JPS63314181A - Magnetic encoder integral type ultrasonic servomotor able to drive one movable piece forward and reverse running - Google Patents

Abstract

PURPOSE:To improve resolving power by forming a motor integrally with a magnetic encoder and using a magnetoresistance element as a magnetic sensor. CONSTITUTION:A rotary magnetic encoder-integrally formed rotary type ultrasonic servomotor 6 enables one rotor to be driven forward and reversely running, and a motor main unit 7 is constituted of a cup-shaped casing 8 and its cover body 9. The servomotor 6 fixes bearings 11, 12, turnably supporting a rotary shaft 10, being provided in an upper part of the casing 8 and a disc- shaped rotor 14 to this rotary shaft 10 through a circular annular connecting ring 13. The servomotor 6 forms a magnetized layer structure 15 in the peripheral part of the rotor and magnetizes an N.S pole in the peripheral direction alternately by a fine pitch, forming a magnetic pole 16 for a rotary magnetic encoder 20 in the above described magnetized layer structure 15. And the servomotor 6, which opposes a magnetoresistance element 19 to a magnetic sensor supporting plate 18 fixed to the casing 8 through that magnetic pole 16 and an air gap 17, obtains an encoder signal of phase A-B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application of the Invention The present invention is directed to a method of converting reciprocating motion of an ultrasonic vibrator into motion of a movable element in a running direction by using ultrasonic vibration. The mover can run in forward and reverse directions.

Regarding the so-called "kitsuki-type" ultrasonic motor, this ultrasonic servo motor with an integrated magnetic encoder is refined to be suitable for servo use by having an integrated magnetic encoder, and is capable of running a single mover in forward and reverse directions. It is.

[Prior art and its problems] An ultrasonic motor is an actuator that uses the powerful vibrational energy of ultrasonic waves to obtain mechanical energy, and in recent years, this type of motor has come into practical use. .

Various types of ultrasonic motors of this kind are known.1 For example, there is a so-called "woodpecker type" as shown in Japanese Patent Publication No. 59-37672, and based on this, its principle was will be explained below.

Referring to FIG. 9, 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 two coils (not shown) are wound around the ultrasonic vibrator 4.

In addition, as the ultrasonic vibrator 4 for generating ultrasonic waves, two types of vibrators, magnetostrictive vibrators and electrostrictive vibrators, are generally put into practical use, and either of them may be used. What is included is the latter magnetostrictive vibrator, 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.

Further, a vibrator piece 3 is formed to protrude from the peripheral edge of the two-rotation shaft 1 by cutting. There are two types of notches: one is formed on the upper right side as shown in FIG. 9, and the other is formed on the lower right side (not shown).

Next, to explain the principle of the actual driving state, first, the 10th
As shown in Figure (A), the lowest point where one end surface 5a of the diaphragm 5 and one end surface 3a of the vibrator piece 3 are in contact is defined as the origin of the X-Y coordinates. At this time, the inclination θ of the vibrator piece 3 with respect to the axial direction needs to be such that the neutral friction angle between the vibrator plate 5 and the vibrator piece 3 is made smaller.

This means that the force that the vibrator piece 3 receives from the diaphragm 5 is the 11th
As shown in the figure, it is expressed as a component of force fx in the normal direction and force fy in the tangential direction of the diaphragm 5, so the friction coefficient μ between the vibrator piece 3 and the diaphragm 5 is the maximum static friction angle θ5=jan -1
μ. Therefore, in order for one end surface 3a of the movable element 3 to efficiently receive the driving force without slipping, the inclination θ of the vibrator piece 3 must be made smaller than the maximum friction angle θS.

Next, as shown in FIG. 10(B), when the diaphragm 5 starts vibrating and is displaced by ΔX in the X direction, one end surface 3a is pushed in the +X direction, but the second rotation axis 1 Since it is fixed, the inclination angle θ and the displacement f in the X direction shown in FIG.
A component force fJ due to x is generated, and the vibrator piece 3 is pushed up in the +y and
Just move.

Next, when the diaphragm 5 starts vibrating as shown in FIG. 10(B) and is displaced by ΔX in the X direction, one end surface 3a is pushed in the +X direction, but the rotation axis 1 is fixed. Therefore, the inclination angle θ and the displacement f in the X direction shown in FIG.
A component force fy is generated due to
move only.

Next, when the diaphragm 5 is displaced by 1 ΔX in the -X direction as shown in FIG. 10(C), one end surface 5a and one end surface 3a
When the two are separated, no frictional force acts between them, and the rotating shaft 1 moves in the +Y direction according to the period of the natural frequency. However, during this period as well, the rotating shaft 1 moves by ΔY2 in the +Y direction due to inertial force.

Furthermore, as the diaphragm 5 continues to vibrate,
The state shown in FIG. 10(A) is reached and the above operation is repeated, so that the rotation of the rotation shaft 1 continues.

Here, to explain the inertial force, as shown in FIG. 10, 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, vibrations of 20 KHz or more are handled, and since the inertial force is proportional to the square of the frequency, it has sufficient inertial force and can obtain uniform continuous rotation.

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

However, the so-called "woodpecker type" 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.

In addition, in order to perform various speed control and position control by applying a servo to this useful ultrasonic motor,
Various displacement detection means such as an encoder are required.

In particular, ultrasonic motors are capable of subtle deviations such as rotational feed in micron units, so if a highly accurate encoder is used, even more accurate positioning control, etc. is possible.

However, if a high-precision encoder is attached to this ultrasonic motor, the encoder etc. will become larger, and since the ultrasonic motor uses vibration, severe coupling accuracy with the encoder is required, making it large and This had the disadvantage of being an expensive ultrasonic motor with an encoder.

In addition, instead of using a single encoder as described above, the main scale for a rotary encoder, which is a component of the encoder, is fixed to the rotating shaft, and an index scale is fixed on the fixed side opposite to the main scale. There is a method of providing a light emitting element and a light receiving element via these two scales and incorporating an optical encoder, but this method also has the drawback of making the ultrasonic motor large and expensive.

Resolvers are also known as an alternative to encoders, but this resolver...

Since the structure is complex and expensive, it has been very difficult to incorporate the resolver into an inexpensive and conventional ultrasonic motor without increasing its size.

(Problems to be solved by the invention) The present invention makes a conventional so-called "woodpecker type" ultrasonic motor suitable as a servo motor so that one mover can run in forward and reverse directions, and also uses an expensive and large encoder and resolver. By using the components of an ultrasonic motor and the empty space of a conventional ultrasonic motor, the ultrasonic motor can be configured into an ultrasonic servo motor, making the ultrasonic servo motor inexpensive and compact. It is designed to be configurable.

In addition, by integrating the magnetic encoder, accurate magnetic encoder signals can be obtained even from the vibrations of the ultrasonic servo motor, and by using a magnetoresistive element as the magnetic sensor of the magnetic encoder, the signal can be obtained from the magnetoresistive element. By electrically increasing the resolution of the encoder signal, a highly accurate magnetic encoder-integrated ultrasonic servo motor can be constructed at low cost.

Furthermore, even with an integrated magnetic encoder, it does not take up a particularly large space compared to conventional ultrasonic motors, and with only slight improvements, ultrasonic servo motors with an integrated magnetic encoder can be mass-produced in a small size and at low cost. To do so.

An object of the present invention is to obtain an ultrasonic servo motor that can exhibit the above-mentioned effects.

[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 freely movable in forward and reverse directions, and a movable element that can be moved in a predetermined direction by being pressed against the movable element. a first ultrasonic vibrating device; a second ultrasonic vibrating device capable of causing the movable device to travel in a direction opposite to that of the first ultrasonic vibrating device by being pressed against the movable device; a first or second ultrasonic vibrating device selection switching means is provided, and one of the first or second ultrasonic vibrating device selection switching means is selectively switched to operate the first or second ultrasonic vibrating device. The movable element is made to be able to run in forward and reverse directions, and magnetic encoder magnetic poles are formed in a magnetized layer formed on the movable element, with N poles and S poles alternately magnetized at a fine pitch. This can be achieved by providing a magnetic sensor opposite to the magnetic encoder magnetic poles so as to be able to obtain at least A-phase and B-phase magnetic encoder signals.

[Embodiment of the Invention] FIG. 1 is a longitudinal cross-sectional view of a rotary magnetic encoder-integrated rotary ultrasonic servo motor 6 that can rotate one rotor in forward and reverse directions as an embodiment of the present invention, and reference numeral 7 indicates an ultrasonic servo motor. The ultrasonic servo motor main body 7 is composed of a cup-shaped casing 8 and a lid 9 that closes the opening at the lower end of the casing 8 .

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 to a position of the rotating shaft 10 in the ultrasonic servo motor main body 7, and a circular disk-shaped rotor 14 made of a metal body is attached to the outer periphery of the connecting ring 13 as appropriate. It is fixed by suitable means.

The disc-shaped rotor 14 preferably has a thinner inner circumference as shown in FIG. 2, and is preferably made of an elastic metal such as phosphor bronze.

The disc-shaped rotor 14 has a flat annular shape as shown in FIG. 2, and a plastic magnet and a rubber magnet are attached to the outer periphery of the rotor 14.

Alternatively, a magnetized layer 15 made of a magnetic paint or the like that can be magnetized by means such as coating is formed in an annular shape.

As shown in FIG. 2, the annular magnetized layer body 15 has N poles and S poles alternately arranged at fine pitches along the circumferential direction (in FIG. 2, N poles are used for convenience of drawing one drawing).

The magnetic pole of the S pole is drawn relatively large) and 1, for example, 2
The rotary magnetic encoder magnetic poles 16 for the rotary magnetic encoder 20 are formed on the magnetized layer body 15 by finely magnetizing the magnetized layer body 15 in alternating polar orientation and radial orientation at a pitch of 00 μm.

Incidentally, a rotary magnetic encoder magnetic pole 16 is attached to the magnetized layer body 15.
To magnetize and form the magnetized layer 1 on the two disc-shaped rotor 14,
After forming 5, multi-polar magnetization may be performed, or the magnetized layer 15 may be formed of a flat annular plastic magnet, rubber magnet, or other appropriate magnet.

The rotary magnetic encoder magnetic poles 16 may be multipolarized in advance and fixed to the outer periphery of the disc-shaped rotor 14 using adhesive or other means.

A magnetic resistor capable of obtaining at least A-phase and B-phase encoder signals is disposed on a magnetic sensor support plate 18 fixed to the casing 8 via the rotary magnetic encoder magnetic pole 16 and a fine radial gap 17. The elements 19 are opposed to each other.

The support plate 18 on the opposite side facing the rotary magnetic encoder magnetic pole 16 of one magnetoresistive element has two
Although the magnetic material 1 (not shown), for example, permalloy, is disposed, it may be omitted if it is not easily affected by an external magnetic field or in order to reduce the cost.

In addition, other magnetic sensors such as a Hall element, a Hall IC, or a magnetic head may be used instead of the magnetoresistive element 19 as a magnetic sensor, but the rotary magnetic encoder magnetic pole 16 has an N pole and an S pole at a fine pitch. Because they are alternately magnetized into multiple poles, in order to obtain the A-phase and B-phase magnetic encoder signals, the two magnetic sensors must be placed with a phase shift of 90 degrees in electrical angle. Therefore, if possible, it is desirable to use a magnetoresistive element 19 as the magnetic sensor, since the two assembly adjustments become troublesome.

In particular, although this magnetoresistive element 19 is a single magnetic sensor, it can not only obtain A-phase and B-phase magnetic encoder signals, but also easily obtain Z-phase signals depending on the design specifications of the pattern of one magnetoresistive element. It is obtainable and desirable. Therefore, in this embodiment, one magnetoresistive element is used as the magnetic sensor.

The above rotary magnetic encoder magnetic pole 16 and magnetoresistive element 1
9 forms a rotary magnetic encoder 20.

This rotary magnetic encoder 20 and magnetoresistive element 1
9 will be explained in detail later.

The upper and lower parts of the disc-shaped rotor 14 in the main body 7 are provided with first and second rotors, respectively. A second ultrasonic vibration device 21.22 is mounted in the axial direction by a sliding member 23.24 so as to be able to vibrate back and forth.

The sliding members 23 and 24 are slidably mounted in the axial direction of the two-rotation shaft 10, respectively. Second ultrasonic vibration device 21
．． 22 1st. It is fixed to the second ultrasonic transducer 25,26.

The first ultrasonic vibrator 21 includes a first ultrasonic vibrator 25 fixed to a sliding member 23, and a first ultrasonic vibrator 25 fixed to a sliding member 23.
5, a first diaphragm 27 fixed to the lower surface of the first ultrasonic transducer 25, a first coil 28 wound around the upper part of the first ultrasonic transducer 25, and a first diaphragm 28 fixed to the lower surface of the first diaphragm 27 in the axial direction. It consists of a first vibrator piece 29 fixedly installed on the upper surface of the disc-shaped rotor 14 facing each other with a gap in between.

The second ultrasonic vibrator 22 includes a second ultrasonic vibrator 26 fixed to a sliding member 24, and a second ultrasonic vibrator 26 fixed to a sliding member 24.
6, a second diaphragm 30 fixed to the upper surface of the second ultrasonic transducer 26, a second coil 31 wound around the lower part of the second ultrasonic transducer 26, and a second diaphragm 31 fixed to the upper surface of the second diaphragm 30 in the axial direction. It consists of a second vibrator piece 32 fixed to the lower surface of the disc-shaped rotor 14 facing each other with a gap in between.

Each disc-shaped rotor 1 of the ultrasonic vibrator 21, 22
1 fixed to the surface opposite to 4. Second diaphragm 27.
30 and a plate-shaped or rod-shaped first. The second vibrator pieces 29 and 32 are respectively connected to the first vibrator pieces 29 and 32, which will be described later. By driving the second pressure contact/release selection switching means 33, 34, they are kept in contact with each other.

1st. The second vibrator pieces 29 and 32 are fixed to the disc-shaped rotor 14 at appropriate inclination angles with respect to the axial direction, as shown in FIGS. 3(a) and 3(b), respectively. As such, the first vibrator piece 29 and the second vibrator piece 32 are formed such that the inclination angles are opposite to each other.

1st. To configure the second vibrator piece 29, 32, 1. Recesses 14a, 14 having a diameter smaller than the diameter of the disc-shaped rotor 14 are formed in the center of each of the upper and lower surfaces of the disc-shaped rotor 14.
b, and then cut at a preset angle in the remaining peripheral portion.

FIGS. 3(a) and 3(b) show first and second vibrations formed by cuts in the circumferential edge surface of the disc-shaped rotor 14 in FIG. 1 so that the directions of the inclination angles are different. Child piece 2
9.32 is formed with a protrusion.

The notch for forming the first vibrator piece 29 is the first
As shown in the figure, there is one that is formed on the upper right side, and one that is formed on the lower right side (not shown). The cut for forming the second vibrator piece 32 is either formed on the upper left side as shown in FIG. 1 or on the lower left side (not shown).

In addition, 1. The second vibrator piece 29.32 has one rotation axis 10
When it is extended and formed near the 1st. Second vibrator piece 29.
32 and the momentum of the disc-shaped rotor 14, there is a large difference between the inner and outer circumferences of the vibrator pieces 29 and 32, and as a result, the first vibrator pieces 29 and the first diaphragm 27 and between the second oscillator piece 32 and the second diaphragm 30, resulting in a decrease in energy efficiency and wear.
．． It is necessary to take into consideration the formation of the second vibrator pieces 29 and 32 at the time of design.

In addition, the above-mentioned 1. The first oscillator wound around each of the second oscillators 25 and 26. A high frequency voltage is applied to the second coil 28° 31 by the drive circuit 36 based on a signal from the controller 35, so that when a high frequency voltage is applied to the coil 28 or 31 in the same manner as described above, The ultrasonic transducer 25 or 26, which is a magnetostrictive material, expands and contracts due to the magnetic field and excites the diaphragm 27 or 30.

At the top of the first ultrasonic vibrating device 21, a first pressure contact/release selection switching means 33 for moving the ultrasonic vibrating device 21 up and down is provided. The first switching means 33 includes: an insulating plate 37 connected and fixed to the side surface of the first vibrator 25 and fixedly formed above the first vibrator 25 and the second coil 28;

A conductive plate 39 is fixed to the upper surface of the insulating plate 37 facing the first electromagnetic coil 38 with an axial gap therebetween.

The first electromagnetic coil 38 is formed into an annular shape by an insulator 40, is fixed to the upper surface of the casing 8, and has the upper end of a spring 41 through which the rotating shaft 10 is rotatably inserted. 10 and is embedded and fixed in the insulator 40.

Further, the lower end of the spring 41 is brought into contact with the sliding member 23.

A second press/release selection switching means 34 for moving the second ultrasonic vibrator 22 up and down is provided at the bottom of the second ultrasonic vibrator 22 . This second switching means 34
includes an insulating plate 42 connected and fixed to the side surface of the second ultrasonic transducer 26 and fixedly formed below the second ultrasonic transducer 26 and the second coil 31, and an axial direction of the insulating plate 42. A conductive plate 44 is fixed to the lower surface facing the second electromagnetic coil 43 with a gap in between.

The second electromagnetic coil 31 is formed into an annular shape by molding an insulator 45, etc., and is fixed inside the upper surface of the lid 9, and has a spring 46 through which the rotating shaft 10 is rotatably passed.
The lower end of the rotary shaft 10 is arranged concentrically with the rotating shaft 10 and is embedded and fixed in the insulator 45. Further, the lower end of the spring 46 is brought into contact with the sliding member 24.

Therefore, in order to rotate the ultrasonic servo motor 6 of the present invention in the normal rotation direction, the changeover switch mechanism 48 is turned on in the changeover circuit 47 in response to a signal from the controller 35, and the first pressure contact/release selection changeover means 33 ( At this time, the second pressure contact/release selection switching means 34 controls the second ultrasonic vibration device 34 so as not to contact the second vibrator piece 32 of the disc-shaped rotor 14), the first The ultrasonic vibrator 21 is moved in the axial direction to contact the first vibrator piece 29 fixed to the disk-shaped rotor 14, and the first ultrasonic vibrator 2
1 and the first coil 28, and select the first coil 28.
drive circuit 36 based on commands from controller 35.
This is made possible by applying a high frequency to excite the first ultrasonic transducer 25.

In order to reversely rotate the ultrasonic motor 6 in the opposite direction, the changeover circuit 47 turns on the changeover switch fl149, and the first pressure contact/release selection changeover means 33 causes the first ultrasonic vibrator 21 to rotate in a circular motion. First vibrator piece 2 of plate rotor 14
9, the second ultrasonic vibrator 22 is moved in the axial direction by the second pressure contact/release selection switching means 34, and the second vibrator is fixed to the disc-shaped rotor 14. The second ultrasonic transducer 26 and the second
This is possible by selecting the coil 31 of , and applying high frequency to the second coil 31 in the same manner as described above to excite the second ultrasonic transducer 26.

No. 1 above. To further explain the second switching means 33 and 34, the four changeover switch mechanisms 48 serve as pulse power supplies that supply pulsed driving current to the electromagnetic coil 38 or 43 based on the signal from the changeover circuit 47. hand,
In this example, the capacitor and switch form an ellipse, respectively.
When the switch is closed, the capacitor's charge is discharged to supply a driving pulse current.

Now, in FIG. 1, when the switch of the switch W449 is closed in response to an operation command from the switching circuit 47, the charge in the capacitor is discharged through the second electromagnetic coil 43, causing a pulsed current to flow.

This generates an induced current in the conductor plate 44.

Due to the electromagnetic repulsive force resisting this tongue spring 46.

Since the conductive plate 44 that had been pressed against the insulator 45 of the second electromagnetic coil 43 is repelled from the insulator 45, the spring 46 causes the second pressure contact/release selection switching means 3
4 rotates together with the disc-shaped rotor 14.

Conversely, in order to rotate the disc-shaped rotor 14 in the forward direction, the switch mechanism 49 is turned off as described above.
This is possible by turning on 8.

4 and subsequent figures are explanatory diagrams of the rotary magnetic encoder 20 and the magnetoresistive element 19. FIG. On the surface of the annular magnetized layer body 15, as described above, magnetic poles of N pole (16N) and S pole (16S) are arranged alternately and evenly spaced at fine pitches and radially aligned. Rotary magnetic encoder magnetic poles 16 are formed with multi-pole magnetization along the circumferential direction. One magnetoresistive element (MR sensor) is disposed facing the rotary magnetic encoder magnetic pole 16 of the disc-shaped rotor 14 at a position of a magnetic sensor support plate 18 that faces the rotary magnetic encoder magnetic pole 16 with a radial gap 17 interposed therebetween.

N poles 16N and S of the above rotary magnetic encoder magnetic poles 16
The magnetic pole width of each pole 16S is magnetized to have a width of λ (equal to the width expressed by 2π in electrical angle).

Furthermore, assuming that the magnetoresistive element 19 is a ferromagnetic magnetoresistive element, for example, the rotary magnetic encoder 20
In order to explain the principle of this, a magnetoresistive element 50, which is a wire made of a ferromagnetic thin film constituting one magnetoresistive element, will be explained with reference to FIG.

This magnetoresistive element 50 is made by forming a Ni-Co metal thin film (ferromagnetic metal thin film) with a thickness of several thousand degrees on a substrate such as glass by means such as vacuum evaporation or etching. A resistive element 19 can be formed.

As shown in FIG. 4, if the magnetoresistive element 50 is arranged so that the direction of the current I flowing through it and the magnetic field (magnetic flux) 51 are perpendicular, the magnetic flux 51 will move from the north pole 16N to the south pole. Head to 16S.

As shown in FIG. 5, this magnetoresistive element 50 causes a decrease in resistance value due to a lateral magnetic flux 51X within a magnetic field 51. In addition, 51Y is.

Indicates longitudinal magnetic flux.

The rate of change in resistance of the magnetoresistive element 50 at this time is
When the width of one magnetic pole of the rotary magnetic encoder magnetic pole 16 is λ, and the resistance value of the magnetoresistive element 50 at the positions λ/4 and 3λ/4 is R1, the change value of the resistance is Δr. The resistance value R(θ) at the phase θ of the magnetic pole (16N or 16S) and the magnetoresistive element 50 (the phase θ is when the −magnetic pole widths 16N and 163 are respectively set to 2π in electrical angle) is:

It can be expressed as R(θ)=R−Δr−cosθ (1).

The lateral magnetic flux (magnetic field) 51X is related to the nine phases θ and the distance between the magnetoresistive element 50 and the rotary magnetic encoder magnetic pole 16, and the magnetoresistive element 50 also takes a resistance value R corresponding thereto.

In addition, in the case of the magnetoresistive element 19, unlike other magnetic sensors such as Hall elements, at the center of the magnetic field (the magnetic field state at the middle of the N pole 16N and the S pole 16S), there is no magnetic field (N
Similar to the magnetic field state at the boundary between the pole 16N and the south pole 16S, the output signal does not change.

Since it is not possible to obtain the A-phase and B-phase magnetic echoer signals with a single magnetoresistive element having one magnetoresistive element 50, as shown in FIG. 6, four magnetoresistive elements 50a, 50b, 50a', 5
0b' are formed by sequentially shifting them by λ/4,
Input phase and B phase magnetic encoder signals are obtained.

This magnetoresistive element 19 includes two magnetoresistive elements 50a and 50a' to obtain an A-phase magnetic encoder signal.
and a magnetoresistive element 50b for obtaining a B-phase magnetic encoder signal.

50b'.

The magnetoresistive elements 50a and 50a' are arranged so that the width of one magnetic pole (N pole 16N or 5i16S) of the rotary magnetic encoder magnetic pole 16 is λ (2 in air angle) so that the magnetoresistive elements 50a and 50a' have opposite phases to each other.
π), they are formed with a width shifted by λ/2.

Similarly, the magnetoresistive elements 50b and 50b' are formed to be shifted by a width of λ/2 so as to have opposite phases.

Also, the magnetoresistive elements 50a and 50b, and 50a°
and 50b' are formed to be shifted by λ/4 width from each other.

Therefore, the magnetoresistive element 19 is sequentially arranged with magnetoresistive elements 50a and 50b shifted by λ/4 pitch.

50a' and 50b' are formed.

As a circuit for processing the magnetic encoder signal from the magnetoresistive element 19 formed in this manner, a circuit as shown in FIG. 7, for example, is used.

This magnetic encoder signal processing circuit 52 includes resistors 53-
1. . . , 53-4 form a bridge to convert resistance changes into voltage changes, and comparators 54-1 .
54-2, 9 as shown in FIG. 8(a>,(b))
Two square wave magnetic encoder signals with 0° phase difference 5
5-1.55-2 can be obtained.

If the square wave magnetic encoder signals 55-1 and 55-2 are counted by a counter, the rotary magnetic encoder 20. That is, the rotation angle of the ultrasonic servo motor 6 can be measured.

This rectangular wave magnetic encoder signal 55-1, 55-2 is added to the double rotation direction discrimination circuit 56 to obtain a clockwise rotation pulse and a counterclockwise rotation pulse, and this up signal or down signal is converted into an up-down signal. By adding it to the counter 57, the current rotation angle is obtained.

Therefore, when the ultrasonic servo motor 6 of the present invention is driven to rotate the disc-shaped rotor 14 in a predetermined direction as described above, the rotary magnetic encoder magnetic pole 1 is formed on the outer periphery of the disc-shaped rotor 14.
6 also rotates, so if this is detected by the magnetoresistive element 19, one rotation angle, one rotation direction, two rotation speeds, etc. are determined, and the rotation speed of the ultrasonic servo motor 6 is determined by feedback loop control.

It is possible to servo positioning in one rotational direction.

In the above embodiment, the rotary magnetic encoder magnetic poles 16 are formed on the magnetized layer body 15 formed on the outer periphery of the disk-shaped rotor 14 made of metal, but as another method, one disk-shaped rotor 14 may be formed. may be formed of a magnet such as a plastic magnet, and a rotary magnetic encoder may be directly magnetized with multiple poles on the magnet.

Further, in the above example, only a one-rotation type ultrasonic servo motor has been described, but the present invention is naturally applicable to a type of linear ultrasonic servo 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. It's okay.

Alternatively, it may be attached and fixed by an appropriate means, and it goes without saying that an appropriate pressure contact/release selection switching means other than those described above may be used.

[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.

A single small and lightweight 9-turn type or linear type movable element with thrust and driving force can be rotated in forward and reverse directions or forward and reverse, and the magnetic encoder is rationally formed and integrated, so it can be used for various positioning and other purposes. A magnetic encoder integrated ultrasonic servo motor that can accurately perform servo control such as speed control can be mass-produced in a small size and at low cost, and the fields of its application will further expand. Further, in the present invention, when the first ultrasonic vibrating device is driven to make the mover move in a predetermined direction, the second ultrasonic vibrating device for making the mover move in the opposite direction is movable. Because they are prevented from coming into contact with their offspring, their lifespans can be expected to be extended.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a rotary ultrasonic servo motor with an integrated rotary magnetic encoder that can rotate the rotor in forward and reverse directions according to an embodiment of the present invention, and FIG. Partially cutaway perspective view, Figure 3(a)
, (b) are top and bottom views of a disk-shaped rotor having a first vibrator and a second vibrator, respectively, and FIGS. 4 to 6 are diagrams explaining the principle of a rotary magnetic encoder and a magnetoresistive element. , FIG. 7 is an explanatory diagram of the magnetic encoder signal processing circuit,
Fig. 8 is a waveform diagram of a magnetic encoder signal, Fig. 9 is a vertical cross-sectional view of a conventional ultrasonic motor, and Figs. 10 (A), (B), and (C) respectively illustrate the operating principle of an ultrasonic motor. The explanatory diagram, FIG. 11, is an explanatory diagram of the components of force applied to the vibrator piece. 1...Rotating shaft, 2...Bearing. 3... Vibrator piece, 4... Ultrasonic vibrator. 5... Vibration plate, 6... Ultrasonic servo motor with integrated rotary magnetic encoder that can rotate one rotor in forward and reverse directions,
7...Ultrasonic servo motor body. 8... Cup-shaped casing, 9... Lid body. 10... Rotating shaft, 11.12... Bearing. 13... Connection ring, 14... Disc-shaped rotor, 15
...Magnetized layer body, 16...Rotary magnetic encoder magnetic pole, 16N...N pole. 165...S pole, 17... air gap. 18... Magnetic sensor support plate, 19... Magnetoresistive element, 20... Rotary magnetic encoder. 21... First ultrasonic vibrator, 22... Second ultrasonic vibrator, 23.24... Sliding member, 25...
First ultrasonic transducer. 26... Second ultrasonic transducer, 27... First diaphragm, 28... First coil. 2...first vibrator piece, 30...second diaphragm 2
31... Second coil, 32... Second vibrator piece,
33...first pressure contact/release selection switching means, 34...
Second pressure contact/release selection switching means, 35... Controller, 36... Drive circuit, 37... Insulating plate, 38...
・First electromagnetic coil, 39... Conductive plate, 40...
...Insulator, 41...Spring, 42...Insulating plate. 43... Second electromagnetic coil 544... Conductive plate, 45
...Insulator, 46...Spring. 47...Switching circuit, 48.49...Switching mechanism. 50.50a, 50a', 50b, 50b'-
-... Magnetoresistive element, 51... Magnetic field (magnetic flux), 52... Magnetic encoder signal processing circuit, 53-1
．． ..., 53-4...Resistor, 54-1.5
4-2... Comparator. 55-1.55-2...Magnetic encoder signal. 56...Double multiplication type rotation direction discrimination circuit 757...Up/down counter.

Claims (8)

[Claims] (1) A movable element supported so as to be freely movable in forward and reverse directions, a first ultrasonic vibrating device capable of causing the movable element to travel in a predetermined direction by being pressed against the movable element, and the movable element. a second ultrasonic vibrating device that can cause the mover to run in the opposite direction to the first ultrasonic vibrating device by being pressed against the first ultrasonic vibrating device; and a first or second ultrasonic vibrating device selection switching means. is provided, and selectively switches one of the first or second ultrasonic vibrating device selection switching means to operate the first or second ultrasonic vibrating device so that the movable element can run in the forward and reverse directions. , a magnetic encoder magnetic pole is formed by alternately magnetizing N-pole and S-pole magnetic poles at a fine pitch on the magnetized layer formed on the movable element, and at least an A-phase magnetic pole is formed opposite to the magnetic encoder magnetic pole. and a magnetic encoder integrated ultrasonic servo motor capable of running one movable element in forward and reverse directions, characterized in that it is provided with a magnetic sensor so as to be able to obtain a B-phase magnetic encoder signal. (2) A movable element supported so as to be freely movable in forward and reverse directions, and a first movable element supported movably in the direction of the movable element and capable of causing the movable element to travel in a predetermined direction by being pressed against the movable element. a second ultrasonic vibrator capable of causing the movable element to run in a direction opposite to the first ultrasonic vibrator; and a first ultrasonic vibrator provided on the fixed side, and
First and second pressure contact/release selection switching means are provided to press or release the second ultrasonic vibration device and the movable element, and one of the first and second pressure contact/release selection switching means is selected. The switch operates one of the first or second ultrasonic vibration devices to enable the movable element to travel in an appropriate direction, and at the same time, N poles are applied to the magnetized layer provided on the movable element at a fine pitch. , a magnetic encoder magnetic pole is formed by alternately magnetizing multiple S poles, and a magnetic sensor is provided opposite the magnetic encoder magnetic pole so as to be able to obtain at least A-phase and B-phase magnetic encoder signals. A magnetic encoder-integrated ultrasonic servo motor capable of moving one movable element in forward and reverse directions as set forth in claim (1). (3) The magnetic sensor integrated with a magnetic encoder capable of moving one mover in forward and reverse directions according to claim (1) or (2), characterized in that the magnetic sensor is a magnetoresistive element. Sonic servo motor. (4) The movable element is a rotor supported rotatably, and one movable element according to claim (1) or (2) can run in forward and reverse directions. Ultrasonic servo motor with integrated magnetic encoder. (5) The movable element is a disc-shaped rotor that is rotatably supported, and the first
an ultrasonic vibration device and a first pressure contact/release selection switching means are provided, and the second ultrasonic vibration device and a second pressure contact/release selection switching device are provided on the other surface side of the disc-shaped rotor. A magnetic encoder-integrated ultrasonic servo motor capable of moving one movable element in forward and reverse directions according to claim (4). (6) The first ultrasonic vibrator and the second ultrasonic vibrator include a first ultrasonic vibrator, a second ultrasonic vibrator,
A first diaphragm provided on one end surface of the first ultrasonic transducer and a second diaphragm provided on one end surface of the second ultrasonic oscillator, A first vibrator piece having an inclination angle is provided between the movable element and the first diaphragm, the first vibrator piece is fixedly formed on either the movable element or the first diaphragm, and the movable element and the first vibrating element are fixed to each other. A second vibrator piece having an inclination angle in the opposite direction to the first vibrator piece is provided between the second vibrator piece and the second vibrator piece. A magnet capable of moving one mover in forward and reverse directions according to any one of claims (1), (2), or (5), characterized in that the magnet is fixedly formed in Ultrasonic servo motor with integrated encoder. (7) Claims characterized in that the magnetic encoder magnetic poles are rotary magnetic encoder magnetic poles formed in a multi-pole magnetized manner on a magnetized layer formed on the outer periphery of the disc-shaped rotor. A magnetic encoder-integrated ultrasonic servo motor capable of forward and reverse rotation of one movable element according to any one of item (1), item (2), or item (6). (8) The rotor is a magnet rotor, and a rotary magnetic encoder magnetic pole is magnetized and formed on the magnet rotor, as set forth in claim (4) or (7). An ultrasonic servo motor with an integrated magnetic encoder that can run a single mover in forward and reverse directions.