JPS60176471A - Drive circuit of vibration wave motor - Google Patents

Abstract

PURPOSE:To efficiently and stably move a moving unit by applying the induced electromotive force generated by turning ON and OFF a DC power source by a frequency signal of a resonance vibration of an electrostrictive element to the element. CONSTITUTION:A pulse signal is applied from an oscillator to the base of a transistor Q to switch the primary side of a transformer T1. The pulse frequency at this time is set to the resonance frequency of an electrostritive element 1. A voltage inductively generated at the secondary side of the transformer T1 is applied as a drive voltage to the element 1. When the pulse width is controlled at this time, the drive power is controlled, and a drive speed is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive circuit for a swing J-wave motor that frictionally drives a moving body using progressive vibration waves.

FIG. 1 shows a schematic diagram of an embodiment of a vibration wave motor driven by progressive vibration waves, which has recently been put into practical use. In the figure, 1 is an electrostrictive element made of, for example, PZT (lead zirconium titanate), and 2 is a vibrating body made of an elastic material, to which the electrostrictive element 1 is bonded.

The vibrating body 2 and the electrostrictive element 1 are held on the stator (not shown) side. Reference numeral 3 denotes a moving body which is in pressure contact with the vibrating body 2 and forms a rotor. A plurality of electrostrictive elements 1 are bonded together, and the electrostrictive elements in one group of the electrostrictive elements in the other group are arranged at a pitch shifted by % wavelength of the wavelength of the vibration wave. The electrostrictive elements l in each group are arranged at a pitch of the local wavelength so that adjacent ones have opposite polarities. Further, although not shown, electrode films are provided on the front and back sides of each electrostrictive element l, respectively, so that a voltage can be applied to each electrostrictive element (-1).

A vibration wave motor with this configuration can be used as a group of electrostrictive elements ■.

An AC voltage of sinωt is applied, and V is applied to the electrostrictive elements of the other group. An alternating current voltage of cosωt is applied. Therefore, each electrostrictive element undergoes stretching and contraction vibrations by applying alternating current voltages in which the polarities of adjacent elements are opposite to each other and the two groups are out of phase by 90 degrees. This vibration is transmitted, and the vibrating body 2 bends and vibrates in accordance with the arrangement pitch of the electrostrictive elements 1. When the vibrating body 2 protrudes at the position of the second electrostrictive element, the position of the other second electrostrictive element retracts. On the other hand, as mentioned above, the bending vibration progresses because the electrostrictive elements of group 1 are at positions shifted by the moon wavelength from the electrostrictive elements of other groups.

While the alternating current voltage is applied, vibrations are excited one after another and propagate through the vibrating body 2 as progressive bending vibration waves.

The progress state of the wave at this time is shown in Figure 2 (a), (b), and (c).
It is shown in (d). Now, the progressive bending vibration wave is pointing to arrow X.
Suppose it moves in one direction. If 0 is the central plane of the vibrating body in a stationary state, then in the vibrating state it will be in the state shown by the chain line, in which the stress due to bending is balanced on the 0 plane 6. Cross section 7 perpendicular to the neutral plane 6. If we look at the intersection line 5I of these two planes,
Then stress is applied [- It is only vibrating downward. At the same time, the cross section 7 is pendulum vibrating left and right about the intersection line 51.

The intersection line 52 or 5 is also rotated for the cross section 72 or 73.
It vibrates left and right around 3.

In the state shown in Figure (a), cross section 7. The point P1 of the intersection line between the surface of the vibrating body 2 and the surface of the vibrating body 3 side is the right dead center of the left-right vibration, and is only moving upward.・This pendulum vibration intersects m 51 ・5. Or if 53 is on the positive side of the wave (center plane O
(when it is on the L side of
Stress is applied in the right direction. That is, in FIG. 5A, when the intersection line 52 and the cross section 72 are in the former state, stress is applied to the point P2 in the direction of the arrow. In the latter state where the line 53 and the cross section 73 intersect, a stress is applied to one point P3 in the direction of the arrow. As the wave progresses, as shown in (tl), the intersection line 5 is on the positive side of the wave, and the point P1 moves to the left and at the same time moves upward. In (C), point P1 moves only to the left with 1-r vibration L-1. In (d), point P1 moves leftward and upward. The wave further advances, moving to the right and in the F direction, moving to the right and upward, and then returning to the state in (a). When this series of movements is combined, the point P is moving in a spheroidal ellipse. - The moving body 3 is in pressure contact with the vibrating body 2, and as shown in the same figure (C), the spheroidal motion of the point P1 on the vibrating body 2 frictionally drives the movable body 3 in the X2 direction. .

Points P2-P3 and all other points of derived body 2F are point P,
The movable body 3 is frictionally driven to rotate.

In this way, in the conventional vibration wave motor, V. It is inconvenient that an AC power supply must be prepared in order to apply the driving voltage of sinωt. Furthermore, in order to adjust the driving speed of the motor, the voltage of the AC power source must be adjusted.

The present invention has been made in consideration of the above-mentioned (1), and an object of the present invention is to provide a driving system for a vibration wave motor that operates effectively and stably.

In order to achieve this object, the present invention provides a driving circuit for a vibration wave motor that drives a moving body using progressive vibration waves of resonant vibrations generated by applying a frequency voltage to an electrostrictive element. This drive circuit is characterized in that an induced electromotive voltage generated by turning a DC power source on and off using a vibration frequency signal is applied to the electrostrictive element as the frequency voltage.

Embodiments of the present invention will be described in detail below.

FIG. 3 shows an embodiment of a circuit to which the present invention is applied.6 In the same figure, ■ is the electrostrictive element f mentioned above (see FIG. 1), Batl is a power supply battery, and TI is an interface between the primary side and the secondary side. One lance, Q, which combines the tangent component with respect to the electrostrictive element l, is a swing transistor.

In such a circuit, an oscillator (
(not shown), the primary side of the transformer Tl is switched by changing the pulse signal as shown in FIG. 4(a). The pulse frequency at this time is set to the resonance frequency of the electrostrictive element l. Then, the voltage with the waveform shown in FIG.
A driving voltage of 11 J is added to the voltage. At this time, pulse I
By controlling I+, the upper drive direction can be controlled and the drive speed can be controlled. In addition, by detecting the vibration frequency of the electrostrictive element /-1,
The oscillator may be Noey I-banked and the pulse frequency may be synchronized to the resonant frequency of the electrostrictive element I.

Figures 5 and 6 show circuits of other embodiments, and Figure 7 shows circuits of other embodiments.
The figure is a signal waveform diagram. Figure 5 φ In Figure 6, O
SC is an oscillator, F/V is a frequency-voltage converter, CPI-
CP, 2 is a comparison amplifier, lN1-lN3 are inverters,
AND 1・～AND4 is ant gate・, 0NI-O
N2 is a Schmitt torque circuit, FFI-FF2 is a flip-flop, R1-R8 is a fixed resistor, VRI-VR
3 is a variable resistor, Cl-C5 is a capacitor, Di-D6 is a diode 1, Q1 to Q7 are transistors, T2 and T3.
is a transformer, and Bat2 is a battery. The LED is a light emitting diode, the FT is a photo-i transistor, and the moving body 31-
This is a photo ink printer 10 that reads the mark 9. P
I-P5 is a connection point connecting the circuit of FIG. 5 and the circuit of FIG. 6, and the signal waveform at each point is shown in FIG.

In this circuit, the oscillation signal Pi of the oscillator O5C (see FIG. 7(a) jj(1,)) turns on and off the primary side of the transformer T2 by the transistor Q3, ). Photo ink printer 1
The drive j speed information of 0 is converted into an analog voltage value by the converter F/V and outputted to the comparison multiplier III CPI-CP2.

The variable resistor VRI is used to adjust the voltage level at this time. The analog voltage value manually applied to the comparator 111 CP2 is compared with the voltage value corresponding to the speed set externally (for example, manually) by the variable resistor VR3. Comparison amplifier CP2 performs the same comparison. Oscillation signal P
The output signal P3 of the ant gate AND2, which goes high at t of i, is maintained until the output of the comparator multiplier CP2 is reversed. That is, setting the speed using the variable resistors V and R3 means adjusting the pulse III of the signal P3. When the signal P3 goes high, the transistor Q6 is turned on, and a voltage in the direction indicated by the solid line arrow is applied to the electrostrictive element =I-1. The output signal P of the AND gate AND4 is maintained from the rising edge of the output signal P3 until the falling edge of the oscillation signal PI.
A high output of 4 turns on transistor Q4. Since the transistor Q6 is already turned off and the electrostrictive element -1 is charged with electric charge, the electric charge is discharged and a current flows in the direction indicated by the solid line arrow in the primary side of the transformer T3. On the other hand, since the PI signal manually input to Antogame LANDI is inverted by the inverter INI, the oscillation signal PI operates in the downward direction of f, and outputs the signal P2 when applying the voltage in the direction indicated by the dotted line arrow to the electrostrictive element l. That's it. Anno 1 - Kate AND
At the output P5 of 3, a current flows to the next side of the transformer 3 in the direction indicated by the dotted line arrow.

Therefore, a voltage having the waveform shown in FIG. 7(f) is applied to the electrostrictive element /-1. Then, the discharge current of the electrostrictive element L flows through the transformer T3 and generates electricity, and the current is
It is rectified by the bridge of 3 to D6 and charges the battery Bat2. Therefore, the charges are not discharged wastefully.

Incidentally, instead of the switching transistor, a transistor such as a silicon transistor or a trianc transistor may be used.

As described in the first and fourth theories above, the drive circuit to which the present invention is applied is convenient because it does not require an AC power source.

The driving speed can be controlled by pulse +l control.

Since pulse 11+ control has a simpler circuit than voltage control, it can be produced at low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main part of a vibration wave motor, FIG. 2 is a diagram explaining the driving principle of the vibration wave motor, FIG. 3 is a diagram showing an embodiment of a drive circuit to which the present invention is applied, and FIG. Figure 4 is a waveform diagram of the circuit, Figures 5 and 6 are circuit diagrams of other embodiments,
FIG. 7 is a waveform diagram thereof. 1 is an electrostrictive element, 2 is a vibrating body, 3 is a moving body, Tl is a transformer, Q is a switching transistor Batl is a power supply battery. Patent applicant: Canon Co., Ltd. - Agent: Fukuguchi] 1. ,・ 1 □ Figure 3 , Figure 1 Figure 4 Figure 6 Figure 2

Claims (1)

[Claims] (1) In the drive circuit of a vibration wave motor that drives a moving object using a progressive vibration wave of resonant vibration generated by applying a frequency voltage to the electrostrictive element r, the frequency signal of the resonant vibration is used to generate a current power supply. 1. A driving circuit characterized in that an induced voltage (l) generated by turning on and off the voltage is applied to the electric element (r) as the frequency voltage.