JPH0471371A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To simplify connections and, further, suppress the uneven rotation of a rotor by a method wherein an elecro-mechanical converting means to which cyclic voltages having a phase difference between each other are applied is provided in the rotor and a voltage delivering means which supplies the voltages to the electro- mechanical converting means is also provided in the rotor. CONSTITUTION:A driving force is transmitted to a rubbing member 12 through an electric element by a driving force which is created by a progressive wave generated by the application of cyclic voltages having, for instance, a phase difference of 1/4lambda between each other to an electro-mechanical converting means 24 to make a rotor 21 rotate. A voltage delivering means such as a set of slip rings is provided on a rotor housing 22. Brushes provided on a stator 11 side are made to rub against the voltage delivering means 25 such as the slip rings to supply the ultrasonic voltages to the electro-mechanical converting means 24 or supply electric signals from the electro-mechanical converting means 24 and electric signals from other electric components to the stator side. Lead wires 26a, 26b and 26c supply the ultrasonic voltages to the electro-mechanical converting means 24 from the slip rings or supply the electric signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic motor driven by traveling waves, and particularly to the structure of its mover.

[Summary of the Invention] A movable element movable opposite to a stator is provided with an electro-mechanical conversion means to which a frequency voltage with a phase difference is applied, and also supplies voltage to the electro-mechanical conversion means. To provide an ultrasonic motor that simplifies wiring and reduces uneven rotation of a moving element by providing a voltage transfer means.

[Conventional technology]

Piezoelectric materials are known as materials that produce electrical polarization when mechanical stress is applied to a certain type of crystal, or mechanical strain when a voltage is applied across the crystal.

The ultrasonic motor is a motor that utilizes the distortion of this piezoelectric material, and is equipped with electro-mechanical conversion means having electrodes provided at both ends of the piezoelectric material. Then, a rotational force is obtained by a driving force generated by a traveling wave generated when a frequency voltage having a phase difference is applied to the electrodes of this electro-mechanical conversion means. Compared to conventional electromagnetic motors, this motor does not require windings, so it has a simpler structure, is smaller, and has the advantage of being able to provide especially high torque when rotating at low speeds, and has attracted attention in recent years.

As such an ultrasonic motor, Japanese Patent Application Laid-open No. 59
Motors with various structures have been proposed in Japanese Patent Application Laid-open No. 122385, Japanese Patent Application Laid-Open No. 59-201685, Japanese Patent Application Laid-Open No. 63-28279, and so on.

For a general electromagnetic motor, regarding the stator and mover,
A stator means something that is fixed, that is, does not move, and a movable element means something that moves, that is, something that moves, and the relationship between the stator and the mover is unchanged. However, the negative side and the secondary side are mutually reversible. For example, in the case of an induction motor, the stator may have a winding on its primary side, and the movable element may have an induction conductor on its secondary side. However, it is easy to use the wound primary side as the mover and the secondary side induction conductor as the stator.

However, in the past, few ultrasonic motors have been seen in which electro-mechanical conversion means made of a piezoelectric material corresponding to the primary side is disposed in the mover to actively emphasize its functions and effects.

[Problems to be Solved by the Invention] The present invention has been made in order to actively solve the above-mentioned problems in the conventional art, and includes disposing an electro-mechanical conversion means on the mover and converting the electrical - It is an object of the present invention to provide an ultrasonic motor that simplifies wiring and reduces uneven rotation of a moving element by providing a voltage transfer means for supplying voltage to a mechanical conversion means.

[Means for Solving the Problems] The ultrasonic motor of the present invention includes a stator and a movable element movable in opposition to the stator, and a frequency voltage having a phase difference is applied to the movable element. The electromechanical conversion means is provided with a voltage transfer means for supplying voltage to the electromechanical conversion means.

A voltage transfer means for supplying voltage to the electro-mechanical conversion means is composed of a slip ring and a brush.

The voltage transfer means for supplying voltage to the electro-mechanical conversion means is a rotary transformer.

[Effect]

As described above, by disposing the electro-mechanical conversion means on the movable element and providing the voltage transfer means for supplying voltage to the electro-mechanical conversion means, it is possible to prevent interference from other electrical components disposed on the movable element. Reverse the electric signal through the voltage transfer means,
It can be sent to the stator side, making the overall wiring easier.

Furthermore, since the stator has a simple structure, the surface of the stator that faces the mover can be formed into an ideal surface, and the mover slides on this ideal surface of the stator. Since it moves smoothly while tracing, uneven rotation of the slider can be reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a sectional view of one embodiment of the ultrasonic motor of the present invention. FIG. 2 is a diagram showing a 9λ electrode pattern of the electro-mechanical conversion means of the mover of the embodiment shown in FIG. 1. FIG. 3 is a driving circuit diagram of the embodiment shown in FIG. 1. And Figure 4 (
A) to (E) are waveform diagrams of each part of the drive circuit diagram shown in FIG. (C) Waveforms of (di) to (d4),
The same figure (C) shows the waveforms of (el) to (e4) during normal/reverse operation, the same figure (D) shows the waveforms of (fl) to (f4) -A phase and B phase, and the same figure (E) shows the waveforms of (fl) to (f4) -A phase and B phase. ((a) - (sha) waveform is shown.

First, the ultrasonic motor used in the present invention, as shown in FIG.

The stator plate includes a sliding material 12, a sliding material support plate 13 to which the sliding material 12 is attached, a support ring 14 that supports the sliding material support plate 13, and a boss. It consists of a fixed shaft 16 fixed via a shaft 15. 17 is a damper member, and 14a is a holding plate that secures the support ring 14 to the boss 15 with the support ring 14 sandwiched therebetween. 30 is a bearing such as a ball bearing, and the inner ring of a ball hair ring (not shown) is fixed to the fixed shaft 16 with a screw 19 with a washer 18 in between.

By configuring the stator plate as described above, the structure of the stator plate has a very simple shape, approximately a disk or ring shape.
It is possible to make the surface of the sliding contact material 12 of the stator (2) facing the slider needle into an ideal surface by, for example, polishing.

On the other hand, the slider needle includes a rotor housing 22 that is movably (rotatably) supported relative to the stator arm by a bearing 30 such as a ball bearing (in this case, the outer ring is fixed).
It consists of an elastic body 23 whose inner circumference is fixed to the rotor housing 22, and an electro-mechanical conversion means 24 stuck to one end surface around the outer circumference of the elastic body 23.

The elastic body 23 has the electro-mechanical conversion means 24 adhered to one end surface as described above, and has a concavo-convex portion that contacts the sliding contact member 12 of the stator U on the other end surface.

For example, when a frequency voltage having a phase difference of 1/4 λ (λ indicates the wavelength) is applied to the electro-mechanical conversion means 24, a driving force generated by a traveling wave causes sliding contact via the elastic body 23. The driving force is transmitted to the material 12, and the moving element (■) is moved.

The rotor housing 22 is provided with voltage transfer means 25 such as a slip ring. A brush (not shown) arranged on the stator ear side slides into contact with, for example, a slip ring of the voltage transfer means 25, and supplies ultrasonic voltage to the electro-mechanical conversion means 24, or converts electricity from the electro-mechanical conversion means 24. Provide signals and electrical signals from other electrical components to the stator side. 26a, b, and C represent lead wires that supply ultrasonic voltage or provide electrical signals from the slip ring to the electro-mechanical conversion means 24.

As shown in FIGS. 2 and 3, the electro-mechanical conversion means 24 includes a piezoelectric body 24a, an A-phase electrode 24b, and a B-phase electrode 2.
4c, common electrode 24d, and feedback electrode 24
It has e. Note that FIG. 2 shows the A-phase electrode 24b, B-phase electrode 24c, and feedback electrode 24e, and the lead wires 26a, b, and c shown in FIG. 1 are connected to these electrodes 24b, c, and e. It is connected. Furthermore, the piezoelectric body 24a and the common electrode 24d are not shown in FIG.

The common electrode 24d is connected via the elastic body 23, bearing 30, etc.
It is electrically connected to the fixed shaft 16.

The illustration of the slip ring of the voltage transfer means 25 in FIG.
Although this is an example of three, the number is not limited to three. For example, it is also possible to provide two more wires and supply alternating current voltage to the mover (2) via a slip ring. This AC voltage can be rectified by a diode or the like on a printed circuit board (not shown) installed on the slider nail, to obtain a DC voltage, which can be used as a power source for the drive circuit of the ultrasonic motor placed on the side of the slider needle 2. .

In FIG. 3, 41 is a motor rotation speed setting and set value controller, 42 is a voltage limiter, 143 is a voltage controlled oscillator,
44 is a shift register, 45 is a forward/reverse switch, 46 is a forward/reverse signal input terminal, 47 is an on/off switch, 48 is an on/off signal input terminal, 49A and 49B are power amplifiers A and B, 50A and 50B. denotes step-up transformers A and B, and 51 denotes a voltage detection and wave detector.

Incidentally, LA and LB are inductances that form a parallel resonant circuit with a capacitor that becomes a stray capacitance between the A-phase and B-phase electrodes 24c and b and the common electrode 24d, and prevent unnecessary current flowing through the capacitor. be.

In FIGS. 3 and 4 (A) to (E), a voltage proportional to the rotational speed of the ultrasonic morph (mover 21) detected by the feedback electrode 24e (the station feeds back the voltage to the voltage detection and detector 51) is shown. As shown in FIG. 4(E), the voltage is detected by the voltage detector 51 and becomes a voltage (h). This voltage (h) is the set voltage of the motor rotation speed setting and set value controller 41. be compared.

This compared difference voltage (a) is set to a predetermined voltage ELIM by the voltage limiter 42 as shown in FIG. 4(A).
It is limited so that it does not become a higher voltage and is supplied to the voltage controlled oscillator 43 as voltage (b). The voltage controlled oscillator 43 generates a pulse 4t with a frequency proportional to the voltage (b).
(C) and is supplied to the shift register 44.

In the shift register 44, as shown in FIG. 4(B), the pulse signal (C) is converted into four-phase pulse signals (dl) to (d
4). This pulse signal (dl) ~ (d4)
is supplied to the forward/reverse switch 45.

A forward/reverse signal is supplied from the forward/reverse signal input terminal 46 to the forward/reverse switch 45, and pulse signals (el) to (e4) during forward and reverse rotation as shown in FIG. 4(C) are generated. is formed. These pulse signals (el) to (e4) are supplied to an on/off switch 47.

An on/off signal is supplied from the on/off signal input terminal 48 to the on/off switch 47, and the on/off switch 47 generates a four-phase pulse signal (fl) shown in FIG. 4(D). ~(f4) is turned on/off.

As shown in this drawing, the four-phase pulse signals (fl) to (f4) generate two phases (A
phase, B phase) signals are obtained.

The two-phase signals of phase A and phase B are amplified by power amplifiers A and B (49A and 49B), and step-up transformers A and B (50A and 50B) are amplified.
As shown in FIG. Supply phase ultrasonic voltage.

By using the above-mentioned forward/reverse signals, it is possible to easily rotate the ultrasonic motor in both forward and reverse directions by making the A-phase or B-phase ultrasonic voltages faster or slower by Xλ relative to each other. Furthermore, it is possible to repeatedly stop and rotate rapidly using an on/off signal, and the ultrasonic motor can repeatedly rotate in the forward direction, stop, rotate in the reverse direction, and then stop.

Return to Figure 1. As shown in the drawings, the rotor housing 22 of the mover 21 has mounting screws 22a.

Although not shown in this drawing, the rotor housing 22
Various members can be attached to the , and the attached members can be rotated. For example, a video tape recorder can be equipped with a rotating drum. A video head is attached to this rotating drum, and input/output signals of this video head are input/output from the stator U side via a slip ring serving as the voltage transfer means 25.

Here, an example of a video head has been described as another electrical component, but the present invention is not limited thereto.

That is, the lead wire processing for supplying and receiving voltage to and from the electro-mechanical conversion means 24 and other electrical components can be done centrally within the mover (2), making the wiring connections simple.

It has been explained that the surface of the sliding member 12 of the stator chain 2 facing the slider nail can be made into an ideal surface. Since the moving element U moves smoothly while sliding and tracing, rotational irregularities such as wow and flutter and jitter of the moving element U, that is, the ultrasonic motor can be reduced.

Although the slip ring has been described as an example of the voltage transfer means 25, a rotary transformer may also be used.

Further, although the moving element (2) has been described as rotating and moving, it may move linearly or may be a near motor.

[Effects of the Invention] The ultrasonic motor of the present invention includes a stator and a movable element movable opposite to the stator, and the movable element is an electric motor to which a frequency voltage having a phase difference is applied. A mechanical conversion means is provided, and a voltage transfer means for supplying voltage to the electro-mechanical conversion means is provided.

A voltage transfer means for supplying voltage to the electro-mechanical conversion means is composed of a slip ring and a brush.

Furthermore, a rotary transformer is used as the transfer and supply means for supplying voltage to the electro-mechanical conversion means.

As described above, by disposing the electro-mechanical conversion means on the movable element and providing the voltage transfer means for supplying voltage to the electro-mechanical conversion means, it is possible to prevent interference from other electrical components disposed on the movable element. Reverse the electric signal through the voltage transfer means,
It can be sent to the stator side, making the overall wiring easier.

Furthermore, since the stator has a simple structure, the surface of the stator that faces the mover can be formed into an ideal surface, and the mover slides on this ideal surface of the stator. Since it moves smoothly while tracing, uneven rotation of the slider can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the ultrasonic motor of the present invention. FIG. 2 is a diagram showing a 9λ electrode pattern of the electro-mechanical conversion means of the mover of the embodiment shown in FIG. 1. FIG. 3 is a driving circuit diagram of one embodiment of FIG. 1. 4(A) to (E) are waveform diagrams of each part of the drive circuit diagram shown in FIG. 3, and FIG. 4(A) shows the waveforms of (a) - (b) - (C), The figure (B) shows the waveforms of (C) (dl) to (d4), the figure (C) shows the waveforms of (el) to (e4) during forward/reverse operation, and the figure (D) shows the waveforms of (fl) to (e4). (f4) - Waveforms of A phase and B phase,
And (E) in the same figure shows the waveform of (g)-011. Once-----One stator 21-----Movers 24--=----One electric-mechanical conversion means 25--
−−−−−−−−1− Voltage transfer means width arrival Minami Meng Kong]

Claims (3)

[Claims] 1. In an ultrasonic motor consisting of a stator and a movable element movable in opposition to the stator, the movable element is equipped with an electro-mechanical conversion means to which a frequency voltage having a phase difference is applied, and this An ultrasonic motor characterized by being provided with voltage transfer means for supplying voltage to an electro-mechanical conversion means. 2. 2. The ultrasonic motor according to claim 1, wherein the voltage transfer means for supplying voltage to the electro-mechanical conversion means is comprised of a slip ring and a brush. 3. 2. The ultrasonic motor according to claim 1, wherein the voltage transfer means for supplying voltage to the electro-mechanical conversion means is a rotary transformer.