JPH072025B2 - Vibration wave motor drive circuit - Google Patents

Description

The present invention relates to a vibration wave motor, and more particularly to a drive circuit for driving a plurality of vibration wave motors.

<Prior Art> In an oscillatory wave motor in which an electrostrictive element is attached to an elastic body such as a metal and a progressive surface wave is generated in the elastic body by exciting by applying a frequency voltage to the electrostrictive element, Efficient excitation cannot be performed unless the frequency of the voltage is set to the resonance frequency of the elastic body and the electrostrictive element.

Since the resonance frequency generally fluctuates according to environmental changes such as temperature and load, there is a method of detecting such fluctuation and automatically changing the frequency so that the oscillation frequency always follows the resonance frequency. No. 276962, Japanese Patent Application No. 60-62836, etc.

FIGS. 1 (a) and 1 (b) are configuration diagrams showing the configuration of a vibrating body used in the vibration wave motor of the above type, in which 1 denotes an elastic body,
Reference numeral 2 denotes an electrostrictive element bonded to the surface of the elastic body.
The electrostrictive element is divided into a 2a group to which a frequency voltage is applied by the electrode 3 and a 2b group to which a frequency voltage is applied by the electrode 4 and a 2c group for vibration detection as shown in FIG. 1 (b). The 2b group is arranged at a pitch deviated from the 2a group by 1/4 of the wavelength λ of the vibration wave to be excited.

Reference numeral 3 is a drive electrode bonded to the electrostrictive element of the 2a group, 4 is a drive electrode bonded to the electrostrictive element of the 2b group, and 5 is the above
A vibration detection electrode joined to the electrostrictive element of the 2c group, 6 is a ground electrode, and 7 to 10 are lead wires of each electrode.

In the driving body of the vibration wave motor configured as described above,
A progressive surface wave is generated in the elastic body 1 by applying a frequency voltage having a phase difference of 90 ° to the electrostrictive elements 2a group and 2b group through the electrodes 3 and 4, and the moving surface is frictionally contacted with the elastic body 1. The body is driven.

Further, the electrode 5 detects the impedance change due to the resonance vibration of the electrostrictive element, and feeds the vibration detection result to an oscillation circuit (not shown) via the lead wire 9 so that the driving frequency of the frequency voltage becomes the resonance frequency. Automatically controlled.

As described above, when the vibration wave motor is driven, the driving frequency is automatically made to follow the environmental changes so that the driving can be efficiently performed.
4 lead wires for driving and vibration detection and for electrodes are required. Therefore, when driving a plurality of motors, the lead wire is required to be a multiple series of 4, and there is a drawback that the number of the lead wire increases.

<Purpose> The present invention has been made in view of the above matters, and as its configuration, a frequency voltage is applied to an electric-vibration conversion element to generate a progressive surface wave in a vibrating body joined to the conversion element, In a drive circuit of a vibration wave motor for driving a moving body by a surface wave, a plurality of vibration wave motors are provided and the frequency voltage applying lead wire of the motor is also used to make the resonance frequency of each motor different, By applying a voltage obtained by multiplexing the resonance frequency for each motor as the frequency voltage applied to the lead wire, the lead wire is also used and the lead wire for vibration detection is also used. .

<Embodiment> FIG. 2 is a configuration diagram showing an embodiment showing a wiring structure of a vibration wave motor according to the present invention.

In the figure, A indicates a first vibrating body for the first vibration wave motor, and B indicates a second vibrating body for the second vibration wave motor. The configurations of the elastic bodies, electrostrictive elements, and electrodes of the first and second vibrating bodies A and B are the same as those shown in FIG.

In the embodiment, 2 in the first and second vibrating bodies A and B
The drive electrode 3 joined to the electrostrictive element of the group a is led out from the common lead wire 7 ', and the drive electrode 4 joined to the electrostrictive element of the group 2b of the vibrating bodies A and B has the common lead. It is drawn from line 8 '.

In addition, the grounding electrode 6 in the vibrating bodies A and B also has a common lead wire 1
0 ', and only the vibration detection electrode 5 in the vibrating bodies A, B is drawn out from the separate lead wires 9a, 9b. In this way, by sharing the lead wire of each vibrating body, the number of lead wires can be remarkably reduced as compared with the case where each vibrating body is driven separately.

When driving two vibration wave motors with the above configuration, the resonance frequencies fa and fb of each vibration wave motor are set to the third frequency.
As shown in the figure, fa ≠ fb and the values of fa and fb must be set so that their mutual harmonic components or other vibration mode components and their harmonic components do not match.
Each vibration wave motor is made to correspond to the driving electrodes 3 or 4 of the vibrating bodies A and B by the frequency multiplexing technique through the same lead wire 7'or 8 ', and driving frequencies of different frequency components respectively. A voltage can be applied, and each vibrator A, B can be driven.

FIG. 4 is a circuit diagram showing another embodiment of the present invention. In FIG. 4, the vibration detection lead wires are also shared.

In the embodiment of FIG. 4, the same symbols as those of the wiring structure of the embodiment of FIG. 2 are given the same symbols, but in this embodiment, the vibration detecting electrodes 5 in the vibrating bodies A and B are connected to the common lead wire 9. ′
The difference from the embodiment of FIG.

The lead wire 9'is input to the input amplifier section 11, and the output of the amplifier 11 is input to the bandpass filters 12a and 12b. The filter 12a has the above fa as a band center frequency, and 12b has the above fb. Then phase shifter 1
After passing through 3a and 13b, the 90 ° phase shifters 14a and 14b
° Generates out-of-phase signals, each power amplification amplifier
Driving signals amplified by 15ab and 16ab and having different phases by 90 ° are applied to the electrodes 3 and 4 of the vibrating bodies A and B through the lead wires 7'and 8 '.

With this configuration, the vibration states of the respective vibrating bodies A and B are detected via the electrode 5 and the lead wire 9 ', and the vibrating states of the respective vibrating bodies A and B are detected by the filters 12 and 12b. The signals from the electrodes 5 are input to the phase shifters 13a and 13b, the frequencies corresponding to the input signals are adjusted by the phase shifters 13a and 13b, and the resonance frequencies for the vibrators A and B are adjusted. The output is determined so that Then, each output is a signal with a 90 ° phase shift in the 90 ° phase shifters 14a and 14b as described above, and is applied to the electrostrictive elements of the 2a group and the 2b group in the vibrators A and B, respectively. In the embodiment of FIG. 4 as well, as in the embodiment of FIG. 2, the lead wire can be used also for the drive electrode of each vibrating body, and the lead wire can also be used for the vibration detection electrode. .

When it is not necessary to drive two or more oscillatory wave motors at the same time in the embodiment of FIG. 4, the drive circuit having the above-mentioned configuration is provided as one, and the center frequency of the filter circuit is switched and the phase shifter is used. If the phase adjustment associated with the switching of the center frequency is performed, each motor can be selectively operated.

<Effect> As described above, according to the present invention, the resonance frequencies for a plurality of vibration wave motors are made different so that signals are multiplexed. Therefore, it is possible to use the lead wire for the signal electrode of each motor, and the wiring thereof, etc. It has a great effect on.

[Brief description of drawings]

1 (a) and 1 (b) are configuration diagrams showing a configuration of a vibrating body in a vibration wave motor, FIG. 2 is a configuration diagram showing a wiring structure by a drive circuit of the vibration wave motor according to the present invention, and FIG. 2 is an explanatory view showing the resonance frequency in the illustrated motor, and FIG. 4 is a circuit diagram showing the configuration of the drive circuit of the vibration wave motor according to the present invention. A, B ... Vibrating body, 7'-10 '... Lead wire

Claims (1)

[Claims] 1. A plurality of electric-vibration conversion elements are applied to generate a progressive vibration wave in a vibrating body on which the conversion element is arranged, and the vibration waves are used as driving force and have different resonance frequencies. In the drive circuit of the vibration wave motor, a plurality of frequency voltage forming circuits that respectively form frequency voltages of different frequencies for each motor, and an output circuit that superimposes and multiplexes the frequency voltages from each frequency voltage forming circuit and outputs them. ,
A common voltage application line for applying the multiplexed voltage from the output circuit to each electric-vibration conversion element and a common detection line for multiplexing and extracting the detection output from the vibration detection means of each motor are provided, and the detection is performed. A drive circuit for a vibration wave motor, wherein the frequency of the frequency voltage from each of the frequency voltage forming circuits is regulated by a detection output via a line.