JPH07337045A - Ultrasonic motor drive - Google Patents

Abstract

PURPOSE:To stabilize the operation of an ultrasonic motor while increasing the speed and thrust thereof by driving the motor through an ultrasonic elliptical oscillation where a vector in the direction for approaching a driven body and a speed vector having a component only in the drive direction of the driven body make an acute angle. CONSTITUTION:A body driven by a driver 15 is driven through an ultrasonic elliptical oscillation where a vector in the longitudinal direction of an ultrasonic elliptical oscillation excited in the vicinity of the driver 15 for a resilient body 11 and directed in the direction approaching the driven body makes an acute angle with a speed vector in the tangential direction of the ultrasonic elliptical oscillation having a component only in the drive diving direction of the driven body. The ultrasonic elliptical oscillation 15 generated by combining two oscillations and the phase difference deltatheta between the oscillations of first and second oscillation modes is set as follows; 0<deltatheta<+pi/2 or +pi<deltatheta<+3pi/2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor driving device.

[0002]

2. Description of the Related Art In recent years, ultrasonic motors have been attracting attention as new motors replacing electromagnetic motors. This ultrasonic motor has the following advantages over conventional electromagnetic motors. (1) Low speed and high thrust can be obtained without gears. (2) Large holding power. (3) The stroke is long and the resolution is high. (4) It is extremely quiet. (5) Magnetic noise is not generated and is not affected by noise.

As a conventional ultrasonic linear motor, there is an invention described in Japanese Patent Application No. 4-321096 previously proposed by the present applicant. Hereinafter, a conventional ultrasonic linear motor will be described based on the above invention. First, the configuration of the ultrasonic elliptical transducer will be described. In FIG. 10, reference numeral 60 is an ultrasonic transducer. On the upper part of the basic elastic body 61, two laminated piezoelectric elements 63 are arranged at a portion substantially corresponding to the antinode of the secondary resonant bending vibration. Then, by the elastic member 62 for holding,
It is fixed on the basic elastic body 61. Although not shown, the basic elastic body 61 has tapped screws at three positions, and the holding elastic member 62 is fixed to the basic elastic body 61 with screws. At this time, the laminated piezoelectric element 63 has the holding elastic member 62.
It is held by being hit by. In addition, the laminated piezoelectric element 6
The portion of the holding elastic member 62 that contacts the holding elastic member 62 is fixed with an epoxy adhesive, and the holding elastic member 62 and the basic elastic body 6 are
The contacting portions of 1 are also joined by an epoxy adhesive.

Sliding members 65 are made of epoxy and are provided at both ends of the surface of the basic elastic body 61 opposite to the surface on which the laminated piezoelectric element 63 is arranged (the surface on the side in contact with the driven body). It is joined using an adhesive. The sliding member 65 is made of polyimide mixed with carbon fiber and mica as a filler (20% by weight of carbon fiber and 30% by weight of mica).

Next, the operation of the ultrasonic transducer 60 will be described. 1 by appropriately sizing the ultrasonic transducer 60
The next resonance longitudinal vibration and the second resonance bending vibration can be excited at almost the same frequency. In FIG. 10, electric terminals taken out from the laminated piezoelectric element 63 on the left side are represented by A, G (hereinafter,
Electrical phase taken out from the laminated piezoelectric element 63 on the right side is referred to as B and G (hereinafter referred to as B phase).

First, a DC voltage of 30 V is applied to the A phase and the B phase. By doing so, a compressive force (pressurization) of approximately 70 N can be applied to the laminated piezoelectric element 63. Therefore, if an alternating voltage having an amplitude of 10 Vp-p with a frequency Fr is applied to the A phase and an alternating voltage having the same frequency and the same amplitude and the same phase is applied to the B phase, the primary resonant longitudinal vibration can be excited. Next, A
When an alternating voltage having an amplitude of 10 Vp-p is applied to the phase at the frequency Fr and an alternating voltage having the same frequency and the same amplitude and an opposite phase is applied to the B phase, the secondary resonance bending vibration can be excited. Furthermore, A
When an alternating voltage having an amplitude of 10 Vp-p with a frequency Fr is applied to the phase B and the phase B and the phase difference is set to 90 degrees or -90 degrees, a clockwise or counterclockwise ultrasonic wave is generated at the position of the sliding portion 65. Elliptical vibration can be excited.

Next, the structure of the ultrasonic linear motor will be described. In FIG. 11, the ultrasonic vibrator 60 is held by a vibrator holding member 74 made of an aluminum material via a silicon rubber (thickness 1 mm) not shown.
The vibrator holding member 74 is U-shaped and is connected to the connecting rod 75 via a thin flange portion (thickness 0.2 mm, length 2 mm) not shown. Furthermore, connecting rod 75
Is connected to the spring receiving portion 76. On the other hand, rail 71
Is made of a hardened stainless steel material 440c,
The surface hardness is 900 by Vickers hardness, and the surface is polished with No. 4000 polishing paper, and is connected to the linear guide fixing portion 72 by a screw (not shown).

A frame 80 is fixed to the linear guide moving portion 73 and is also integrally connected to the upper frame 81. The upper frame 81 is tapped at the center and a bolt 79 is attached to the upper frame 81. A spring retainer 78 is attached to the bolt 79 as shown in the figure.
Is installed. By adjusting the length of the spring 77, the contact pressure between the ultrasonic transducer 60 and the rail 71 can be adjusted.

Next, the operation of the ultrasonic linear motor will be described. As described above, an alternating voltage having a frequency Fr, an amplitude of 10 Vp-p, and a phase difference of +90 degrees or -90 degrees is applied to the A phase and the B phase of the ultrasonic transducer 60. Then, since the ultrasonic elliptical vibration is formed on the sliding portion of the ultrasonic transducer 60, the ultrasonic transducer 60 is driven rightward or leftward with respect to the rail 71.

[0010]

However, the following problems have been clarified in the above-described conventional ultrasonic linear motor. In the case of this ultrasonic motor,
The resonance frequency of the longitudinal vibration and the resonance frequency of the bending vibration are made to substantially match with each other in the ultrasonic vibrator to generate the ultrasonic elliptical vibration. However, the operation was not always stable. That is, even when the resonance frequency of the longitudinal vibration and the resonance frequency of the bending vibration are exactly matched, the operation is unstable, or even when the resonance frequency of the longitudinal vibration and the resonance frequency of the bending vibration are slightly different from each other. There were some that worked well and some that didn't, and the cause was unclear.

An object of the present invention according to claims 1 to 3 is to clarify the above-mentioned problems and to provide an ultrasonic motor drive device which has a large speed and thrust and operates stably.

[0012]

An ultrasonic motor driving device of the present invention according to claim 1 comprises at least two or more electromechanical conversion elements, an elastic body and a driver,
An ultrasonic transducer that combines two vibration modes to generate ultrasonic inertial vibration, and a driven body driven by a driver,
In an ultrasonic motor drive device having a power supply means for applying an alternating voltage to an electromechanical conversion element, a vector in the long axis direction of ultrasonic elliptical vibration excited near a driver of an elastic body, which is a vector to be driven. The angle formed by the vector in the approaching direction and the velocity vector in the tangential direction of the ultrasonic elliptical vibration, which has a component only in the direction and direction in which the driven body is driven, is an acute angle. It is characterized by being driven by the ultrasonic elliptical vibration formed as follows.

An ultrasonic motor drive device according to a second aspect of the present invention comprises at least two or more electromechanical conversion elements, an elastic body and a driver, and combines two vibration modes to generate ultrasonic elliptical vibration. Of the two vibration modes, in an ultrasonic motor drive device having an ultrasonic vibrator for driving, a driven body driven by a driver, and a power supply means for applying an alternating voltage to the electromechanical conversion element. One vibration mode is vibration in the driving direction of the driven body in the vicinity of the driver of the elastic body and excites vibration with the driven direction of the driven body being positive. The second vibration mode is a vibration in the direction perpendicular to the driven direction of the driven body in the vicinity of the driver of the elastic body, which excites vibration with the positive direction toward the driven body, and the vibration of the first vibration mode is generated. The second vibration mode for the phase of Phase difference .delta..theta of vibration has a 0 <δθ <+ π / 2 or + π <δθ <+ 3π / 2, characterized in that it is driven by the ultrasonic elliptical vibration formed as made.

An ultrasonic motor drive device according to a third aspect of the present invention comprises at least two or more electromechanical conversion elements, an elastic body and a driver element, and combines two vibration modes to generate ultrasonic elliptical vibration. Of the two vibration modes, in an ultrasonic motor drive device having an ultrasonic vibrator for driving, a driven body driven by a driver, and a power supply means for applying an alternating voltage to the electromechanical conversion element. One vibration mode is vibration in the driving direction of the driven body in the vicinity of the driver of the elastic body and excites vibration with the driven direction of the driven body being positive. The second vibration mode is a vibration in the vicinity of the driver of the elastic body in a direction perpendicular to the direction in which the driven body is driven, and excites a vibration having a positive direction toward the driven body, causing resonance of the first vibration mode. The frequency is the same as that of the second vibration mode. The phase difference δα of the vibration with respect to the alternating voltage of the first vibration mode and the second vibration in the frequency range that is set higher than the frequency and is lower than the resonance frequency of the first vibration mode and higher than the resonance frequency of the second vibration mode. The phase difference δβ of vibration with respect to the alternating voltage of the mode is composed of an ultrasonic transducer formed so that 0 <(δα-δβ) <+ π / 2, and the phase is ± π for two or more electromechanical conversion elements. / 2 different alternating voltage is applied, and it is characterized by being driven at a frequency lower than the resonance frequency of the first vibration mode and higher than the resonance frequency of the second vibration mode.

The action of claim 1 is a vector in the long axis direction of the ultrasonic elliptical vibration excited near the driver of the elastic body, and a vector in the direction of approaching the driven body, Since the ultrasonic elliptical vibration is formed such that the angle formed by the velocity vector in the tangential direction of the acoustic wave elliptical vibration and the velocity vector having only the direction and direction components in which the driven body is driven is an acute angle, It is possible to obtain an ultrasonic motor drive device that has a large speed and thrust and operates stably.

According to a second aspect of the present invention, the first vibration mode of the two vibration modes is vibration in the driving direction of the driven body near the driver of the elastic body, and the driven body is driven. The vibration of which the direction is positive is excited, and the second vibration mode of the two vibration modes is the vibration in the vicinity of the driver of the elastic body in the direction perpendicular to the driven direction of the driven body and Exciting vibration having a positive direction, the phase difference δθ of the vibration of the second vibration mode with respect to the phase of the vibration of the first vibration mode is 0 <δθ <+ π / 2, or + π <δθ <+ 3π / By driving as described above, the ultrasonic elliptical vibration having the shape described in claim 1 is formed, and the velocity and thrust are large,
An ultrasonic motor driving device that operates stably can be obtained.

According to the third aspect of the invention, the first vibration mode of the two vibration modes is vibration in the driving direction of the driven body near the driver of the elastic body, and the driven body is driven. The second vibration mode of the two vibration modes is the vibration in the direction perpendicular to the driven direction of the driven body and the driven body. To the positive direction, the resonance frequency of the first vibration mode is set higher than the resonance frequency of the second vibration mode, and the resonance frequency of the first vibration mode is higher than the resonance frequency of the first vibration mode. Ultrasonic vibration formed so that the phase difference δα of the vibration with respect to the alternating voltage of the first vibration mode and the phase difference δβ of the vibration with respect to the alternating voltage of the second vibration mode are 0 <(δα-δβ) <+ π / 2 It is composed of a child and has a position of two or more Is applied by applying an alternating voltage different by ± π / 2, and is driven at a frequency lower than the resonance frequency of the first vibration mode and higher than the resonance frequency of the second vibration mode. Since ultrasonic elliptical vibration can be formed, an ultrasonic motor driving device that has a large speed and thrust and operates stably can be obtained.

[0018]

1 to 9 show the present embodiment, FIG. 1 is a perspective view of an ultrasonic oscillator, FIGS. 2a and 2b are explanatory views of the action of the ultrasonic oscillator, and FIG. 3 is an ultrasonic linear motor. Front view, FIG. 4a is a front view of the driver, FIG. 4b is a rear view of the driver, FIG. 4c is a side view of the driver, FIGS. 5 to 8 are explanatory views of the action of the ultrasonic transducer, and FIG. 9 is a graph. Is.

As shown in FIG. 1, the basic elastic body 11 of the ultrasonic transducer 10 is made of brass material and has a convex shape. The dimensions are 30 mm in width and 4 m in depth, excluding the convex portion.
m. About height (dimension H), 6mm-9mm
Prototypes in the range of The size of the convex part is 4 mm in width,
The height is 2.5 mm and the depth is 4 mm. A pin 16 made of a stainless steel material having a diameter of φ2 is driven by press fitting at the center of the basic elastic body 11 in the width direction and at a position 6 mm from the bottom surface. The multi-layer piezoelectric element 12, which is an electromechanical conversion element, is a stack of several tens to several hundreds of electrode-processed piezoelectric elements. In this embodiment, the multi-layer piezoelectric element NLA of Tokin Corp. -2x3x9 was used.
Its dimensions are 2 mm x 3.1 mm x 9 mm. Although not shown in FIG. 1, portions other than both ends of the laminated piezoelectric element 12 are coated with an epoxy resin (coating thickness: about 0.
5 mm).

Next, a method of assembling the ultrasonic transducer 10 will be described. As shown in FIG. 1, the laminated piezoelectric elements 12 are arranged on both sides of the convex portion of the basic elastic body 11. Then, the elastic member for holding 13 (width 4 mm, height 2.5 mm, depth 4 m
It is fixed on the basic elastic body 11 by m). Although not shown, the basic elastic body 11 has tapped screws at two places, and as shown in FIG. 1, the holding elastic member 13 has a basic elasticity by two screws 14 and an epoxy adhesive. Body 1
It is fixed at 1. At this time, the laminated piezoelectric element 12 is held and fixed in a state in which a compressive force is applied between the convex portion of the basic elastic body 11 and the holding elastic member 13.

Both ends of the laminated piezoelectric element 12, the convex portion of the basic elastic body 11, and the holding elastic member 13 are fixed by an epoxy adhesive, and the side surface of the laminated piezoelectric element 12 in contact with the basic elastic body 11. The part is adhered to the basic elastic body 11 by using an epoxy adhesive as well. A position 9 mm from both ends of the surface of the basic elastic body 11 opposite to the surface on which the laminated piezoelectric element 12 is arranged (the surface in contact with the driven body) (the vibration amplitude of the resonance bending vibration is maximum). A rectangular shape (dimensions: width 3 mm, depth 4 mm, thickness 1 mm)
Driver 15 (grinding stone material: abrasive grains of alumina ceramics dispersed in resin) is bonded using an epoxy adhesive.

Next, the operation of the ultrasonic transducer 10 will be described. According to the dimensions and shapes described above, the primary resonant longitudinal vibration mode and the secondary resonant bending vibration mode can be excited at substantially the same frequency Fr (53 kHz to 56 kHz). As a result of computer analysis of these vibrations using the finite element method, the resonance longitudinal vibration mode as shown in FIG.
The resonance flexural vibration mode as shown in Fig. 3 is expected, and it was verified as a result of the vibration measurement.

In FIG. 1, the laminated piezoelectric element 1 on the left front side
The electric terminals taken out from 2 are A, GND (hereinafter,
The electric terminals taken out from the laminated piezoelectric element 12 on the far right side are B and GND (hereinafter, referred to as B phase). First, the amplitude of 10 Vp-
When an alternating voltage of p was applied and an alternating voltage of the same frequency and the same phase and the same phase was applied to the B phase, the primary resonant longitudinal vibration as shown in FIG. 2a could be excited. Next, an alternating voltage having an amplitude of 10 Vp-p with a frequency Fr is applied to the A phase, and the same frequency is applied to the B phase.
When an alternating voltage of the same amplitude and opposite phase was applied, a secondary resonant bending vibration as shown in FIG. 2b could be excited. Next, when an alternating voltage having a frequency Fr and an amplitude of 10 Vp-p is applied to the A phase, and an alternating voltage having the same frequency and the same amplitude and a phase difference of ± 90 degrees is applied to the B phase, the position of the driver 15 in FIG. The ultrasonic elliptical vibration was excited.

Next, an ultrasonic linear motor using the ultrasonic vibrator 10 will be described. As shown in FIG. 3, the ultrasonic transducer 10 has two holding plates 2 at the pins 16 thereof.
It is held from both sides by 1. A hole having substantially the same diameter as the pin 16 is formed in the holding plate 21, and the hole and the pin 16 are engaged with each other. By holding in this way, the ultrasonic transducer 10 has a degree of freedom only with respect to the rotation around the pin 16. The holding plate 21 is fixed to the holding plate fixing member 22 with screws 23. A linear bush 24 is held by the holding plate fixing member 22. The linear bush 24 moves linearly along the shaft 25.

The shaft 25 is fixed to a shaft fixing member 26, and the shaft fixing member 26 is fixed to a base 27 with screws.
The shaft fixing member 26 has a tap at substantially the center thereof, and a pressing screw 28 is screwed therein. A spring 29 is inserted between the pressing screw 28 and the holding plate fixing member 22. The base 27 has a fixed portion 30 for the cross roller guide.
Are fixed by screws 31. A sliding member holding portion 33 is fixed to the moving portion 32 of the cross roller guide by screws (not shown), and zirconia ceramics is bonded to the sliding member holding portion 33 as a sliding member 34. With such a configuration, the pressing force on the sliding member 34 (driven member) of the ultrasonic transducer 10 can be adjusted by adjusting the pressing screw 28.

Next, the operation of the ultrasonic linear motor of this embodiment will be described. As described above, the frequency Fr (53 kHz to 56 kHz) is applied to the A phase and the B phase of the ultrasonic transducer 10.
alternating frequency), amplitude 10Vp-p, and phase difference +90 degrees or -90 degrees. Then, the driven part is driven rightward or leftward. As described above, the ultrasonic transducer 10 having the H dimension shown in FIG. 1 changed was prototyped and the motor characteristics were evaluated. The results are shown in Table 1.

[0027]

[Table 1]

In Table 1, the motors marked with "○" mean that they worked, and those marked with "X" did not work.
Or, it operates but has almost no speed and thrust. The mark Δ indicates that it works but is very unstable. The driving frequency was higher than the bending vibration resonance frequency and lower than the longitudinal vibration resonance frequency. From this result,
It was clarified that stable operation cannot be achieved unless the bending vibration resonance frequency is lower than the longitudinal vibration resonance frequency.

Based on the above experimental results, the following experiments were conducted to find out the cause. As shown in FIG. 4, two piezoelectric elements 102, which are polarized in the thickness direction, are bonded to the front and back as vibration detection elements below the basic elastic body 101 of the ultrasonic transducer 100. This piezoelectric element 102 has a width of 1 in FIG.
It is 0 mm, height 3 mm, and thickness 0.3 mm. The bonding position is directly above the driver element 103. Arranged on the front (front) surface of the basic elastic body 101 so that their polarization directions are the same, and connected in series to form an F1 terminal. On the back surface of the basic elastic body 101, the polarization direction is set. Are arranged in the opposite direction and connected in series to form an F2 terminal. As can be seen from the vibration mode diagram of FIG. 2, the F1 terminal is the basic elastic body 101.
It is possible to detect only the vertical vibration near the driver element 103. Further, the F2 terminal is the driver 103 of the basic elastic body 101.
Only bending vibrations in the vicinity can be detected.

Now, the prototype No. Regarding the ultrasonic transducers 100 of 0 to 9, the state of vibration when a voltage is applied is shown in F1 above.
Longitudinal vibration and bending vibration were simultaneously detected by the terminal and F2 terminal, respectively. The result is shown in FIG. In this figure, there is a driven body on the upper side, which is driven to the left and right of the figure. Further, positive and negative represent driving in the positive direction and driving in the negative direction.

FIG. 5 shows the prototype No. 0 ultrasonic transducer 100
It is a schematic form of the vibration shape of, and is almost a linear reciprocating vibration.
In this case, it does not work, or it works but has almost no speed and thrust.

FIG. 6 shows the prototype No. 1 to No. 5 is an elliptical schematic shape of the ultrasonic transducer 100 of FIG. In this case, the operation is good and stable. In particular, the phase difference between longitudinal vibration and bending vibration is + π / 8 to + 3π / 8, 9π / 8 to 11π.
The maximum thrust and speed were obtained when the elliptical vibration was in the range of / 8.

FIG. 7 shows the prototype No. 6 ultrasonic transducer 100
Is a schematic shape of an elliptical shape. From this, if one of the principal axes of the ellipse is parallel to the driven direction of the driven body,
It turned out to be unstable. FIG. 8 shows the prototype No.
7 to No. 9 is an elliptical schematic shape of the ultrasonic transducer 100 of FIG. Also in this case, it does not work, or it works but has almost no speed and thrust.

From the above results, it has been clarified that with respect to the elliptical shape, the motor cannot operate stably unless the ultrasonic vibrator has the shape as shown in FIG. That is, a vector in the long axis direction of the ultrasonic elliptical vibration excited in the vicinity of the driver of the basic elastic body, which is a vector in the direction toward the driven body, and a tangential direction of the ultrasonic elliptical vibration. The ultrasonic motor does not operate stably unless the ultrasonic elliptical vibration is formed such that the angle formed by the velocity vector, which is a velocity vector and has only components in the direction and direction in which the driven body is driven, becomes an acute angle. is there.

More specifically, the first vibration mode of the two vibration modes is vibration in the driving direction of the driven body near the driver of the elastic body, and the driving direction of the driven body is changed. The positive vibration is excited, and the second vibration mode of the two vibration modes is the vibration in the direction perpendicular to the driven direction of the driven body in the vicinity of the driver of the elastic body and the direction toward the driven body. The difference between the phase of the vibration of the first vibration mode and the phase of the vibration of the second vibration mode δ
θ is 0 <δθ <+ π / 2 (when driven in the forward direction), or +
It is necessary to drive as π <δθ <+ 3π / 2 (during negative drive).

Next, the trial manufacture No. in the table is shown. For the ultrasonic transducers 100 of 0 to 9, the relationship between the amplitude and the phase of each vibration mode with respect to the applied voltage was examined by sweeping the frequency. The result is shown in Fig. 9. fl is the resonance frequency of longitudinal vibration, and fb is the resonance frequency of bending vibration. The prototype No. of the ultrasonic transducer 100 prototype. In the case of the ultrasonic transducer of 0, the one corresponding to the vibration mode 1 is the longitudinal vibration mode, and the one corresponding to the vibration mode 2 is the bending vibration.
The phase difference between fl and fb was π / 2. Prototype N
o. 1 to No. In the case of the ultrasonic transducer of No. 5, the one corresponding to the vibration mode 1 is the longitudinal vibration mode, and the one corresponding to the vibration mode 2 is the bending vibration. The phase difference between fl and fb was more than 0 and less than π / 2.

Prototype No. In the case of the ultrasonic transducer No. 6, the one corresponding to the vibration mode 1 is the longitudinal vibration mode, and the one corresponding to the vibration mode 2 is the bending vibration, but these curves are almost the same. Therefore, both fl and fb were in agreement, and the phase difference was 0. Prototype No. 7 to N
o. In the case of the ultrasonic transducer of No. 9, the one corresponding to the vibration mode 1 is the bending vibration mode, and the one corresponding to the vibration mode 2 is the longitudinal vibration. The phase difference between fl and fb was 0 or more.

From the above experimental results, the first vibration mode of the two vibration modes is the vibration in the driving direction of the driven body near the driver of the elastic body, and the driving direction of the driven body. The second vibration mode of the two vibration modes is the vibration in the direction perpendicular to the driven direction of the driven body, which is toward the driven body, in the vicinity of the driver of the elastic body. In the frequency range in which the resonance frequency of the first vibration mode is equal to or higher than the resonance frequency of the second vibration mode, the phase difference δα of the vibration with respect to the alternating voltage of the first vibration mode The phase difference δβ of the vibration with respect to the alternating voltage in the second vibration mode is composed of an ultrasonic vibrator formed so that 0 <(δα−δβ) <+ π / 2, and the phase difference is applied to two or more electromechanical transducers. , ± π / 2 different alternating voltage is applied, and the first vibration By being driven by a second frequency above the resonance frequency of the vibration mode in the following resonant frequencies over de, it is possible to perform stable operation.

In the present embodiment, the example of obtaining the ultrasonic elliptical vibration by synthesizing the longitudinal vibration and the bending vibration has been described, but other examples such as torsional vibration, sliding vibration, respiration vibration, and spreading vibration are obtained. The same is true when combined. Further, in the present embodiment, the application is described only for the linear type ultrasonic motor, but if the moving body is a rotating body using the ultrasonic transducer of the present invention, the application is also applied to the rotating type ultrasonic motor. It is possible.

[0041]

The effects common to claims 1, 2 and 3 are that it is possible to obtain an ultrasonic motor driving device which has a large thrust and speed and operates stably. Claim 2,
The common effect of 3 is that the parallel vibration and the orthogonal vibration are combined with respect to the driven body, so that the phase condition to be satisfied by both vibrations is simplified. The effect peculiar to claim 3 is that the setting of the resonance frequency is clarified, the phase delay condition of the vibration that the ultrasonic transducer should satisfy is clarified, and the driving frequency is clarified.

[Brief description of drawings]

FIG. 1 is a perspective view of an ultrasonic transducer showing an embodiment.

FIG. 2A and FIG. 2B are explanatory diagrams of the operation of the ultrasonic transducer according to the embodiment.

FIG. 3 is a front view of an ultrasonic linear motor showing an embodiment.

4A to 4C show driver elements of the embodiment, a is a front view,
b is a rear view and c is a side view.

FIG. 5 is an explanatory diagram of the operation of the ultrasonic transducer according to the embodiment.

FIG. 6 is an explanatory view of the action of the ultrasonic transducer showing the embodiment.

FIG. 7 is an explanatory diagram of the operation of the ultrasonic transducer according to the embodiment.

FIG. 8 is an explanatory diagram of the operation of the ultrasonic transducer according to the embodiment.

FIG. 9 is a graph showing an example.

FIG. 10 is a perspective view of an ultrasonic transducer showing a conventional example.

FIG. 11 is a front view of an ultrasonic linear motor showing a conventional example.

[Explanation of symbols]

 10 Ultrasonic Transducer 11 Basic Elastic Body 12 Laminated Piezoelectric Element 13 Retaining Elastic Member 15 Driver 16 Pin 21 Holding Plate 22 Holding Plate Fixing Member 24 Linear Bushing 25 Shaft 26 Shaft Fixing Member 27 Base 28 Press Screw 29 Spring 30 Fixing Part 32 Moving part 33 Sliding member holding part 34 Sliding member

Claims (3)

[Claims] 1. An ultrasonic transducer which is composed of at least two electromechanical conversion elements, an elastic body and a driver element, and which is driven by a driver element and an ultrasonic transducer for synthesizing two vibration modes to generate an ultrasonic inertia circular vibration. In the ultrasonic motor drive device having a driven body to be driven and a power supply means for applying an alternating voltage to the electromechanical conversion element, a vector in the long axis direction of the ultrasonic elliptical vibration excited near the driver of the elastic body. And a velocity vector in the direction approaching the driven body, and a velocity vector in the tangential direction of the ultrasonic elliptical vibration, which has a component only in the direction and direction in which the driven body is driven. The ultrasonic motor drive device is characterized in that it is driven by ultrasonic elliptical vibrations formed so that the angle formed by the angle becomes an acute angle. 2. An ultrasonic transducer that is composed of at least two electromechanical conversion elements, an elastic body, and a driver, and that is driven by a driver and an ultrasonic transducer that synthesizes two vibration modes to generate ultrasonic elliptical vibration. In the ultrasonic motor drive device having a driven body and a power supply means for applying an alternating voltage to the electromechanical conversion element, the first vibration mode of the two vibration modes is in the vicinity of the driver of the elastic body. Exciting vibration in the driven direction of the driven body and positive in the driven direction of the driven body, the second vibration mode of the two vibration modes is in the vicinity of the driver of the elastic body, Excitation of the vibration in the direction perpendicular to the driven direction of the driven body and positive in the direction toward the driven body, of the phase of the vibration of the second vibration mode with respect to the phase of the vibration of the first vibration mode The difference δθ is 0 <δθ <+ π / 2, or It is + π <δθ <+ 3π / 2 driven that the ultrasonic elliptical vibration formed as a ultrasonic motor driving apparatus according to claim. 3. An ultrasonic transducer which is composed of at least two electromechanical conversion elements, an elastic body and a driver, and which is driven by a driver and an ultrasonic transducer that synthesizes two vibration modes to generate ultrasonic elliptical vibration. In the ultrasonic motor drive device having a driven body and a power supply means for applying an alternating voltage to the electromechanical conversion element, the first vibration mode of the two vibration modes is in the vicinity of the driver of the elastic body. Exciting vibration in the driven direction of the driven body and positive in the driven direction of the driven body, the second vibration mode of the two vibration modes is in the vicinity of the driver of the elastic body, Excites vibration in a direction perpendicular to the driven direction of the driven body and positive in the direction toward the driven body, and sets the resonance frequency of the first vibration mode higher than the resonance frequency of the second vibration mode. Is
In the frequency range below the resonance frequency of the first vibration mode and above the resonance frequency of the second vibration mode, the phase difference δα of the vibration with respect to the alternating voltage of the first vibration mode and the vibration with respect to the alternating voltage of the second vibration mode The phase difference δβ is 0 <(δα−δβ) <+ π / 2, and the two or more electromechanical transducers are provided with alternating voltages different in phase by ± π / 2. An ultrasonic motor driving device, wherein the ultrasonic motor driving device is applied and driven at a frequency equal to or lower than a resonance frequency of a first vibration mode and equal to or higher than a resonance frequency of a second vibration mode.