second voltage phase) both determine the duty ratio of the PWM signal. It can be controlled by setting.

The selection unit 700 supplies a plurality of AC signals to the vibration type actuator 600 in an energization pattern corresponding to the drive order (order instruction) designated (instructed) by the order indicating means 300 (instruction unit) in the control unit. (input). As a result, the vibration type actuator 600 is driven by the drive order instructed by the instruction unit 300.

In this overall view, the selection unit 700 can be placed between the control unit 200 and the inverter 400, or between the inverter 400 and the transformer and the smoothing circuit 500.

FIG. 2 is a diagram schematically showing the configuration of the vibration type actuator 600 according to the first embodiment of the present invention. The mechanical configuration of the vibrating body 620, the contact body 610, and the pressurizing mechanism for pressurizing them in the vibrating actuator 600 is functionally equivalent to, for example, the rotation driving device described in Japanese Patent Application Laid-Open No. 2017-108615. ..

The feeding unit 100 has a driving connector 102, a terminal board 104, and a flexible board 101a. The flexible substrate 101a is arranged on opposite surfaces with the contact body 610 and the vibrating body 620 interposed therebetween. A plurality of types of AC signals are supplied (input) to the drive connector 102 through the external power feeding harness 103 using the eight harnesses.

Each of these eight harnesses is assigned (input) any one of a plurality of AC signals, and this allocation is determined according to the selection unit. Further, the vibrating body 620 and the contact body 610 are grounded through the external power feeding harness 103.

FIG. 3 is a cross-sectional view schematically showing the configuration of the vibration type actuator 600 according to the first embodiment of the present invention. A driving piezoelectric element 105, a feeding panel 140, an electrode 111, and a flexible substrate 101a are arranged in this order on the bottom surface of the vibrating body 620.

An AC voltage is supplied (input) to the power supply panel 140 via the electrode 111 by the drive wiring 130 on the flexible substrate 101a. On the other hand, since the vibrating body 620 is grounded, the driving piezoelectric element 105 contracts according to the AC voltage due to the AC voltage, vibrates the vibrating body 620 by the vibration, and generates (generates) a traveling wave on the upper surface thereof. ).

FIG. 4 is a diagram for explaining a mode of deformation of the driving vibration when a general traveling wave is excited (when generated) in the vibrating body 620 according to the first embodiment of the present invention. be. In FIG. 4, the displacement is exaggerated more than it actually is in order to facilitate the understanding of the displacement of the drive vibration excited in the vibrating body 620. The feeding unit 100 is not shown.

When such a traveling wave is generated (generated) on the upper surface of the vibrating body 620, friction is generated between the traveling body and the contact body 610 in contact with the traveling body 620. The contact body 610 and the vibrating body 620 are pressurized with each other by a pressurizing mechanism (not shown), and the frictional force corresponding to the applied pressure is transmitted from the vibrating body 620 to the contact body 610, and the contact body 610 is a vibrating body. It moves (rotates) relative to 620.

FIG. 5 shows an arrangement diagram (plan view showing the arrangement) of the electrodes and the driving wiring 130 on the flexible substrate 101a according to the first embodiment of the present invention. FIG. 5 shows a state in which the flexible substrate 101a is viewed from the side of the vibrating body 610.

The flexible substrate 101a includes wiring and terminals provided on a flat substrate made of a flexible resin. The flexible substrate 101a is provided with a plurality of drive terminals 151 to 158, a plurality of drive wirings 130, a plurality of electrode groups 111 to 118, and a plurality of power supply panels 140. Each of the plurality of electrode groups 111 to 118 has a plurality of electrodes 111a to 111d, ..., 118a to 118d. The plurality of electrodes of each of the plurality of electrode groups 111 to 118 are conducting with each other.

Each of the plurality of drive terminals 151 to 158 is connected to the plurality of drive wires 130. Each of the plurality of drive wirings 130 is connected to the plurality of electrode groups 111 to 118. Each of the plurality of electrodes 111a to 111d, ..., 118a to 118d possessed by each of the plurality of electrode groups 111 to 118 is connected to the plurality of feeding panels 140.

The power supply panel 140 applies an AC voltage to the drive piezoelectric element 105. Further, the drive wiring 130 supplies (inputs) an AC signal to each of the plurality of electrodes. Further, the plurality of drive terminals 151 to 158 supply (input) an AC signal from the terminal board 104a.

A total of 32 power feeding panels 140 are evenly provided along the circumferential shape of the flexible substrate 101a. Then, it has one electrode corresponding to each of the 32 power feeding panels. In each of the eight drive wirings 130, a plurality of (4) electrodes are connected at intervals of 90 degrees on the circumference. In the present embodiment, the electrodes connected by these common drive wirings are collectively referred to as an electrode group. For example, in FIG. 5, the same AC signal is supplied (input) to the electrodes 111a to 111d via a common drive wiring 130. A plurality of (8) electrode groups are formed on the flexible substrate 101a. In addition, 8 or more electrode groups may be formed.

In the first embodiment of the present invention, when the eighth drive order is specified, the AC signal A is supplied (input) to the first drive terminal 151 and the fifth drive terminal 155. Further, the AC signal B is supplied (input) to the second drive terminal 152 and the sixth drive terminal 156. Further, the AC signal XA is supplied (input) to the third drive terminal 153 and the seventh drive terminal 157. Further, the AC signal XB is supplied (input) to the fourth drive terminal 154 and the eighth drive terminal 158. That is, the AC signal A, the AC signal B, the AC signal XA, and the AC signal XB appear repeatedly 8 times on the circumference every 45 degrees.

Eight pairs of AC signal A and AC signal XA form an eighth-order standing wave. Further, there are eight pairs of AC signal B and AC signal XB, and an eighth-order standing wave is formed independently of the pair of AC signal A and AC signal XA.

Assuming that 45 degrees is one cycle on the circumference, as can be seen from the arrangement of the feeding panel 140 and the electrodes, the AC signal of the A phase and the AC signal of the B phase are each shifted by a quarter cycle. Therefore, the plurality (two) standing waves generate (generate) a traveling wave having a certain velocity on the vibrating body 620 by superposition. Here, the AC signals of the A phase (first voltage phase) are the AC signal A and the AC signal XA. Further, the AC signals of the B phase (second voltage phase) are the AC signal B and the AC signal XB.

FIG. 6 is a circuit diagram of a control device for a vibration type actuator when an eighth-order drive order is specified (first pattern) according to the first embodiment of the present invention. The control device for the vibration type actuator includes a control unit 200, an inverter 400, a transformer and a smoothing circuit 500, and a selection unit 700.

A plurality of AC signals are input to the selection unit 700. Further, the selection unit 700 includes a plurality of switching elements 161 to 166 having an enable terminal to which an enable signal output from the control unit 200 is input. An IGBT was used as the switching element. However, the switching element is not limited to this, and any device such as a bipolar transistor or MOSFET that can realize ON / OFF can be used. The selection unit 700 has a plurality of (8) output terminals, and the plurality of output terminals are connected to a plurality of drive terminals 151 to 158, respectively.

Any two of the AC signal A, the AC signal B, the AC signal XA, and the AC signal XB are input as input signals to each of the plurality of switching elements 161 to 166. Each of the plurality of enable signals 181 to 186 is input to each of the plurality of switching elements 161 to 166 from the indicator unit 300. Each of the plurality of switching elements 161 to 166 determines which of the two AC signals constituting the input signal is output as the output signal according to the respective values of the plurality of enable signals 181 to 186.

In the case of FIG. 6, the vibrating body 620 is instructed to generate (generate) a traveling wave having a drive order of 8th order. Specifically, the first switching element 161 and the fifth switching element 165 connect the AC signal B to the output. Further, the second switching element 162 and the sixth switching element 166 connect the AC signal XA to the output. Further, the third switching element 163 connects the AC signal XB to the output. Further, the fourth switching element 164 connects the AC signal A to the output.

In this way, the AC signal A is supplied (input) to the first drive terminal 151 and the fifth drive terminal 155 among the plurality of drive terminals 151 to 158. Further, the AC signal B is supplied (input) to the second drive terminal 152 and the sixth drive terminal 156 among the plurality of drive terminals 151 to 158. Further, the AC signal XA is supplied (input) to the third drive terminal 153 and the seventh drive terminal 157 among the plurality of drive terminals 151 to 158. Further, an AC signal XB is supplied (input) to the fourth drive terminal 154 and the eighth drive terminal 158 among the plurality of drive terminals 151 to 158. The plurality of types of AC signals supplied (input) in this way form (generate) a traveling wave having a drive order of 8th order on the vibrating body 620.

FIG. 7 is a circuit diagram of a drive circuit of a vibration type actuator when a fourth-order drive order is specified (second pattern) according to the first embodiment of the present invention.

In this case, of the switching elements 161 to 166, the AC signal A is connected to the output of the first switching element 161. Further, in the second switching element 162 and the third switching element 163, the AC signal B is connected to the output. Further, in the fourth switching element 164 and the fifth switching element 165, the AC signal XA is connected to the output. Further, in the sixth switching element 166, the AC signal XB is connected to the output.

In this way, the AC signals to the plurality of drive terminals 151 to 158 are AC signal A, AC signal A, AC signal B, AC signal B, AC signal XA, AC signal XA, AC signal XB, and AC, respectively. The signal XB is supplied (input).

As a result, as shown in FIG. 5, when the flexible substrate 101a is viewed from the side of the vibrating body 610, the pair of electrodes to which the AC signal A and the AC signal XA are input are on the circumference with a cycle of 90 degrees. 4 appear. Further, four pairs of electrodes to which the AC signal B and the AC signal XB are input appear on the circumference in a cycle of 90 degrees, like the pair of electrodes to which the AC signal A and the AC signal XA are input. .. Further, it can be seen that the pair of the AC signal A and the AC signal XA and the pair of the AC signal B and the AC signal XB are displaced by a quarter cycle from each other. From this, it can be seen that these AC signals generate (generate) a traveling wave having a drive order of 4th order on the circumference.

In the present embodiment, the voltage phase of the AC signal is applied to each of the plurality of drive terminals 151 to 158 and the plurality of electrode groups connected to the plurality of drive terminals 151 to 156 by each of the plurality of switching elements 161 to 166, depending on the drive order. And the polarity can be specified. The phase of the AC signal can also be specified. The voltage phase of the AC signal is the A phase or the B phase. Further, the polarity of the AC signal is A or XA, B or XB.

As described above, by switching between the case where the 8th order drive order is specified in FIG. 6 and the case where the 4th order drive order is specified in FIG. 7, the drive order becomes the 2Nth order progressive wave. It is possible to perform order conversion that switches between a traveling wave whose drive order is Nth.

In the present embodiment, the driving order is switched between the traveling wave having a driving order of 4th order and the traveling wave having a driving order of 8th order. However, depending on how the electrode group is arranged, the driving order can be switched between other driving orders. It is possible. In each case, in low order, for each of two or more electrodes (for each of a plurality of electrodes adjacent to each other), an A-phase AC signal, a B-phase AC signal, an XA-phase AC signal, and an XB-phase AC signal are used. Supply is made (input is made). Then, since the voltage phase, phase, and polarity of some of the electrodes in the two or more electrodes are switched at higher order, it can be seen that at least eight or more electrode groups are required.

In this embodiment, a rotation drive type vibration type actuator is exemplified. However, even a straight-ahead drive type vibration type actuator can exhibit the same effect as the rotation drive type vibration type actuator with the same configuration as the rotation drive type vibration type actuator. In the linear drive type vibration type actuator, each of the plurality of electrode groups 111 to 118 may have only one electrode instead of the plurality of electrodes.

[Second Embodiment]
FIG. 8 is an overall view (block diagram) of the vibration type drive device according to the second embodiment of the present invention. The driving device of the vibration type actuator of the present embodiment includes a control unit 200, an inverter 400, a transformer, and a smoothing circuit 500. Unlike the first embodiment, in the present embodiment, the driving device of the vibration type actuator does not have the conversion circuit 700 (selection unit).

The multi-phase (2-phase) pulse width modulation signal (PWM signal) generated inside the control unit 800 using the microcomputer is a multi-phase (2-phase) AC voltage by the inverter 400, the transformer, and the smoothing circuit 500. It is converted to (AC signal).

The control unit, inverter, transformer, and smoothing circuit send multiple types of AC signals to the vibration type actuator in an energization pattern according to the drive order (order instruction) that is instructed and selected by the instruction unit and selection unit in the control unit. , Supply (enter). As a result, the vibration type actuator 600 is driven by the driving order instructed and selected by the indicating unit and the selecting unit 900.

In the present embodiment, the arrangement of the drive terminal, the drive wiring, and the electrodes on the flexible substrate 101a (see FIGS. 2 and 3) is the same as that in the first embodiment.

FIG. 9 is a circuit diagram of a control unit 200, an inverter 400, a transformer, and a smoothing circuit 500 when an eighth-order drive order is specified according to the second embodiment of the present invention.

The control unit 200 includes a plurality of PWM ports 171 to 178 that can independently instruct the duty ratio and phase. A plurality of PWM signals corresponding to the AC signal A, the AC signal B, the AC signal XA, the AC signal XB, the AC signal A, the AC signal B, the AC signal XA, and the AC signal XB in order to the plurality of PWM ports 171 to 178. Is output.

The plurality of drive terminals 151 to 158 have an AC signal A, an AC signal B, an AC signal XA, an AC signal XB, an AC signal A, an AC signal B, an AC signal XA, and an AC signal corresponding to these (based on these). XB is supplied (input).

FIG. 10 is a circuit diagram of a control unit 200, an inverter 400, a transformer, and a smoothing circuit 500 when an eighth-order drive order is specified according to the second embodiment of the present invention.

The control unit 200 includes a plurality of PWM ports 171 to 178 that can independently instruct the duty ratio and phase. A plurality of PWM signals corresponding to the AC signal A, the AC signal A, the AC signal B, the AC signal B, the AC signal XA, the AC signal XA, the AC signal XB, and the AC signal XB in order to the plurality of PWM ports 171 to 178. Is output.

The plurality of drive terminals 151 to 158 have AC signal A, AC signal A, AC signal B, B, AC signal XA, AC signal XA, AC signal XB, and AC signal XB corresponding to these. Supplied (entered).

In the present embodiment, the voltage phase of the AC signal is applied to each of the plurality of drive terminals 151 to 158 and the plurality of electrode groups connected to the plurality of drive terminals 151 to 178 by each of the plurality of PWM ports 171 to 178, depending on the drive order. , The phase of the AC signal and the polarity of the AC signal can be specified independently. As described above, by switching between the case where the 8th order drive order is specified in FIG. 9 and the case where the 4th order drive order is specified in FIG. 10, the drive order becomes the 2Nth order progressive wave. It is possible to perform order conversion that switches between a traveling wave whose drive order is Nth.

In the present embodiment, the driving order is switched between the traveling wave having a driving order of 4th order and the traveling wave having a driving order of 8th order. However, depending on how the electrode group is arranged, the driving order can be switched between other driving orders. It is possible. In each case, in low order, for each of two or more electrodes (for each of a plurality of electrodes adjacent to each other), an A-phase AC signal, a B-phase AC signal, an XA-phase AC signal, and an XB-phase AC signal are used. Supply is made (input is made). Then, since the voltage phase, phase, and polarity of some of the electrodes in the two or more electrodes are switched at higher order, it can be seen that at least eight or more electrode groups are required.

In this embodiment, a rotation drive type vibration type actuator is exemplified. However, even a straight-ahead drive type vibration type actuator can exhibit the same effect as the rotation drive type vibration type actuator with the same configuration as the rotation drive type vibration type actuator.

[Comparison form]
FIG. 11 shows an overall view (block diagram) of the vibration type drive device according to the comparative mode. The comparative form does not have a selection unit and an order indicating means. FIG. 12 shows an arrangement diagram (plan view showing the arrangement) of the electrodes and the driving wiring 130 on the flexible substrate 101b according to the comparative form. FIG. 12 shows a state in which the flexible substrate 101b is viewed from the side of the vibrating body 610.

The flexible substrate 101b includes wiring and terminals provided on a flat substrate made of a flexible resin. The flexible substrate 101b is provided with a plurality of drive terminals 151 to 154, a plurality of drive wirings 130, a plurality of electrode groups 111 to 114, and a plurality of power supply panels 140. Each of the plurality of electrode groups 111 to 114 has a plurality of electrodes 111a to 111h, ..., 114a to 114h. The plurality of electrodes of each of the plurality of electrode groups 111 to 114 are conducting with each other.

Each of the plurality of drive terminals 151 to 154 is connected to the plurality of drive wires 130. Each of the plurality of drive wirings 130 is connected to the plurality of electrode groups 111 to 114. Each of the plurality of electrodes 111a to 111h, ..., 114a to 114h possessed by each of the plurality of electrode groups 111 to 114 is connected to the plurality of feeding panels 140.

The power supply panel 140 applies an AC voltage to the drive piezoelectric element 105. Further, the drive wiring 130 supplies (inputs) an AC signal to each of the plurality of electrodes. Further, the plurality of drive terminals 151 to 154 supply (input) an AC signal from the terminal board 104b.

Similar to the first embodiment, 32 power supply panels 140 are provided in total. Then, it has one electrode corresponding to each of the 32 power feeding panels. In each of the four drive wirings 130, a plurality of (8) electrodes are connected at intervals of 45 degrees on the circumference.

In this comparative embodiment, the electrodes connected by these common drive wirings are collectively referred to as an electrode group. For example, in FIG. 12, the same AC signal is supplied (input) to the electrodes 111a to 111h via a common drive wiring 130. A plurality of (4) electrode groups are formed on the flexible substrate 101b.

AC signals are supplied (input) to the drive terminals 151 to 154 and the drive wiring 130 in the order of AC signal A, AC signal B, AC signal XA, and AC signal XB, respectively. A plurality of electrodes 111a to 111h connected to the drive terminal 151 form one electrode group.

Then, eight A-phase (first voltage phase) AC signals are supplied (input), and eight are connected to the drive terminals 153 to which the XA signal is supplied (input). An eighth-order standing wave is generated on the vibrating body 620 together with a group of electrodes having electrodes. When a standing wave of 8th order or higher is generated on the vibrating body, it may be used with an electrode group having 8 or more electrodes.

Similarly, an eighth-order standing wave is generated from the AC signal of the B phase (second voltage phase) and the AC signal of the XB phase (second voltage phase) supplied (input) to the drive terminals 152 and 154. Generated on the vibrating body 620. The standing wave generated by the A-phase AC signal and the XA-phase AC signal and the standing wave generated by the B-phase AC signal and the XB-phase AC signal are generated (generated) with a quarter-period shift. Therefore, a traveling wave having a drive order of 8th order is generated (generated) on the vibrating body 620.

[Superiority of embodiments over comparative embodiments]
As described above, in the first embodiment and the second embodiment, the drive order of the traveling wave generated on the vibrating body can be switched. On the other hand, in the comparative mode, the drive order of the traveling wave generated on the vibrating body cannot be switched.

As the frequency of the AC signal supplied (input) to the vibrating body 620, a resonance frequency corresponding to the driving order of the traveling wave used for driving the AC signal is used. Further, it is known that the drive order and the resonance frequency are almost proportional to each other.

Generally, the velocity of the traveling wave is v, the amplitude is ξ, the frequency is f, the drive order is n, the thickness of the vibrating body 620 is h, and the circumference of the vibrating body 620 is L.

According to this equation, the drive order n is proportional to the speed v, and the frequency f is proportional to the drive order n. Therefore, when the drive order n is doubled, the speed v increases in proportion to the square of the drive order. Therefore, when the drive order is changed from the Nth order to the 2Nth order, the speed of the traveling wave becomes four times.

When no slip occurs between the vibrating body and the contact body, the frictional force acting between the vibrating body and the contact body becomes a static friction force, and the static friction force causes the contact body 610 at the same speed as the traveling wave. Can be driven. Further, when slipping occurs between the vibrating body and the contact body, the frictional force acting between the vibrating body and the contact body becomes a dynamic friction force, and the contact body 610 is driven by the dynamic friction force (contact body 610). Is moved relative to the vibrating body 620).

In either case, it is possible to drive a large drive load depending on the magnitude of the frictional force.

The frictional force is generally expressed as the product of the normal force and the coefficient of friction μ. The coefficient of friction μ is known to be proportional to the true contact area. Hereinafter, the relationship between the drive order and the true contact area will be described.

The shape of the traveling wave generated on the vibrating body 620 is such that the coordinates on the circumference are x, the drive order is n, the amplitude is ξ, and the circumference is L.

It is expressed as. In this case, the radius of curvature R of the wave front is

It is expressed as. Further, assuming that the pressing force between the vibrating body 620 and the contact body 610 is F, the force applied to one crest of the traveling wave of the driving order n is

Will be. According to Hertz's contact theory, a cylinder with radius R forces a plane.

When pressed with, the contact radius a is

Is in proportion to.

As described above, the contact area S of one wave front with the contact body 610 is the contact radius a and the contact area S.

There is a relationship. From the above, the contact area per wave head when the drive order is N and the amplitude of the traveling wave is ξ, and the amplitude of the traveling wave when the drive order is mN

In the case of, the ratio of the contact area per wave crest is

Will be.

However, in the case of the drive order mN, there are m times more wave fronts than in the case of the drive order N, so the ratio of the contact area is

Will be. That is, in the case of the drive order mN, the true contact area is larger than in the case of the drive order N.

Twice as large and has a coefficient of friction

It will be twice as big.

On the other hand, the speed of the traveling wave is

It is expressed as. Drive order mN and amplitude

So, when the frequency mf corresponding to the drive order is input, the speed of the traveling wave is

Will be. On the other hand, when the drive order is N and the amplitude is ξ, the velocity of the traveling wave is

Will be. Therefore, the drive order is multiplied by m to increase the amplitude.

When doubled, the coefficient of friction and the coefficient of friction (generally expressed as the product of the normal force effect and the coefficient of friction μ) are increased while maintaining the velocity.

Can be doubled. Then, it is possible to drive a drive target having a larger load.

In particular, in the case of the first embodiment and the second embodiment, it corresponds to the case of m = 2. When driving with the 8th drive order, the frequency is doubled and the amplitude is 1/4 of the frequency when driving with the 4th drive order, so that the frictional force and torque are maintained while maintaining the speed. Can be increased by about 1.4 times.

On the other hand, if the drive frequency f is increased when the drive order is increased, the switching loss in the inverter increases, the bridge circuit used in the inverter rises, and the bridge circuit may stop.

Therefore, when accelerating the drive target, drive in a drive mode with a higher drive order, and drive in a drive mode with a lower drive order when a load is not so much applied, such as at a constant speed. Is preferable. As a result, it is possible to suppress the temperature rise of the inverter (the bridge circuit used in the inverter) and to reliably control the drive target.

Therefore, the first embodiment and the second embodiment of the present invention, in which the drive order can be switched, are superior to the comparative mode in which the drive order cannot be switched.

100 Power supply unit 101a, 101b Flexible board 102 Drive connector 103 External power supply harness 104 Terminal board 105 Drive piezoelectric element 111a to 111d Electrodes 112a, 113a, 114a, 115a, 116a, 117a Electrodes 118a to 118d Electrode 130 Drive wiring 140 Power supply panel 151 to 158 Drive terminal 161 to 166 Switching element 171 to 178 PWM port 181 to 186 Enable signal 200 Control unit 300 Order indicating means (indicating unit)
400 Inverter 500 Transformer and smoothing circuit 600 Vibration wave motor (vibration type actuator)
610 Contact body 620 Vibrating body 700 Conversion circuit (selection part)
800 Control unit 900 Indicator and selection unit

Claims (7)

Multiple types of AC signals formed in a vibrating body, each having only one electrode or a plurality of electrodes conducting with each other, each having at least one of different voltage phases and polarities from each other. A vibration wave motor control device that moves a contact body in contact with the vibrating body relative to the vibrating body by applying any of the above to generate a traveling wave in the vibrating body.
A selection unit that selects a plurality of types of PWM signals based on the plurality of types of AC signals applied to each of the plurality of electrode groups or the plurality of types of AC signals applied to each of the plurality of electrode groups. When,
It has an instruction unit for instructing the plurality of types of AC signals or the plurality of types of PWM signals selected by the selection unit.
The indicator has a first voltage phase and a first polarity, a second voltage phase and the first polarity, the first voltage phase and the first for each of one or a plurality of electrodes adjacent to each other. It is characterized in that the selection unit is instructed to select the plurality of types of AC signals or the plurality of types of PWM signals in the order of the two polarities, the second voltage phase, and the second polarity. Vibration wave motor control device. A control unit that outputs a PWM signal based on the AC signal of the first voltage phase and the AC signal of the second voltage phase.
An inverter that outputs an AC signal of the first voltage phase and the first polarity, the second voltage phase and the first polarity based on the PWM signal output from the control unit.
Based on the AC signal output from the inverter, the first voltage phase and the first polarity, the second voltage phase and the first polarity, the first voltage phase and the second polarity. And a transformer that outputs an AC signal of the second voltage phase and the second polarity.
From the AC signal output from the transformer, the selection unit selects the plurality of types of AC signals to be applied to each of the plurality of electrode groups and applies them to each of the plurality of electrode groups. The control device for a vibration wave motor according to claim 1. The first voltage phase and the first polarity AC signal, the second voltage phase and the first polarity AC signal, the first voltage phase and the second, selected by the selection unit. A control unit that outputs a PWM signal based on the AC signal of the polarity of the above, and the second voltage phase and the AC signal of the second polarity.
Based on the PWM signal output from the control unit, the first voltage phase and the first polarity, the second voltage phase and the first polarity, the first voltage phase and the second polarity. , And an inverter that outputs AC signals of the second voltage phase and the second polarity.
Based on the AC signal output from the inverter, the first voltage phase and the first polarity, the second voltage phase and the first polarity, the first voltage phase and the second polarity. , And a transformer that outputs an AC signal of the second voltage phase and the second polarity and applies to each of the plurality of electrode groups, according to claim 1. Vibration wave motor control device. The control device for a vibration wave motor according to any one of claims 1 to 3, wherein the plurality of electrode groups are composed of eight or more electrode groups. The instruction unit according to any one of claims 1 to 3, wherein when the driving target is accelerated and driven, the driving order is switched from a low-order driving order to a high-order driving order. The control device described. The control device is characterized in that, when the drive order is switched from a low-order drive order to a high-order drive order, the amplitude of the voltage phase is set to be smaller in the electrode group. The control device according to any one of the above items. The control device according to any one of claims 1 to 6.
A vibration type drive device comprising: a vibration type actuator controlled by the control device.

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