JPS62259485A - Piezoelectric driving apparatus - Google Patents

Abstract

PURPOSE:To convert electrical energy to mechanical driving force with high efficiency by providing a contact member consisting of a plurality of plate members stacked each other through elastic members and allowing said plate members to be elastically connected to each surface of the opposed sides of vibration unit. CONSTITUTION:Since high frequency voltages having phase difference are applied to the piezoelectric elements 4 attached to adjacent two surfaces of opposed sides 3 of vibration material 2, each opposed side 3 makes circular or elliptic movement at the maximum amplitude point. Since a contact member 6 is placed in contact with the one surface of such opposed sides 3, this contact member 6 or vibration unit l is driven, generating mechanical driving force. In this case, since the vibration material 2 is formed in the shape of letter ? or ?, both opposed sides 3 resonate with each other and thereby large vibration amplitude can be obtained. Moreover since the contact member 6 is placed in contact with the one surface of opposed sides 3, any of the contact member 6 or vibration unit 1 is driven and thereby mechanical driving force may be obtained. In this case, since each vibration material 2 is formed in the shape of letter ? or ?. Both opposed sides 3 resonate with each other and thereby large vibratlon amplitude can be obtained. Moreover, since the contact member 6 is formed by a plurality of plate materials stacked through elastic members 6c, the contact member6 and vibration unit 1 are always placed in contact with almost constant pressure even if these do not have highly accurate sizes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a piezoelectric drive device, such as a reciprocating type or a rotary type, using a piezoelectric element.

[Background technology]

Conventionally, as an ultrasonic motor using piezoelectric elements,
There is one shown in Publication No. 9-037672.

This involves attaching a piezoelectric element to a vibrating body to generate longitudinal vibration, forming a tilted drive piece at the tip of the vibrating body, and causing the tip to move in an ellipse due to the longitudinal vibration, and connecting it to a disk. When they come into contact, the friction force causes the circle to rotate.

However, with this conventional structure, the direction of rotation is determined by the direction of inclination of the drive piece, and the tip of the drive piece is thin, so wear is large due to friction, and there are problems in terms of service life.

Another conventional example is disclosed in Japanese Patent Application Laid-open No. 148682/1982. In this example, the entire vibration of the piezoelectric element is transmitted to the vibrating body, and one waveform is 99 times larger than the other waveform.
By vibrating with a 0'' phase shift, a traveling wave is generated on the surface of the vibrating body, and by bringing the rotor into contact with the traveling wave, the rotor is rotated by friction.

According to this example, reversal is also possible, but it is necessary to always apply energy to the entire vibrator, and moreover, it is necessary to absorb vibrations to the opposite side of the piezoelectric element. Therefore, energy loss is large and it is difficult to improve efficiency. Furthermore, in forming a linear motor, unless a measure is taken to circulate the traveling waves, the energy loss is too large to be a problem, and the circulation method is also extremely difficult.

[Purpose of the invention]

This invention enables piezoelectric actuators that can efficiently obtain mechanical driving force with low power consumption by keeping the contact pressure between the contact member and the vibrator almost constant without requiring high precision, and that enables stable driving. An object of the present invention is to provide a driving device.

[Disclosure of the invention]

The piezoelectric drive device of the present invention has at least one vibrating body formed of a metal elastic material into a mouth shape or a mouth shape and having a pair of opposing sides each having a rectangular cross-sectional shape. A piezoelectric element is attached to at least two adjacent sides of each opposing side, a predetermined high frequency voltage is applied to the piezoelectric element, and the opposing side vibrates resonantly. A power supply device that applies a cylindrical frequency voltage with a phase difference, and a contact member that contacts each side of the opposite sides of the vibrator, wherein the maximum amplitude point of the opposite sides of the vibrator is a circle or an ellipse. In the piezoelectric drive device in which either the contact member or the vibrator is driven by movement, the contact member is composed of a plurality of plate-like members stacked on top of each other with an elastic member in between.

According to the configuration of the present invention, a high frequency voltage with a phase difference is applied to the piezoelectric elements attached to two adjacent sides of each opposing side of each vibrating body, so that the maximum amplitude point of each opposing side moves in a circular or elliptical motion. do. Since the contact member comes into contact with one of the opposing sides, either the contact member or the vibrator is driven, and a mechanical driving force is obtained.

In this case, since each vibrating body is shaped like an opening or an opening, both sides of the vibrating body resonate with each other, and a large amplitude can be obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. In addition, since the resonance of the vibrating body occurs in a non-vibrating state at the base end where the two opposing sides are continuous, by using the base end as the support part, the vibration is not hindered by the support. , this also provides high efficiency. Furthermore, since there are parts of the vibrating body that do not vibrate, either the vibrator or the contact member can be used as either a fixed side or a movable side. Further, the vibrating body has two opposing sides, both of which are in contact with the contact member, and the vibrating force of both vibrations v1 acts additively, so that the number of contact points is multiplied.

Therefore, wear is reduced and stable driving is possible.

Furthermore, since the contact member is made of a plurality of plate members stacked one on top of the other with an elastic member interposed in between, the contact member and the vibrator always come into contact with a substantially constant pressure even if high dimensional accuracy is not required. Therefore, there is no unevenness in the thrust force when the contact member or the vibrator moves, and it is possible to obtain a large thrust force.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. This piezoelectric drive device is an example applied to a linear motor, and consists of one vibrating body 2 made of a metal elastic material in the shape of a mouthpiece and having a pair of opposing sides 3 each having a rectangular cross-sectional shape. The vibrating body 2 includes a piezoelectric element 4 attached to two adjacent surfaces of each of the opposing sides 3, and a vibrator l whose opposing sides 3 vibrate resonantly when a predetermined high frequency voltage is applied to the piezoelectric element 4. The vibrator is composed of a power supply device 5 that applies a high frequency voltage to adjacent piezoelectric elements 4 on opposing sides 3 with a phase difference, two plate-like members 6a and 6b, and an elastic member 6C interposed between them. The contact member 6 is provided with an upper plate-like member 6a in elastic contact with each of the opposing sides 1223 of the vibrator 1, and the maximum amplitude point of the opposing side 3 of the vibrator 1 moves in a circular or elliptical manner. Alternatively, either the vibrator 1 is driven.

The vibrating body 2 is made of a constant elastic body such as Erinba, but if stability against temperature is not particularly required, a metal material such as general steel may be used.

The base end 2a of the vibrating body 2 has a length that does not affect vibration even if it is fixed, and is fixed to the base 7 as shown in FIG.

The elastic member 6C of the contact member 6 is made of a wavy leaf spring.

Guide bins 10 are installed upright at the four corners of the lower plate-like member 6b as shown in FIG. 7, and the upper plate-like member 6a and the elastic member 6
The guide pin 10 is inserted through the guide holes 11 and 12 provided at C. Thereby, the upper and lower plate-like members 6a, 6b and the elastic member 6C are integrated so that they are mutually movable only in the thickness direction. The contact member 6 is supported on a base 7 (FIG. 2) via guide means (not shown) so that the lower plate member 6b can move forward and backward in the direction of arrow P in FIG. It is. In addition, in FIGS. 4 and 5, the contact member 6 is shown in a simplified manner as if it were an integral part, in order to make the explanation easier to understand.

As shown in FIG. 6, the electric dJA device 5 has a high frequency power source 8 and a 90'' phase shifter 9, and each piezoelectric element 4 (4, to 44)
Apply voltage as shown in the figure. The symbols ■■ in the figure indicate the polarity of polarization.

Each piezoelectric element 4□ to 44 on the two opposite sides 3 of the motion vibrating body 2,
When a high frequency voltage is applied and excited by the power supply device 5 of FIG. 6, each opposing side 3 vibrates in the vertical and horizontal directions in accordance with the excitation of the respective piezoelectric elements 4□ to 44. At this time, piezoelectric element 4
2. When a voltage whose phase is delayed by 90'' from the piezoelectric elements 4□ and 43 is applied to 2.44, the X point at the tip of the opposite side 3 of the vibrator l.

The Y point moves in a circular or elliptical orbit as shown in FIG. Therefore, when the contact member 6 is arranged so as to be in contact with one surface of the opposing side 3, the contact member 6 moves linearly in the direction of the arrow P. The flatness of the elliptical orbit of the X point and the Y point is
It can be adjusted by the difference in bending rigidity depending on the bending direction of the opposing sides 3, the one phase difference in the magnitude of the voltage applied to each piezoelectric element 4□ to 44, etc.

If a voltage with a phase advance of 90'' is applied to the piezoelectric elements 4□, 44, the contact member 6 will move in the opposite direction to the arrow P, drawing a trajectory opposite to that shown in FIG.

Although it operates in this way, since each vibrating body 2 is U-shaped, both of its radial sides 3 resonate with each other, and a large amplitude is obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. Further, the resonance of the vibrating body 2 is performed in such a manner that the base end 2a where the two opposing sides 3 are continuous is in a non-vibrating state as shown in FIG. 3(A).
By using a as a support part, vibrations are not hindered by the support, and high efficiency can also be obtained from this fact.

Further, since there are parts of the vibrating body 2 that do not vibrate in this way, either the vibrator 1 or the contact member 6 can be used as either a fixed side or a movable side.

Further, the vibrating body 2 has two opposing sides 3, both of which are in contact with the contact member 6, and the vibration force due to the vibration of both acts additively, thereby increasing the number of contact points. Therefore, wear is reduced and stable driving is possible.

Further, the contact member 6 is composed of two plate members 6a and 6b with an elastic member 6C interposed between them, and the elastic member 6c
Since the plate member 6a is brought into elastic contact with the opposite side 3 by the restoring force, the contact pressure between the contact member 6 and the opposite side 3 is always kept substantially constant. Therefore, the unevenness of the thrust is eliminated, and it becomes possible to obtain a large thrust.

In this embodiment, the opposite side 3 is 1s as shown in Fig. 3 (A>).
Although we have explained the case of vibration in t mode, Fig. 3 (
B) As shown in (C), when vibrating in a higher order mode such as the 2nd mode or 3rd mode, the contact member 6 on the opposite side 3
This allows for even more contact points. This makes it possible to further reduce wear at the contact points and stabilize the operation. The 1st mode occurs when one piezoelectric element 4 is attached to the opposite side 3 in the longitudinal direction. The 2nd mode occurs when this single piezoelectric element 4 is divided into two in the longitudinal direction and pasted with the polarization directions reversed. In the 3rd mode, one piezoelectric element 4 is divided into three parts in the longitudinal direction, and the central divided piezoelectric element and the divided piezoelectric elements on both sides are pasted with opposite polarization directions, and the electrodes on the same side of each divided piezoelectric element are shared. This shows the amplitude mode that occurs when the same voltage is applied as .

FIG. 8 shows a contact member 6' in a second embodiment. In this example, the lower plate-like member 6b' is made longer than the upper plate-like member 6a' in order to be attached to another member, and a mounting hole 13 is provided in the extended portion thereof. An upper plate member 6a' is brought into elastic contact with the vibrator l (FIG. 1).

In each of the above embodiments, the elastic member 6C of the contact member 6.6' is a wavy plate spring with wave peaks arranged in the longitudinal direction of the contact member 6.6', but as shown in FIG. A wavy leaf spring having wave crests lined up in the width direction may be used as the elastic member 6c'. In addition, as shown in FIGS. 10 and 11, respectively, U
The contact member 6'' may be configured by providing an elastic member 60'', which is a temporary spring curved in a character shape, facing inward or outward.

Furthermore, the elastic member 6C is a flat plate made of sponge, rubber, etc.
Or it may be a bronc-like body. When the elastic member 6C is a sponge or the like, the elastic member may be bonded to the plate-like bodies 6a, 6b with an adhesive.

Furthermore, the contact members 6 to 6' may be formed by stacking three or more plate members and interposing an elastic member between each plate member.

12 to 15 show fifth to seventh embodiments, respectively. The example shown in FIG. 12 is an example in which two mouth-shaped vibrators 2, 2 are integrated with each other at the base end 2a' to form one vibrator 1'. The contact member 6 is interposed between the upper and lower vibrating bodies 2.

In addition, in FIG. 12 and subsequent figures, the contact member 6 is the same as the example of FIG. 1, but is shown in a simplified manner.

The example shown in FIG. 13 is an example in which two mouth-shaped vibrating bodies 2 are oriented in opposite directions to form an integrated H-shaped vibrator 1''. Two contact members 6 are provided.

The recontact members 6 may be connected to each other.

In the example shown in FIG. 14, the vibrator 101 is composed of one mouth-shaped vibrating body 102. 6 is a contact member, and 103 is an opposing side.

In the example shown in FIG. 15, two mouth-shaped vibrating bodies 102 are integrated via a spacer 105, and one vibrator 101'
This is an example. The contact member 6 is interposed between both vibrators.

In each of the embodiments described above, the contact member 6 moves linearly forward and backward, but the contact member 6 may be rotatably supported.

〔Effect of the invention〕

In the piezoelectric drive device of the present invention, each vibrating body is shaped like a mouth or a mouth, so both sides of the vibration resonate with each other, and a large amplitude can be obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. In addition, since the resonance of the vibrating body occurs in a non-vibrating state at the base end where the two opposing sides are continuous, by using the base end as the support part, the vibration is not hindered by the support. , this also results in high efficiency. Furthermore, since there are parts of the vibrating body that do not vibrate, either the vibrator or the contact member can be used as either a fixed side or a movable side. Further, the vibrating body has two opposing sides, both of which are in contact with the contact member, and the vibration force due to the vibration of both acts additively, thereby increasing the number of contact points. Therefore, wear is reduced and stable driving is possible.

Furthermore, since the contact member is made up of a plurality of plates stacked one on top of the other with an elastic member in between, the contact member and the vibrator always come into contact with a constant pressure. Therefore, there is an effect that unevenness in the thrust force during movement of the contact member or the vibrator is eliminated, and it becomes possible to obtain a large thrust force.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a cutaway side view thereof, Fig. 3 is an explanatory diagram of its vibration mode, and Fig. 4 (
A) and (B) are respectively a plan view and a front view of the vibrator, FIG. 5 is an explanatory diagram of its operation, FIG. 6 is a block diagram of the electric device, and FIG. 7 is an exploded perspective view of its contact member. FIG. 8 is a perspective view of the contact member of the second embodiment, FIG. 9 is a perspective view of a modified example of the elastic member, and FIGS. 10 and 11 are the contact members of the third and fourth embodiments, respectively. Perspective view of 1st
2 to 15 are perspective views of vibrators of fifth to seventh embodiments, respectively. 1.1', 1''... vibrator, 2... vibrator, 3...
・Opposing side, 4.41~44...Piezoelectric element, 6~6''・
...Contact member, 5a, 5b...Plate member, 6C...
Elastic member, 101.101'... Vibrator, 102-...
- Vibrating body, 103... Opposite side Patent applicant Hiroshi Shimizu f2', -1 chamber (A) (B) Figure 4 Figure 5 Figure 6 Figure 't'J-Tachi-v'0 Q Figure 9 Figure 10 Figure 11a Figure 12 Figure 13 Figure 15

Claims (1)

[Scope of Claims] At least one vibrating body is formed of a metal elastic material into a U-shape or a C-shape, and each of a pair of opposing sides has a rectangular cross-sectional shape, and this vibrating body is connected to each of the opposing sides. A piezoelectric element is attached to at least two adjacent sides, and a predetermined high frequency voltage is applied to the piezoelectric element, and the opposite side vibrates resonantly. a power supply device that applies a high-frequency voltage by applying a high-frequency voltage; and a contact member comprising a plurality of plate-like members stacked one on top of the other with an elastic member in between, and the plate-like members are in elastic contact with each one of the opposite sides of the vibrator. A piezoelectric drive device, wherein either the contact member or the vibrator is driven by circular or elliptical motion of the maximum amplitude point on the opposite side of the vibrator.