JPS63240383A - Ultrasonic motor capable of forward/reverse running - Google Patents

Abstract

PURPOSE:To forwardly or reversely rotate a movable element by providing first and second vibration plates at first and second ultrasonic vibrators, and switching and selecting either vibrator. CONSTITUTION:An ultrasonic motor body 7 is composed of a cup-shaped casing 8 and a cover 9 for closing its lower end opening. The top of the casing 8 is so supported by bearings 11, 12 as to protrude the top of a rotary shaft 10, and a rotor 14 is secured to an annular connecting ring 13. First and second ultrasonic vibrators 15, 16 are so mounted at the top and bottom of the rotor 14 as to be reciprocate to vibrate. First and second vibration plates 17, 18 are secured to the vibrators 15, 16, and first and second vibration pieces 19, 20 are further secured to the rotor 14. First and second coils 21, 22 are wound on the pieces 19, 20. Thus, the first or second vibrator is selected and vibrated to forwardly or reversely drive a motor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field of the Invention] The present invention is directed to a forward/reverse motor which utilizes ultrasonic vibration to convert the reciprocating motion of an ultrasonic vibrator into a motion in the running direction of a movable element. 9 Regarding ultrasonic motors that can run Motors have come into practical use.

Various types of ultrasonic motors of this kind are known, and for example, there is one shown in Japanese Patent Publication No. 59-37672, and the principle thereof will be explained in 3 and below based on this.

Referring to FIG. 3, a rotating shaft 1 is rotatably supported by a bearing 2, and a plate-shaped vibrator piece 3 is mounted on one end surface of the rotating shaft 1 in the axial direction of the rotating shaft 1. It is provided integrally with the rotating shaft 1 with an appropriate inclination angle. On the opposite side of the vibrator piece 3.

A diaphragm 5 fixed to the ultrasonic vibrator 4 is held so as to be in contact with it. The ultrasonic vibrator 4 is arranged so as to be able to vibrate back and forth in the direction of arrow a, and five coils (not shown) are wound around the ultrasonic vibrator 4.

As the ultrasonic vibrator 4 for generating ultrasonic waves, there are two types that have been put into practical use: a magnetostrictive vibrator and an electrostrictive vibrator, so either of them may be used. The latter type of magnetostrictive vibrator is used, and when a high frequency is applied to the coil, the ultrasonic vibrator 4, which is a magnetostrictive body, expands and contracts, thereby exciting the diaphragm 5.

Next, to explain the principle of the actual driving state, first, as shown in FIG. Set as the origin of coordinates. At this time, the inclination θ of the vibrator piece 3 with respect to the axial direction is
It is necessary to keep the friction angle between the vibrator plate 5 and the vibrator piece 3 smaller.

This is because the force that the vibrator piece 3 receives from the diaphragm 5 is expressed as a component of a force fx in the normal direction of the diaphragm 5 and a force fy in the tangential direction, as shown in FIG. The friction coefficient μ between the piece 3 and the diaphragm 5 is the maximum static friction angle θ5=tan−'μ
It is. Therefore.

In order for one end surface 3a of the vibrator 3 to efficiently receive the driving force without slipping, the inclination θ of the vibrator piece 3 must be smaller than the maximum friction angle θS.

Next, when the diaphragm 6 starts vibrating as shown in No. 41B, and the diaphragm 5 is displaced by ΔX in the X direction, it pushes the one end surface 3a in the +X direction, but since the rotation axis 1 is fixed, A component force fy is generated due to the inclination angle θ and the displacement fx in the X direction as shown in FIG.
A force that pushes up in the direction acts to move the rotation axis 1 by ΔY1.

Next, when the diaphragm 5 starts vibrating and is displaced by -ΔX in the -X direction as shown in FIG. Frictional force no longer acts on the shaft 1 due to the period of the natural frequency.
It will move in the Y direction. However, during this period as well, the rotating shaft 1 moves by ΔY2 in the +Y direction due to inertia force.

Furthermore, as the diaphragm 5 continues to vibrate,
The state shown in FIG. 5A is reached and the above operation is repeated, and the rotation of the rotation shaft 1 continues.

Here, to explain the inertial force, as shown in FIG. 5, it is a mechanism that converts the vibration motion of the diaphragm 5 into a unidirectional motion of the vibrator piece 3, and the vibrator piece 3 is not subject to intermittent driving force. It is now possible to do so. On the other hand, ultrasonic vibration generally handles vibrations of 20 KHz or higher, and since the inertial force is proportional to the square of the frequency, it has sufficient inertial force,
Uniform continuous rotation can be obtained.

The conventional ultrasonic motor described above is useful because it rotates on the above driving principle.

However, the ultrasonic motor having such a configuration has the disadvantage that it cannot be used as a servo motor for performing various types of control because it can only rotate in one direction.

[Objectives of the Invention] An object of the present invention is to provide a rotary ultrasonic motor that can rotate in forward and reverse directions and an ultrasonic linear motor that can run in forward and reverse directions so as to be suitable as a servo motor.

[Means for achieving the object of the present invention] The object of the present invention is to provide a movable element that is supported so as to be able to run in forward and reverse directions, a first ultrasonic transducer, a second ultrasonic transducer, and a first ultrasonic transducer. a first diaphragm provided on one end surface of the ultrasonic transducer and a second diaphragm provided on one end of the second ultrasonic oscillator, the movable element and the first diaphragm A first vibrator piece having an inclination angle is provided between the movable element and the first vibrator piece, and the first vibrator piece is fixed to either the movable element or the first diaphragm.

A second vibrator piece having an inclination angle in the opposite direction to the first vibrator piece is provided between the movable element and the second diaphragm,
The second transducer piece is fixedly formed on either the movable element or the second diaphragm, and the first or second ultrasonic transducer is switched and selected. This can be achieved by converting the ultrasonic vibration of the ultrasonic vibrator into the running motion of the movable element.

U First Embodiment of the Invention FIG. 1 is a vertical sectional view of a rotary ultrasonic motor 6 capable of forward and reverse rotation as a first embodiment of the invention. The motor body 7 includes a cup-shaped casing 8 and a lid 9 that closes a lower opening of the casing 8.
It is composed of.

The rotating shaft 10 is rotatable by bearings 11 and 12 fixed approximately at the center inside the casing 8 and the lid 9 so that the upper part of the rotating shaft 10 protrudes from the upper part of the casing 8. is supported by An annular connecting ring 13 is fixed at a position within the main body 7 of the rotating shaft 10, and an annular and disk-shaped rotor 14 is fixed to the outer periphery of this connecting ring 13 by appropriate means. .

The upper and lower parts of the rotor 14 in the main body 7 are provided with first and second rotors, respectively. A second ultrasonic transducer 15.degree. 16 is mounted so as to be able to vibrate back and forth in the direction of arrow a. Also, ultrasonic transducer 1
5.16, each of which faces the rotor 14 through an axial gap, has a first .5. Second diaphragm 17.
18 is fixed. on each surface of the rotor 14.

The first plate-shaped or rod-shaped. One second transducer piece.

20 are fixed and held in contact with the diaphragms 17 and 18, respectively. 1st. One second transducer piece.

20 is fixed to the rotor 14 at an appropriate inclination angle with respect to the axial direction, but the inclination angles of the first vibrator piece 19 and the second vibrator piece 20 are inclined in opposite directions. It is formed by letting.

Since the shape of the vibrator pieces 19, 20 is explained in FIG. 4 above, the enlarged shape thereof will be omitted here.

Vibrator piece 1.9. ．． To configure 2'O, the rotor 14
It can be created by forming recesses 14a and 14b with diameters smaller than the diameter of the rotor 14 in the center of both the upper and lower surfaces of the rotor 14, and forming a cut at a preset angle in the remaining peripheral portion.

Figure 2(a) and Figure 2(b) are respectively x-
FIG.
The first one formed by the notch. Second vibrator piece 19
．． 2'O is formed with a protrusion. First vibrator piece 1
There are two types of cuts for forming the cut 9: one is formed on the upper right side as shown in FIG. 1, and the other is formed on the lower right side (not shown). The cut for forming the second vibrator piece 20 may be formed on the upper left side as shown in FIG. 1, or on the lower left side (not shown).

Note that when the vibrator pieces 19.20 are extended to the vicinity of one rotational axis 1o, the momentum of the vibrator pieces 19.20 and the rotor 14 are
There is a large difference in the resultant momentum between the inner and outer circumferences of the vibrator pieces 19 and 20, and as a result,
Slip occurs between one vibrator piece and the diaphragm 17 and between the vibrator piece 2o and the diaphragm 18, resulting in a decrease in energy efficiency.

Since wear may occur, place the vibrator piece 19 in the optimum position.
It is necessary to consider this at the time of design so as to form 20.

At the end of each of the vibrator pieces 19 and 20 opposite to the diaphragm 17 and 18, a first. A second coil 21, 22 is wound thereon. A high frequency voltage is applied to the coils 21 and 22 as described above.
or 22, the ultrasonic S oscillator 15 or 16, which is a magnetostrictive body, expands and contracts due to the magnetic field and excites the diaphragm 17 or 18.

Therefore, in order to rotate the ultrasonic motor 6 of the present invention in the normal rotation direction, the first ultrasonic vibrator 15 and the first coil 21 are
is selected, and a high frequency is applied to the coil 21 to excite the ultrasonic transducer 15. Further, in order to reversely rotate the ultrasonic motor 6 in the opposite direction, the second ultrasonic vibrator 16 and the second coil 22 are selected, and a high frequency is applied to the coil 22 to excite the ultrasonic vibrator 16.

In the above example, only a one-rotation type ultrasonic motor was explained, but the present invention is naturally applicable to a type of linear motor that performs linear motion. In addition, the example in which the vibrator piece is fixedly formed on the rotor side is shown, but it may also be formed fixedly on the diaphragm.Furthermore, when the vibrator piece is fixed to the rotor or the diaphragm, it can be integrated with these. Alternatively, it may be attached and fixed by appropriate means.

[Effects of the Invention] As is clear from the above, according to the present invention, a strong rotational force can be obtained without using any special or troublesome means.

It is possible to obtain at low cost a small, lightweight, single-rotation type or linear type ultrasonic motor capable of forward/reverse rotation or forward/reverse rotation having a strong thrust and driving force.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an ultrasonic motor according to an embodiment of the present invention;
2(a) and 2(b) are a sectional view taken along the line XX' in FIG. 1, a sectional view taken along the Y-Y' line in FIG. 1, and FIG. Figure 4 (A), (B) and (C)
) are explanatory diagrams of the operating principle of the ultrasonic motor, and FIG. 5 is an explanatory diagram of the components of force applied to the vibrator pieces. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 2... Bearing, 3... Vibrator piece, 4... Ultrasonic vibrator, 5... Vibration plate, 6...
Ultrasonic motor, 7... Ultrasonic motor, 8... Casing, 9... Lid, 10... Rotating shaft, 11.12.
...Bearing, 13...Connecting member, 14...Rotor, 1
5... First ultrasonic transducer, 16... Second ultrasonic transducer, 17... First diaphragm, 18... Second diaphragm, 19... First vibrator piece, 20... second vibrator piece, 21... first coil, 22... second coil.

Claims (3)

[Claims] (1) A movable element supported so as to be freely movable in forward and reverse directions, and a first
an ultrasonic transducer, a second ultrasonic transducer, a first diaphragm provided on one end surface of the first ultrasonic transducer, and a first diaphragm provided on one end surface of the second ultrasonic transducer. a second diaphragm having a second diaphragm, a first oscillator piece having an inclination angle between the movable element and the first diaphragm; A second vibrator piece is fixedly formed on any one of the diaphragms, and a second vibrator piece having an inclination angle in the opposite direction to the first vibrator piece is provided between the movable element and the second vibrator plate, A second transducer piece is fixedly formed on either the movable element or the second diaphragm, and either the first or second ultrasonic transducer is switched and selected, and the first or second ultrasonic wave is generated. An ultrasonic motor capable of running in forward and reverse directions, characterized by converting ultrasonic vibrations of a vibrator into running motion of a movable element. (2) The ultrasonic motor capable of forward and reverse running as set forth in claim (1), wherein the movable element is a rotatably supported rotor. (3) The movable element is a disc-shaped rotor supported rotatably, and the first vibrator, the first diaphragm, and the first vibration plate are disposed on one side of the disc-shaped rotor. Claim (2) characterized in that a vibrator is provided, and the second vibrator, the second diaphragm, and the second vibrator are provided on the other surface side of the rotor. An ultrasonic motor that can run in both forward and reverse directions.