JP2605121B2 - Ultrasonic vibrator and ultrasonic motor using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic vibrator and an ultrasonic motor that drives a rotor or the like using the ultrasonic vibrator.

[Conventional technology]

Japanese Patent Application Laid-Open No. Sho 61-5216 discloses this type of ultrasonic motor.
The technology disclosed in Japanese Patent Application Laid-Open No. 3 (1999) and the technology disclosed in Japanese Patent Application Laid-Open No. 63-87184 are known.

The technique disclosed in Japanese Patent Application Laid-Open No. 61-52163 discloses a torsion mode in which a bending mode and a torsion mode in which a bending vibration in which both sides of the beam perform bending vibration in opposite phases around an axis along the length of the cantilever beam are combined. A rotor is crimped to an end face of an ultrasonic transducer that performs bending vibration, and the rotor is rotated in a plane.

The technique disclosed in Japanese Patent Application Laid-Open No. 63-87184 discloses a technique in which a piezoelectric vibrator is arranged on one end face of a resonator, and a half-wavelength or an integral multiple of the half-wavelength is applied in the vertical direction due to the thickness vibration of the piezoelectric vibrator. The other end face of the ultrasonic vibrator which resonates with the ultrasonic vibrator is provided with one or a plurality of bending vibration protruding pieces which generate bending vibration of one amplitude in synchronization with the resonance of the ultrasonic vibrator around the rotation axis of the rotor. The rotor is disposed and the rotor is brought into contact with the free end of the flexural vibration piece.

[Problems to be solved by the invention]

However, the above-mentioned prior art has the following problems. That is, the above-described conventional ultrasonic motor has a disadvantage that the portion for amplifying the longitudinal vibration and the portion for generating the lateral vibration are separately provided in terms of their functions, thereby complicating the structure. However, since the vertical vibration generating mechanism and the horizontal vibration generating mechanism are separated from each other, a step is formed at the boundary thereof, and there is a major drawback that vibration energy is lost at this step. . Especially,
In the case of an ultrasonic motor using a vibrating projection tuned to the resonator (Japanese Patent Laid-Open No. 63-87184), there are the following problems other than the above disadvantages. That is, since the vibrating protrusions are individually arranged on the resonator, when a load acts on one vibrating protrusion, only the vibrating protrusion on the loaded side works to rotate the rotor. Since the other vibrating piece vibrates in a state near no load, there is a problem that it is difficult to effectively transmit this vibration energy to the vibrating piece on the load side.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the related art, and has as its object to provide a simple and efficient ultrasonic vibrator and an ultrasonic motor using the same.

[Means for solving the problem]

An ultrasonic vibrator according to a first aspect of the present invention is an ultrasonic vibrator comprising a piezoelectric element and a columnar resonator having one end fixed to the piezoelectric element, wherein the resonator is fixed to the piezoelectric element. On the other end surface side facing the one end, a gentle slope from the outer periphery to the other end surface is formed, and a frequency voltage that resonates in the axial direction of the resonator is applied to the piezoelectric element, whereby the other end surface is formed. To excite the elliptical vibration.

An ultrasonic vibrator according to a second aspect of the present invention is an ultrasonic vibrator comprising a piezoelectric element and a columnar resonator having one end fixed to the piezoelectric element, wherein the resonator is fixed to the piezoelectric element. A plurality of gentle slopes from the outer periphery to the other end face are formed on the other end face side facing the one end, and the center of the remaining other end face of the resonator is decentered from the center axis of the resonator. An elliptical vibration is excited on the other end face by applying a frequency voltage that resonates in the axial direction of the resonator to the piezoelectric element.

An ultrasonic motor according to a third aspect of the present invention is an ultrasonic motor comprising: a piezoelectric element; a cylindrical resonator having one end fixed to the piezoelectric element; and a rotor pressed against the other end of the resonator. On the other end of the resonator facing the one end fixed to the piezoelectric element, a gentle slope from the outer periphery to the other end is formed, and the piezoelectric element resonates in the axial direction of the resonator. By applying a frequency voltage, an elliptical vibration is excited on the other end face, and the rotor is driven by the elliptical vibration.

An ultrasonic motor according to a fourth aspect of the present invention is an ultrasonic motor comprising: a piezoelectric element; a cylindrical resonator having one end fixed to the piezoelectric element; and a rotor pressed against the other end of the resonator. A plurality of gentle inclined surfaces extending from the outer periphery to the other end surface are formed on the other end surface side of the resonator facing the one end fixed to the piezoelectric element, and the center of the remaining other end surface of the resonator is formed. Is decentered from the center axis of the resonator, and by applying a frequency voltage that resonates in the axial direction of the resonator to the piezoelectric element, elliptical vibration is excited at the other end surface, and the rotor is excited by the elliptical vibration. It is driven.

(Operation)

In the above-mentioned ultrasonic vibrator, when the resonator is resonated via the piezoelectric element, the resonator vibrates in the vertical direction and at the same time strikes the slope to generate a horizontal vibration, thereby generating an elliptic mode vibration at the tip of the resonator. .

Further, in each of the ultrasonic motors, the rotor or the work is efficiently rotated or linearly driven by the action of the ultrasonic vibrator.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First Embodiment FIG. 1 shows a first embodiment of an ultrasonic vibrator 1 according to the present invention. FIG. 1a is a front view of the ultrasonic vibrator, and FIG.
FIG. B shows a perspective view thereof.

As shown in the figure, an ultrasonic transducer 1 has a piezoelectric element 2 connected to a high-frequency generator (not shown), and a contact surface parallel to the vibration surface of the piezoelectric element 2 (contact surface with an actuated body). A horn (resonator) 4 having a horn 3 and bolts 6 for fastening and fixing the horn 4 and the piezoelectric element 2 via a collar 5 are provided. Reference numeral 7 denotes a terminal plate.

The horn 4 has a slope 9 formed obliquely from the contact surface 3 to the outer peripheral surface. The slope 9 is formed by being inclined at a predetermined angle with respect to the axis 8 of the ultrasonic transducer 1. is there.

In the ultrasonic vibrator 1 having the above configuration, when an appropriate high frequency is applied to the piezoelectric element 2 via the high frequency generator and vibrates in the vertical direction (vertical direction in the figure), the vibration is amplified by the horn 4 and the horn 4 The contact surface 3 vibrates largely in the vertical direction 10 (vertical vibration) due to resonance. At the same time, the vibration wave hits the slope 9 of the horn 4 so that the horn 4
The tip starts to vibrate in the left-right direction 11. Then, the elliptical mode vibration is generated by the vibration in the vertical direction 10 and the vibration in the horizontal direction (left / right direction) 11.

Therefore, if a rotating body (not shown) such as a rotor is pressed against the contact surface 3, the rotor or the like can be rotated.
If a flat plate (not shown) is pressed against the contact surface 3, the flat plate can be moved in parallel.

As described above, according to the present embodiment, it is possible to manufacture the ultrasonic vibrator 1 that directly generates the elliptical mode vibration with an extremely simple configuration at a low cost. Further, conventionally, since the longitudinal vibration generating section and the horizontal vibration generating section were separated from each other, vibration loss was inevitably generated at the step portion of the connecting portion of the two vibration generating sections, but in this embodiment, Since the elliptic mode vibration generating mechanism is integrated, the vibration loss as in the conventional case described above is eliminated, and an extremely efficient ultrasonic vibrator 1 can be obtained.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention. This embodiment shows a configuration example of an ultrasonic motor 200 using the ultrasonic vibrator 1 of the first embodiment.

The ultrasonic motor 20 includes an ultrasonic vibrator 1 and a rotor 21 that is pressed against the contact surface 3 of the ultrasonic vibrator 1 with a predetermined pressing force.
It consists of:

Since the same ultrasonic transducer as that of the first embodiment is used, the description thereof is omitted.

The rotor unit 21 includes an annular rotor 22 and a bearing 23
And a support shaft 24 supported through
Is set so as to be pressed against the contact surface 3 of the horn 4 with a predetermined pressing force.

 Next, the operation based on the above configuration will be described.

When an appropriate high frequency is applied to the piezoelectric element 2 via a high-frequency generator (not shown) and vibrates in the vertical direction, elliptic mode vibration is generated on the contact surface 3 as described above.
Therefore, the rotor 22 pressed against the contact surface 3 rotates in the elliptical rotation direction 25, and the ultrasonic motor 20 is driven to rotate.

As described above, according to the present embodiment, the ultrasonic motor 20 can be obtained with an extremely simple configuration, and the ultrasonic motor 20 can be manufactured at low cost. Further, as described in the first embodiment, since the elliptical mode vibration generating mechanism in the ultrasonic vibrator 1 is integrated, the vibration loss can be reduced to zero. Therefore, in this embodiment, An extremely efficient ultrasonic motor 20 can be provided.

Third Embodiment FIG. 3 shows a third embodiment of the present invention. The feature of the present embodiment is that the second embodiment shows the configuration example of the ultrasonic motor 20 for rotating the rotor 22,
This is a point showing an example of the configuration of an ultrasonic motor (linear motion driving device) 31 configured to move the linear motion of the linear motor 30. That is,
In the present embodiment, two (not limited to two) ultrasonic transducers 1 described in the first embodiment are juxtaposed, and both ultrasonic transducers 1
The elliptical mode vibration synchronized with the contact surface 3 is generated. Since the configuration and operation of each ultrasonic transducer 1 are the same as those of the first embodiment, the description is omitted.

According to the linear drive ultrasonic motor 31 of the present embodiment, each contact surface 3
, An elliptical mode vibration synchronized with the above can be generated.
Therefore, the work 30 movably supported on each contact surface 3 can move the work 30 in the direction of the arrow 32 by driving the linear drive ultrasonic motor 31.

As described above, according to the present embodiment, a rectilinear motion mechanism can be obtained with an extremely simple configuration.

(Fourth Embodiment) FIGS. 4a and 4b show a fourth embodiment of the present invention. This embodiment shows an example of the configuration of an ultrasonic transducer 1 that can move a moving object in two directions simply by changing the frequency to be applied. That is, in the present embodiment, the center of the contact surface 3 of the horn 4 is shifted from the center axis 8 of the ultrasonic vibrator 1 as shown in FIG. 4b which is a plan view of FIG. It is set as follows. In addition, four slopes 40, 41, 42 and 43 are formed at the tip of the horn 4, and each slope 40
43 are set and formed as follows. That is, when the horn 1 is viewed from the front side of the slope 40 (the direction of the arrow 44),
The slopes 42 and 43 are formed so that the tip of the horn 4 has an asymmetric trapezoidal shape. When the horn 4 is viewed from the direction of the arrow 45 shifted from the direction of the arrow 44 by 90 °, the horn 4 Are formed so that the shape of the tip portion of each of them becomes an asymmetric trapezoidal shape different from the trapezoidal shape when viewed from the direction of the arrow 44. The other configuration is the same as that of the first embodiment, and the same members are denoted by the same reference numerals and description thereof will be omitted.

 Next, the operation based on the above configuration will be described.

When the piezoelectric element 2 is vibrated at a frequency that resonates in the direction of arrow 46, that is, in the same direction as arrow 44, through a high-frequency generator (not shown), the same operation as that described in the first embodiment is performed. Elliptical mode vibration starts on a plane including the arrow 44 and the central axis 8. The elliptic mode vibration is generated by the vibration in the vertical direction 47 and the horizontal vibration in the direction of the arrow 46 generated on each of the slopes 40 and 41 as described above. Therefore, in this case, when the moving object (not shown) of the contact surface 3 is pressed, the moving object can be moved in the direction of the arrow 44 or in the direction opposite to the arrow 44.

Similarly, the piezoelectric element 2 is moved in the direction of arrow 48, that is, in the direction of arrow 45.
If a frequency that resonates in the same direction is applied, elliptic mode vibration can be generated on the plane including the arrow 45 and the central axis 8 in the same manner as described above. Therefore, in this case, when the moving object is pressed against the contact surface 3, the moving object can be moved in the direction of the arrow 45 or in the direction opposite to the direction of the arrow 45.

As described above, according to the present embodiment, the moving object (object) can be moved in two directions by one ultrasonic transducer 1 simply by changing the frequency to be applied, which is extremely convenient and efficient. It is a target.

(Fifth Embodiment) FIG. 5 shows a fifth embodiment of the present invention. In this embodiment, an example of the configuration of an ultrasonic motor 50 having a feature in the configuration of the horn 4 is shown. That is, the horn 4 of this embodiment has a pair of projections 51 formed axially symmetrically about the central axis 8,
51 are arranged at positions shifted from each other by 180 ° about the axis 8. Each projection 51 is the same horizontal contact surface 3
And a slope 52 formed from the contact surface 3 to the cylindrical side surface of the horn 4. 53
The vertical plane is indicated by. In addition, each projection 51 is formed with a slope 54 provided to a position where the projection 51 interferes with the other projections 51 so that the vibration of the two projections 51 does not become independent from each other during vibration. Is configured. The bolt 6 includes a relatively large-diameter screw portion 6a, a small-diameter shaft portion 6b,
The piezoelectric element 2 and the main body of the horn 4 are fixed by the large-diameter screw portion 6a of the bolt 6 via the collar 5 with a small-diameter screw portion 6c threaded at the tip of the shaft portion 6b. Has become. The small-diameter shaft portion 6b of the bolt 6 is inserted through the shaft hole 55 of the horn 4, and a space is provided between the small-diameter shaft portion 6b and the shaft hole 55 so as not to contact each other when the horn 4 vibrates. It is provided.

A rotor 56 is supported on a small-diameter shaft portion 6b passing through the shaft hole 55 of the horn 4 via a bearing 57.
Each protrusion of the horn 4 is provided via a nut 58 screwed to the small diameter screw portion 6c and a spring 59 elastically mounted between the nut 58 and the bearing 57.
The contact surface 3 of 51 is pressed and contacted. The other configuration is the same as that of the first embodiment, and the description is omitted.

 Next, the operation based on the above configuration will be described.

When an appropriate high frequency is applied to the piezoelectric element 2 via a high-frequency generator (not shown), the vibration is amplified by the horn 4 and becomes large in the vertical direction 60 on the contact surface 3.
At the same time, the longitudinal vibration wave hits the slope 52, and the projection 51 of the horn 4
Vibrates in the lateral direction 61. This vibration is generated by the pair of projections 51.
Since the phases are shifted by 180 °, two elliptical mode vibrations with a phase shift of 180 ° are generated on the two contact surfaces 3, and the rotor 56 is driven to rotate by the elliptic mode vibration.

In particular, in the present embodiment, since the slope 54 of each projection 51 is set so as to interfere with the drawing, the vibration of the two projections 51 is not independent, and therefore, when the rotor 56 hits the contact surface 3 in one side. However, the energy of the vibration on the no-load side is easily transmitted to the load-side protrusion 51. As a result, the ultrasonic motor 50 that is strong against one end of the rotor 56, that is,
Is obtained. Further, since a space is formed between the bolt small-diameter shaft portion 6b and the shaft hole 55 of the horn 4, there is no loss of vibration energy at the horn 4 portion and an efficient ultrasonic rotor.
50 is obtained.

〔The invention's effect〕

As described above, according to the present invention, it is possible to manufacture an ultrasonic transducer having an extremely simple configuration and high efficiency, and an ultrasonic motor using the same.

[Brief description of the drawings]

FIGS. 1a and 1b are a front view and a perspective view showing a first embodiment of the present invention, FIGS. 2, 3, 4a and 5b, and FIGS. It is explanatory drawing which shows the 2nd, 3rd, 4th and 5th Example. 2 ... Piezoelectric element, 3 ... Contact surface 4 ... Horn, 9 ... Slope 22,56 ... Rotor, 30 ... Work

Claims (4)

(57) [Claims] 1. An ultrasonic vibrator comprising a piezoelectric element and a columnar resonator having one end fixed to the piezoelectric element, wherein the resonator opposes one end of the resonator fixed to the piezoelectric element. On the end face side, a gentle slope from the outer circumference to the other end face is formed, and by applying a frequency voltage that resonates in the axial direction of the resonator to the piezoelectric element, elliptical vibration is excited on the other end face. An ultrasonic transducer characterized by the above-mentioned. 2. An ultrasonic vibrator comprising a piezoelectric element and a columnar resonator having one end fixed to the piezoelectric element, wherein the other end of the resonator opposes one end fixed to the piezoelectric element. On the end face side, a plurality of gentle slopes from the outer periphery to the other end face are formed, and the center of the remaining other end face of the resonator is decentered from the center axis of the resonator. An ultrasonic vibrator characterized in that elliptical vibration is excited at the other end face by applying a frequency voltage that resonates in the axial direction of the body. 3. An ultrasonic motor comprising: a piezoelectric element; a columnar resonator having one end fixed to the piezoelectric element; and a rotor pressed against the other end of the resonator. Forming a gentle slope from the outer periphery to the other end surface on the other end surface side opposite to the one end fixed to the piezoelectric element, and applying a frequency voltage that resonates in the axial direction of the resonator to the piezoelectric element. Thereby exciting the elliptical vibration on the other end face and driving the rotor by the elliptical vibration. 4. An ultrasonic motor comprising a piezoelectric element, a columnar resonator having one end fixed to the piezoelectric element, and a rotor pressed against the other end of the resonator, wherein: On the other end face side opposite to the one end fixed to the piezoelectric element, a plurality of gentle slopes from the outer periphery to the other end face are formed, and the center of the remaining other end face of the resonator is set to the center of the resonator. By eccentrically deviating from the center axis and applying a frequency voltage that resonates in the axial direction of the resonator to the piezoelectric element, elliptical vibration is excited on the other end surface, and the rotor is driven by the elliptical vibration. Ultrasonic motor.