JPH0648911B2 - Ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention uses an ultrasonic oscillator vibrating by a piezoelectric oscillator as a stator, and the ultrasonic oscillator drives a rotor to rotate. It is about.

<Prior Art> A piezoelectric vibrator or the like is used as a drive source to form a stator,
There are various ultrasonic motors for rotating a rotor by means of the stator as disclosed in JP-A-59-96882 and the like, but all of them have a multi-phase structure in which the stator is formed in an annular shape or the like. The traveling wave is generated by applying the driving voltage of (1), and the rotor is rotated by the traveling wave.

It is an object of the present invention to provide an ultrasonic motor having a structure capable of rotating a rotor by longitudinal vibration of a resonator caused by thickness vibration of a piezoelectric vibrator, unlike the case of rotating a rotor by a traveling wave. Is.

<Means for Solving Problems> According to the present invention, a piezoelectric vibrator is provided on one end surface of a solid vibration enlarging horn, and a half wavelength or an integer multiple thereof is obtained depending on thickness vibration of the piezoelectric vibrator. Then, a supporting hole is formed at the center of the other end face of the ultrasonic transducer that resonates in the vertical direction, and at the peripheral portion of the supporting hole, a bending side portion is projected from one circumferential edge of the pedestal portion, A plurality of L-shaped cross-section vibrating protrusions, which are tuned to the resonance of the ultrasonic transducer and generate single-sided swing flexural vibration in one direction orthogonal to the radial direction, are connected to the flexible side portion, On the free end of the vibrating bar, the rotation axis from the center of one side,
A disk-shaped rotor with a support shaft protruding from the center of the other side,
The end of the support shaft is inserted into the support hole of the vibrating horn to make contact with the free end of the vibrating protrusion, and the rotor can be rotated by the support shaft fixed at the node position of the vibrating horn. The ultrasonic motor is characterized in that the rotating shaft is supported and protrudes outward.

Here, the flexural vibration of the one-sided swing means the vibration in which the flexure in one direction is larger than the flexure in the other direction, and does not necessarily mean the vibration limited to only one direction.

<Operation> When a voltage having a predetermined frequency is applied to the piezoelectric vibrator, the ultrasonic vibrator resonates in the vertical direction. Then, due to this vibration, the vibrating projection piece induces a flexural vibration of a swing width in the circumferential direction. Then, the vibration protrusion converts the longitudinal vibration of the ultrasonic transducer into the rotation vibration.

Here, each of the vibrating protrusions has an L-shape formed by projecting a bending side portion from one side edge in the circumferential direction of the pedestal portion, and the base portion of the bending side portion is held by the pedestal portion. , It becomes easy to bend in the side edge direction in which the holding action of the pedestal part is released. Therefore, the reciprocating vibrations are canceled out, the amplitude in the direction in which the bending easily occurs is effective, and the swinging bending vibration in the same direction is generated.

Since the vibration locus at the tip of the vibrating projection piece is a combination of the vertical vibration and the bending vibration of the single swing, a circumferential component is generated at the upper end of the vibration locus. For this reason,
The rotor, which is in contact with the tip of the vibrating protrusion, is given a circumferential feed force, is supported by the support shaft, and is rotated, and is taken out as an output by the rotary shaft protruding outward from the support shaft. Will be done.

<Embodiment> An embodiment of the present invention will be described with reference to the accompanying drawings.

Reference numeral 2 denotes a solid cylindrical vibrating horn which serves as a resonator, and a pair of annular piezoelectric elements 5 and 5 and a space between the elements are provided on an end surface of a large-diameter mounting seat 3 formed at a rear end portion thereof. The piezoelectric vibrator 4 including the terminal plates 6a and 6b arranged on the lower surface of the piezoelectric vibrator 4 contacts the piezoelectric vibrator 4, and the metallic ring-shaped contact body 7 is attached to the lower surface of the piezoelectric vibrator 4. The vibrating horn 2 is screwed through the abutment body 7 to be connected.
The vibrating horn 2 has a function of amplifying the vibration from the piezoelectric vibrator 4 at one end surface thereof, and thus the ultrasonic vibrator 1
Is configured.

A support hole 11 is formed at the center of the front end surface 10 of the vibrating horn 2. Further, in the front end face 10, around the support hole 11, two vibrating projecting pieces 12, 12 project in the radial direction in the figure.

The vibrating projections 12 and 12 are L-shaped, which is formed by projecting a bending side portion 14 from one side edge in the circumferential direction of a pedestal portion 13 which is formed by grinding the front end surface 10 and is formed continuously. The side portion 14 is easily bent in the direction (x direction in FIG. 3) orthogonal to the radial direction without the pedestal portion 13 due to the base holding action of the pedestal portion 13. The respective vibrating protrusions 12, 12 have the same arrangement along the circumferential direction.

A disc-shaped rotor 15 is fitted into the support hole 11 by inserting a support shaft 16, and the disc portion 17 is attached to the vibrating protrusion 1.
A rotary shaft 18, which abuts on the upper ends of the flexible side portions 2 and 12 and projects upward from the central portion of the disk portion 17, projects upward at the concentric position with the vibration horn 2. The upper end of the vibrating horn 2 has a support shaft 21 at the upper end.
A support cylinder 20 having an open lower surface shielded by is externally fitted, and a flange 19 protruding from the peripheral surface of the vibration horn 2 at the node position allows
The lower end edge of the support cylinder 20 is locked, and the support shaft body 2 on the upper end side is locked.
1, the rotary shaft 18 is inserted into a bearing 22 provided inside, and the lower end of the support cylinder 20 is welded and fixed to a flange 19, whereby the rotary shaft 18 is supported by the bearing 22 of the support shaft body 21. Holding An elastic material 24 is interposed between the disk portion 17 and the support shaft 21.

In such a configuration, the front edge of the mounting seat 3 in charge of the position of the node and the peripheral edge of the flange 19 are connected to the support portions 25 and 2.
5, the distance from the flange 19 to the tip of the bending side portion 14 of the vibrating protrusions 12, 12 is set to a length of a quarter wavelength and a length of one wavelength.

Next, the operation of the above embodiment will be described.

When an alternating voltage having a frequency matching the resonance frequency of the ultrasonic transducer 1 is applied to the terminal plates 6a and 6b, as shown in FIG.
Like the amplitude distribution curve shown along the axial direction of the ultrasonic transducer 1, the supporting portions 25, 25 are set to the node position, and resonate vertically at one wavelength. Then, the vertical vibration having the maximum amplitude is generated at the tip positions of the vibrating protrusions 12, 12. Then, the vibration projections 12 and 12 convert the longitudinal vibration of the ultrasonic transducer into the rotational vibration.

Here, each of the vibrating protrusions 12, 12 has an L shape in which a bending side portion projects from one side edge in the circumferential direction of the pedestal portion, and the base portion of the bending side portion is held by the pedestal portion 13. Therefore, it is easy to bend in the side edge direction in which the holding action of the pedestal portion 13 is released. Therefore, the reciprocating vibrations are canceled out, and the amplitude in the direction of easy bending becomes effective. Therefore, in synchronism with the resonance of the ultrasonic oscillator 1, a flexural vibration having a oscillating width in the direction of arrow x in FIG. The tip of the flexible side portion 14 is combined with the axial vibration of the vibrating horn 2 to generate an arcuate or elliptical vibration locus y as shown in FIG. A circumferential component force f is generated. Therefore, the rotor 15 has a disc portion 17 on the upper end of the flexible side portion 14.
Since the lower surfaces are in contact with each other, a rotational force is applied by the component force f to rotate around the support shaft 16. Then, the turning force can be taken out from the rotary shaft 18.

In the outer shape shown in FIG. 1, the ultrasonic transducer 1 has a total length of 271 mm, and the main portion of the vibrating horn 2 has an outer shape of 40 mm.
Resonance frequency 20.5KHz, input 10W under the size of mmφ
When a voltage was applied to the terminal plates 6a and 6b under the condition of, the rotor 15 was rotated at 250 rpm.

In the above embodiment, the large-diameter mounting seat 3 may be removed to form a cylindrical resonator.

Furthermore, the vibrating protrusions 12 can be properly formed in the circumferential direction.

<Effects of the Invention> As described above, the present invention is provided with a piezoelectric vibrator on one end face of a vibration horn for amplitude amplification, and the piezoelectric vibrator vertically vibrates at a half wavelength or an integral multiple length thereof due to thickness vibration of the piezoelectric vibrator. Direction of the ultrasonic vibrator, the end face of the vibrating horn is provided with a bending side portion projecting from one side edge in the circumferential direction of the pedestal portion, and the bending side portion causes resonance of the ultrasonic vibrator. A plurality of L-shaped vibrating protrusions having a cross section, which are synchronized with each other and generate unidirectional swing flexural vibration in one direction orthogonal to the radial direction, are coupled to convert the axial vibration of the ultrasonic vibrator into flexural vibration. Then, the rotor is rotated by the feed force in the circumferential direction generated at the top end of the vibration locus, and the rotor is supported by the support shaft fixed to the node position of the vibration horn, and the rotation shaft of the rotor is projected outward. , Can be taken out as an output.

For this reason, a) it was possible to provide a new ultrasonic motor that uses the thickness vibration of the piezoelectric vibrator as a drive source.

B) Since the thickness vibration of the piezoelectric vibrator is used,
Unlike the annular stator that requires multi-phase voltages, voltage control becomes easy.

C) By supporting at the node position of the above-mentioned amplitude, the motor can be held without disturbing the vibration of the vibrating projection piece, and the assembly is easy.

D) By changing the outer shape of the resonator, it is possible to generate an output at a desired rotation speed.

E) Since the rotor is held by the support shaft fixed to the node position of the amplitude expanding vibration horn, the rotation loss is small, and unlike the case where the rotor is supported by surrounding members,
A single jig is constructed as a whole, which gives versatility.

F) Since an L-shaped vibrating protrusion having a cross section formed by projecting a bending side portion from one side edge in the circumferential direction of the pedestal portion is used, it is possible to couple to the vibrating horn, the number of parts is small, and the structure is simple. Become.

G) Adopting a disc-shaped rotor with a special structure in which a rotary shaft is projected from the center of one side and a support shaft is projected from the center of the other side.
Since the rotor is directly supported by the vibrating horn, receives the rotational force from the vibrating piece, and directly takes out the output by the rotating shaft, there is no need to interpose other members, and the drive system has a simple structure. Is constructed, and the structure is simplified.

And so on.

[Brief description of drawings]

The attached drawings show an embodiment of the present invention. FIG. 1 is a vertical sectional side view in which an amplitude distribution curve of longitudinal vibration is added in the axial direction, and FIG.
FIG. 3 is a sectional view taken along the line -A, and FIG. 1; ultrasonic transducer, 2; vibrating horn, 3; mounting seat,
4; Piezoelectric vibrator, 11; Support hole, 12; Vibration protrusion, 1
3; pedestal part, 14; bending side part, 15; rotor, 16; support shaft, 18; rotating shaft, 21; support shaft body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Michiyuki Masuda Inventor Michiyuki Masuda 14-18 Takatsuji-cho, Mizuho-ku, Nagoya, Aichi Nihon Special Ceramics Co., Ltd. (56) Reference JP-A-60-109776 (JP, A) " Applied Mechanical Engineering ”May issue, Vol. 24, No. 5, published May 1, 1983, Taiga Publishing Co., Ltd. 88-92

Claims (1)

[Claims] 1. An ultrasonic wave which comprises a piezoelectric vibrator on one end surface of a solid vibration amplitude horn and which resonates in the longitudinal direction at a half wavelength or an integral multiple length thereof due to thickness vibration of the piezoelectric vibrator. A supporting hole is formed at the center of the other end surface of the vibrator, and a bending side portion is projected from one side edge in the circumferential direction of the pedestal portion at the peripheral portion of the supporting hole, and the ultrasonic vibration is generated at the bending side portion. A plurality of L-shaped vibrating protrusions having a cross-section, which are adapted to generate unidirectional swing flexural vibrations in one direction orthogonal to the radial direction in synchronization with the resonance of the child, are formed on the free ends of the vibrating protrusions. The rotation axis from the center of one side,
A disk-shaped rotor with a support shaft protruding from the center of the other side,
The end of the support shaft is inserted into the support hole of the vibrating horn to make contact with the free end of the vibrating protrusion, and the rotor can be rotated by the support shaft fixed at the node position of the vibrating horn. An ultrasonic motor characterized in that it is supported and its rotation shaft is projected outward.