JPH11206157A - Ultrasonic motor and electronic apparatus with the motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an ultrasonic motor small by providing small tolerance on the whole, and generate given torque against the whole tolerance. SOLUTION: In an ultrasonic motor, a rotor body 23 is rotated through bending oscillation of an oscillator 22 caused by excitation of a piezoelectric element 21 while the rotor body 23 is supported by a supporting shaft 13. A dish-shaped flexible member 26 is provided at a projected part 13a of the supporting shaft 13 projected from the rotor body 23. The dish-shaped flexible member 26 generates given pushing force on the rotor body 23 through displacement in a load stability region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor which is used for auto-focusing a watch, a camera, opening and closing a blind, driving an XY stage, etc., and which presses a vibrating body and a rotor body. The present invention relates to an improvement in an ultrasonic motor for pressing a vibrating body and a rotor body by using a dish-shaped elastic member or a plate-shaped elastic member fixed to a support shaft, and an electronic device with an ultrasonic motor.

[0002]

2. Description of the Related Art In recent years, an ultrasonic motor that generates a traveling wave on a vibrating body joined to a piezoelectric element, presses the vibrating body against a rotor body with a predetermined pressing force, and moves the rotor body has attracted attention ( For example, see Japanese Patent Publication No. 62-92781). As shown in FIGS. 12 and 13, the rotary motion type ultrasonic motor includes a support plate 101 for supporting an ultrasonic device, a piezoelectric element lead 102 disposed on the support plate 101, and a support plate 101. A fixed central axis 103;
, A piezoelectric element 105 joined to the lower surface of the vibrating body 104, and a projection 104 of the vibrating body 104.
a, a bush 107 provided between the rotor 106 and the central shaft 103, and a rotor 106
, A pivot 109 fixed to the center of rotation of the rotor 106, a plate-like pressing spring 111 urged against the pivot 109, and a pressing spring 11.
1 and a set screw 113 for fixing the presser spring seat 112 and the presser spring 111 (see, for example, Japanese Patent Application Laid-Open No. 8-107686).

According to this, when an excitation signal is input to the piezoelectric element 105, the piezoelectric element 105 is excited to
4 generates a bending vibration wave, and the protrusions 10 on the vibrating body 104
4a is brought into contact with the rotor 106 periodically. Here, the pressing spring 111 presses and biases the pivot 109 to generate a frictional force at the pressure contact portion between the rotor 106 and the projection 104a. The frictional force causes the rotor 106 to rotate in a predetermined direction.

[0004]

However, the holding spring seat 112, the central shaft 103, the vibrating body 104, and the rotor 1
When the tolerances of 05 accumulate, the displacement amount of the pressing spring 111 changes and deviates from an appropriate range, and there is a problem that the pressing force becomes excessive or insufficient and an appropriate torque is not generated in the ultrasonic motor.

In addition, since the pressing force of the plate-shaped pressing spring 111 is proportional to the amount of displacement, the range of the amount of displacement showing an appropriate pressing force is narrow. Also, a plate-shaped holding spring 11
In (1), the pressing spring seat 112 for fixing is required at a position distant from the rotor 106, so that the size of the ultrasonic motor is increased.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to reduce the tolerance of the entire device configuration, reduce the size of the device configuration, and generate an ultrasonic wave that generates a constant torque even with the tolerance of the entire device configuration. A motor and an electronic device with an ultrasonic motor are provided.

[0007]

First, the characteristics of the dish-shaped elastic member used in the present invention will be described. FIG. 1 is a graph comparing the relationship between the amount of displacement and the load for a disc spring and a coil spring. That is, in the case of the disc spring, the load initially increases linearly as the displacement of the elastic deformation increases, but there is a load stable region where the load becomes constant after a certain displacement. By using this, a constant pressing force can be applied in the load stable region even when the displacement is changed. On the other hand, in the case of the coil spring, the load increases linearly as the displacement increases, and there is no load stable region.

That is, according to the present invention, the rotor body is rotated by the vibrating body that bends and vibrates based on the excitation of the piezoelectric element while the rotor body is supported by the support shaft. In the ultrasonic motor, a dish-shaped elastic member for applying a constant pressing force to the rotor body by displacement in a load stable region is provided at a protruding portion of the support shaft protruding from the rotor body.

According to this, when the piezoelectric element is excited,
A bending vibration wave is generated in the vibrating body based on the excitation of the piezoelectric element,
The vibrating body periodically contacts the rotor body. The dish-shaped elastic member applies a constant pressing force to the rotor body by the displacement in the load stable region, and the pressing force presses the vibrating body and the rotor body to generate a certain frictional force, and the frictional force is generated by the rotor body. Is rotated at a constant speed. Therefore, even if the tolerances of the vibrating body, the rotor body, and the support shaft are integrated and the displacement of the dish-shaped elastic member changes, the rotational speed of the rotor body and the torque of the ultrasonic motor are kept constant.

Further, since the dish-shaped elastic member is provided at the protruding portion of the support shaft so that other members for installation other than the support shaft are not required, the tolerance of the device configuration is reduced and the size of the entire device is reduced. Is achieved. According to a second aspect of the present invention, in the ultrasonic motor according to the first aspect, a center hole is provided at a center portion of the elastic member, and a protruding portion of the support shaft is inserted through the center hole. A peripheral portion of the center hole applies a pressing force to the rotor body, and further includes an outer edge supporting member that supports the outer edge of the dish-shaped elastic member and is fixed to the protrusion of the support shaft. It is characterized by.

According to this, a constant pressing force is applied to the rotor body by the peripheral portion of the center hole of the dish-shaped elastic member. Further, since the outer edge support member supports the outer edge of the dish-shaped elastic member and is fixed to the protruding portion of the support shaft, another member for installing the dish-shaped elastic member at another place is not required. According to a third aspect of the present invention, in the ultrasonic motor according to the second aspect, the outer edge supporting member has a locking portion that is locked to a protrusion of the support shaft.

According to this, by reducing the number of parts, the structure of the device is simplified, and the tolerance of the structure of the device is further reduced. According to a fourth aspect of the present invention, in the ultrasonic motor according to the first aspect, an outer edge portion of the dish-shaped elastic member is directly pressed against the rotor body, and furthermore, is rotatable with a protruding portion of the support shaft. And a rolling bearing member having a flange portion for supporting a peripheral portion of a center hole provided in a center portion of the dish-shaped elastic member.

According to this, the outer edge of the dish-shaped elastic member applies a constant pressing force to the rotor body. Further, the rolling bearing member supports the peripheral portion of the center hole of the dish-shaped elastic member with the flange portion, and does not require a member for mounting the dish-shaped elastic member at a position away from the support shaft. In addition, since the rotation is performed around the support shaft, the dish-shaped elastic member is rotated integrally with the rotor body, and does not hinder the movement of the rotor body.

According to a fifth aspect of the present invention, in the ultrasonic motor according to the first aspect, a peripheral portion of a center hole provided in a center portion of the dish-shaped elastic member is fixed to a projecting portion of the support shaft. And a pressing force transmitting member for transmitting a pressing force to a stationary inner ring of a rolling bearing provided on an inner peripheral surface of the rotor body while pressing an outer edge portion of the dish-shaped elastic member. According to this, the outer edge of the dish-shaped elastic member presses the pressing force transmitting member, and the pressing force is transmitted to the rotor body via the inner ring of the rolling bearing, and the movement of the rotor body is not hindered.

Also, since the peripheral edge of the center hole provided in the center of the dish-shaped elastic member is fixed to the protruding portion of the support shaft, another installation member is not required at a location away from the support shaft. According to a sixth aspect of the present invention, in the ultrasonic motor according to the first aspect, a peripheral portion of a center hole provided in a center portion of the dish-shaped elastic member is fixed to a protruding portion of the support shaft. A rolling bearing transmitting member that transmits the pressing force of the outer edge of the dish-shaped elastic member and that rotatably contacts the rotor body is provided.

According to this, the pressing force is transmitted to the rotor by the rolling bearing transmitting member, and the rolling is freely rotated on the rotor, so that the movement of the rotor is not hindered. Also, since the peripheral edge of the center hole provided in the center of the dish-shaped elastic member is fixed to the protruding portion of the support shaft, another installation member is not required at a location away from the support shaft. Also,
According to a seventh aspect of the present invention, in the ultrasonic motor according to any one of the first to sixth aspects, the dish-shaped elastic member has a conical shape having a center hole at a center portion. .

According to this, an excellent load stability region can be obtained. According to an eighth aspect of the present invention, in the ultrasonic motor according to any one of the first to sixth aspects, the dish-shaped elastic member has a conical shape having a center hole at a center portion, and has an outer edge. A flange is provided on at least one of the peripheral portion of the portion or the center hole.

According to this, the pressing of the rotor body or the support of the dish-shaped elastic member is reliably performed. According to a ninth aspect of the present invention, in the ultrasonic motor according to any one of the first to sixth aspects, the dish-shaped elastic member has a conical shape provided with a center hole at a central portion, and A conical surface is provided with a window hole for reducing rigidity.

According to this, the load stable region where the load is small is adjusted. The ultrasonic motor according to claim 10, wherein the rotor body is rotated by a vibrating body that bends and vibrates based on excitation of a piezoelectric element while the rotor body is supported on a support shaft. A plate-like elastic member which applies a pressing force to the body in proportion to the displacement is provided at a projecting portion of the support shaft projecting from the rotor body.

According to this, when the piezoelectric element is excited,
A bending vibration wave is generated in the vibrating body based on the excitation of the piezoelectric element,
The vibrating body periodically contacts the rotor body. The plate-like elastic member applies a pressing force proportional to the displacement to the rotor body, presses the rotor body and the vibrating body to generate a frictional force, and rotates the rotor body by the frictional force. In addition, since the plate-like elastic member is provided at the protruding portion of the support shaft, another installation member is not required at a location away from the support shaft. Therefore, the tolerance of the device configuration is reduced, and the size of the device configuration is reduced.

According to an eleventh aspect of the present invention, in the ultrasonic motor according to the tenth aspect, the plate-shaped elastic member is annular. According to this, excellent elastic performance can be obtained. According to a twelfth aspect of the present invention, in the ultrasonic motor according to the tenth aspect, the plate-shaped elastic member has an annular shape, and a window hole for reducing rigidity is provided on the annular surface. And

According to this, excellent performance can be obtained in a small load area. Also, as described in claim 13,
An electronic device with an ultrasonic motor, comprising the ultrasonic motor according to any one of claims 1 to 12. According to this, an electronic device with an ultrasonic motor to which the present invention is applied is realized.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment according to the present invention will be described in detail with reference to FIGS. Embodiment 1 FIG. 2 shows a sectional view of Embodiment 1 in which the present invention is applied to an ultrasonic motor, and FIG.
FIG. 6 is a diagram showing a structure in the oblique direction of FIG.

In this embodiment, a support plate 11 for supporting an ultrasonic motor, a piezoelectric element lead 12 disposed on the support plate 11, and a central shaft 13 as a support shaft of the present invention fixed to the support plate 11 are provided. A piezoelectric element 21 connected to the piezoelectric element lead 12, a vibrating body 22 joined to the piezoelectric element 21,
A projection 22a protruding above the vibrating body 22;
A rotor 23 as a rotor body of the present invention pressed against the upper protrusion 22a; a rolling bearing 24 provided on the inner peripheral surface of the rotor 23; a spacer 25 provided on the upper surface of the rolling bearing 24; Disc spring 26 as a disc-shaped elastic member of the present invention pressed against the upper surface, and outer edge 2 of disc spring 26
An outer edge support member 27 is in contact with 6a and fixed to the upper surface of the central shaft by a stopper 28.

Here, the center shaft 13 is a substantially columnar body made of a rigid material, and the protrusion 1 protrudes above the rotor 23.
3a. The vibrating body 22 is fixedly supported, the rotor 23 is rotatably supported, and the disc spring 26 is
Install using. The piezoelectric element 21 is formed in a substantially disk shape, and is made of barium titanate, lead titanate, lithium niobate, lithium tantalate, or the like. Also,
It is divided into twelve equal parts in the circumferential direction in a fan shape, and six sets of polarization processing units are provided with two adjacent divisions as one set of polarization processing units. The polarization process is performed such that the divided portions of each set of polarization processing units alternately reverse the direction of the polarization process. here,
The polarization direction is a positive direction, a positive electric field is applied toward the joint surface with the vibrator 22, and the reverse direction is a vibrator 2
A negative electric field was applied toward the joint surface between the second and the second.

On the non-bonding surface of the piezoelectric element 11, a substantially fan-shaped electrode pattern corresponding to each divided portion is formed by means such as CVD, and every other polarized portion is short-circuited. And
One electrode pattern is connected to a first lead wire 12a connected to the piezoelectric element lead 12, and the other electrode pattern is connected to a second lead wire 12b. Also, the vibrating body 22
The whole surface electrode is formed on the joint surface with the substrate. And
An excitation signal having a phase difference of 90 ° is input to one of the electrode patterns and the other electrode pattern, and the respective electrode patterns are excited by shifting the phase by 90 ° to generate a traveling wave in the circumferential direction of the vibrating body 22.

When the standing wave method is used, the protrusion 22
a is arranged every other boundary of the division. When driving in the positive direction, an excitation signal is input to one of the electrode patterns to be excited, and a standing wave is generated in the vibrating body 22. When driving in the opposite direction, an excitation signal having the same phase is input to the other electrode pattern to be excited, and a standing wave having a 90 ° phase different from the standing wave is generated in the rotor 22.

The vibrating body 22 has a disk shape corresponding to the piezoelectric element 11, and is made of an elastic material such as an aluminum alloy, stainless steel, brass or the like. The columnar projections 2 are arranged at equal intervals at positions corresponding to the boundaries of the divided portions of the piezoelectric element 11.
2a is provided. The rotor 23 has a disk shape, and has a central portion provided with an insertion hole through which the central shaft 13 is inserted.
Then, the projection 22a is rotated in a predetermined direction by applying a frictional force.

The rolling bearing 24 includes an annular inner ring 24a fixed to the peripheral surface of the center shaft 13 and formed into a concave cross section, an annular outer ring 24b fixed to the inner peripheral surface of the rotor 23 and formed into a concave cross section, It consists of a plurality of spherical bodies 24c incorporated in the concave portions of the inner ring and the outer ring. When the rotor 23 rotates in a predetermined direction, the spherical body 24c rotates on the spot while the inner ring 24a is stationary, and the outer ring 24b rotates with the rotor 23.

The spacer 25 is a rigid columnar body, and is disposed on the upper surface of the stationary inner ring 24 a of the rolling bearing 24.
The pressing force of the disc spring 26 is transmitted to the rotor 23. Disc spring 2
As shown in FIG. 3 (a), reference numeral 6 denotes a conical shape which spreads toward the outer edge 26a, and has a circular center hole 26 at the center.
b is formed. Examples of the material include steel, stainless steel, beryllium copper, and phosphor bronze exhibiting spring characteristics. In this method, both edges of a fan-shaped thin plate made of the above-mentioned material are fixed to each other by means of welding, an adhesive or the like to form a conical shape, and the central portion of the conical shape is cut to form a central hole 26b. Then, a constant pressing force is applied to the rotor 23 while being used while being displaced within the load stable region as described above.

As shown in FIG. 3B, the disc spring 26 may be provided with a plurality of rectangular window holes 26c in a conical surface. According to this, the rigidity is reduced, and the load stable region is adjusted to a low load. The window 26c may be provided singly or plurally, and the shape of the window 26c may be any one of a circle, an ellipse, a triangle, a polygon, and other shapes.

Further, as shown in FIG.
The annular flanges 26d and 26e having a fixed width may be provided on the outer edge 26a and the peripheral edge of the center hole 26b.
According to this, the outer edge support member 27 and the spacer 25
The contact area with the contact is increased to provide reliable support and pressing. The flange may be provided on either the outer edge 26a of the disc spring 26 or the peripheral edge of the center hole 26b.

The outer edge support member 27 is made of a rigid material, and has a disk-shaped main body 27a and an annular projection 27b which is vertically projected toward the disc spring 26 on the outer edge of the disk-shaped main body 27a. A stopper hole 27c through which the stopper 28 is inserted is formed in the center of the disk-shaped main body 27a. Then, the displaced outer edge portion 26a of the disc spring 26 is brought into contact with and supported by the protruding portion 27b of the outer edge portion support member 27.

The stopper 28 is, for example, a screw having a T-shaped cross section. The stopper 28 is inserted into a stopper hole 27c of the outer edge support member 27, and is engaged with a screw groove formed in the central shaft 13 so that the outer edge is The support member 27 is fixed by screwing. According to the above configuration, the projection 1 of the central shaft 13 is
3a is inserted, and the outer edge 26a of the disc spring 26 in a displaced state is supported by the protrusion 27b of the outer edge support member 27,
The stopper 28 is inserted through the stopper hole 27c of the outer edge support member 27, and is fixed to the upper end of the central shaft protrusion 13a. Therefore, the disc spring 26 is supported by using the protrusion 13a of the center shaft 13.

Next, the operation of the ultrasonic motor will be described with reference to FIG. First, when excitation signals having a phase difference of 90 ° are input to one electrode pattern and the other electrode pattern of the piezoelectric element 21, each electrode pattern performs excitation having a phase difference of 90 °. The vibrating body 22 joined to the piezoelectric element 21 bends and vibrates to generate a traveling wave, and the projection 22a provided integrally with the vibrating body 22 performs an elliptical motion. The projection that performs the elliptical motion contacts the rotor 23 from the origin position to the vertex position in the longitudinal direction of the elliptical motion.

On the other hand, the peripheral portion of the center hole 26b of the disc spring 26 displaced in the range of the load stable region applies a pressing force to the spacer 25, and the pressing force is applied via the spacer 25 to the stationary inner ring 24a of the rolling bearing 24. Is transmitted to The rolling bearing 24 transmits the downward pressing force to the rotor 23,
Is pressed against the protrusion 22a located at the vertex position from the origin position. By this pressure contact, the rotor 23 is applied with a frictional force in the circumferential direction, and is rotated in a predetermined direction.

At this time, if the amount of displacement of the disc spring 26 changes in the range of the load stable region, the pressing force is kept constant without changing, and a constant frictional force is applied to the rotor 23, and
3 is rotated at a constant speed. As described above, according to the present embodiment, when the amount of displacement changes within the range of the load stabilization region using the disc spring 26, the pressing force is kept constant, so that the vibrating body 22, the rotor 23, the center Even if the tolerances of the shaft 13 and the like are integrated, the rotation speed and the torque of the ultrasonic motor are kept constant.

Further, the center hole 26b of the disc spring 26 is inserted through the projection 13a of the center shaft 13, and the disc spring 26 is displaced so as to be supported and fixed using the projection 13a of the center shaft 13. This eliminates the need for another installation member at a position away from the central shaft 13, thereby reducing the tolerance of the entire apparatus and miniaturizing the entire apparatus. Also,
The periphery of the center hole 26b of the disc spring 26 is
The stationary inner ring 24a is pressed, so that the disc spring 26 is prevented from being worn and the rotation of the rotor 23 is not hindered.

FIG. 4 is a diagram showing a sectional structure according to a modification of the first embodiment. The modified embodiment has substantially the same configuration as that of the first embodiment, and is characterized in that an integrated outer edge support member 29 provided integrally with an outer edge support member 27 and a stopper 28 is provided. The integral outer edge support member 29 has a T-shaped cross section, and a T-shaped protrusion 29a serving as a locking portion of the present invention is threaded. The integral outer edge support member 29 is fixed to the central shaft 13 by locking the screw groove formed in the protrusion 13a.

According to this, the number of parts is reduced, the structure of the apparatus is simplified, and the tolerance of the entire apparatus is reduced. Second Embodiment FIG. 5 is a diagram showing a cross-sectional structure of a second embodiment in which the present invention is applied to an ultrasonic motor.

The present embodiment has substantially the same configuration as that of the first embodiment. The outer edge 26a of the disc spring 26 is directly in contact with the upper surface of the rotor 23.
b and the projection 1 of the central shaft 13
For example, a rolling bearing 31 with a flange as a rolling bearing member of the present invention fixed to the upper end 3a and a stopper 32 for stopping the rolling bearing 31 with a flange from above are provided.

Here, the flanged rolling bearing 31 is
It comprises an annular inner ring 31a having a concave cross section, an annular outer ring 31b having a concave cross section, and a plurality of spherical bodies 31c incorporated into the concave portions of the inner ring 31a and the outer ring 31b. Further, an annular flange portion 31d is provided on the outer peripheral surface of the outer ring 31b,
The peripheral portion of the center hole 26b of the disc spring 26 is supported. Then, with the inner ring 24a stationary, the spherical body 24c rotates on the spot, and the outer ring 24b rotates with the disc spring 26.

Next, the operation of the ultrasonic motor will be described. The protrusions 22a of the vibrating body 22 are periodically pressed against the rotor 23, and a frictional force is applied to the rotor 23 in the circumferential direction, so that the rotor 23 is rotated around the central axis 13 in a predetermined direction. At this time, the disc spring 26 presses the rotor 23 with a constant force at the outer edge portion 26a, and the rotor 23 and the flanged rolling bearing 3
It rotates around the central axis 13 together with the first outer ring 31b.

Therefore, the same effect as that of the first embodiment can be obtained, and the disc spring 26
3, so that the rotation of the rotor 23 is not hindered and wear of the disc spring 26 and the rotor 23 is prevented. Third Embodiment FIG. 6 is a diagram showing a sectional structure of a third embodiment in which the present invention is applied to an ultrasonic motor.

The present embodiment has substantially the same configuration as that of the first embodiment. The center hole 26b of the disc spring 26 is arranged on the upper end surface of the center shaft 13, and is supported by being pressed from above by a stopper 35. . On the other hand, a pressing force transmitting member 34 for contacting the outer edge 26a of the disc spring 26 is provided so as to be freely inserted into the center shaft 13, and further,
It is characterized in that a spacer 33 is arranged between the pressing force transmitting member 34 and the inner ring 24a of the rolling bearing 24.

Here, the pressing force transmitting member 34 is disk-shaped, and has a circular insertion hole 34a at the center thereof, through which the center shaft 13 can be inserted. Then, the pressing force of the disc spring 26 is transmitted to the spacer 33. According to this, the outer edge 26a of the disc spring 26 presses the end of the pressing force transmitting member 34, and this pressing force is transmitted to the spacer 33 by the peripheral edge of the insertion hole 34a of the pressing force transmitting member 34, and the rolling is performed. The power is transmitted to the rotor 23 through the stationary inner ring 24 a of the bearing 24.

Therefore, according to the present embodiment, the same effect as that of the first embodiment can be obtained, and the pressing force is transmitted to the rotor 23 without hindering the rotation of the rotor 23. Fourth Embodiment FIG. 7 is a diagram showing a cross-sectional structure of a fourth embodiment in which the present invention is applied to an ultrasonic motor.

This embodiment has substantially the same configuration as that of the first embodiment. The peripheral portion of the center hole 26b of the disc spring 26 is disposed on the upper end surface of the center shaft 13 and is held down by a stopper 35 from above. A supporting member 36 for supporting the outer edge 26a of the disc spring 26 is provided so as to be able to be inserted through the center shaft 13, and a rolling bearing transmitting member 37 for inscribing a projecting portion below the supporting member 36.
The feature is that it provided.

Here, the rolling bearing transmitting portion 37 includes an annular inner ring 37a fixed to the support member 36 and having a concave cross section, an outer ring 37b having a concave cross section opposed to the inner ring 37a, and an outer ring 37b and an inner ring 37a. It is composed of a plurality of spherical bodies 37c incorporated between them. And the spherical body 37 is
With the rotation of the rotor 23, it rotates in place. According to this, the outer edge 26a of the disc spring 26 presses the support member 36, and this pressing force causes the support member 36 and the spherical body 37c of the rolling bearing 37 to move. Is transmitted to the rotor 23. Also,
Since the spherical body 37c rotates in place, the rotation of the rotor 23 is not hindered.

Therefore, according to the present embodiment, the same effect as that of the first embodiment can be obtained, and the rotation of the rotor 23 is not hindered. Fifth Embodiment FIG. 8 is a diagram showing a sectional structure of a fourth embodiment in which the present invention is applied to an ultrasonic motor, and FIG. 9 shows a structure of a disk spring 39 as viewed from a perspective direction.

The present embodiment has substantially the same configuration as that of the first embodiment. Instead of the disc spring 26, a disc spring 39 as a plate-like elastic member of the present invention is used, and an outer edge portion 39a of the disc spring 39 is used. Is supported by the outer edge support member 27, and the peripheral portion of the center hole 39b is supported by the spacer 41 in a displaced state. Here, as shown in FIG. 9 (a), the disc spring 39 is an annular shape having a center hole 39b at the center of the disc shape.
Stainless steel, beryllium copper, phosphor bronze. This elastic characteristic shows a linear characteristic proportional to the displacement similarly to the coil spring.

As shown in FIG. 9B, the disc-shaped spring 39 is provided with a plurality of arc-shaped window holes 39c on the circumferential surface to reduce rigidity in order to cope with displacement under a low load. You may. The shape of the window 39c may be rectangular, circular, elliptical, triangular, polygonal, or any other shape. According to the above configuration, the projection 13a of the center shaft 13 is inserted into the center hole 39b of the disc spring 39, and the outer edge 39a is supported by the outer edge support member 27 while the disc spring 39 is displaced. Since the stopper 28 is inserted into the insertion hole 27c of the portion support member 27 and is fixed to the upper end of the center shaft protruding portion 13a, another member for installation at another place is not required for supporting the disc spring 39. .

Next, the operation of the ultrasonic motor will be described. First, when excitation signals having a phase difference of 90 ° are input to one electrode pattern and the other electrode pattern of the piezoelectric element 21, each electrode pattern performs excitation having a phase difference of 90 °. The vibrating body 22 joined to the piezoelectric element 21 bends and vibrates to generate a traveling wave, and the projection 22a provided integrally with the vibrating body 22 performs an elliptical motion. The projection that performs the elliptical motion contacts the rotor 23 from the origin position to the vertex position in the longitudinal direction of the elliptical motion.

On the other hand, the peripheral portion of the center hole 39b of the disc spring 39 applies a pressing force to the spacer 41, and this pressing force is applied via the spacer 41 to the stationary inner ring 24a of the rolling bearing 24.
Is transmitted to The rolling bearing 24 transmits the downward pressing force to the rotor 23, and the rotor 23 is pressed against the protrusion 22a located at the vertex position from the origin position. Due to this pressure contact, the rotor 2
3 is applied with a frictional force in the circumferential direction and is rotated in a predetermined direction.

As described above, according to the present embodiment, the use of the projection 13a of the central shaft 13 eliminates the need for another member for mounting the disc spring 39 in another place. The overall tolerance is reduced and the size of the entire apparatus is reduced. Embodiment 6 FIG. 10 is a block diagram of an electronic device with an ultrasonic motor to which the present ultrasonic motor is applied.

This electronic device comprises a vibrating body 51 and a vibrating body 51.
, Movable body 52 and vibrating body 5
This is realized by including a pressure mechanism 53 for pressing the pressure of the transmission mechanism 1, a transmission mechanism 54 that moves in conjunction with the moving body 52, and an output mechanism 55 that moves based on the operation of the transmission mechanism 54.
Here, the electronic device with an ultrasonic motor is applied to, for example, an electronic timepiece, a measuring instrument, a camera, a printer, a printing machine, a machine tool, a robot, and a moving device.

As the transmission mechanism 54, for example, a transmission wheel such as a gear wheel or a friction wheel is used. The output mechanism 55 includes, for example, a shutter drive mechanism and a lens drive mechanism in a camera, and a pointer drive mechanism and a calendar drive mechanism in an electronic timepiece.
In a machine tool, a blade feed mechanism, a processing member feed mechanism, or the like is used. If the output shaft is attached to the moving body 52 and a power transmission mechanism that transmits torque from the output shaft is provided, a driving mechanism is realized by the ultrasonic motor itself.

[0058]

As described above, according to the present invention, the dish-shaped elastic member and the plate-shaped elastic member are provided at the protruding portion of the support shaft so that other members for installation other than the support shaft are not required. Therefore, the tolerance of the entire device configuration is reduced, and the size of the entire device is reduced. The dish-shaped elastic member is
A constant pressing force is applied to the rotor body by the displacement in the load stable area,
Since the rotor body is rotated at a constant speed by applying a constant frictional force, the tolerance of the vibrating body, the rotor body, and the support shaft is integrated, and even if the displacement amount of the dish-shaped elastic member changes, the ultrasonic The motor torque is kept constant.

[Brief description of the drawings]

FIG. 1 is a graph comparing the relationship between the amount of displacement and the load for a disc spring and a coil spring.

FIG. 2 is a first embodiment in which the present invention is applied to an ultrasonic motor.
It is explanatory drawing which shows the cross-section of FIG.

3A is a diagram illustrating a diagonal structure of the disc spring shown in FIG. 2, and FIGS. 3B and 3C are explanatory diagrams illustrating modifications thereof.

FIG. 4 is an explanatory diagram showing a cross-sectional structure according to a modification of FIG. 2;

FIG. 5 is a second embodiment in which the present invention is applied to an ultrasonic motor.
It is explanatory drawing which shows the cross-section of FIG.

FIG. 6 is a third embodiment in which the present invention is applied to an ultrasonic motor.
It is explanatory drawing which shows the cross-section of FIG.

FIG. 7 is a fourth embodiment in which the present invention is applied to an ultrasonic motor.
It is explanatory drawing which shows the cross-section of FIG.

FIG. 8 is a fifth embodiment in which the present invention is applied to an ultrasonic motor.
It is explanatory drawing which shows the cross-section of FIG.

FIG. 9A is a perspective view of a structure of the disc spring shown in FIG. 8, and FIG. 9B is an explanatory view showing a modified example thereof.

FIG. 10 is an explanatory diagram showing blocks of an electronic device with an ultrasonic motor to which the present ultrasonic motor is applied.

FIG. 11 is an explanatory view showing a cross-sectional structure of an ultrasonic motor according to the related art.

FIG. 12 is an explanatory view showing an exploded structure in a perspective direction according to FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Support plate 12 Piezoelectric element lead 13 Center axis (support axis) 13a Projection 21 Piezoelectric element 22 Vibrating body 22a Projection 23 Rotor (rotor body) 24 Rolling bearing 25 Spacer 26 Disc spring (dish-shaped elastic member) 26a Outer edge 26b Center Hole 27 Outer edge support member 28 Stopper 29 Integrated type outer edge support member 31 Rolling bearing with flange 32 Stopper 33 Spacer 34 Pressing force transmission member 35 Stopper 36 Support member 37 Rolling bearing transmission member 39 Disc spring (plate-like elastic member) )

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Suzuki 1-8-1, Nakase, Mihama-ku, Chiba-shi, Chiba In-house Iko Instruments Inc. (72) Takashi Yamanaka 1-8-8, Nakase, Nakase, Mihama-ku, Chiba-shi, Chiba Iko Instruments Inc.

Claims (13)

[Claims] In a state where a rotor body is supported on a support shaft,
In an ultrasonic motor for rotating the rotor body by a vibrating body that bends and vibrates based on excitation of a piezoelectric element, a dish-shaped elastic member that applies a constant pressing force to the rotor body by a displacement in a load stable region is provided from the rotor body. An ultrasonic motor provided on a protruding portion of the support shaft that protrudes. 2. A pressing force is applied to the rotor body at a peripheral edge of the center hole in a state where a center hole is provided in a center portion of the dish-shaped elastic member and a protruding portion of the support shaft is inserted through the center hole. 2. The ultrasonic motor according to claim 1, further comprising an outer edge support member that supports an outer edge of the dish-shaped elastic member and is fixed to a protruding portion of the support shaft. 3. The ultrasonic motor according to claim 2, wherein the outer edge portion support member has a locking portion that is locked to a protrusion of the support shaft. 4. An outer edge portion of the dish-shaped elastic member is directly pressed against the rotor body, and is further rotatably supported by a protruding portion of the support shaft, and is provided at a center of the dish-shaped elastic member. 2. The ultrasonic motor according to claim 1, further comprising a rolling bearing member having a flange supporting a peripheral portion of the center hole formed. 5. A peripheral portion of a center hole provided at a central portion of the dish-shaped elastic member is fixed to a protruding portion of the support shaft, and an outer edge of the dish-shaped elastic member is pressed against the rotor body. 2. The ultrasonic motor according to claim 1, further comprising a pressing force transmitting member for transmitting a pressing force to a stationary inner ring of the rolling bearing provided on an inner peripheral surface of the motor. 6. A peripheral portion of a center hole provided at a central portion of the dish-shaped elastic member is fixed to a projecting portion of the support shaft, and further, a pressing force of an outer edge of the dish-shaped elastic member is transmitted.
The ultrasonic motor according to claim 1, further comprising a rolling bearing transmission member rotatably contacting the rotor body. 7. The ultrasonic motor according to claim 1, wherein the dish-shaped elastic member has a conical shape having a center hole at a center portion. 8. The dish-shaped elastic member has a conical shape having a center hole at a center portion, and a flange is provided at at least one of an outer edge portion and a peripheral edge portion of the center hole. An ultrasonic motor according to claim 6. 9. The dish-shaped elastic member according to claim 1, wherein the dish-shaped elastic member has a conical shape having a center hole at a center portion, and a window hole for reducing rigidity is provided on the conical surface. The ultrasonic motor according to any one of the above. 10. An ultrasonic motor in which a rotor body is rotated by a vibrating body that bends and vibrates based on excitation of a piezoelectric element in a state where the rotor body is supported by a support shaft, the ultrasonic motor being proportional to a displacement of the rotor body. An ultrasonic motor, wherein a plate-shaped elastic member for applying a pressing force is provided on a protruding portion of the support shaft protruding from the rotor body. 11. The ultrasonic motor according to claim 10, wherein said plate-shaped elastic member is annular. 12. The ultrasonic motor according to claim 10, wherein said plate-shaped elastic member has an annular shape, and a window hole for reducing rigidity is provided on said annular surface. 13. An electronic device with an ultrasonic motor, comprising the ultrasonic motor according to claim 1. Description: