JPH01315271A - Piezoelectric motor - Google Patents

Abstract

PURPOSE:To enhance conversion efficiency and to increase a torque by dispersively forming a plurality of protrusions protruding toward a rotor circumferentially on the face of the support of a stator in contact with the rotor. CONSTITUTION:First, second piezoelectric vibration plates 24, 25 respectively adhere to the inner faces of disclike supports 22, 23 opened at the outside of a turning forklike crosssectional circular support 21. A rotor 28 is so provided as to surround a stator from the side formed with protrusions 26, 27. The rotor 28 is composed by coupling disclike metal plates 29, 30 formed with annular walls extending in a direction at the outer peripheral edge through an elastic material 31. In this case, the protrusions 26, 27 are formed at the side of the stator to be brought into pressure contact with the rotor 28. Thus, when the plate 24 is vibrated, the support 22 is largely displaced as compared with the base at the end side of the protrusion 26. Slip between the stator and the rotor is effectively reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an annular piezoelectric motor that utilizes traveling waves based on solid-state resonance in an ultrasonic band. Regarding improvements.

[Conventional technology]

FIG. 2 is a partially cutaway perspective view of a conventional piezoelectric motor.
FIG. 3 is a sectional view of essential parts of the piezoelectric motor.

With reference to FIGS. 2 and 3, this piezoelectric motor has the following characteristics:
A stator is constructed using an annular support 1 having a tuning fork-shaped cross section. That is, the first... A second piezoelectric diaphragm 4.5 is pasted on the piezoelectric diaphragm 4.5.
A traveling wave is generated in the circumferential direction of the support 1 by bending and vibrating the support 1 .

1st. In the second piezoelectric diaphragm 4.5, a plurality of regions connected in the circumferential direction are decentralized as shown in FIG. That is, in the first piezoelectric diaphragm 4, a plurality of polarization regions 7a for configuring a first excitation source, a plurality of polarization regions 7b for configuring a second excitation source, a bipolarization region 7c, 7d is formed. In Figure 4, the + and - symbols enclosed in circles indicate the polarization direction of each polarization region, respectively, with + indicating polarization extending from the top side to the bottom side, and - indicating polarization from the bottom side. Indicates that the top surface is polarized.

As is clear from FIG. 4, in the second piezoelectric diaphragm 5 as well, a plurality of Fi 8N regions 7a, 7b are formed in order to constitute the first and second excitation sources. Polarized regions 7c and 7d are arranged between them.

Note that the polarization direction of the polarized region in the second piezoelectric diaphragm 5 is polarized in the opposite direction to that of the corresponding polarized region in the first piezoelectric diaphragm 4. This is the first. This is because by vibrating the second piezoelectric diaphragm 4.5 in an opposite phase, a rotor, which will be described later, is rotated.

Although not particularly illustrated, the first. Appropriate electrodes are formed on the bidirectional surfaces of the second pressure t* dynamic plates 4.5 in order to vibrate each piezoelectric diaphragm 4.5.

Since the piezoelectric diaphragm 4.5 is polarized as shown in FIG. 4, when a voltage is applied to the piezoelectric diaphragm 4.5 to generate a traveling wave,
- The following bending vibrations occur and the support 1 is vibrated as shown schematically in FIG. And the first. By generating a traveling wave based on the above-described bending vibration in the second piezoelectric diaphragm 4.5, the rotor 11, which is pressed against the support l, is rotationally driven.

As shown in FIG. 3, the rotor 11 has a first rotor attached to cover the support l. Second annular metal plate 12.1
3 are connected by bolts 14. Reference numeral 15 denotes an elastic material, which is provided to adjust the degree of connection between the two metal plates 12 and 13 using bolts 14, thereby adjusting the pressure force between the rotor 11 and the support 1.

[Technical Problem to be Solved by the Invention] In the piezoelectric motor using the support 1 having a tuning fork cross-sectional shape as described above, the two support parts 2.3 disposed one above the other are subjected to bending vibration, and The rotor 11 is rotationally driven by the traveling wave based on this.

Therefore, since the rotor 11 is rotated by the driving sources arranged above and below, it has the advantage of excellent rotational efficiency.

However, when the piezoelectric motor shown in FIG. 2 was actually rotated, it was found that it was not necessarily possible to achieve the intended efficiency, that is, high conversion efficiency and high torque.

Therefore, an object of the present invention is to provide a piezoelectric motor that exhibits higher energy conversion efficiency and has high torque.

[Means for solving technical problems]

The piezoelectric motor of the present invention includes an annular support member having a tuning fork shape in cross section;
The first one supported by this support. The stator is configured using a stator having a second piezoelectric diaphragm. 1st. The second piezoelectric diaphragm is supported by the support body while being concentrically arranged at intervals in the thickness direction. Also, 1st. Second
The piezoelectric diaphragm is vibrated in a bending imaging mode to generate a traveling wave in the circumferential direction of the support.

A rotor is pressed into contact with the stator, and is configured to be rotationally driven by a traveling wave caused in the stator.

In the present invention, a plurality of protrusions protruding toward the rotor are formed distributed in the circumferential direction on the surface of the stator support that comes into contact with the rotor.

[Effect]

The present invention was made based on the fact that the inability to obtain the intended efficiency in conventional piezoelectric motors with a tuning fork cross section is caused by slippage between the rotor and stator. In this case, a plurality of protrusions are formed distributed in the circumferential direction on the surface of the stator support that comes into contact with the rotor in a state that protrudes toward the rotor, so that the support band is displaced more greatly in the circumferential direction. It is considered possible. That is, as is clear from the examples described below,
A plurality of protrusions are formed in a dispersed manner, and the tips of the protrusions are displaced in the traveling direction to a greater extent than the surface of the support body on which the protrusions are formed. Furthermore, since the support body is largely displaced in the direction of movement and the plurality of protrusions abut point contact with the rotor, slippage between the rotor and stator is also reduced.

(Description of Embodiments) FIG. 1 is an exploded perspective view for explaining essential parts of a first embodiment of the present invention, and FIG. 7 is a partial sectional view of the first embodiment.

Referring to the 7th article, a first tube is attached to the inner surface of the disk-shaped support portion 22.23 that is open to the outside of the annular support member 21 whose cross section is shaped like a tuning fork. A second piezoelectric diaphragm 24,25 is attached. The piezoelectric diaphragms 24.25 are constructed in the same manner as the conventional piezoelectric diaphragm 4.5 shown in FIG.

The feature of this embodiment is that, as shown in FIG. 1, a plurality of upwardly and downwardly protruding portions are provided on the outer main surfaces of the plate-shaped support portions 22 and 23, that is, on the surfaces that are pressed into contact with the rotor, which will be described later. The reason is that the protrusions 26 and 27 are formed in a distributed manner in the circumferential direction.

Returning to FIG. 7, the rotor 28 is provided so as to surround the stator from the side where the protrusions 26 and 27 are formed. This rotor 28 is constructed in the same manner as the conventional example shown in FIG. It is constructed by connecting the two.

In this embodiment, protrusions 26 and 27 that protrude toward the rotor 28 are formed on the surface of the stator that is pressed against the rotor 28, that is, on the upper surface of the support portion 22 and the lower surface of the support portion 23.

Therefore, when the piezoelectric diaphragm 24 is vibrated, the support portion 22
is deflected as schematically shown in FIG. In this case, as is clear from FIG. 8, the distal end side of the protrusion 26 is largely displaced compared to the base, that is, the upper surface of the support section 22. Therefore, since the amount of displacement of the protrusion 26 in the advancing direction is larger than that of the base of the protrusion 26, a larger torque is applied to the rotor 28 side. At the same time, since the plurality of protrusions 26 are formed in a distributed manner, the protrusions 26 can be attached to the rotor 28.
It can be seen that the slip between the stator and the rotor is effectively reduced because the stator and the rotor are pressed one after another in a point contact manner.

Although the above embodiment utilizes the primary resonance mode of the annular elastic body, a similar piezoelectric motor can also be constructed using the secondary resonance mode.

FIG. 9 is a sectional view showing a second embodiment using a secondary resonance mode.

When the secondary resonance mode is used, the stator undergoes bending vibration as shown in FIG. Therefore, as shown in FIG. 9, fixing parts 42 and 43 for fixing the stator to a bracket (not shown) are provided above and below the tuning fork-shaped support 41. Further, the support body 41 having a tuning fork-shaped cross section is
As shown in FIG. 6, the central region of the disc-shaped support 44, 45 is displaced the most. Therefore, in this embodiment, a plurality of protrusions 46, 47 protruding toward the rotor 48 are distributed in the circumferential direction in the central region of the support part 44, 45. Since the other structures are the same as those in the first embodiment, explanations thereof will be omitted by assigning corresponding reference numbers.

In the second embodiment as well, a plurality of protrusions 46 and 47 are formed distributed in the circumferential direction on the surface of the stator support 41 that is in pressure contact with the rotor 48. The displacement in the direction of travel is amplified by the projections 46,47. Furthermore, slippage between the rotor and stator is also reduced.

It goes without saying that when using the secondary resonance mode as in this embodiment, the piezoelectric diaphragms 44a and 45a need to be polarized so that secondary resonance is likely to occur.

1st. In the second embodiment, the outer surfaces of the support portions 22, 23, 44.45 of the support body 21.41 were used to transmit the driving force to the rotor, but the rotor is attached to the inner surface of the support portion. The rotor may be rotated by arranging the rotor.

FIG. 10 is a sectional view showing a third embodiment in which a rotor is arranged between support parts.

As is clear from FIG. 10, in the piezoelectric motor using the secondary resonance mode, the support 41 constituting the stator
Piezoelectric diaphragms 44a and 45a are attached to the outer surfaces of the supporting parts 44 and 45, respectively.This is because the inner surfaces of the supporting parts 44 and 45 are pressed against the rotor 48. A plurality of protrusions 46,47 that protrude toward the rotor 48 are formed on the inner surface of the support portions 44,45.

On the other hand, the rotor 48 is disposed in the space between the support parts 44 and 45, and is constituted by a metal ring having a U-shaped cross section. Reference numeral 49 denotes an elastic material, which is provided to adjust the degree of repulsion between the driven parts 48a and 48b of the rotor 48, thereby adjusting the pressure contact force with the protruding parts 46 and 47.

Also in the embodiment of FIG. 10, a plurality of protrusions 46, 47
is formed protruding from the rotor 48 side, so that the first. Second
As in the embodiment, the amount of displacement in the advancing direction is the same as that of the protrusion 46.
47.

〔Effect of the invention〕

As described above, in the present invention, a plurality of protrusions protruding toward the rotor are formed distributed in the circumferential direction on the surface of the stator support that comes into contact with the rotor, so that the amount of displacement in the advancing direction is reduced. is amplified by the protrusion. Therefore, compared to a piezoelectric motor using a conventional annular support having a tuning fork-shaped cross-section, conversion efficiency can be further increased, and a high-torque piezoelectric motor can be realized.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view for explaining the main parts of the first embodiment of the present invention, FIG. 2 is a partially sectional perspective view of a conventional piezoelectric motor, and FIG. 3 is a sectional view of a conventional piezoelectric motor. Figure 4 is a perspective view for explaining the polarization state of the piezoelectric diaphragm, and Figure 5 is 1
FIG. 6 is a schematic diagram for explaining the bent state of the stator when using the secondary resonance mode. FIG. 6 is a schematic diagram for explaining the bent state of the stator when using the secondary resonance mode. 8 is a schematic sectional view for explaining the function of the protrusion in the first embodiment, and FIG. 9 is a sectional view of the second embodiment of the present invention. The figure is a sectional view of a third embodiment of the invention. In the figure, 21 is an annular support body, 22.23 is a support part, 24.25 is a piezoelectric diaphragm, 26.27 is a protrusion part, 2
8 indicates a rotor. Figure 1 Figure 7 Figure 2 Figure 5 j Figure 6 Figure 9! Ladder 1Of21 L17LI-513b

Claims (1)

[Scope of Claims] An annular support member having a tuning fork-shaped cross section, and a ring-shaped support member that is supported by the support member in a state in which the support member is arranged concentrically at intervals in the thickness direction, and that is vibrated in a bending vibration mode. The first and second waves generate traveling waves in the circumferential direction of the body.
A piezoelectric motor comprising: a stator having a piezoelectric diaphragm; and a rotor that is pressed into contact with the stator and rotated by a traveling wave caused in the stator; A piezoelectric motor, characterized in that a plurality of protrusions protruding toward the rotor are distributed in a circumferential direction.