JP2002142477A - Vibration wave driver and method for handling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration wave driver for simply electrically discharging a piezoelectric element after opening an alternating voltage supply terminal via a carrier or the like in the driver using the elements all polarized in the same direction. SOLUTION: When a connector from a power supply circuit is removed and opened for the alternating voltage supply terminal 12 of the vibration wave driver, a conductive clip-like short-circuit component 14 is mounted at a four- phase terminal and a GND terminal of the terminal 12, and a front surface and a rear surface of the element are electrically short-circuited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type driving device such as a vibration wave motor for generating a vibration in an elastic body and applying a driving force by using the vibration energy, and a method of handling the same.

[0002]

2. Description of the Related Art A vibration type driving device is provided with a polarized electric-
A piezoelectric element as a mechanical energy conversion element is fixed to an elastic body by adhesion or the like as a vibrating body, and the elastic body is formed by applying an alternating voltage having a frequency near the natural frequency of the elastic body to the piezoelectric element. Exciting the driving vibration to the driving unit of the elastic body by vibrating, the vibrating body, and a contact body that presses and contacts the vibrating body using a frictional force, as a typical one, There is a vibration wave motor using the contact body as a moving body.

FIG. 11 is a diagram showing a vibrating body composed of a piezoelectric element and an elastic body of a vibration wave driving device. In FIG. 11, reference numeral 101 denotes a metal elastic body to which a piezoelectric element 102 is adhered. An electrode 103 is deposited on the piezoelectric element 102.

FIG. 12 shows an arrangement of electrodes deposited on the piezoelectric element 2. As shown in FIG. 12, electrodes divided into 18 regions are deposited on the piezoelectric element 102. The vibrating body shown in FIGS. 11 and 12 is configured to generate a ninth progressive vibration wave in the circumferential direction on an annular vibrating body.

[0005] This vibration wave driving device is driven by supplying two-phase alternating voltages (A phase, B phase) having a phase difference of 90 °. The phase B is switched between advancing the phase A by 90 ° and delaying it from the phase A.

In FIG. 12, the electrodes in the area indicated as “A phase” are electrodes for driving the A phase, and the electrodes in the area indicated as “B phase” are electrodes for the B phase. Both the A-phase drive electrode and the B-phase drive electrode have an oscillation wavelength (at the resonance frequency) of 2
It has a one-half length.

In FIG. 12, "+" and "-"
, Which indicates the direction of polarization when the piezoelectric element is polarized.

FIG. 13 is a sectional view of the piezoelectric element during polarization.

In FIG. 13, reference numeral 103a denotes an electrode polarized by applying a positive voltage during polarization, and 103b denotes an electrode polarized by applying a negative voltage during polarization. 103c is an electrode on the surface to be bonded to the elastic body, and is deposited on the entire back surface of the piezoelectric element. By performing the polarization processing with the above configuration, 103a and 103b are polarized to opposite polarities.

When a vibration wave motor is formed by using the piezoelectric element polarized in the above configuration, for example, as shown in FIG. 12, the alternating voltage of two phases is A phase in the right half and B phase in the left half. Because the vibration amplitude generated in the vibrating body differs depending on the location because it is applied and driven, there is a limit in achieving high-precision rotation, or when the vibrating body is worn for a long time, there is a lot of wear of the vibrating body depending on the location In such a case, uneven wear that causes a small portion to occur may occur, and a problem such as a decrease in output may occur.

In order to solve the above problem, a vibration wave motor using a piezoelectric element in which electrodes are deposited in a pattern as shown in FIG. 14 and the polarization direction is the same in all regions has been proposed by the present applicant. I have.

In FIG. 14, the circumferential length of each electrode is:
The length is one quarter of the oscillation wavelength. The electrode on the bonding surface is deposited on the entire surface. When the piezoelectric element is polarized, it is polarized by applying a positive voltage to all the electrodes as shown in FIG.

When a vibration wave motor is constituted by using the piezoelectric element polarized in the above-described configuration, a four-phase alternating voltage (A phase, B phase, A * phase, B * phase) is applied at the time of driving. use. In the above-described four-phase alternating voltages, the A-phase and the B-phase are alternating voltages having a 90 ° phase difference, and switching between advancing or delaying the A-phase by 90 ° is performed according to the rotation direction. A * phase is 180 ° to A phase
The B * phase is an alternating voltage having a 180 ° phase difference with respect to the B phase. By applying the above four-phase alternating voltages evenly over the entire circumference in the order of A phase, B phase, A * phase, and B * phase as shown in FIG. Can be excited.

In the above-mentioned electrode patterns, the reason why the polarization directions are all the same is that when adjacent electrodes are polarized in the opposite direction, not only the lines of electric force from the front surface to the back surface for generating a driving force, but also the adjacent electrodes. This is because lines of electric force are also generated in the electrodes, and unnecessary vibrations occur.

As described above, a vibration wave motor using a piezoelectric element manufactured by depositing an electrode having a length of a quarter of the vibration wavelength in the circumferential direction and polarizing all the electrodes in the same direction. By applying a four-phase alternating voltage and driving, it is possible to generate a traveling wave of uniform amplitude on the vibrating body, and it is possible to perform high-precision rotation and to contact the vibrating body and the moving body. Partial uneven wear can be prevented, and it is possible to prevent a decrease in output even after long-time driving.

When a voltage is applied to the polarized piezoelectric element, the piezoelectric element is deformed by an inverse piezoelectric effect. On the contrary, an electric charge is generated on the front and back surfaces of the piezoelectric element due to the deformation or the temperature change.

In the above-described vibration wave motor using piezoelectric elements all polarized in the same direction, when charges are generated when the terminal for supplying the alternating voltage is opened, the state in which the charges are accumulated is maintained. After connecting to the circuit, the current will flow instantaneously, which may be a source of noise.Therefore, before connecting to the circuit, short-circuit the alternating voltage supply terminals of the vibration wave motor to discharge the charge, and then connect to the circuit. The method of doing was taken.

[0018]

However, as described above, in the vibration wave driving device using the piezoelectric elements all polarized in the same direction, after the alternating voltage supply terminal is opened by carrying or the like, each time it is connected to the circuit. The operation of short-circuiting and discharging is complicated, and if the above operation is neglected, there is a problem that the circuit may be broken.

[0019]

In order to solve the above-mentioned problems, according to the present invention, a polarized piezoelectric element is fixed to an elastic body, and distortion is generated in the piezoelectric element by applying an alternating voltage to the piezoelectric element. In the vibration-type actuator configured to vibrate the elastic body, when the alternating voltage supply terminal of the vibration-type actuator is open at the time of transport or the like, at least a part of the surface of the piezoelectric element,
A member is attached such that at least a part of the back surface of the piezoelectric element is electrically short-circuited.

Further, in the present invention, the polarized piezoelectric element is fixed to the elastic body, and by applying an alternating voltage to the piezoelectric element, the piezoelectric element is distorted to vibrate the elastic body. In vibration type actuators,
Switching means capable of electrically shorting or opening at least a part of the front surface of the piezoelectric element and at least a part of the back surface of the piezoelectric element is attached, and the switch is used when the vibration wave motor is driven. Is used in an open state.

Further, according to the present invention, a polarized piezoelectric element is fixed to an elastic body, and an alternating voltage is applied to the piezoelectric element to cause a distortion in the piezoelectric element to vibrate the elastic body. Type actuator
At the time of production of the vibration-type actuator, at least a part of the front surface of the piezoelectric element and at least a part of the back surface of the piezoelectric element are electrically short-circuited by a cuttable circuit. It is characterized in that a possible circuit is cut and used.

Further, according to the present invention, a polarized piezoelectric element is fixed to an elastic body, and an alternating voltage is applied to the piezoelectric element to cause a distortion in the piezoelectric element to vibrate the elastic body. Type actuator
At least a part of the front surface of the piezoelectric element and at least a part of the back surface of the piezoelectric element are connected by a resistor or an inductance element.

[0023]

FIG. 2 is a sectional view of a vibration wave motor as a vibration wave driving device, and FIG. 3 is a plan view of the vibration wave motor. Hereinafter, the vibration wave motor will be described with reference to FIGS.

Reference numeral 1 denotes a metal elastic body, which is manufactured by a method such as sintering. The piezoelectric element 2 is bonded to the elastic body 1. Electrodes are deposited on the piezoelectric element 2 in regions as shown in FIG. 14, and polarization treatment is performed in the same direction in all regions in a process before bonding to the elastic body 1. In FIG. 14, A phase, B phase, A * phase, and B * phase are described for each electrode, but this indicates the type of alternating voltage applied when the vibration wave motor is driven, and is not shown. An alternating voltage is externally supplied to each phase by the flexible printed circuit board and the connector 12. The frequency of the alternating voltage is elastic
This is a frequency near the resonance frequency of the vibrating body composed of the piezoelectric element 1 and the piezoelectric element 2. The phase of the A phase and the phase of the B phase are different by 90 °. A
Whether the phase B is advanced by 90 ° or delayed by 90 ° with respect to the phase is switched according to the rotation direction of the vibration wave motor. The A phase and the A * phase are alternating voltages having a 180 ° phase difference, and the B phase and the B * phase are alternating voltages having a 180 ° phase difference.

In FIG. 2, reference numeral 3 denotes a moving body as a contact body, which is an annular member made of metal. The moving body 3 is pressed against the elastic body 1 by a pressing spring 4 with a predetermined force.
When the four-phase alternating voltage is applied to the piezoelectric element 2, a progressive vibration wave is generated on the elastic body. As a result, the moving body 3 pressed against the elastic body rotates by the frictional force.

Reference numeral 5 denotes a shaft, and the moving body 3 and the pressing spring 4
Connected through. When the moving body 3 rotates, the shaft 5 also rotates. The shaft 5 is supported by two bearings 6,7.

Reference numeral 8 denotes a code wheel for detecting a rotation speed or a rotation position of the shaft 5. Reflective surfaces and non-reflective surfaces are alternately formed on the surface of the code wheel in the circumferential direction. Reference numeral 9 denotes a reflection-type encoder, which includes a light-emitting unit and a light-receiving unit, and irradiates a light beam to a code wheel, and outputs a voltage signal corresponding to the reflected light.
It is. The output signal of the encoder is the connector 1 shown in Fig. 3.
3 is connected to a control circuit (not shown).

2 and 3, reference numeral 11 denotes a metal housing.

FIG. 1 is a perspective view of a connector portion of the vibration wave motor. As described above, the connector 12 is used to apply an alternating voltage to the vibration wave motor. The connector 12 is provided with five contact terminals as shown by broken lines, and each terminal is connected to the A phase, the B phase, the A * phase, and the B * phase shown in the figure. Further, the GND terminal is electrically connected to the housing 11 of the vibration wave motor, and is configured to have the same potential as the electrode on the bonding surface side of the vibration body 1 and the piezoelectric element 2. That is, the bonding surface side of the piezoelectric element 2 is connected to the GND terminal, and the opposite surface is connected to any one of the remaining four terminals.

In FIG. 1, reference numeral 14 denotes a short-circuit component formed of a conductive metal. The short-circuit component 14 has a spring property,
The insertion state is maintained by pushing the lower part in the drawing and inserting it into the connector. Short-circuit parts 14
Is shown in the circled portion of FIG.

When the short-circuit component 14 is inserted, all five terminals of the connector 12 are electrically short-circuited. As described above, among the five terminals, GND is the piezoelectric element 2
Since the electrode on the adhesive side of the other terminal is connected to one of the electrodes on the opposite side, both sides of the piezoelectric element 2 are short-circuited by inserting a short-circuit component,
No charge is accumulated.

By inserting the short-circuit component 14 into the connector before transporting or the like in which there is a concern about temperature change, no charge is accumulated in the piezoelectric element 2 and the piezoelectric element 2 does not enter a charged state. Then, immediately after connecting the vibration wave motor to the drive circuit after transportation, the short-circuit component 14 is removed, and by connecting the connector 12 and the drive circuit with electric wires, a current can flow instantaneously as described in the section of the related art. This eliminates the possibility of generating noise. (Second Embodiment) FIG. 4 is a diagram showing a second embodiment of the present invention. FIG. 4 shows a vibration wave motor similar to that described in the first embodiment, except that a switch 14 is added to the vibration wave motor of the first embodiment. Less than,
The operation of the switch 14 will be described.

The switch 14 is configured to be slidable in the left and right directions in the figure. When the switch 14 is slid to the right, the five terminals of the connector 12 are open. Also,
When the switch 14 is slid to the left, all five terminals of the connector 12 are constituted by a printed circuit board (not shown) so as to be in a short-circuit state.

When the vibration wave motor is not connected to the drive circuit during transportation or the like, the switch 14 is slid to the left to short-circuit the five terminals of the connector 12. Then, when connecting the vibration wave motor to the drive circuit, the switch is slid to the right. By the above operation, the first aspect of the present invention
The same effect as that of the embodiment can be obtained. (Third Embodiment) FIG. 5 is a diagram showing a third embodiment of the present invention. FIG. 5 is also a vibration wave motor similar to that described in the first embodiment, but has a flexible printed circuit board for supplying an alternating voltage to the vibration wave motor.
This is different from that of the first embodiment.

In FIG. 5, reference numeral 15 denotes a terminal short circuit pattern.
A part of the flexible printed circuit
Are formed to short-circuit each of the terminals.
By keeping the state as shown in FIG. 5 during production and transportation, it is possible to short-circuit each of the five terminals of the connector 12, thereby preventing electric charges from being accumulated in the piezoelectric element 2 of the vibration wave motor. be able to.

Then, just before connecting the vibration wave motor to the drive circuit, the terminals of the connector 12 can be changed from the short-circuited state to the open state by cutting the flexible printed circuit board at the portion shown by the broken line in the figure. With the above operation, the same effect as that of the first embodiment of the present invention can be obtained. (Fourth Embodiment) FIG. 6 is a diagram showing a fourth embodiment of the present invention. FIG. 6 is also a vibration wave motor similar to that described in the first embodiment, but the shape of a flexible printed circuit board for supplying an alternating voltage to the vibration wave motor, and mounted on the flexible printed circuit board The elements are different.

In FIG. 6, reference numeral 16 denotes a chip resistor mounted on a flexible printed circuit board.
The D terminal and the other terminals are connected with a certain resistance value. Even if a temperature change occurs during transportation or the like and electric charges are generated on both surfaces of the piezoelectric element 2, an operation is performed to prevent electric charges from being accumulated due to the flow of current through the chip resistor 16.

If the resistance value of the chip resistor 16 is too small, a large amount of current flows through the chip resistor at the time of driving, thereby deteriorating the driving efficiency of the vibration wave motor, causing heat generation, or destroying the chip resistor. Therefore, the value of the chip resistance is selected to be at least larger than the impedance at the time of driving the vibration wave motor.

With the above operation, the same effects as in the first embodiment of the present invention can be obtained.

It is needless to say that the same effect can be obtained by using a lead-shaped resistor as well as a chip resistor. (Fifth Embodiment) FIG. 7 is a diagram showing a fifth embodiment of the present invention. FIG. 7 shows a case where the chip resistor used in the fourth embodiment is changed to an inductance element 17.

The electric charge stored in the piezoelectric element is discharged via the inductance element 17. Since the alternating voltage when driving the vibration wave motor is a high frequency, by setting the inductance value of the inductance element 17 to an appropriate value,
The current flowing through the inductance element does not matter.

With the above operation, the same effects as in the first embodiment of the present invention can be obtained. (Sixth Embodiment) In the fifth embodiment of the present invention, an inductance element is added inside the vibration wave motor, but the inductance element may be mounted on the drive circuit side.

FIG. 8 shows a driving circuit used in the sixth embodiment of the present invention. 8, 20, 21, 22, and 23 indicate piezoelectric elements of the vibration wave motor, 20 is A phase, 21 is B phase,
22 is the A * phase and 23 is the B * phase. 19 and 20 are transformers. Reference numerals 24 to 31 denote switching elements for controlling the current on the temporary side of the transformer. A pulse signal corresponding to the drive frequency is input from a pulse generator (not shown).

At the time of driving, a driving voltage for the vibration wave motor can be supplied by applying a pulse signal having a frequency of an alternating voltage applied to the vibration wave motor and having a different phase to the gate input to perform switching. In addition, both sides of the piezoelectric elements 20 to 23 are
Since it is connected to the secondary-side inductance element, it is possible to prevent charges from being accumulated on both surfaces of the piezoelectric element.

[0045]

As described above, according to the present invention, an alternating voltage supply terminal of a vibration wave motor, particularly a vibration wave motor using a piezoelectric element polarized in the same direction, is short-circuited by short-circuit means, and is connected to a drive circuit. By removing the short-circuit means at the time of connection, the procedure of discharging before connecting the circuit can be omitted, and generation of noise and destruction of circuit elements can be reliably prevented.

Further, according to the present invention, electric charges can be prevented from being accumulated on both sides of the piezoelectric element by electrically connecting both sides of the piezoelectric element with a resistor or an inductance element.

[Brief description of the drawings]

FIG. 1 is a view for explaining a vibration wave motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a vibration wave motor.

FIG. 3 is a plan view of the vibration wave motor.

FIG. 4 is a diagram illustrating a vibration wave motor according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a vibration wave motor according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a vibration wave motor according to a fourth embodiment of the present invention.

FIG. 7 is a view for explaining a vibration wave motor according to a fifth embodiment of the present invention.

FIG. 8 is a diagram showing a driving circuit used in a sixth embodiment of the present invention.

FIG. 9 is a perspective view of a vibrating body.

FIG. 10 is a diagram showing electrodes of a piezoelectric element.

FIG. 11 is a diagram showing a method of polarizing a piezoelectric element.

FIG. 12 is a diagram showing electrodes of a piezoelectric element all polarized in the same direction.

FIG. 13 is a view showing a polarization method of a piezoelectric element all polarized in the same direction.

[Explanation of symbols]

 1,101… elastic body 2,102… piezoelectric element 3… moving body 4… pressure spring 5… shaft 6,7… bearing 8… code wheel 9… encoder 10… cover 11… housing 12,13… connector 14… switch 15… Flexible printed circuit board 16 ... Chip resistance 17 ... Inductance element 18,19 ... Transformer 20-23 Piezoelectric element 24-31 ... Switching element 103 ... Electrode

Claims (12)

[Claims] A vibrating body having a polarized electro-mechanical energy conversion element fixed to an elastic body, wherein the electro-mechanical energy conversion element is distorted by applying an alternating voltage to the electro-mechanical energy conversion element. In the vibration wave driving device that vibrates the elastic body, when the alternating voltage supply terminal of the vibration wave driving device is open, at least a part of the surface of the electro-mechanical energy conversion element, A vibration wave driving device, wherein a member is attached such that at least a part of the back surface of the electro-mechanical energy conversion element is electrically short-circuited. 2. An electromechanical energy conversion element, comprising: a vibrating body having a polarized electromechanical energy conversion element fixed to an elastic body, wherein a distortion is applied to the electromechanical energy conversion element by applying an alternating voltage to the electromechanical energy conversion element. In the vibration wave driving device that vibrates the elastic body, at least a part of a front surface of the electro-mechanical energy conversion element and at least a part of a back surface of the electro-mechanical energy conversion element are electrically short-circuited or A vibration wave driving device, further comprising an opening / closing means that can be opened, wherein the vibration wave driving device is used with the opening / closing means opened when the vibration wave driving device is driven. 3. An electromechanical energy conversion element having a vibrating body in which a polarized electromechanical energy conversion element is fixed to an elastic body, wherein a distortion is applied to the electromechanical energy conversion element by applying an alternating voltage to the electromechanical energy conversion element. In the vibration wave driving device for causing the elastic body to vibrate, at the time of production of the vibration wave driving device, at least a part of the surface of the electro-mechanical energy conversion element,
At least a part of the back surface of the mechanical energy conversion element is electrically short-circuited by a severable circuit, and the severable circuit is cut and used when the vibration wave driving device is driven. apparatus. 4. A vibrating body having a polarized electro-mechanical energy conversion element fixed to an elastic body, wherein a distortion is applied to the electro-mechanical energy conversion element by applying an alternating voltage to the electro-mechanical energy conversion element. Wherein at least a part of the front surface of the electro-mechanical energy conversion element and at least a part of the back surface of the electro-mechanical energy conversion element are connected by a resistor. A vibration wave driving device. 5. The vibration wave driving device according to claim 4, wherein a resistance value of the resistor is larger than an impedance when the vibration wave driving device is driven. 6. The vibration wave driving device according to claim 4, wherein the resistance value of the resistor is 100Ω or more. 7. A vibrating body having a polarized electro-mechanical energy conversion element fixed to an elastic body, wherein a distortion is applied to the electro-mechanical energy conversion element by applying an alternating voltage to the electro-mechanical energy conversion element. In the vibration wave driving device that causes the elastic body to vibrate, at least a part of a front surface of the electro-mechanical energy conversion element and at least a part of a back surface of the electro-mechanical energy conversion element are connected by an inductance element. A vibration wave driving device. 8. Electrodes are attached to both sides of the electro-mechanical energy conversion element, and at least one side of the electro-mechanical energy conversion element is divided into a plurality of regions by electrodes. The vibration wave driving device according to any one of claims 1 to 7, wherein the region is polarized so that the polarization direction from the front surface to the rear surface of the region is the same. 9. The vibration according to claim 8, wherein one surface of the electro-mechanical energy conversion element is circumferentially divided into regions each having a length of a quarter of the vibration wavelength. Wave drive. 10. An electromechanical energy conversion element having a vibrating body in which a polarized electromechanical energy conversion element is fixed to an elastic body, wherein the electromechanical energy conversion element is distorted by applying an alternating voltage to the electromechanical energy conversion element. Causes
In the method of handling a vibration wave driving device that vibrates the elastic body, when an alternating voltage supply terminal of the vibration wave driving device is open, at least a part of a surface of the electro-mechanical energy conversion element and the electric device. -A method for handling a vibration wave driving device, wherein a member is attached such that at least a part of the back surface of the mechanical energy conversion element is electrically short-circuited. 11. A vibrator in which a polarized electro-mechanical energy conversion element is fixed to an elastic body, and a distortion is applied to the electro-mechanical energy conversion element by applying an alternating voltage to the electro-mechanical energy conversion element. Causes
In the handling method of the vibration wave driving device that vibrates the elastic body, at least a part of a front surface of the electro-mechanical energy conversion element and at least a part of a back surface of the electro-mechanical energy conversion element are electrically short-circuited or opened. A method of handling a vibration wave driving device, comprising an opening / closing means capable of being opened, and using the opening / closing means when the vibration wave driving device is driven. 12. An electromechanical energy conversion device comprising a vibrating body having a polarized electro-mechanical energy conversion device fixed to an elastic body, wherein the electro-mechanical energy conversion device is distorted by applying an alternating voltage to the electro-mechanical energy conversion device. Causes
In the method for handling a vibration wave driving device that vibrates the elastic body, at the time of producing the vibration wave driving device, at least a part of a surface of the electro-mechanical energy conversion element and the electric-
At least a part of the back surface of the mechanical energy conversion element is electrically short-circuited by a severable circuit, and the severable circuit is cut and used when the vibration wave driving device is driven. How to handle the device.