JP2981471B2 - Double-sided drive ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a piezoelectric element as a vibrator to form a traveling wave on the surface of a vibrating body as a stator, and the traveling wave causes a moving body as a rotor to come into contact with the vibrating body. The present invention relates to a driving ultrasonic motor.

[0002]

2. Description of the Related Art In a conventional ultrasonic motor, a piezoelectric element is bonded to one surface of a vibrating body made of a disc-shaped elastic body to form a stator disk, and the other surface is formed by a moving body forming a rotor. Contact surface. A sine wave voltage is applied to the piezoelectric element to expand and contract the piezoelectric element to form a traveling wave on the moving body contact surface of the vibrating body, and the moving body is frictionally driven by applying a preload to the moving body and pressing the moving body. The method is adopted.

In a conventional ultrasonic motor, one surface of the vibrating body is a piezoelectric element mounting surface, and the other surface is a vibrating surface (contact surface of the moving body). Therefore, the moving body can be arranged only on the vibrating surface side. As a result, there is a problem that a high torque output cannot be generated.

Therefore, moving bodies are arranged on both sides of the vibrating body,
A double-sided drive ultrasonic motor capable of generating a high torque output using a double-sided drive system has been proposed and registered as a utility model registration No. 256.
No. 0873 is known.

[0005]

An ultrasonic motor vibrates a vibrating body constituting a stator disk to resonate,
The moving body which is a rotor is moved by the vibration in the resonance state. Therefore, the vibrating body must be driven to a resonance state. By the way, any resonance vibration must go through an unstable transient vibration start state until a transition from a state without vibration to a stable resonance state occurs.

FIG. 10 is an explanatory diagram of a driving start state of a conventional one-side drive type ultrasonic motor. In the conventional one-sided driving ultrasonic motor, even if the moving body C is pressed down with a preload on one side of the vibrating body A, it is only on one side.
Therefore, when the piezoelectric element B is driven and the vibrating body A is driven, the vibrating body A is allowed to deform in the direction opposite to the surface on which the moving body C is pressed. As a result, even if the center of the vibrating body A is fixed by the shaft D or the like, the vibration can be started and the state can be shifted to the resonance state.

On the other hand, the utility model registration No. 2560873
In the double-sided drive ultrasonic motor described in
As shown in FIG. 11, an end of a vibrating body A as a driving source driven by a piezoelectric element B is sandwiched by applying a preload to a moving body C from both sides to generate a driving force.
The center of the vibrating body A is fixedly supported for transmitting torque. As a result, even if a voltage is applied to the piezoelectric element B to drive it, the vibrating body A is sandwiched by the moving body C on both sides of the vibrating body by the preload and the center part is fixed to the shaft D. There is no free site to start. Therefore, the vibrating body A has a problem that vibration is generated and it is difficult and almost impossible to shift to the resonance state.

In the above-described one-side drive ultrasonic motor, since the moving body (rotor) or the vibrating body (stator) is fixed to the shaft, when the shaft receives a load in the axial direction, the moving body (rotor) or the vibrating body is fixed between the vibrating body and the moving body. There is a problem that the working preload changes, the vibration becomes unstable, and the moving body cannot be moved in a stable manner, and there is a problem that the load in the axial direction cannot be received.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic motor which can generate a high output torque and which can be made compact even if an ultrasonic motor having a multilayer structure is formed.

[0010]

According to the present invention, there is provided a vibrating body made of a disc-shaped elastic body to which a piezoelectric element is attached, and two moving members for pressing and holding a driving force transmitting portion of the vibrating body by a preload means. An ultrasonic motor by connecting the two moving bodies and supporting the vibrating body in the vicinity of the center thereof in an axially movable and rotationally restrained manner on a shaft. In addition, the moving bodies are freely movable in the axial direction of the shaft and are connected to each other while restraining the rotation direction around the shaft, and a preload means is provided at one place to press all the moving bodies against the driving force transmitting portion of the vibrating body. It was configured to be in contact.

Further, in order to increase the output torque, a plurality of the vibrating bodies and the two moving bodies are provided as a set, and all the moving bodies are connected to each other to take out the rotational torque. Alternatively, vibrating bodies and moving bodies are alternately arranged, and each vibrating body is supported on a shaft so as to be movable in the axial direction near its center and to be restrained in the rotating direction, and each moving body is moved in the axial direction of the shaft. It is movable and restrained in the direction of rotation around the shaft and connected to each other, and the preload means is provided at one or both locations at one or both ends of the shaft, and all the moving bodies are brought into pressure contact with the driving force transmitting portion of the vibrating body. By doing so, a high rotation torque is taken out.

The supporting structure of the vibrating body to the shaft and the structure of connecting the moving body are movable in the axial direction of the shaft and are restricted in the rotating direction. It consists of. Further, the preload means is constituted by a spring.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the arrangement of front and back electrodes of a piezoelectric element 2 used in an embodiment of the present invention.
1A shows one side (front side) of the piezoelectric element 2 and FIG.
Indicates the other side (back side). This piezoelectric element 2
It has the same configuration as the piezoelectric element of a conventional ultrasonic motor driven by a two-phase sine wave. The piezoelectric element 2 is formed in a flat ring shape, and has two A-phase and B-phase electrode groups. The A-phase and B-phase electrode groups
The standing waves are arranged at a specific angle depending on the type of the standing waves to be excited (the type divided by the number of waves generated during one round of the ring-shaped piezoelectric element 2). In the example shown in FIG. 1, the A-phase and B-phase electrode groups are arranged at 1/4 of 60 degrees corresponding to one cycle of the standing wave, that is, at an interval of 15 degrees.

FIG. 1 shows one side of the piezoelectric element 2.
As shown in FIG. 3A, divided electrodes 21 having a half cycle of 30 degrees are formed by baking a conductor or the like, and the piezoelectric elements in adjacent electrode portions are polarized in opposite directions.
The two electrode groups are symmetrical, and the electrodes 21,.
Are arranged such that the directions of polarization of the piezoelectric elements 2 in the regions corresponding to are reversed. In the example shown in FIG.
One direction of polarization with respect to 1, ... is +, and the other direction is-
Then, in the A phase, the region corresponding to the adjacent electrodes 21,... Is polarized as +, −, +, −, +, and the adjacent B phase arranged symmetrically with respect to the A phase Electrode 21,
The region corresponding to ... is polarized as-, +,-, +,-. The electrodes 21 on one side (front side) of the piezoelectric element 2
.. Have the same configuration when one cycle is at an arbitrary angle. The surface on which the electrode is divided is hereinafter referred to as a front side. As shown in FIG. 1B, the other surface of the piezoelectric element 2, that is, the structure on the back side is A-phase, B-phase,
Each of the phases is composed of one pattern of common electrodes 22, 22, and is formed in one pattern at a position opposed to the portion where the front-side divided electrodes 21,.
2, 22 are insulated at intervals.

FIG. 2 is a view showing a first embodiment of a stator disk 1 for an ultrasonic motor using two piezoelectric elements 2 described above. The center of the vibrating body 3 made of a disc-shaped elastic body is cut off and formed in a flat ring shape. The inner diameter of the ring-shaped vibrating body 3 is the same as the inner diameter of the piezoelectric element 2 ( The inner diameter of the vibrating body 3 and the inner diameter of the piezoelectric element do not necessarily have to be the same, for example, the inner diameter of the vibrating body 3 may be smaller. Further, the outer diameter of the vibrating body 3 is formed larger than the outer diameter of the piezoelectric element 2, and the outer peripheral portion of the vibrating body 3 to which the piezoelectric element 2 is not adhered has a driving force transmitting portion 31 for driving the moving body. Is done. As shown in FIG. 2 (b), two piezoelectric elements 2a and 2b are concentrically arranged on the vibrating body 3 so that the vibrating body 3 is sandwiched between the back and back sides. Glued. That is, if the surface to be bonded to the vibrating body 3 is on the front side of one of the piezoelectric elements 2a, the surface of the other piezoelectric element 2b on the front side is also bonded to the vibrating body 3. Conversely,
When the back surface of one piezoelectric element 2a is bonded to the vibrating body 3, the back surface of the other piezoelectric element 2b is bonded to the vibrating body 3. When the back sides of the piezoelectric elements 2a and 2b are bonded to the vibrating body 3, each divided electrode 2 in each of the A-phase and the B-phase is used.
1,... Are connected by conducting wires so as to be conductive. As described above, the two-sided drive stator disk 1 in which the outer peripheral portion of the vibrating body 2 is exposed by bonding the two piezoelectric elements 2a and 2b to the center of the vibrating body 3 back to back is provided.

FIG. 3 is an illustration of a second embodiment of a stator disk 1 'used in the ultrasonic motor of the present invention. The second embodiment is different from the first embodiment shown in FIG. 2 in that the exposed driving force transmitting portion 31 of the vibrating body 3 is a vibrating body 3 ′ having a structure thicker than a central portion. Only the difference from the first embodiment is the same in that the piezoelectric elements 2a and 2b are bonded to the center of the vibrating body 3 'back to back.

FIG. 4 is an explanatory view of a third embodiment of the stator disk 1 "used in the ultrasonic motor of the present invention.

The third embodiment is different from the second embodiment shown in FIG. 3 in that the middle portion of the vibrating body 3 is thicker than the center of the vibrating body 3 at the driving force transmitting portion 31 except for the intermediate portion over the entire circumference. ,
The piezoelectric elements 2a, 2 are different from the second embodiment only in that a vibrating body 3 "having radial slits 32,.
The point that b is adhered to the center of the vibrator 3 ″ back to back is the same.

FIG. 5 shows a voltage applied to the piezoelectric elements 2a, 2b of the stator disks 1, 1 ', 1 "in which the piezoelectric elements 2a, 2b are bonded back to back on both surfaces of the vibrating bodies 3, 3', 3". It is a diagram showing a wiring diagram to be applied, for convenience of description,
Some have been cut. Although FIG. 5 shows a wiring diagram for the stator disk 1 'of the second embodiment, the same applies to stator disks of other embodiments.

Reference numeral 4a denotes a power source for the A phase, and reference numeral 4b denotes a power source for the B phase. Voltages having shifted phases (for example, 90 ° out of phase, and if the A phase is sinωt, the B phase is cosω).
t voltage). The vibrating body 3 ′ (3,
3 "), the vibrating body 3 '(3, 3") is supplied from the A-phase and B-phase power supplies 4a and 4b corresponding to the A-phase and B-phase electrodes of the piezoelectric elements 2a and 2b adhered to both surfaces of the central part. ) To apply a sinusoidal voltage. As a result, a total of four electrodes of the A and B phases of the piezoelectric elements 2a and 2b are combined into two electrodes as shown in FIG.

If the front sides of the piezoelectric elements 2a and 2b are bonded to the vibrating body 3 '(3, 3 "), the A-phase and B-phase split electrodes 21 on the front sides of the piezoelectric elements 2a and 2b can be used. …
Is conducted by the vibrating body 3 ′ (3, 3 ″), but when the back side is connected, as described above,
A-phase split electrodes 21,... On the front side of the piezoelectric elements 2a, 2b
Each of the B-phase split electrodes 21,... Is electrically connected by a conducting wire for each phase.

When a sine wave voltage is applied to each of the phases A and B, when the front sides of the piezoelectric elements 2a and 2b expand in the circumferential direction, the piezoelectric elements on the rear side contract and the vibrating bodies 3 '(3, 3) Since the same surface (front side or back side) of the piezoelectric elements 2a and 2b is adhered to the front and back of "), the vibrating body 3 '(3, 3") is bent in cooperation with each other. Moreover, the piezoelectric element 2
Since the polarization regions of a and 2b are opposite to each other,
Continuous bending occurs, and the continuous bending is caused by the vibrating body 3 ′.
(3, 3 ") is transmitted to the exposed driving force transmitting portion 31 of the outer peripheral portion, and the driving force transmitting portion 31 of the vibrating body 3 '(3, 3").
, Two sets of standing waves excited from the A phase and the B phase are formed. As a result of the combination of the two-phase standing waves, a traveling wave traveling in one direction is formed in the driving force transmitting portion 31 of the vibrating body 3 ′ (3, 3 ″). Are the same on the front and back of the vibrating body 3 ′ (3, 3 ″).
If the exposed outer peripheral portion of '(3, 3 ") is sandwiched between two moving bodies (rotor disks), these moving bodies will rotate in the same direction.

In the above-described embodiment of the second stator disk, the thickness of the driving force transmitting portion 31 on the exposed outer peripheral portion of the moving body 3 '(3, 3 ") is large, so that the piezoelectric elements 2a, 3' The displacement of the center of the moving body 3 'due to the expansion and contraction of the moving body 2' is enlarged on the front and back surfaces of the exposed driving force transmitting portion 31, and the moving speed of the moving body (rotor disk) can be increased.

Further, in the third stator disk configuration, the radially extending slits 32,... Are provided in the exposed driving force transmitting portion 31 having a large thickness of the moving body 3 ", so that the resonance of the stator disk 1" Frequency lowering and wear can be reduced.

FIG. 6 shows the above-described stator disk 1 (1).
FIG. 6 is a cross-sectional view of the ultrasonic motor according to the first embodiment of the present invention in which a single stator is formed.
In the first embodiment shown in FIG. 1 and the second and third embodiments described later, examples using the stator disk 1 ′ shown in FIG. 3 are shown. It is expressed as

The vibrating body 3 has spline teeth or spline tooth grooves formed on the inner peripheral surface thereof, and has spline tooth grooves or spline teeth formed on the outer peripheral surface of the shaft 44 over a region where the vibrating body 3 is engaged. The vibrating body 3 and the shaft 44 are connected by a spline structure 41, and are movable in the shaft axis direction and are restrained around the shaft axis.
4 is configured so as not to be able to rotate relative thereto.
On both sides of the vibrating body 3, flat ring-shaped moving bodies (rotor discs) 40 are arranged. The outer periphery of the moving body (rotor disk) 40 is formed with spline teeth or spline teeth grooves.
Are connected by a spline structure 42 by spline tooth grooves or spline teeth provided on the inner peripheral surface of the rotor case 45 surrounding the rotor case 45. This moving body (rotor disk)
The moving body 40 is movable with respect to the rotor case 45 in the shaft axis direction and is restrained around the shaft axis, and is connected to the rotor case 45 by a spline structure 42. Are configured so that relative rotation is not possible.

The inner end face of the rotor case 45 and the moving body 40
Spring 43 as a preload means is respectively provided between
The moving body 40 is pressed against the driving force transmitting portion 31 of the vibrating body 3. The moving body 40 is in pressure contact with the vibrating body 3 only at the driving force transmitting portion 31. The rotor case 45 is rotatably mounted on a shaft 44 by a bearing 46.

Therefore, a voltage is applied to the A-phase electrodes of the piezoelectric elements 2a and 2b from the A-phase power supply, and a voltage is applied to the B-phase electrodes from the B-phase power supply to transmit the driving force of the vibrating body 3 as described above. If a traveling wave is generated in the portion 31, each moving body 40 pressed by the spring 43 against the driving force transmitting portion 31 rotates in one direction, and is connected to each moving body 40 by a spline 42. The rotor case 45 has a shaft 44
Will rotate relative to.

FIGS. 12 (a) and 12 (b) are explanatory diagrams of the principle of the ultrasonic motor according to the present invention at the start of vibration of the vibrator A (3). When a sine wave voltage is applied to each of the A phase and the B phase of the piezoelectric element B (2A, 2B), the vibrating body A (3) starts vibrating. At this time, the outer peripheral portion of the vibrating body A (3) Since the moving body C (40) is pressed by the preload means at the driving force transmitting portion 31, the first portion hardly generates vibration. However, since the center of the vibrating body A (3) is spline-coupled to the shaft D (44), the vibrating body A (3) has a shaft D (44) at the center as shown in FIG. The vibration starts by waving vertically (in the vertical direction with respect to the plane of the vibrating body A) in the axial direction of FIG.
As shown in (1), the driving force transmitting portion 31 at the outermost peripheral portion is caused to vibrate, and finally, a stable resonance state of the driving force transmitting portion 31 is realized. Note that the operation is instantaneously performed from the initial state to a stable resonance state. As described above, in the present invention, since the vibrating body A (3) is merely locked at the center so as to be movable in the axial direction of the shaft D (44), the vibration of the vibrating body A (3) is achieved. It is easy to generate and a resonance state can be immediately obtained.

FIG. 7 shows a second embodiment of the present invention.
The difference from the first embodiment described above is that only one spring 43 is used as preload means. That is, the moving body 40 rotates together with the rotor case 45, and both the moving body 40 and the vibrating body 3 can move in the axial direction of the shaft 44, so that one moving body 40 is brought into contact with the end face of the rotor case 45. When pressure is applied by the spring 43 from the other side, the two moving bodies 40 are driven by the driving force transmitting portions 3 of the vibrating body 3.
1 will be pressed against each other. In the second embodiment, since only one spring 43 is required as the preload means,
A compact ultrasonic motor having a simple structure can be constructed.

In the first and second embodiments described above, an example of an ultrasonic motor using only one stator disk 1 as a driving source has been described. However, in order to obtain a higher torque output, 6 and 7 for one shaft 44.
It is sufficient to connect a plurality of stator disks 1, moving bodies (rotor disks) 40, springs 43, rotor cases 45, and the like as shown in FIG. 1, but an example of an ultrasonic motor that can generate high output torque and has a simplified structure. A third embodiment will be described with reference to FIGS.

FIG. 8 is a sectional view, and FIG. 9 is a three-dimensional view. The moving bodies (rotor disks) 53 and the vibrating bodies 3 constituting the stator disk 1 are alternately arranged, and a shaft 52 penetrates a central portion. The moving body (rotor disk) 53 is disposed so as to abut only on the exposed driving force transmitting portion 31 of the vibrating body 3 of the stator disk 1. The stator disk 1 and the moving body (rotor disk) 53 are stacked to form a multilayer structure. That is,
Moving body (rotor disk) 53, stator disk 1,
The moving body (rotor disk) 53,... Are stacked with the stator disk 1 and the moving body (rotor disk) 53. Spline tooth grooves are formed on the inner peripheral surface of the vibrating body 3 of the stator disk 1, and the shaft 52 penetrating through a hole at the center of the stator disk 1 is longer than a region where the vibrating body 3 of the stator disk 1 is engaged. The spline teeth which engage with the spline tooth grooves are formed over the area, and the vibrating body 3 and the shaft 52 of each stator disk 1 are connected to the spline structure 55.
Are joined by

Note that, as shown in FIG.
The spline connection of the shaft 52 and the shaft 52 is different from the normal spline connection, in which the spline teeth and the spline tooth grooves are thinned out to increase the degree of freedom of the movement of the vibrating body 3 in the axial direction.

Both ends of the shaft 52 are connected to a rotor case 56 via bearings 51. A spline tooth groove is formed on the inner peripheral surface of the rotor case 56, and engages with spline teeth formed on the outer periphery of the moving body (rotor disk) 53, so that the moving body (rotor disk) 53 and the motor case 56 Are connected by a spline structure 57.

Further, at one end (the right end in FIGS. 8 and 9) where a plurality of sets of the stator disk 1 and the moving body (rotor disk) 53 are stacked, the side wall and the end of the rotor case 56 are provided. A spring 54 as a preload means is disposed between the moving body (rotor disk) 53 (the rightmost side in FIGS. 8 and 9) and presses the moving body 53. Also,
The moving body 53 at the other end (the left end in FIGS. 8 and 9) where a plurality of sets of the stator 1 and the moving body 53 are stacked is in contact with the side wall of the rotor case 56. A spring as a preload means may be provided at this end as shown in FIG.

Each moving body (rotor disk) 53 is connected by a rotor case 56 and a spline structure 57, and the vibrating body 3 of each stator disk 1 is connected by a shaft 52 and a spline structure 55. The stacked body in which a plurality of bodies (rotor disks) 53 are stacked is movable in the axial direction of the shaft 52, and the moving body (rotor disk) 53 at one end is pressed in one direction by a spring 54 of preload means. Therefore, each moving body (rotor disk) 53 is pressed by the driving force transmitting portion 31 on the exposed outer peripheral portion of the vibrating body 3 of each stator disk 1.

Also in this embodiment, a voltage is applied to the A-phase electrode of each stator disk 1 from the A-phase power supply, and a voltage is applied to the B-phase electrode from the B-phase power supply. When a traveling wave is generated, each moving body (rotor disk) 53 rotates in one direction, and the rotor case 56 rotates relatively to the shaft 52.

The connection between each of the vibrators 3 and the shaft 52 can be relatively moved in the axial direction such as a protrusion and a groove connection other than the spline connection so as to be movable in the motor axial direction but not in the circumferential direction. Any connection that does not allow relative movement in the circumferential direction may be used. Further, the connection between each moving body (rotor disk) 53 and another member (the rotor case 56 in the above example) is also performed.
Any connection may be used as long as the connection has a structure that allows relative movement in the motor axis direction but does not allow relative movement in the circumferential direction. The above-described spline connection, the groove and the protrusion that engages with the groove, and the moving body ( The outer peripheral portion of the rotor disk 53 is made to protrude in the radial direction from the outer peripheral portion of the vibrating body 3, holes are provided in the protruding portion at equal intervals in the circumferential direction, and each moving body (rotor disk) is loosely fitted with the hole. ) 53 may be connected, and the rods may be connected to each other to form a member that rotates relative to the rotor, that is, the shaft 52.

[0039]

According to the present invention, a driving force for bonding a piezoelectric element having an outer diameter smaller than the outer diameter of a vibrating body to both surfaces of a vibrating body constituting a stator disk and pressing the exposed outer peripheral portion of the vibrating body against a moving body. Since the transmitting portion is used, the volume of one piezoelectric element is reduced, and the vibration energy transmitted to the vibrating body is reduced.
However, since the piezoelectric elements are bonded to both sides of the vibrating body, the vibration energy generated by the vibrating body is increased as compared with the conventional case where the piezoelectric element is bonded to only one side,
By using the stator disk, an ultrasonic motor having a high output torque can be configured.

Further, since the vibrating body of the stator disk is driven on both sides, it is possible to adopt a structure in which the vibrating body of the stator disk is sandwiched from both sides by the moving body (rotor disk).
Are alternately laminated to form a multilayer double-sided drive ultrasonic motor. Therefore, it is easy to create a double-sided drive ultrasonic motor. In addition, since each moving body (rotor disk) and the stator disk can be moved only in the motor axis direction, each moving body (rotor disk)
Can be provided at one place, and a double-sided drive ultrasonic motor can be made compact.

Further, since the shaft and the stator disk are configured to be movable in the axial direction and constrained in the rotational direction, the preload acting between the vibrating body and the moving body changes even when the shaft is loaded in the axial direction. And a stable movement of the moving body becomes possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a piezoelectric element used in an embodiment of the present invention.

FIG. 2 is an explanatory view of a first embodiment of a stator disk used in a double-sided drive ultrasonic motor of the present invention.

FIG. 3 is an explanatory view of a second embodiment of the stator disk used in the double-sided drive ultrasonic motor of the present invention.

FIG. 4 is an explanatory view of a third embodiment of the stator disk used in the double-sided drive ultrasonic motor of the present invention.

FIG. 5 is a wiring diagram for applying a voltage to a piezoelectric element of the stator disk of the present invention.

FIG. 6 is a sectional view of an embodiment of a double-sided drive ultrasonic motor according to the present invention.

FIG. 7 is a sectional view of a second embodiment of a double-sided drive ultrasonic motor according to the present invention.

FIG. 8 is a sectional view of a third embodiment of a double-sided drive ultrasonic motor according to the present invention.

FIG. 9 is a three-dimensional view of the third embodiment.

FIG. 10 is an explanatory diagram illustrating a vibration start state of a conventional single-sided drive ultrasonic motor.

FIG. 11 is an explanatory diagram illustrating a vibration start state of a conventional double-sided drive ultrasonic motor.

FIG. 12 is an explanatory diagram illustrating a vibration start state of the double-sided drive ultrasonic motor of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator disk 2, 2a, 2b Piezoelectric element 3, 3 ', 3 "Vibration body 4a A-phase power supply 4b B-phase power supply 21 Split electrode provided on one side of piezoelectric element 22 On the other side of piezoelectric element Provided electrode 31 Driving force transmitting portion 32 Slit 40, 53 Moving body (rotor disk) 41, 42, 55, 57 Spline structure 43, 54 Spring (preload means) 44, 52 Shaft 45, 56 Rotor case 46, 51 Bearing

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-7173 (JP, A) JP-A-9-37573 (JP, A) JP-A-4-124898 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) H02N 2/00

Claims (10)

(57) [Claims] 1. A double-sided driving ultrasonic having a vibrating body made of a disc-shaped elastic body and having a piezoelectric element attached thereto, and two moving bodies for pressing and holding a driving force transmitting portion of the vibrating body by a preload mechanism. In the motor, the two moving bodies are connected to each other, and the vibrating body is supported by a shaft while being movable in an axial direction near a center portion thereof and constrained in a rotating direction. motor. 2. The moving body is movable in the axial direction of the shaft, is restricted in a rotational direction around the shaft, and is connected to each other, and the preload means is provided at one place, and is all provided by the one preload means. 2. The double-sided drive ultrasonic motor according to claim 1, wherein said moving body is brought into pressure contact with a driving force transmitting portion of said vibrating body. 3. The double-sided drive ultrasonic motor according to claim 1, wherein a plurality of the vibrating bodies and the two moving bodies are provided as a set, and all the moving bodies are connected to each other. 4. A double-sided drive ultrasonic motor comprising a vibrating body made of a disc-shaped elastic body and having a piezoelectric element attached thereto, and a moving body pressed against a driving force transmitting portion of the vibrating body by a preload means. The vibrating body and the moving body are alternately arranged, and each of the vibrating bodies is supported by a shaft so as to be movable in an axial direction near the center thereof and to be constrained in a rotating direction, and the moving bodies are It is movable in the axial direction of the shaft and is connected to each other while being restrained in the direction of rotation about the shaft. The preload means is provided at one or two places and all the moving bodies are transmitted by the preload means to transmit the driving force of the vibrating body. A double-sided drive ultrasonic motor characterized by being brought into pressure contact with a part. 5. The double-sided drive ultrasonic motor according to claim 1, wherein a support structure of the vibrating body to the shaft is a spline connection. 6. The double-sided drive ultrasonic motor according to claim 5, wherein said spline connection increases the degree of freedom of vibration by uniformly thinning out spline teeth in a circumferential direction. 7. The structure according to claim 1, wherein the supporting structure of the vibrating body to the shaft is constituted by a groove provided on one side and a projection engaging with the groove provided on the other side. 2. A double-sided drive ultrasonic motor according to claim 1. 8. The double-sided drive ultrasonic motor according to claim 1, wherein the structure for connecting the moving bodies is spline-coupled with each moving body and a member surrounding each moving body. 9. A structure for connecting said moving bodies, wherein each of the moving bodies and a member surrounding each of the moving bodies is constituted by a groove provided on one side and a projection engaging with the groove provided on the other side. The double-sided drive ultrasonic motor according to any one of claims 1 to 7, wherein: 10. The double-sided drive ultrasonic motor according to claim 1, wherein said preload means is constituted by a spring.