JPH0446573A - wave motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The wave motor of the present invention relates to an ultrasonic motor that can easily be switched between continuous drive and step drive.

[Prior art] A conventional ultrasonic motor is disclosed in Japanese Patent Application Laid-Open No. 58-93477,
Japanese Patent Publication No. 59-37673, Japanese Patent Publication No. 59-1223
Many configurations have been proposed, such as in Japanese Patent Application No. 85 and Japanese Patent Application Laid-Open No. 60-51478, but most of them excite the stator with a traveling wave, and when driving intermittently, a detection means is added. This was achieved by ``disconnecting'' and ``continuing'' the drive. On the other hand, as in Japanese Patent Application No. 1-273082, a step drive method using vibration nodes of a standing wave has also been proposed.

[Problem to be solved by the invention] However, in the case of conventional ultrasonic motors using traveling waves, the above-mentioned detection means is required for use in determining the rotation angle, which hinders miniaturization and cost reduction. . In addition, simply step driving does not allow smooth driving at a constant speed, and continuous high-speed feeding is difficult, which limits the application.

Therefore, an object of the wave motor of the present invention is to provide a configuration that allows easy selection between continuous drive using traveling waves and step drive using standing waves.

[Means for Solving the Problems] The wave motor of the present invention is a wave motor in which a rotor in contact with the stator is driven by frictional force by minute vibrations of a stator attached with a vibrator consisting of a plurality of vibrating elements. The present invention is characterized in that the vibration mode of the stator can be selected between a standing wave and a traveling wave by switching the phase of the driving waveform of the vibrating element.

[Embodiment] FIG. 1 is a block diagram showing an outline of the present invention, and 100
is a control circuit for step drive and control of a wave motor, 1
01 is an oscillation circuit that generates a signal to vibrate the stator to which the vibrator 3 is attached, 102 is a phase shifter that also shifts the phase by 90 degrees, 103 is a waveform forming circuit A that generates a step drive drive waveform, and 104 is a traveling wave drive waveform. This is the waveform forming circuit B that creates the .

The switching circuit 105 sends the output of the waveform forming circuit A in the case of step drive, and the output of the waveform forming circuit B in the case of continuous drive, to the driver circuit 106 to vibrate the stator 2.

FIG. 2 is a sectional view showing a configuration example of the wave motor of the present invention, and FIG. 3 is a plan view showing the relationship among the rotor, stator vibrator, and vibration element in FIG. 2.

1 indicated by a dashed dotted line is a rotor that is in contact with a stator 2, to which a vibrator 3 made of a piezoelectric element is attached, at a convex portion 2a;
By applying a voltage to the electrode pattern 3a through the lead cotton 8, the stator 2 bends and vibrates, causing the rotor 1 to rotate. A pinion 9 , which is fitted into the rotor and positioned by the gear train bridge 5 and has a tooth profile for extracting rotational force to the outside, is a pressing spring that presses the rotor 1 against the stator 2 . The stator 2 is fixed to the frame 4 with set screws 6. The rotor 1 has a plurality of protrusions 1a in the radial direction, and the vibrator 3 shown by the broken line is composed of a plurality of vibrating elements 30. In this embodiment, a case is shown in which there are four protrusions 1a and twelve vibration elements 30, but the present invention is not limited to this embodiment.

Figure 4 shows two vibration modes (
This is an explanatory diagram showing an excitation method when exciting a two-wavelength vibration state. By deforming three waves with opposite phases at ten and -, vibration nodes can be created in the direction of the dashed-dotted line. . In the case of step vibration, since the protrusion of the rotor is attracted to node 1, it can be realized by gradually shifting the combination of vibrating elements that are driven simultaneously.

The + and - transformations are possible by making the voltage positive or negative, or by changing the polarization direction to positive or negative.

FIG. 5 is an explanatory diagram of the case where a vibration mode of 3λ is excited in the stator described above, and three nodes are formed by driving two stators at a time.

FIG. 6 is an explanatory diagram showing an example of exciting three traveling wave vibration modes in the stator. When part A is used as a reference, part B, which is separated by 1/4, has a phase of 90°. This can be achieved by applying a waveform with a degree shift and a waveform with the opposite phase.

Incidentally, since the intention of the present invention is to switch between a traveling wave and a standing wave, the vibration mode is not limited to the mode of the above-mentioned embodiment.

FIG. 7 is a circuit diagram showing an example of a drive circuit for a wave motor according to the present invention, and a case will be described in which switching between a 2E standing wave and a 3E traveling wave is shown. In this case, the oscillation circuit has two inputs and one input
01a and 3-use 101b, the phase shifter 10
2 forms a waveform whose phase is shifted by 90 degrees with respect to the waveform of the oscillation circuit BIO1b.

The case where step feeding is performed in the standing wave vibration mode will be described below. Section 8 is a timing chart showing the signal states of parts ① to ② in FIG. 7. Switching circuit 105
has switches 31 to 42 corresponding to the vibrating elements a-ρ of the vibrator 3 attached to the stator 2 and the drivers 19 to 30 in the driver circuit 106 for driving them. The switches 31 to 42 are interlocked, and in the case of step drive, they are all tilted toward the a side, that is, the waveform forming circuit AlO3 side. The output signal ■ of the control circuit 100 is the timing for step feeding, and is the timing for the shift register 107 and 1/
The 6 frequency divider circuit 108 generates signals whose phases are shifted as shown by ◎, ◎, and ■. The oscillation circuit A101a sends out a signal for making the stator 2 resonate, and forms signals G and [F] whose phases are sequentially inverted by the exclusive elements 11, 12, and 13. has a combination as shown in FIG. 4, for example, for d, e, f, j, h, I2 of the vibrating element 30,
, g, h, and i are driven in opposite phases. When sending one step, h, 1, J, b, c, and d should be driven in opposite phases to e, f, gth, h, I2, and a. By sequentially shifting the combinations, step driving is possible. will be realized. In this case, no matter what combination they have, the vibrating elements at opposing positions, for example a and g, are in phase,
Positions shifted by 90 degrees, for example d and j, are always in opposite phase. Such a relationship is realized by connection using inverters 14, 15, and 16.

Therefore, in this configuration, it is possible to step feed by 30 degrees at the timing of ■, but by changing the number of vibrating elements and the timing of driving them, it is also possible to drive them at different angles. It is not limited to combinations.

Next, the case of continuous rotation in the traveling wave vibration mode will be explained.The zero oscillation circuit B101b oscillates in the stator 2 at a resonant frequency of 3λ, and the phase sick 102 forms a signal shifted by 90 degrees. Switch 31 of the switching circuit 105 ~
42 is interlocked and falls to the side of b. Waveform forming circuit B1
04 has inverters 17 and 18, and oscillation circuit B101
b and phase shifter 1020 to create an inverted waveform and vibrating element 30
is supplied to. Therefore, a three-way traveling wave vibration mode is realized, and the rotor rotates continuously. However, various methods have been proposed for creating traveling waves, and the present invention is not limited to this. Also, in this example, the standing waves are 2
Although the combination in which the traveling wave is 3λ has been described in detail, it is sufficient that the standing wave and the traveling wave can be switched and excited, and the combination is not limited to this in any way.

In addition, in the case of step drive, the direction in which the node position is moved is reversed, and in the case of continuous drive, reversal can be easily achieved by reversing the phase of the drive waveform applied to one side and reversing the direction of the traveling wave. can.

[Effects of the Invention 1] As detailed above, according to the present invention, step drive is possible with sequence control that does not require feedback means, etc.
Rotational position control is easy. Furthermore, since continuous driving by traveling waves is possible, smooth rotation and high-speed feeding are also possible. Therefore, the effects of the present invention are tremendous.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an overview of the present invention. FIG. 2 is a sectional view showing an example of the configuration of the wave motor of the present invention. FIG. 3 is a plan view showing the relationship among the rotor, stator, vibrator, and vibrating element in FIG. 2. FIG. 4 is an explanatory diagram showing an excitation method when exciting a 2λ vibration mode. FIG. 5 is an explanatory diagram when exciting three-like vibration modes. FIG. 6 is an explanatory diagram showing an example of exciting a three-like traveling wave vibration mode. FIG. 7 is a circuit diagram showing an example of a drive circuit for a wave motor according to the present invention. FIG. 8 is a timing chart of the drive circuit shown in FIG. 7. 100 ・ ・ 101 ・ ・ 102 ・ ・ 103 ・ ・ 106 ・ ・ 3 ・ ] ・ ・ a 2 a ・ ・Control circuit, oscillation circuit, phase thick, waveform forming circuit to waveform forming circuit 1iJB switching circuit driver circuit, stator, vibration Sub-vibrating element, rotor, protrusions, convex parts and above Figure Figure 4 Figure Figure 5

Claims (1)

[Claims] In a wave motor that uses minute vibrations of a stator attached to a vibrator consisting of a plurality of vibrating elements to drive a rotor in contact with the stator using frictional force, the vibration of the stator is reduced by switching the phase of the drive waveform of the vibrating element. A wave motor characterized in that the mode can be selected between standing wave and traveling wave.