JPS6339473A - Ultrasonic linear motor - Google Patents

Abstract

PURPOSE:To lighten an ultrasonic linear motor, and to thin the linear motor by generating ultrasonic resonance in the base body of an elastic block and a driving piece and changing over and displacing a body to be driven in both forward and reverse directions by the nose section of the driving piece. CONSTITUTION:A T-shaped elastic block 11 is formed in the integral structure of a base body 12 and a driving piece 13 vertically extending from the central section of the base body 12, a first piezoelectric element 14 at a bending mode is stuck onto the upper surface of the base body 12, and second piezoelectric elements 15-16 at the bending mode are each pasted onto the oppositely faced two surfaces of the driving piece 13. The piezoelectric element 14 has a partially divided feedback terminal 14a. The first piezoelectric element 14 is each connected in parallel with the second piezoelectric elements 15-16 by changing over a switch, and adjusted so that bending-mode resonance frequency in respective ultrasonic region of the base body 12 and the driving piece 13 in the in-face direction of the elastic block 11 is equalized. Accordingly, the base body 12 and the driving piece 13 are operated under the state of composite resonance as a whole, and the direction of a body to be driven is changed by said changeover means.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic linear motor, and particularly to an ultrasonic linear motor using a bending mode piezoelectric element.

[Conventional technology]

Conventionally, this kind of thing was proposed by the present inventor (patent application filed in 1983).
There is a piezoelectric actuator (No. 0-218891),
This is illustrated in FIG. a second piezoelectric displacement means (5) coupled to (4) to form an integral T-shape;
is provided. The piezoelectric displacement means (41 (51) are each of a bimorph structure including a piezoelectric element exhibiting a piezoelectric transverse effect (a5+).

An adapter (6) is attached to the upper end of the second piezoelectric displacement means (5).

With the above configuration, by applying a voltage to the piezoelectric displacement means f41 (51), the driven body (not shown) that is engaged with the adapter (6) is displaced. The change is made by reversing the polarity of the voltage applied to the piezoelectric displacement means.

[Problem that the invention seeks to solve]

Conventional piezoelectric actuators such as those described below have low mechanical strength and cannot efficiently displace the driven body because the first and second piezoelectric displacement means (4H51 or bimorph structure are separate from each other). In addition, since the direction of displacement of the driven body is changed by changing the polarity of the voltage applied to the piezoelectric displacement means,
There was also the problem that it became complicated.

This invention was made in order to solve these problems, and aims to provide a super-gamma wave linear motor that can efficiently displace a driven body and easily change the direction of displacement. It is something to do.

[Means for solving problems]

The ultrasonic linear motor according to the present invention has a base body and a driver element ζ of an elastic block in which the base body and the driver element are integrated.
First and second bending mode piezoelectric elements are attached to each of these,
It has a switching means that changes the vibration phase between the base and the driver by switching either the first or second piezoelectric element, and applies an electric signal of 20 KH2 to 5 Q KHz to the piezoelectric element to connect the base and drive. It is equipped with a drive power source that causes the child to generate complex resonance.

[Effect]

In this invention, the driven body, which is pressed against the tip of the driver, is displaced by ultrasonic resonance of the elastic block. Furthermore, the direction of displacement can be changed by switching the connection of the piezoelectric element.

〔Example〕

1 to 5 show an embodiment of the present invention, and FIG.
In FIG. 2, a T-shaped elastic block (11) made of metal such as iron or aluminum or plastic deck is connected to a base (12).
) and a driver (13) extending vertically from the center of the base (12). The upper surface of the base (12) is HI, and the first piezoelectric element (14) on the surface is A.
I+ has arrived 1. Second piezoelectric elements (+5) (16) in bending mode are disposed on two opposing surfaces of the driver (13).
are attached to each. A portion of the piezoelectric element (14) is divided to form a feedback terminal (14a). An atabuku (17) made of a lightweight wear-resistant material is attached to the lower end of the driver (16). The first piezoelectric element (1
4) is due to the switching of the switch t, thereby increasing the second pressure 11! They are connected in parallel to the elements (15) and (16), respectively. In addition, the base body (
The bending mode resonance frequencies in the ultrasonic regions of the driver (12) and the driver (16) are adjusted to be equal.

Nodes during this resonance operation (18a) (1ab)
is the fixed position of this device.

With the above configuration, when the first piezoelectric element (14) and the second one piezoelectric element (15) are polarized to ■ on the outside, the sine of ■ is connected in parallel to these piezoelectric elements. When a wave voltage is applied, each part obtains the displacement of the curved line in FIG. 1. Conversely, when a voltage of ◯ is applied, the direction of bending of this broken line is reversed.

Similarly, when the first piezoelectric element (14) and the second other piezoelectric element (16) are simultaneously driven, the displacement of each part becomes as shown by the chain line, and the direction of movement is reversed.

In the above operation, the base (12) to which the first and second piezoelectric elements are attached and the driver (13) operate at a frequency of 2°KHz to
Since each resonance state occurs at a frequency in the ultrasonic region of 50 KH2, the entire device operates in a complex resonance state. Therefore, the first and second piezoelectric elements are always connected in parallel. In addition, the direction change relative to the driven body is performed by changing the direction of the first piezoelectric element (14) (the two second piezoelectric elements (1s
) (16) is achieved by switchingly connecting the terminals ζ with a switching means ζ such as a switch.

To explain the above operation in more detail, when a sine wave signal in the ultrasonic range as shown in Fig. 6 is applied to the piezoelectric element shown in Figs. 1 and 2, the elastic flock (11) is brought into a resonant state. It vibrates. In response to this, the behavior of the atabuk (17) is to vibrate vertically from the base (12) as shown in Figure 1 and horizontally by the driver (13), and the combined trajectory is In the diagram (a) - (b) or (c) -
form). Then, in the case of (a) – (b), (
The adapter (17) moves the driven body in the (c) direction, that is, in the left direction, when it is in the a) direction, that is, in the right direction in FIG. 4, ()→-). The drive speed at this time is, for example, when the joint drive is performed at 30KH2, and the amount of movement in one operation is 1 μm, the speed per second is multiplied by this frequency, that is, 1x30x10 = 30 (Ginshoku) becomes. Also, it goes without saying that as the input voltage increases, the above-mentioned speed per second increases.

FIG. 5 is a wiring diagram in which a feedback signal is taken out from the feedback terminal (14a) and fed back to the drive power source (19) to perform resonance frequency tracking. The switch (20) changes the mutual vibration phase between the base body and the driver by switching the second piezoelectric elements (15) and (16) of the driver (16), and controls the kicking direction of the adapter (17). Change the direction of movement of the driven object.

FIG. 6 and FIG. 7 show another embodiment, in which the driver (13) of the T-shaped elastic block (11) includes a first piezoelectric element (2).
1) is attached. The first piezoelectric element (21) is provided with a divided feedback terminal (21a). The base body (12) has a plurality of second
Piezoelectric elements (22a) (22b) and (23a) (
25b) are attached with the front and back facing each other.

With the above configuration, the elastic block (11) is caused to resonate in the ultrasonic region, and the driving direction of the adapter (17) at the tip of the driver (16) is set to the two groups (22a) of the second piezoelectric elements.
(22b) and C23a) (23b) are switched.

Note that the second piezoelectric element may be provided only on one side of (22a) and (22b).

FIG. 8 shows another embodiment in which the shirt 1-(24), which is the driven body, is moved using the elastic block (11) to which the piezoelectric element described in each of the above embodiments is attached. (11) has a node (+aa) (
tab). A roller (26) such as a pole bearing or a roller bearing is arranged opposite to the adapter (17), and the shirt I- (24) is held therebetween and moved smoothly.

(27) is a pair of bearings supporting the shirt l-(24).

With the above configuration, the shirt l-(24) is moved in the direction of arrow (a) due to ultrasonic resonance of the elastic block (11).

Furthermore, an encoder for detecting the absolute position of the shirt I-(24) may be attached to the base (25).

Additionally, special specifications such as non-magnetic and high vacuum applications are also possible.

Figures 9 to 15 further illustrate the drive mechanism,
In FIG. 9, two elastic flocks (11a) and (11b) are arranged in parallel to move the shaft (24).

FIG. 1a shows two elastic blocks (t+a,)(+rb
) are arranged facing each other, and the shirt l-(24) is kicked and moved in the same phase.

Figure 11 shows two pairs of elastic bands D7 (11a) to (11d).
) This is an example in which the driving speed is doubled by changing the drive generation timing to 18o0 from each other, and applying this to Figs. 6 and 4, the elastic flocs (++a) (11b) are +
When at point (a) of P, another pair (r+c) (11d)
(The polarization polarity and arrangement are such that it is held back at one point. Therefore, when the next -P position ζ is reached, the standby bear performs the kicking drive, so the shirt t- (
24) twice, the driving speed is 10th.
It will be twice the size of the one in the figure.

Figure 12 shows two opposing elastic fluorocarbons 11a) (tl
b) Hold the rotatable disc (28) between the discs (28
). At this time, the elastic flock (11a)
It goes without saying that the driving directions of (11b) are opposite to each other.Furthermore, the number of elastic blocks may be six or four.

In FIG. 13, the elastic flock (11) ζ thereby rotationally drives the engine 1 to the rest bell 1- (29).

In FIG. 14, a traveling body (31) to which an elastic block (11) is attached runs on a flat fixed rail (60).

Figure 15 is the reverse arrangement of the one in Figure 10.
A traveling body (33) mounted with a pair of opposite elastic blocks (11) runs between a pair of parallel fixed rails (32).

By increasing the number of elastic blocks (11) on each of the above sides, a high load type can be achieved.

The ultrasonic linear motor of the present invention described above can be used not only to move shafts in and out and to run moving objects, but also to move the magnetic head of a frossopetisque, move the printer's →j--marhesode, and move the sample stage of a microscope. It is advantageous for use in many applications such as for high-precision mechanical adjustment.

〔Effect of the invention〕

As is clear from the above description, this invention generates ultrasonic resonance in the base of the elastic block and the driver, and enables the tip of the driver to switch and displace the driven body in both forward and reverse directions. , works efficiently, is lightweight, thin and portable46
As a resonance point tracking type, it is possible to save labor and design, and has effects such as less noise.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a front view, FIG. 2 is a side view, and FIG. 3 is a drive signal waveform diagram.
FIG. 4 is a diagram explaining the operation of the driver, and FIG. 5 is a wiring diagram. FIG. 6 is a perspective view of another embodiment, FIG. 7 is a side view, FIGS. 8 to 15 are schematic front views of applied examples, and FIG. 16 is a front view of a conventional piezoelectric actuator. (11)...Elastic flock, (12)...Base, (16
)...driver, (14), (21)...first piezoelectric element, (4s), (16), (22a), (22b), (2
6a), (2xb), , second piezoelectric element, (+4a
) (21a)...Feedback terminal, (17) --Adapter, (1aa) (18b) --Node, (19)
... Drive power supply, (20) ... Switch (switching means). Fig. 1 15.16 Second piezoelectric element Fig. 2 Fig. 3 +P □, Fig. 4 Fig. 5

Claims (3)

[Claims] (1) an elastic block consisting of a base body and a driver unit formed vertically from the center of the base body and integrally with the base body; and a bending mode block that is attached to the base body and the driver unit respectively and connected to each other. 1. a second piezoelectric element; a switching means for changing the mutual vibration phase of the base and the driver by switching the connection of the plurality of piezoelectric elements of either the first or second; and the first and second piezoelectric elements; An ultrasonic linear motor comprising: a drive power source that applies an electric signal with a frequency of 20 KHz to 50 KHz to the piezoelectric element to cause complex resonance in the elastic block. (2) The ultrasonic linear motor according to claim 1, which is provided with a feedback terminal for automatic resonance frequency tracking. (3) The ultrasonic linear motor according to claim 1, which is fixed near the node of the base body during resonance operation.