JP2000245177A - Equipment and method for driving oscillatory wave motor and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely start up the rotation of an oscillatory wave motor smoothly without increasing the driving voltage, when starting up the motor. SOLUTION: An oscillatory wave motor drive generates stationary waves in an oscillator, when starting up an oscillatory wave motor (S1). After a stationary wave is generated, it is resified if the oscillatory motor is started up (S2). If it cannot be verified that the motor starts up, the position of the maximum amplitude of the stationary wave is changed and then another stationary wave is generated in the oscillator (S5), If the anchoring state still cannot be eliminated (S4), the position of the maximum amplitude of the stationary wave is changed again, and another stationary wave is generated (S5). When the anchoring state is eliminated, a normal drive control is performed to generate a progressive wave in the oscillator (S6-S8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration wave motor driving device, a driving method, and a storage medium, and more particularly, to exciting a vibrating body by applying an AC signal to an electro-mechanical energy conversion element. TECHNICAL FIELD The present invention relates to a driving device for a vibration wave motor that applies a driving force due to friction to a moving body pressed by a motor, a driving method applied to the driving device, and a storage medium storing a program for executing the driving method.

[0002]

2. Description of the Related Art Conventionally, a vibration wave motor called an ultrasonic motor or a piezoelectric motor has been developed and has been put to practical use by the present applicant. As is well known, this vibration wave motor generates a high-frequency vibration by applying an alternating voltage to an electro-mechanical energy conversion element such as a piezoelectric element or an electrostriction element, and generates the vibration energy. This is a new type of non-electromagnetic drive motor configured to extract as continuous mechanical movement. The principle of this operation has already been described in many patent publications and the like, and a description thereof will be omitted here.

FIG. 13 is a sectional view showing the structure of an example of a conventional vibration wave motor.

In the figure, reference numeral 1 denotes a ring-shaped metal elastic body made of, for example, stainless steel or phosphor bronze,
Reference numeral 2 denotes a piezoelectric element group in which two groups of plural polarized piezoelectric elements are formed in a ring shape, and reference numeral 3 denotes a slider material made of resin, metal, ceramic, or the like. The piezoelectric element group 2 is adhered concentrically to one end face of the elastic body 1, electrodes are arranged on both end faces so as to generate traveling waves on the surface of the slider material 3 bonded to the other end face, and polarization processing is performed. Have been. A plurality of comb-shaped grooves are regularly formed in the circumferential direction on the end surface of the elastic body 1 on the side of the slider member 3 in order to increase the electric-mechanical energy conversion efficiency. The elastic body 1, the piezoelectric element group 2, and the slider material 3 constitute a vibrating body (stator).

[0005] A flexible substrate 4 is fixed to the surface of the piezoelectric element group 2 opposite to the elastic body 1. The flexible substrate 4 is for supplying a drive signal to the piezoelectric element group 2 and extracting a signal from a sensor unit provided in the piezoelectric element group 2 for detecting a vibration state. Also, the elastic body 1
Is formed in a thin disk shape, and is fixed to the base 5 with an adhesive or a screw on the inner peripheral side.

[0006] A moving body 6 is brought into pressure contact with the surface of the slider member 3 via a vibration isolating rubber 7 by a leaf spring 8, and the moving body 6 has a coaxial structure with the elastic body 1. The inner diameter of the leaf spring 8 is fixed to a disk flange 9 that is tightly fitted to the shaft 10. Also, the shaft 10
The bearing 11 and the bearing 12 fitted to the base 5 are fitted into the bearing 11, and the retaining ring 13 holds the pressing force. In addition,
The spacer 14 applies a preload to the bearing 11 to reduce the amount of whirling of the shaft 10.

FIG. 14 is a circuit diagram showing a configuration of a drive circuit for driving a vibration wave motor.

Reference numeral 21 denotes a control circuit including a microcomputer for driving and controlling the vibration wave motor.
2 is an alternating voltage of four phases of A phase, inverted A phase (having a phase difference of 180 ° with respect to A phase), B phase, and inverted B phase (having a phase difference of 180 ° with respect to B phase) Oscillator that generates
3, 24, 25 and 26 are switching elements for switching the power supply voltage with the alternating voltage from the oscillator 22.
Transformers 7 and 28 perform impedance matching with the vibration wave motor and increase the power supply voltage. 40 is a capacitor for smoothing the voltage of the power supply, and 41 to 48 are resistance elements for controlling the drive current of the switching elements 23 to 26. 15 is a pulse generating means for generating a pulse according to the rotation of the vibration wave motor, 50 is a pulse generating means 15
Is a rotation speed detection circuit that detects the rotation speed of the vibration wave motor based on the pulse train sent from the controller and outputs the detected rotation speed to the control circuit 21. Here, in order to generate a traveling wave, a phase difference of 90 ° is set between the A phase and the B phase.

In the driving circuit having such a configuration, the control circuit 21 controls the oscillator 22 based on the target rotation speed specified externally and the actual rotation speed detected by the rotation speed detection circuit 50. And outputs a command signal relating to the frequency of the drive voltage. As a result, switching control pulses having different phases are output from the oscillator 22, and the switching elements 23 to 26 and the transformers 27 and 2 are output.
8 generates a high alternating voltage. The alternating drive voltage is applied to the vibration wave motor, and a traveling wave is generated in the vibrating body, and the vibration wave motor is driven to rotate.

FIG. 15 is a graph showing the relationship between the frequency (f) of the drive voltage supplied to the vibration wave motor and the rotation speed (N) of the vibration wave motor.

Since the vibration wave motor has such characteristics, the rotation speed of the vibration wave motor is controlled by utilizing these characteristics. That is, when the vibration wave motor is started, usually, the drive voltage frequency at the time of starting is set to a frequency f ₀ sufficiently higher than the resonance frequency. When the frequency is gradually lowered from the frequency f ₀ , the vibration wave motor starts operating at the frequency f ₁ . When the frequency is further reduced, the rotation speed gradually increases until the rotation speed reaches the rotation speed corresponding to the frequency. On the other hand, the rotation speed detection circuit 50 provided in the drive circuit
, The rotational speed (rotational speed) of the vibration wave motor is detected, and when the detected rotational speed reaches the target value _Ncon , the frequency reduction is stopped.

In order to stop the vibration wave motor, on the contrary, the frequency is gradually increased, the rotation speed is reduced, and the motor is stopped smoothly.

[0013]

However, when such a vibration wave motor is used in various environments, the coupling force of the friction surface between the vibrating body (stator) and the moving body 6 may be strong in some cases. Therefore, as described above, a phenomenon occurs in which the vibration wave motor cannot be started even if the frequency is gradually lowered from the frequency f ₀ and is lower than the frequency f ₁ . As a means for solving this problem, the present applicant has disclosed that the drive frequency is not gradually lowered from the frequency f ₀ but is swept from a predetermined frequency f ₂ lower than the frequency f ₁ to a higher frequency. It has been proposed to control the drive frequency gradually from the frequency after confirming that the drive has started, in the same manner as in the above-described conventional apparatus.

However, such a control method makes it possible to start the vibration wave motor. However, since the rotation speed rapidly rises immediately after the start, there arises a problem that the rotation cannot be started smoothly.

Further, when the frictional surface has a larger coupling force, it cannot be started by the above-described method alone, and there is also a problem that it cannot be started unless the applied driving voltage is made higher.

Further, in order to adjust the position and the like of a member which is rotated by the vibration wave motor, it is attempted to manually rotate the vibration wave motor from outside without supplying a drive voltage to the vibration wave motor (manual operation). Driving mode), the frictional surface between the vibrating body and the moving body has a strong coupling force, and a large force may be required to rotate the vibration wave motor.

The present invention has been made in view of the above problems, and a vibration wave motor driving device, a driving method, and a driving method that can start rotation of a vibration wave motor reliably and smoothly without increasing a driving voltage when starting the vibration wave motor. And a storage medium.

It is another object of the present invention to provide a vibration wave motor driving device, a driving method, and a storage medium capable of rotating a vibration wave motor with a small torque in a manual driving mode.

[0019]

According to the first aspect of the present invention, an oscillator is excited by applying an AC signal to an electro-mechanical energy conversion element. A driving device for a vibration wave motor that applies a driving force due to friction to a moving body pressed by the vibration wave motor, wherein when the vibration wave motor is activated, a standing wave generating means for generating a standing wave on the vibration body; Confirmation means for confirming whether or not the vibration wave motor has been started after generation of the standing wave by the generation means, and when the activation of the vibration wave motor cannot be confirmed by the confirmation means, the standing wave generation means Control means for changing the maximum amplitude position of the standing wave generated in the vibrating body and then generating a new standing wave.

According to the present invention, the vibrating body is excited by applying an AC signal to the electro-mechanical energy conversion element, and the driving force due to friction is applied to the moving body pressed by the vibrating body. A vibration wave motor driving method applied to a vibration wave motor driving device that provides a standing wave generating step of generating a standing wave on the vibrating body when the vibration wave motor is started, A confirmation step of confirming whether or not the vibration wave motor has started after the generation of the standing wave; and, when the activation of the vibration wave motor cannot be confirmed by the confirmation step, a maximum of a standing wave to be generated in the vibrating body. A standing wave generation step of generating a new standing wave after changing the amplitude position.

Further, according to the twelfth aspect of the present invention,
Vibration wave motor drive applied to a vibration wave motor drive device that excites a vibration body by applying an AC signal to an electro-mechanical energy conversion element and applies a driving force by friction to a moving body pressed by the vibration body. In a computer-readable storage medium storing a method as a program, the vibration wave motor driving method includes a step of generating a standing wave in the vibrating body when the vibration wave motor is started, A confirmation step of confirming whether or not the vibration wave motor has been started after the standing wave is generated by the standing wave generation step, and when the activation of the vibration wave motor cannot be confirmed by the confirmation step, A standing wave generation step of generating a new standing wave after changing the maximum amplitude position of the standing wave to be generated.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) The configuration of a vibration wave motor and the configuration of a drive circuit according to a first embodiment of the present invention are as follows.
The configuration of the conventional vibration wave motor shown in FIG. 13 and the configuration of the conventional drive circuit shown in FIG. 14 are basically the same. Therefore, in the description of the first embodiment, FIG.
The configuration of the vibration wave motor shown in FIG. 3 and the configuration of the drive circuit shown in FIG. In the first embodiment, the drive control procedure of the vibration wave motor executed by the control circuit 21 is different from the conventional device.

FIG. 1 is a flowchart showing a drive control procedure of the vibration wave motor according to the first embodiment of the present invention. The drive control procedure according to the first embodiment corresponds to a case where a state in which the coupling force of the friction surface between the vibrating body (stator) and the moving body 6 is increased (hereinafter, referred to as a “fixed state”). To this end, in addition to the conventional drive control procedure, a procedure for releasing from the fixed state is added before the drive control procedure.

First, in step S1, the control circuit 21 causes the oscillator 22 to output pulse signals of only the A phase and the inverted A phase. The frequency of those pulse signals is
Higher than the resonant frequency, normally the vibration wave motor is set to a frequency f ₁₁ begins to start. Alternatively, the frequency is set to the frequency at which the vibration wave motor stopped last time.

FIG. 2 is a graph showing the relationship between the drive frequency and the number of revolutions of the vibration wave motor for explaining the drive frequency control performed in the first embodiment. That is, in the fixed state, at a frequency higher than the frequency f _11, shows that sticking there is easily peeled off frequency f _12.

FIG. 3 is a diagram showing a pulse signal output from the oscillator 22 in the first embodiment. In step S1, the oscillator 22 outputs a pulse signal as shown in a region t _11.

FIG. 4 shows a vibrating body as a stator (shaded area).
FIG. 3 is a diagram illustrating a contact state between the robot and a moving object. In the figure, S indicates a fixed portion between the vibrating body and the moving body. The adhered state is a phenomenon that a part of the contact surface adheres with a strong force, not the entire contact surface.

[0029] The vibrating element receives the pulse signal as shown in a region t _11, the standing wave W1 is generated as shown in FIG. 4 (A).
When the vibration due to the standing wave W1 acts on the fixed portion S,
There is a possibility that the sticking between the vibrating body and the moving body can be removed. In particular, peeling can be expected as the fixed portion S is closer to the maximum amplitude portion (abdomen).

Returning to FIG. 1, it is determined in step S2 whether or not the fixed state of the vibration wave motor has been released by the generation of the standing wave in step S1 and the motor can be started.
That is, when a vibration is detected by a vibration detector (not shown), it is determined that the fixation state has not originally existed or, if any, has been released, and the process proceeds to step S7. If no vibration is detected by the vibration detector, it is determined that it is still in a fixed state, and the process proceeds to step S3.

In step S3, the control circuit 21
There the oscillator 22, sticking is to output a pulse signal of the A-phase and inverted A-phase only with easily peeled off frequency f _12. Then, the frequency is swept down to a lower side. Or it is fixed to the frequency f _12.

As a result, if the adherence between the vibrating body and the moving body is peeled off (step S4), the flow proceeds to step S6, and if not, the flow proceeds to step S5.

In step S5, the control circuit 21
Causes the oscillator 22 to output a pulse signal of only the B phase and the inverted B phase. Then, the frequency of the pulse signal is swept down. That is, the oscillator 22 outputs a pulse signal as shown in a region t ₁₂ in FIG. 3, the vibrating member, FIG. 4
A standing wave W2 shown in FIG.

If the standing state of the vibration wave motor is not released by the standing wave W2 (step S4), in step S5, the control circuit 21 causes the oscillator 22 to output the A phase, the inverted A phase, and the A phase. In-phase B phase and inverted A
Each pulse signal of the inverted B phase which is the same as the phase is output. Then, the frequency of the pulse signal is swept down. That is, the oscillator 22 outputs the pulse signals as shown in a region t ₁₃ in FIG. 3, the vibrating member, the standing wave W3 is generated as shown in FIG. 4 (C). In the example shown in FIG. 4, in this case, the maximum amplitude portion (abdomen) is closest to the fixed portion S.

If the standing state of the vibration wave motor is not released by the standing wave W3 (step S4), the control circuit 21 instructs the oscillator 22 to output the A phase, the inverted A phase, and the A phase in step S5. B phase of opposite phase (same phase as inverted A phase) and inverted B of opposite phase (same phase as A phase)
Output each phase pulse signal. Then, the frequency of the pulse signal is swept down. That is, the oscillator 22
There outputs the pulse signals as shown in a region t ₁₄ in FIG. 3,
The standing wave W4 shown in FIG. 4D is generated in the vibrator.

As described above, by changing the position of the maximum amplitude portion (abdomen) of the generated standing wave, the maximum amplitude portion (abdomen) comes closest to the fixed portion S at any position, and the vibration wave motor There is a high possibility that the sticking state is released.

Since the vibration is a standing wave, the vibration wave motor does not rotate when the adhesion is removed, and there is no danger that the motor will suddenly start rotating.

In step S6, the control circuit 21
Is the frequency of the pulse signal₁₁I returned to
That is, each pallet having a phase difference of 90 ° between the phase A and the phase B
Signal from the oscillator 22 to generate a traveling wave on the vibrating body.
Let it live. In addition, normal drive control to reduce the frequency is performed.
(Step S7), similarly to the conventional device, the target speed N
_conFrequency f reached_conStop sweep with (Step
S8) Finally, the vehicle decelerates and stops (step S8).
9).

By changing the position of the maximum amplitude portion (abdomen) of the standing wave as described above, the fixed state is released when the vibration wave motor is started, and the vibration wave motor can be reliably and smoothly performed without increasing the driving voltage. Can be started to rotate.

(Second Embodiment) The configuration of the vibration wave motor and the configuration of the drive circuit according to the second embodiment are basically the same as the configuration of the vibration wave motor and the configuration of the drive circuit according to the first embodiment. Is the same for each. Therefore, in the description of the second embodiment, the configuration of the vibration wave motor and the configuration of the drive circuit according to the first embodiment are used. In the second embodiment, the content of step S5 in the drive control procedure of the vibration wave motor executed by the control circuit 21 is different from that of the first embodiment.

FIG. 5 is a diagram showing a pulse signal output from the oscillator 22 in the second embodiment.

Although the pulse width (duty) of each pulse signal is constant in the first embodiment, the pulse width (duty) of each pulse signal is changed in the second embodiment. As a result, the output voltage of the transformer of the drive circuit changes, and the position of the maximum amplitude portion (abdomen) of the standing wave is arbitrarily changed. This is shown in FIG. 6 and FIG.
This will be described with reference to FIG.

FIG. 6 is a diagram showing the relationship between the pulse width of the pulse signal and the output voltage of the transformer of the drive circuit.

[0044] For example, as shown in a region t ₂₂ in FIG. 5, A
Relative phase and inverted A-phase only the pulse width PW ₂₁ of each pulse signal, reducing the pulse width of the B-phase and inverted B-phase only the pulse signals of the _{PW 22 (= PW 21/2} ). In this case, the output voltage of the transformer 28 (FIG. 14) becomes V ₂₁ with respect to the pulse width PW _{21 as} shown in FIG.
₂₂ and about half.

[0045] As shown in a region t ₂₂ in FIG. 5, the pulse signals of B-phase and inverted B-phase as well A-phase and inverted A-phase are applied to the vibration wave motor, and the voltage applied to the vibration wave motor, When the A-phase applied voltage: the B-phase applied voltage = 2: 1, a standing wave W22 shown in FIG. 7B is generated in the vibrator.

FIG. 7 is a diagram showing a position where a standing wave is generated when each pulse signal shown in FIG. 5 is input. In addition,
When the pulse signal of the A-phase and inverted A-phase only, as shown in a region t ₂₁ in FIG. 5 is applied to the vibration wave motor,
As in the first embodiment, a standing wave W1 shown in FIG. 7A is generated in the vibrator.

The standing wave W22 is shifted to the B-phase side by 1/12 of one wavelength in comparison with the standing wave W1.

Next, as shown in a region t ₂₃ in FIG. 5, the pulse width is the same A-phase and inverted A-phase and B-phase and inverted B
When each phase pulse signal is applied to the vibration wave motor, a standing wave W23 shown in FIG. 7C is generated in the vibration body. The standing wave W23 is shifted by one-eighth of one wavelength to the B phase side compared to the standing wave W1 (the phase difference between the A phase and the B phase is 1).
/ 4 wavelength). This shift position is a position where each pulse signal of only the A phase and the inverted A phase is applied to the vibration wave motor, and a position where each pulse signal of only the B phase and the inverted B phase is applied to the vibration wave motor. The position is an intermediate position from the position when the operation is performed.

[0049] Further, as shown in a region t ₂₄ in FIG. 5, the pulse signals of B-phase and inverted B-phase as well A-phase and inverted A-phase are applied to the vibration wave motor, and the A-phase and B-phase voltage applied to the vibration wave motor each pulse width is inverted with area t ₂₂ is, a-phase applied voltage: B-phase applied voltage = 1: when a 2, the vibrator, the constant shown in FIG. 7 (D) A standing wave W24 is generated.

The standing wave W24 is shifted to the B phase side by 2/12 = 1/6 of one wavelength as compared with the standing wave W1.

By changing the position at which the standing wave is generated in this manner, in the example shown in FIG. 7, in the case of FIG. 7C, the position of the maximum amplitude portion (abdomen) of the standing wave is fixed. S, thereby enabling the return from the fixed state.

If the ratio (duty) of the pulse width of the pulse signal can be freely changed, the position of the maximum amplitude portion (abdomen) of the standing wave can be smoothly changed.

Thus, also in the second embodiment, the position of the maximum amplitude portion (abdomen) of the standing wave can be changed.
When the vibration wave motor is started, the fixed state is released, and the rotation of the vibration wave motor can be reliably and smoothly started without increasing the drive voltage.

(Third Embodiment) The configuration of the vibration wave motor and the configuration of the drive circuit according to the third embodiment are basically the same as the configuration of the vibration wave motor and the configuration of the drive circuit according to the first embodiment. Is the same for each. Therefore, in the description of the third embodiment, the configuration of the vibration wave motor and the configuration of the drive circuit according to the first embodiment are used.

In the third embodiment, there is provided a rotating torque detecting means for detecting a rotating torque required when the vibration wave motor is manually rotated from the outside without supplying a driving voltage to the vibration wave motor. . The drive control procedure of the vibration wave motor executed by the control circuit 21 in the third embodiment is different from that in the first embodiment.

FIG. 8 is a flowchart showing a drive control procedure of the vibration wave motor which is executed in advance by the control circuit 21 when the vibration wave motor is rotated from the outside in the third embodiment.

When the vibration wave motor is manually rotated from the outside without supplying a driving voltage to the vibration wave motor for the purpose of adjusting the position or the like of a member rotated and moved by the vibration wave motor, When starting to move, the manually required rotational torque is greatest due to the static friction. Once moving, only the kinetic friction is required, so the required rotational torque is very small. Therefore, in order to easily move the vibration wave motor when the vibration wave motor is manually rotated from the outside, it is necessary to reduce the torque required to start the operation. The third embodiment has responded to such a request.

First, in step S11, when the vibration wave motor is to be manually rotated from the outside, a manual drive mode is set. Then, in step S12, the frequency of the pulse signal is set to a frequency at which the vibrating body reliably vibrates.

[0059] In step S13, the respective pulse signals of the A-phase and inverted A-phase only, as shown in a region t ₃₁ of FIG. 9 the oscillator 22 generates.

FIG. 9 is a diagram showing a pulse signal output from the oscillator 22 in the third embodiment.

[0061] Such A-phase and inverted A-phase only vibrators each pulse signal is inputted generates a standing wave W ₃₁ shown in FIG. 10 (A).

FIG. 10 is a diagram showing a state of contact between a moving body and a vibrating body (hatched portion) as a stator. The moving object is
There is not a uniform contact state with the vibrating body, and there are a portion that is in contact and a portion that is not in contact.

[0063] In a state where such standing waves W ₃₁ is generated, torque detecting means detects the rotational torque required when an attempt is made manually rotated the vibration wave motor from the outside.

[0064] In step S14, A-phase and inverted A-phase arrangement the oscillator 22 a each pulse signal of B phase and the inverted B-phase as shown in a region t ₃₂ in FIG. 9 is generated. These A-phase and inverted A-phase arrangement in B phase and inverted B-phase vibration body each pulse signal is inputted generates a standing wave W ₃₂ shown in FIG. 10 (B).

[0065] In a state where such standing waves W ₃₂ is generated, torque detecting means detects the rotational torque required when an attempt is made manually rotated the vibration wave motor from the outside.

[0066] In step S15, the respective pulse signals of only the B-phase and inverted B-phase as shown in a region t ₃₃ of FIG. 9 the oscillator 22 generates. Such B-phase and inverted B-phase only vibrators each pulse signal is inputted generates a standing wave W ₃₃ shown in FIG. 10 (C).

[0067] In a state where such standing waves W ₃₃ is generated, torque detecting means detects the rotational torque required when an attempt is made manually rotated the vibration wave motor from the outside.

[0068] In step S16, A-phase and inverted A-phase arrangement in B phase and inverted B oscillator 22 to the pulse signals of phase as shown in a region t ₃₄ in FIG. 9 is generated. These A-phase and inverted A-phase arrangement in B phase and inverted B-phase vibration body each pulse signal is inputted generates a standing wave W ₃₄ shown in FIG. 10 (D).

[0069] In a state where such standing waves W ₃₄ is generated, torque detecting means detects the rotational torque required when an attempt is made manually rotated the vibration wave motor from the outside.

Then, in step S17, the minimum required rotational torque among the required rotational torques detected in steps S13 to S16 is determined, and the standing wave generation state in which the required rotational torque is detected is selected. I do.

That is, for example, when the standing wave W ₃₃ as shown in FIG. 10C is generated, the maximum amplitude portion (abdomen) of the standing wave W ₃₃ is formed at the contact portion between the moving body and the vibrating body. Is highly likely to be located. In step S17, FIG.
Required rotational torque is detected to be the minimum when the standing wave W _33, as shown in (C) is generated.

Then, the selected standing wave generation state is continued (region t ₃₃ on the right side in FIG. 9), during which the vibration wave motor is manually rotated from the outside. When the rotation is completed, the generation of the standing wave is stopped (step S18).

Thus, in the manual drive mode, the vibration wave motor can be manually rotated from outside by a light load.

(Fourth Embodiment) In the fourth embodiment, a part of the control operation in the third embodiment is changed.

The configuration of the vibration wave motor and the configuration of the drive circuit according to the third embodiment are basically the same as the configuration of the vibration wave motor and the configuration of the drive circuit according to the third embodiment. Therefore, in the description of the fourth embodiment,
The configuration of the vibration wave motor and the configuration of the drive circuit according to the third embodiment are used. In the fourth embodiment, no rotational torque detecting means is provided.

FIG. 11 is a diagram showing a pulse signal output from the oscillator 22 in the fourth embodiment.

In the third embodiment, a rotating torque detecting means is provided to obtain a standing wave generating state in which the required value of the rotating torque is the smallest. However, in the fourth embodiment, a plurality of standing waves having different wavelengths are obtained. The standing wave generation state is periodically switched at a high speed. That is, as shown in FIG. 11, a pulse signal outputted from the oscillator 22 from that shown in the area t ₃₁ to those shown in the area t _34, sequentially switched.

If such sequential switching is performed, the state where the maximum amplitude portion (abdomen) of the standing wave is located at the contact portion between the moving body and the vibrating body, and the state where the required rotational torque is reduced repeatedly occurs. Should do it. On the other hand, if the driving force is manually applied to the vibration wave motor in order to rotate the vibration wave motor from outside, even if the vibration wave motor has a small required rotation torque at the occasion where the required rotation torque is small, The rotation is started, and even if it is not possible to start the rotation sufficiently in one opportunity, the above-mentioned opportunity occurs repeatedly and frequently, and eventually reaches a state where the static friction disappears.

Thus, in the fourth embodiment, it is possible to easily rotate the vibration wave motor manually from outside without providing the rotation torque detecting means.

(Fifth Embodiment) In a fifth embodiment, a paper feeder provided with the vibration wave motor according to any one of the first to fourth embodiments will be described.

FIG. 12 is a sectional view showing a schematic configuration of a paper feeder built in a copying machine, a printer, or the like using the vibration wave motor of the present invention.

Reference numeral 51 denotes a roller for transporting a sheet. One side is connected to a vibration wave motor (the right side in FIG. 12), and the other side is supported by a bearing 52. The bearing 52 is appropriately preloaded. Vibration wave motor and roller 51
The motor shaft 10 is lightly press-fitted into a hole provided along the axis of the roller 51 at the connecting portion, and the motor shaft 10 is fixed to the roller 51 by a set screw 56.

The motor shaft 10 has a pulse plate 5 for detecting the rotation speed and rotation angle of the vibration wave motor.
3. An optical detection element 54 and a detection element mounting case 55 are provided. The pulse plate 53 is directly connected to the motor shaft 1
Since it is attached to 0, detection accuracy is good.

With such a device configuration, the vibration wave motor can be started reliably and smoothly at the start.

A storage medium storing a program code of software realized by the control circuit in each of the above-described embodiments is supplied to a system or an apparatus, and the computer (or CPU or MPU) of the system or the apparatus stores the storage medium in the storage medium. It goes without saying that the present invention is also achieved by reading and executing the stored program code.

In this case, the program code itself read from the storage medium realizes the function of the control circuit in each of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. become.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the control circuit in each of the above-described embodiments are realized, but also the computer operates based on the instructions of the program code. It is needless to say that the present invention includes a case where the OS or the like performs part or all of the actual processing, and the processing realizes the function of the control circuit in each of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The present invention also includes a case where a CPU or the like provided in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the function of the control circuit in each of the above-described embodiments. Needless to say.

[0090]

As described in detail above, claims 1 and 8
According to the twelfth aspect of the invention, a standing wave is generated in the vibrating body when the vibration wave motor is started. If it is not possible to confirm the activation of the vibration wave motor by the generation of the standing wave, a new standing wave is generated after changing the maximum amplitude position of the standing wave generated in the vibrating body.

As a result, it is possible to reliably and smoothly start the rotation of the vibration wave motor without increasing the driving voltage when starting the motor.

According to the sixth, tenth or fourteenth aspect of the present invention, the maximum amplitude position of the standing wave generated in the vibrating body in the manual driving mode in which the vibration wave motor is manually rotated from the outside. Is changed and the standing wave is repeatedly generated, and every time a standing wave is generated in the vibrating body, a rotational torque required for rotationally driving the vibration wave motor before starting is detected. Then, among the detected rotation torques, a standing wave generation state that is the lowest torque is detected,
The vibrating body reproduces the standing wave generation state.

Thus, in the manual drive mode, the vibration wave motor can be manually rotated with a small torque.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a drive control procedure of a vibration wave motor according to a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a driving frequency and a rotation speed of a vibration wave motor for explaining driving frequency control performed in the first embodiment.

FIG. 3 is a diagram illustrating a pulse signal output from an oscillator according to the first embodiment.

FIG. 4 is a diagram illustrating a state of contact between a vibrating body (hatched portion) as a stator and a moving body.

FIG. 5 is a diagram illustrating a pulse signal output from an oscillator according to the second embodiment.

FIG. 6 is a diagram illustrating a relationship between a pulse width of a pulse signal and an output voltage of a transformer of a driving circuit.

FIG. 7 is a diagram showing a position where a standing wave is generated when each pulse signal shown in FIG. 5 is input.

FIG. 8 is a flowchart illustrating a drive control procedure of the vibration wave motor executed in advance by the control circuit when the vibration wave motor is rotated from the outside in the third embodiment.

FIG. 9 is a diagram illustrating a pulse signal output from an oscillator according to the third embodiment.

FIG. 10 is a diagram showing a contact state between a moving body and a vibrating body (hatched portion) as a stator.

FIG. 11 is a diagram illustrating a pulse signal output from an oscillator according to a fourth embodiment.

FIG. 12 shows a copying machine using the vibration wave motor of the present invention;
FIG. 2 is a cross-sectional view illustrating a schematic configuration of a paper feeding device built in a printer or the like.

FIG. 13 is a cross-sectional view illustrating a configuration of an example of a conventional vibration wave motor.

FIG. 14 is a circuit diagram showing a configuration of a driving circuit for driving a conventional vibration wave motor.

FIG. 15 is a graph showing the relationship between the frequency (f) of the drive voltage supplied to the vibration wave motor and the rotation speed (N) of the vibration wave motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Elastic body 2 Piezoelectric element group 3 Slider material 4 Flexible board 5 Base 6 Moving body 7 Anti-vibration rubber 8 Plate spring 9 Disc flange 10 Shaft 11, 12 Bearing 13 Retaining ring 14 Spacer 15 Pulse generating means 21 Control circuit 22 Oscillator 23, 24, 25, 26 Switching element 27, 28 Transformer 41-48 Resistance element 50 Rotation speed detection circuit 51 Roller 52 Bearing 53 Pulse plate 54 Optical detection element 55 Detection element mounting case 56 Set screw

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinji Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tadashi Hayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Jun Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) 5H680 AA09 BB03 BB16 BC04 BC05 CC06 CC07 DD01 DD03 DD15 DD23 DD39 DD53 DD57 DD66 DD73 DD87 DD92 EE03 EE21 EE22 EE23 EE24 FF04 FF08 FF25 FF35 FF38 GG23 GG27

Claims (15)

[Claims] 1. A driving apparatus for a vibration wave motor that excites a vibrating body by applying an AC signal to an electro-mechanical energy conversion element and applies a driving force due to friction to a moving body pressed by the vibrating body. When starting the vibration wave motor, a standing wave generating means for generating a standing wave on the vibrating body; and confirming whether or not the vibration wave motor has been started after the standing wave generation by the standing wave generating means. Confirming means, and when the activation of the vibration wave motor cannot be confirmed by the confirming means, the standing wave generating means changes the maximum amplitude position of the standing wave to be generated in the vibrating body, and then newly establishes A vibration wave motor driving device, comprising: control means for generating a standing wave. 2. The apparatus according to claim 1, wherein said standing wave generating means includes a wavelength changing means for smoothly changing the wavelength of the standing wave after generating the standing wave in said vibrator. Vibration wave motor drive. 3. The standing wave generating means includes: a pulse signal generating means having a frequency higher than a resonance frequency of the vibration wave motor and generating a plurality of types of pulse signals having a phase difference of 180 °; A plurality of switching means for switching a power supply current based on a pulse signal output from the signal generating means; a current output from the plurality of switching means is supplied to a primary side; and a secondary side is connected to the vibration wave motor. 3. The vibration wave motor driving device according to claim 1, comprising a plurality of transformers. 4. The vibration wave motor driving device according to claim 3, wherein said control means controls generation of a pulse signal by said pulse signal generation means to change a maximum amplitude position of said standing wave. 5. The vibration wave motor according to claim 3, wherein said control means controls a pulse width of a pulse signal generated by said pulse signal generation means to change a maximum amplitude position of said standing wave. Drive. 6. A torque detecting means for detecting a rotational torque required for rotationally driving the vibration wave motor before starting, and wherein the standing wave is in a manual drive mode for manually rotating the vibration wave motor from outside. Generating means for changing a maximum amplitude position of a standing wave generated in the vibrating body, and then generating a new standing wave; and Among the rotating torques detected by the torque detecting means each time a standing wave is generated, a standing wave generation state that is the lowest torque is detected,
6. The vibration wave motor driving device according to claim 1, further comprising: a reproduction unit configured to reproduce the standing wave generation state on the vibrating body. 7. In a manual drive mode in which the vibration wave motor is manually rotated from the outside, the standing wave generation means changes a maximum amplitude position of a standing wave generated in the vibrating body and newly sets the position. 6. The vibration wave motor driving device according to claim 1, further comprising a repetition control unit that repeatedly performs an operation of generating a standing wave. 8. A driving device for a vibration wave motor which excites a vibrating body by applying an AC signal to an electro-mechanical energy conversion element and applies a driving force by friction to a moving body pressed by the vibrating body. A standing wave generating step of generating a standing wave on the vibrating body when the vibration wave motor is started; and the vibration wave motor after the standing wave is generated by the standing wave generating step. And a confirmation step of confirming whether or not the vibration wave motor has been activated, and when the activation of the vibration wave motor cannot be confirmed by the confirmation step, the maximum amplitude position of the standing wave generated in the vibrating body is changed, and then a new A standing wave generating step for generating a standing wave again. 9. The method according to claim 8, wherein the step of generating a standing wave includes a step of changing a wavelength of the standing wave smoothly after generating a standing wave in the vibrator. Vibration wave motor driving method. 10. A standing wave for generating a new standing wave after changing the maximum amplitude position of the standing wave generated in the vibrating body in a manual drive mode in which the vibration wave motor is manually rotated from the outside. Each time a standing wave is generated in the vibrating body by the generation control step, and the standing wave generation step and the standing wave generation control step, the rotation required when the vibration wave motor before starting is driven to rotate. A reproducing step of detecting a standing wave generation state having the lowest torque among the rotational torques detected by the torque detecting means for detecting the torque, and reproducing the standing wave generation state on the vibrating body. 10. The vibration wave motor driving method according to claim 8, wherein: 11. In a manual driving mode in which the vibration wave motor is manually rotated from the outside, an operation of generating a new standing wave after changing the maximum amplitude position of the standing wave generated in the vibrating body is repeated. 10. The method according to claim 8, further comprising a repetition control step for performing the operation.
The driving method of the vibration wave motor according to the above. 12. A vibration wave motor driving device which excites a vibrating body by applying an AC signal to an electromechanical energy conversion element and applies a driving force by friction to a moving body pressed by the vibrating body. A computer-readable storage medium storing a vibration wave motor driving method as a program, wherein the vibration wave motor driving method comprises: generating a standing wave in the vibrating body when the vibration wave motor is started. A wave generation step, a confirmation step of confirming whether or not the vibration wave motor has been started after the standing wave is generated by the standing wave generation step, and when the activation of the vibration wave motor cannot be confirmed by the confirmation step. A standing wave generation step of generating a new standing wave after changing the maximum amplitude position of the standing wave generated in the vibrating body. Storage medium characterized. 13. The method according to claim 12, wherein the step of generating a standing wave includes a step of changing a wavelength of the standing wave smoothly after generating a standing wave in the vibrator. Storage medium. 14. The vibration wave motor driving method according to claim 1, further comprising: changing a maximum amplitude position of a standing wave generated in the vibrating body in a manual driving mode in which the vibration wave motor is manually rotated from the outside. A standing wave generation control step of generating a standing wave, and each time a standing wave is generated in the vibrating body by the standing wave generation step and the standing wave generation control step, the vibration wave motor before starting is driven. Among the rotational torques detected by the torque detecting means for detecting a rotational torque required for rotational driving, a standing wave generating state having a minimum torque is detected, and the standing wave generating state is determined by the vibrating body. 13. A reproducing step for reproducing the image data in the following manner.
Or the storage medium according to claim 13. 15. The vibration wave motor driving method according to claim 1, further comprising: changing a maximum amplitude position of a standing wave generated in the vibrating body in a manual driving mode in which the vibration wave motor is manually rotated from the outside. 4. The storage medium according to claim 12, further comprising a repetition control step of repeatedly performing an operation of generating a standing wave.