JPH072028B2 - Ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an ultrasonic motor using a stretchable laminated piezoelectric element as a drive source.

[Conventional technology]

FIG. 11 shows an example of a conventional ultrasonic motor using a laminated piezoelectric element.

FIG. 11 is a perspective view showing an example of a conventional ultrasonic motor, in which a vibration plate 19 is fixed to the upper portion of a ring-shaped piezoelectric body 18, and these are attached to a case 15. Also the diaphragm
The disc surface of 19 is made to face, the disc surface of the rotating disc 17 is brought into close contact, and the disc spring 20 is pressed from the side surface of the rotating disc 17 so that this face is strongly pressed. 16 etc. are integrally attached to the shaft 13 so that it can rotate,
The electric wire 14 is connected to 18 to integrally construct an ultrasonic motor.

In the ultrasonic motor configured as described above, when the DC power is supplied in a pulsed manner from the electric wire 14, the piezoelectric body 18 is divided into a plurality of circular rings, and the polar operations are alternately adjacent to each other. , Individual ring-shaped element parts expand and contract in the thickness direction. Since the diaphragm 19 is fixed to this surface, it is displaced integrally, and since the frequency of expansion and contraction is equal to the natural frequency of the circular ring portion of the diaphragm 19, the expansion and contraction vibration is amplified and vibrates. The surface of plate 19 vibrates laterally, that is, rotating disk 17
Due to the vibration in the rotation direction, the waves wavyly displace in the thickness direction, and the waves sequentially propagate and rotate on the plate surface of the circular ring in response to the application of the power source.

Since the rotating disc 17 is pressed against this surface, it rotates in the direction opposite to the traveling direction of the wave due to the frictional action of this pressing portion, that is, the reaction of the rotating disc 17 against the lateral vibration action of the diaphragm 19. The disc 17 rotates.

[Problems to be solved by the invention]

However, in the above-mentioned configuration, the velocity of the surface wave of the diaphragm 19 moves to a constant velocity in the width direction (indicated by W in the figure) with respect to the tangent line of the circular ring. Therefore, the displacement angle θ with respect to the axis 13,
The relationship of S = Rθ is required between the radius of gyration R and the moving distance S of the wave. However, unless the width W of the diaphragm 19 is a line, the radius of gyration R is the difference of the width W in the upper and lower limits. Therefore, if the movement of the wave is constant, the displacement angle θ always has different values, and as long as the diaphragm 19 is a rigid body, movements with different displacement angles θ are not allowed, and there is a slip on the width W. The rotating disc 17 will move.

As a result, even if the rotational torque cannot be effectively obtained or the force on the piezoelectric body 18 side is increased, the rotating disc that receives it can receive it.
If the width W ₀ on the 17 side is increased, as described above, slips increase and heat is generated, so that the width W ₀ must be reduced. Of course, even if the friction area is small, increasing the pressing force will increase the friction force, but if the surface pressure increases, the friction amount of the plate surface material will increase, so it will not be used in practice and as a result only a small capacity will be obtained. Moreover, the efficiency becomes poor. Further, if the radius is increased, the torque is increased. However, if the current technology is increased, the torque cannot be increased so much due to problems such as accuracy and stability. That is, as a result, only a small capacity is manufactured,
It's a big problem.

As a general traveling wave type currently marketed,
Most of them are extremely small with a capacity of 4 W and a torque T of 4 kg-cm.

The present invention has been made in view of the above points, and an object thereof is to propose an ultrasonic motor of high efficiency and large capacity.

[Means for Solving Problems] In other words, the means for achieving the purpose are a. In the ultrasonic motor using the expanding and contracting laminated piezoelectric element as a drive source according to claim 1, a drive block is integrally formed by fixing a drive body that propagates a wave to a tip of a movable portion of the piezoelectric element, A rotary drum that is axially supported by a bearing or the like is provided at this tip, and the tip of the drive body is formed in an arc shape or a horizontal plane along the circumference of the rotary drum, and the required circumferential length of this arc shape is provided. Alternatively, a surface cut off at an angle of 45 degrees is formed leaving a horizontal length, and the cut-off portion is the right side for left rotation and the left side for right rotation, and the width of the driving body is the width of the piezoelectric element. The width of the drive block is equal to that of the rotary drum, and the gap between the tip of the driving body and the rotary drum is set to a required distance δ, and the driving blocks are arranged in plural, and a pulsed voltage is applied to each piezoelectric element. The one that obtains the required rotational force A.

B. In Claim 2, the tip of the drive body is a horizontal plane, and is cut off at an angle of 45 degrees leaving a required length in the same direction as in Claim 1, and the cut-off tip surface is horizontal or It is formed in an arc shape along the circumference of the rotary drum, and the cut-off portion is arranged on the circumference side of the rotary drum.

C. According to a third aspect of the present invention, the drive body surface on the side facing the 45-degree inclined surface of the drive body according to the second aspect is arranged on the circumferential side of the rotary drum.

D. 5. The weight according to claim 4, wherein a weight is attached to a fixed portion of the rear end of the piezoelectric element of the drive block, the weight is supported by a leaf spring, and the position of the leaf spring is set substantially relative to the outer peripheral surface of the rotary drum. The tangential direction, the spring force of the leaf spring is in the same direction as the movable direction of the driving body, and the required force is applied so that the driving body always presses the outer diameter surface of the rotating drum statically. Further, a stopper is provided to prevent the weight from moving beyond a predetermined distance except in the pressing direction of the leaf spring, and these are integrally constructed.

E. According to claim 5, a hole of any shape such as a circle, a square, a triangle, a rhombus, or an ellipse is bored in the vicinity of the tip of the drive body according to claim 1 in the same direction as the axial direction of the rotary drum. It is provided so that the wave from the piezoelectric element can concentrate the stress at this hole portion, and the displacement amount due to the wave is amplified by this effect.

F. In Claim 6, the end portion on the opposite side of the inclined surface obtained by cutting off the front end portion of the driving body according to Claim 1 at 45 degrees is outside the substantially same position as the width side end portion of the piezoelectric element. A bulge that is cut off at 45 degrees facing the inclined surface is provided, and the bulge is further extended to the piezoelectric element side, and this extended portion has the wave propagation system path from the piezoelectric element at the side end of the driver. The wave from the piezoelectric element is made to be a circle by forming an inclined surface that is cut off at an angle so that it can be reflected at a portion and can be incident on the substantially central portion of the circumferential surface opposite to the rotary drum.

G. In claim 7, the shape of the driving body according to claim 1 is cut into a hook shape, that is, a taper oblique shape from the root of the piezoelectric element in the movable direction toward the tip, and the narrowed position From the angled straight line of the bottom cut off at 45 degrees (in the direction opposite to the 45-degree cut), the required amount of deviation was made, and from here, the areas facing along the circumferential surface of the rotary drum were made continuous. It is formed integrally and the displacement amount due to the wave motion from the piezoelectric element is amplified by the oblique portion.

J. In Claim 8, the front end portion of the driving body according to Claim 1 is a horizontal plane,
It is equipped with a horizontal shaft that can be moved horizontally with bearings facing this surface, and drive blocks are arranged vertically so that multiple horizontal movements can be made with a required gap between this horizontal shaft and the horizontal plane of the driver. However, the horizontal axis can be linearly driven to the left and right, and the first, second, fifth, sixth, or seventh claims are described.

[Action]

The operation will be described in detail in the embodiments described below.

An embodiment of the ultrasonic motor of the present invention will be described below for each claim with reference to the drawings.

〔Example〕

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, and FIG. 2 is a side sectional view of FIG.

1) In the ultrasonic motor using the expandable and contractable laminated piezoelectric element 1 as a drive source, a driving body 2 for propagating a wave is integrally fixed to a tip of a movable portion of the piezoelectric element 1 for driving. A block drum is obtained, and a rotary drum 3 pivotally supported by a bearing 4 or the like is provided at the tip of the block. The tip of the driving body 2 is formed along the circumference of the rotary drum 3 in an arc shape or a horizontal plane shape. A surface (hereinafter also referred to as an inclined surface) 2a is formed by cutting off at an angle of 45 degrees, leaving the required arcuate circumferential length or horizontal length, and the cut-off portion is the right side for left rotation and the right rotation. The width of the driving body 2 is equal to the width of the piezoelectric element 1, the distance between the tip of the driving body 2 and the rotary drum 3 has a required distance δ, and the driving block is , B are symmetrically arranged for left rotation and right rotation, and It is obtained so as to obtain a required rotational force brought applying a pulse voltage E to conductive elements 1.

Next, the operation will be described with reference to FIG.

When the pulsed high-frequency voltage E is applied to the left driving block B to the piezoelectric element 1, the piezoelectric element 1 is extended and displaced in the vertical direction. This displacement movement is transmitted to the driving body 2, and at the same time as the movement thereof, its force becomes waves Y, Y '(hereinafter referred to as longitudinal waves) and is transmitted in a certain direction of the rotary drum. When the longitudinal wave Y included in the 45 ° inclined surface of the driving body 2 hits the cut surface 2a, that is, the inclined surface 2a, the acoustic impedance of the medium in contact with this surface, that is, the product of the density ρ and the wave propagation velocity C When σC is extremely different, for example, since aluminum was used for the driver 2 in the experiment, the density ρ = 2.7 g / cm ³ , the wave propagation velocity C = about 4000 m / s, and the air ρ = 1.3 × 10 ^{− 3} g / cm ³ , C
= 340 m / s, there is a large difference, so the existence of the medium is ignored, and if the surface is smooth, almost 100% is reflected at point C. The angle of reflection in this case is treated exactly like light,
At point C, which is a reflection of degrees, the wave propagates in the horizontal direction at a right angle to the incident angle and becomes a transverse wave Y _x , which travels leftward. In addition, driver 2
A surface wave (generally Ray-Ray wave) B is generated on the side surface of
It merges with the transverse wave Y _x to raise the potential and propagate waves.
At the same time, it is combined with the longitudinal wave Y ′ transmitted from the driving body 2 other than the 45 ° plane.

That is, the longitudinal and transverse wave velocities V _x and V _y are combined, and the driving body 2
The elliptic movement X in the clockwise direction of the minute movement with the Z plane as the apex is obtained inside the. At this time, the displacement of the piezoelectric element 1 is caused by the driving body 2
The tip surface (hereinafter also simply referred to as the surface) Z of is lowered downward, and the outer diameter surface of the rotary drum 3 is pressed with displacement ε ₀ . A frictional force is generated according to this pressing force, and the outer diameter surface of the rotary drum 3 is moved leftward by the elliptic motion. Then, at the next moment, the power source is a pulse voltage E, so when the power source is turned off, the piezoelectric element 1 contracts upward, the surface Z of the driving body 2 is moved upward, and the rotary drum 3 and the driving body 2 are initially moved. Make a gap up to the interval δ of. At this time, the small displacement due to the wave motion is
Since the wave breaks, it returns to the original position according to the density and elastic modulus of the material of the driving body 2. By repeating this,
The rotary drum 3 continuously rotates to the left. Generally, the cycle of this high frequency power supply is 20KHz ~ 100KHz, but in the experiment, it was driven at about 80KHz and good rotation drive was obtained.

2) Claim 2 is different from Claim 1 in that, as shown in FIG. 3, the surface 2a obtained by cutting off the driving body 2 at an angle of 45 degrees is arranged on the circumferential side of the rotary drum 3. Especially. And this cut off surface
2a has a horizontal plane or the above-mentioned arc shape. Therefore, the tip of the driving body 2 is formed horizontally.

The operation of the driving body 2 arranged in this way is almost the same as the operation described in claim 1, and the displacement of the piezoelectric element 1 causes the driving body 2 to be displaced downward ε _3. The outer diameter surface of the rotating drum 3 is pressed to generate a frictional force and drive the rotation.

3) In claim 3, the present invention also uses the same drive blocks a and b as in claim 1, and the 45 ° inclined surface of the driver 2, that is, the driver surface on the side facing the cut surface 2a is It is arranged on the circumferential side of the rotary drum 3.

In the drive block thus arranged, the expansion displacement of the piezoelectric element 1 becomes a transverse wave Y _x reflected on the inclined surface of 45 degrees and a longitudinal wave Y ′ other than that, which is applied to the surface P opposite to the inclined surface. The transverse wave Y _x and the longitudinal wave Y'of are combined to obtain an elliptic motion with a slight movement, whereby the rotary drum 3 is rotated by the displacement ε ₄ .

4) In claim 4, the present invention is to fix what is obtained in claim 1 to the following.

In other words, the weight bar 8 is attached to the fixed portion of the rear end of the piezoelectric element of the drive blocks B and B shown in FIG. 1, and the weight 8 is supported by the plate spring 9, and the position of the plate spring 9 is set to the rotary drum 3. Is substantially tangential to the outer peripheral surface of the rotary drum 3 so that the spring force of the leaf spring 9 is in the same direction as the moving direction of the driving body 2 and a required force is applied to statically keep the outer diameter of the rotary drum 3 constant. A stopper that allows the surface Z of the driving body to be pressed against the surface and prevents the weight bar 8 from moving more than the required distance except in the pressing direction of the leaf spring 9.
11 is provided and these are integrated.

Thus, in the drive block fixed in such a state, the displacement amount of the piezoelectric element 1 is a few + micron, which is extremely small, so that the eccentricity of the rotary drum 3 and the wear of the surface Z of the drive body 2 abutting on the rotary drum 3 are caused. As a result, the mechanical relative condition becomes extremely unstable. That is, the interval δ shown in FIG.
Becomes larger, the displacement ε ₀ does not press the surface Z, and becomes smaller if it becomes too small, the micro elliptical motion is impaired and the displacement is stopped. Therefore, by constantly pressing the surface Z by the leaf spring 9 with a constant required force, the drive blocks a and b are made to follow only the fluctuation of the outer diameter surface of the rotary drum 3, and the leaf spring 9 is arranged in the tangential direction. Even if it receives a driving reaction force of the vertical surface Z, no rotational moment is generated, it acts on the action other than the vertical direction, and the rotational speed of the rotary drum 3 is generally extremely slow at 50 to 1000 rpm, so that its fluctuating acceleration is small. On the other hand, the elongation displacement of the piezoelectric element 1 is tens of thousands of Hz, which is extremely fast, and the stress of the leaf spring 9 does not hinder the movement of the piezoelectric element 1 when returning, and the moment when the piezoelectric element 1 is displaced. The reaction force is received by the inertial mass of the weight 8 and maintains a mechanical balance.

As a result, even if there is eccentricity or wear, the surface Z of the driving body 2 can be stably driven.

5) In claim 5, the rotary drum 3 is provided in the vicinity of the front end portion of the driving body 2 of claim 1.
A circular hole 7b is formed in the same direction as the axial direction of the piezoelectric element 1
This is the driving body 7 that allows the further wave to concentrate the stress in the hole 7b portion and to amplify the displacement amount due to the wave by this effect. The number of holes is not limited to one, and there are various kinds of hole diameters.

In such a driving block, the waves of the longitudinal wave Y ′ and the transverse wave Y _x of the driving body 7 are remarkably amplified by the stress concentration effect, and the elliptical movement of the minute movement is amplified, resulting in a strong and fast rotating drive. To be According to the experimental results, by providing a round hole of 2 mm with a thickness of about 0.8 mm left from the surface Z ′ of the driving body 7 opposite to the rotary drum 3, the concentrated expansion rate is four times, which is about 2 times as compared with the case without the hole. 〜3 times more power up.

6) In claim 6, the end opposite to the inclined surface 5a obtained by cutting off the tip of the driving body 5 similar to claim 1 at 45 degrees is referred to as the width side end of the piezoelectric element 1. Protruding part 5b cut off at 45 degrees by facing the inclined surface outward from approximately the same position is provided, and this protruding part 5b is further extended to the piezoelectric element side. The piezoelectric element 1 is provided with an inclined surface 5c that is cut off at an angle so that it can be reflected by the side end portion of the driving body 5 thus obtained and can be incident on the substantially central portion of the circumferential surface opposite to the rotary drum. It is made to make the wave motion of the circle.

In such a driving block, the driving body 2 shown in FIG.
The longitudinal wave Y ′ and the transverse wave Y _x of the rotary drum 3 transmit the minute movement to the rotational drive on the outer diameter surface of the rotary drum 3, but the energy conversion is performed only on the surface Z of the driving body 2. Therefore, this surface Z
The wave motion inside the driving body 2 on the inner side heats its own movement and becomes a moving fingertip.

Therefore, in the driving body 5 of the present invention, in order to effectively use the wave that does not contribute to the direct drive by making a circle, the reflected wave of the inclined surface 5a of 45 degrees is used as the convex surface facing the inclined surface 5a.
It is received by the inclined surface 5d of 5b, and is reflected upwards here, and the inclined surface 5c
Advance to. Of course, since this portion is raised outside the width-side end of the piezoelectric element 1, it is arranged so as not to be confused with the longitudinal wave Y'from the piezoelectric element 1. next,
The wave reflected on the inclined surface 5c hits the side end D of the driving body 5, is reflected there, and further advances to approximately the center of the surface Z ″ facing the rotating drum 3. The longitudinal waves Y ', Y are strengthened downward by this amount. If the friction coefficient of the surface Z ″ is μ, then the downward wave Y ′ is not strong enough by this μ, so it cannot be driven in proportion to the transverse wave Y _x . , The wave enhancement of the longitudinal wave Y ′ is extremely effective, and the rotating drum 3 rotates with the displacement ε ₁ .

7) In claim 7, the shape of the driving body 2 according to claim 1 is changed to a key shape,
In other words, from the movable direction of the piezoelectric element 1 to a taper slanted shape 6a toward the tip, cut the tapering position 6b to 45 degrees from the bottom straight line of the angular position (in the direction opposite to the 45 degree cut) The portion 6c is deviated by a required amount, and the portion 6c facing the circumferential surface of the rotary drum 3 is continuously formed integrally from here, so that the displacement amount due to the wave from the piezoelectric element 1 is amplified by the oblique portion. It was done.

Thus, in the drive block configured in this way,
In contrast to the longitudinal wave Y of the driving body 2 shown in FIG. 1, in the driving body 6 of the present invention, since the slanting shape 6a is narrowed toward the root, the cross-sectional area of this root and the cross-sectional area of the tapered tip are shown. The longitudinal waves Y and Y ′ are amplified and strengthened by the ratio of, and the longitudinal wave Y is incident on the reflection surface of 45 degrees and moves at a right angle to become a transverse wave Y _x . Further, on the lower surface of the left end portion of the bottom end of the 45-degree inclined surface, the surface Z facing the rotary drum 3, the amplified longitudinal wave Y ′ and the transverse wave Y _x are combined, and a strong slight movement is generated. An elliptical wave is obtained.

8) In claim 8, the tip end portion of the driving body 2 according to claim 1 is a horizontal plane, and a horizontal shaft 12 that is opposed to this surface and can be horizontally moved by a bearing or the like is provided. The horizontal shaft 12 can be linearly driven by disposing a drive block that can be horizontally moved in a plurality with a required gap δ between the horizontal planes of the upper and lower driving bodies 2, 2.

Here, in the drive block thus arranged, when the horizontal axis 12 is moved to the left or right, a pulse is input to the piezoelectric element 1 by the left power source or the right power source. As a result, the surface Z'of the tip portion of the drive body 2 shown in FIG.
The horizontal shaft 12 is moved in a predetermined direction.

〔The invention's effect〕

As described above, according to the present invention, the ultrasonic motor according to claims 1 to 7 has no sliding frictional motion due to the radius difference due to the width W of the driving friction surface unlike the conventional case, and the rotary drum is Since a force is applied to the circumferential surface of No. 3 like a plane, the driving efficiency is high and a long service life is obtained. Further, by increasing the diameter and length of the rotary drum 3 and correspondingly increasing the number of blocks of the driving bodies 2, 5, 6, 7, it is possible to easily and reasonably manufacture a large capacity. That is, the conventional one had a practical limit of about 4 W at the most, but the present invention allows a practically large capacity. Further, in the conventional example, since the thrust force is applied to the rotating disc 17 by the disc spring 20 to obtain the frictional force, this force is applied to the bearing and the shaft 13, which is disadvantageous in terms of life and strength. However, in the present invention, the blocks of the driving bodies 2, 5, 6, 7 are arranged symmetrically so as to cancel each other out as the internal force of the rotary drum 3, so this kind of addition to the bearing and shaft is not necessary. Extremely economical long service life.

Further, in claims 5 and 7, the efficiency is remarkably improved by a simple method such as making holes in the shape of the driving bodies 6 and 7 or making it oblique, and for example, in our experiment, it is 2-3 times as much. It is effective because it can increase the capacity.

Further, in claim 6, the wave propagation is circled by a simple method in which the convex shape facing the 45 ° surface is added to the shape of the driving body 5, and the longitudinal wave Y ′ is enhanced to obtain extremely high efficiency. .

According to the fourth aspect, even if the rotating drum 3 is eccentric or the pressing surface Z is worn, the driving bodies 2, 5, 6, 7 are tracked according to the surface position fluctuation.
Provides a certain mechanical requirement for the rotating drum 3 and is extremely effective for practical use. In addition, the driver 2,5,6,
The distance δ between the 7 and the rotary drum 3 becomes zero, and in addition, the force is transmitted by the minute movement due to the wave motion inside the driving bodies 2, 5, 6, 7, so that there was no noise in the experiment.

Furthermore, in claim 8, a linear drive instead of the rotary drive can be obtained by a simple means of arranging on the horizontal shaft 12 instead of the rotary drum 3, and in recent years, a drive source which requires ultra-precision positioning. If it is used for, the power of submicron can be obtained by turning the power supply on and off once, and this can be continuously moved at high frequency, so high precision positioning can be easily obtained by digital command.

Therefore, the ultrasonic motor of the present invention has high capacity and high efficiency, and has the same capacity with a very small moment of inertia as compared with the conventional electric motor. Moreover, the static brake can be applied and the sub-micro drive setting can be easily achieved. It is a useful item that is practically used for a wide variety of equipment and robots.

[Brief description of drawings]

FIG. 1 is a conceptual front view of an essential part showing an embodiment of the structure of the ultrasonic motor of the present invention according to claim 1, FIG. 2 is a side view conceptual view of FIG. 1, and FIG. 2 is a front view of an essential part of claim 3, FIG. 5 is an overall configuration diagram of claim 4, and FIG. 6 is an operation explanatory view of FIG. FIG. 7 is a front view of an essential part of claim 5, FIG. 8 is a front view of an essential part of claim 6, FIG. 9 is a front view of an essential part of claim 7, and FIG. FIG. 10 is an overall configuration diagram of item 10, and FIG. 11 is a perspective view of a conventional device. 1 ... Piezoelectric element, 2,5,6,7 ... driving body, 3 ... rotating drum, 4 ... bearing, 8 ... weight, 9 ... leaf spring,
10 …… Receipt, 11 …… Stopper, 12 …… Horizontal axis, 13 ……
Axis, 14 …… electric wire, 15 …… case, 16 …… presser plate, 17 ……
Rotating disk, 18 ... Piezoelectric body, 19 ... Vibration plate, 20 ... Disc spring.

Claims (8)

[Claims] 1. In an ultrasonic motor using an expanding and contracting laminated piezoelectric element as a drive source, a drive block for integrally propagating a wave is fixed to the tip of the movable portion of the piezoelectric element to obtain a drive block, and the tip is obtained. A rotary drum that is supported by bearings and the like, and the tip of the driving body is formed in an arc shape or a horizontal plane along the circumference of the rotary drum, and the arc has a required circumferential length or horizontal. Form a surface cut off at an angle of 45 degrees leaving the length, the cut-off part is the right side for left rotation, the left side for right rotation, and the width of the driving body is the width of the piezoelectric element. Similarly, the required distance δ is provided between the tip of the driving body and the rotary drum, and a plurality of the driving blocks are arranged, and a pulsed voltage is applied to each piezoelectric element to obtain the required distance. Super characterized by trying to obtain rotational force Sonic motor. 2. A tip end portion of the drive body is a horizontal plane, and is cut off at an angle of 45 degrees leaving a required length in the same direction as in claim 1, and the cut-out tip end surface is a horizontal plane or the rotary drum. An ultrasonic motor according to claim 1, wherein the ultrasonic motor is formed in an arc shape along the circumference of the rotary drum, and the cut-off surface is arranged on the circumferential side of the rotary drum. 3. The drive body surface of the drive body according to claim 2, which is opposed to the 45-degree inclined surface, is arranged on the circumferential side of the rotary drum. Range first
Item 2. The ultrasonic motor according to item 2 or item 2. 4. A weight is attached to a fixed portion of the rear end of the piezoelectric element of the drive block, and the weight is supported by a leaf spring, and the position of the leaf spring is arranged substantially tangential to the outer peripheral surface of the rotary drum. So that the spring force of the leaf spring is in the same direction as the movable direction of the driving body, and the required force is applied so that the driving body constantly presses the outer diameter surface of the rotating drum. The ultrasonic motor according to claim 1, wherein a stopper is provided so that the weight does not move beyond a predetermined distance except in the pressing direction of the leaf spring, and these are integrally constructed. 5. A circle, a square, a triangle, in the same direction as the axial direction of the rotary drum, in the vicinity of the tip of the driving body according to claim 1.
A hole of any shape, such as a rhombus or an ellipse, is drilled so that waves from the piezoelectric element can concentrate stress at this hole.
The ultrasonic motor according to claim 1, wherein the displacement amount due to the wave is amplified by this effect. 6. The front end portion of the driving body according to claim 1
An end on the opposite side of the inclined surface cut off at 45 degrees is provided with a raised portion cut off at 45 degrees by facing the inclined surface outward from substantially the same position as the width side end of the piezoelectric element. The raised portion is extended to the piezoelectric element side, and the extended portion is reflected by the wave propagation system path from the piezoelectric element at the side end portion of the driving body and is incident on the substantially central portion of the circumferential surface opposite to the rotary drum. The ultrasonic motor according to claim 1, characterized in that the inclined surface is cut off at an angle that allows the wave to be generated from the piezoelectric element to be circled. 7. The shape of the driving body according to claim 1 is cut into a hook shape, that is, an oblique taper from the root of the piezoelectric element in the movable direction toward the tip, and the narrowed position is 45.
The part that is offset by the required amount from the straight line of the angular position of the bottom part that is cut off in the opposite direction (in the direction opposite to the 45-degree cut) is formed continuously from this part so that the facing parts along the circumferential surface of the rotating drum are continuous. The ultrasonic motor according to claim 1, wherein the displacement amount due to the wave from the piezoelectric element is amplified by the oblique portion. 8. A front end portion of the driving body according to claim 1 is formed into a horizontal plane, and a horizontal shaft which is opposed to this surface and can be horizontally moved by a bearing or the like is provided, and between the horizontal shaft and the horizontal plane of the driving body. The drive block is arranged vertically so that a plurality of movable blocks can be moved to the left and right with a required clearance, and the horizontal axis can be linearly driven to the left and right. The ultrasonic motor according to item 5, item 5, item 6, or item 7.