JPH01255478A - Ultrasonic linear motor - Google Patents

Abstract

PURPOSE:To obtain the title motor, thin in thickness, small in size and high in torque thereof, by a method wherein a poligonal annular substrate is formed by a plurality of oscillating pieces consisting of square rod type elastic bodies while piezoelectric elements are secured to respective oscillating pieces and the opposed sides of the substrate are oscillated with the same phase. CONSTITUTION:The substrate 20 of an elastic body of nickel steel or the like is constituted of four pieces of rod type oscillating pieces 1-4 having square section which are connected integrally so as to have a square annular shape. Sheet type piezoelectric elements 5a-5d are secured to the outer side surfaces of the oscillating pieces 1-4 respectively while sheet type piezoelectric elements 6a-6d are secured to the upper surfaces and the sheet type piezo-electric elements 7a-7d are secured to the lower surfaces of the oscillating pieces 1-4 respectively. A column type slider 8 is inscribed to the square ring of the substrate 20 and it abutted against the inner peripheral surface of the same to retain it movably into the axial direction thereof. According to this method, the opposing oscillating pieces 1-4 clamp the slider 8 alternately while becoming one set respectively and provide the slider 8 with a monoaxial displacement when a signal is an ultrasonic zone is impressed on respective piezoelectric elements 5a-5d, 6a-7d.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic linear motor, and more specifically, it generates driving force by generating bending mode ultrasonic vibration in an elastic member provided with a piezoelectric element. This invention relates to a piezoelectric ultrasonic linear motor that functions as a -axis actuator.

[Conventional technology]

Conventionally, as this type of ultrasonic linear motor, there is one proposed by the present inventor (Utility Application No. 161013/1982), and this will be explained with reference to FIG. 9. Two drivers (22a), (22
b) is provided protrudingly, and two pressures for the bending mode are provided.
Tone elements (2, 33) and (23b) are provided. A piezoelectric element (2
4) are provided respectively. A mounting hole (25) is formed in the base (21).

(A1), (A2), (B1), (B2), and (B) are terminals of connection leads of each piezoelectric element, and (F'B) is a feedback terminal.

With the above configuration, the voltage in the ultrasonic range can now be applied to the terminal (
When the voltage is applied between A1) and (B), the base body (21) and the driver elements (22a) and (22b) are bent as shown by the dashed line, and the slider (22a) to which the driver element (22a) is pressed is bent. (not shown) in the direction of arrow (M). Terminal (
When a voltage e is applied between AI) and (B), the substrate (21
) and the drivers (22a) and (22b) are bent as shown by the breakage, and the driver (22b) then similarly kicks out the slider in the direction of the arrow (M).

When the above voltage is applied between the terminals (A2) and (B), the polarization of the piezoelectric elements (23a) and (23b) is opposite to each other, so the operation is reversed and the slider moves as indicated by the arrow (N). being kicked in the direction

In the manner described above, the slider, which is the driven body, can be given linear movement in any direction.

[Problem to be solved by the invention]

Conventional ultrasonic linear motors as described above require a considerable length in the slider drive direction, are difficult to design thinly, and have the drawbacks of being difficult to obtain a compact and high-torque motor. .

The present invention was made to solve the above problems, and an object of the present invention is to obtain an ultrasonic linear motor that is thin, small, and capable of generating high torque.

[Means to solve the problem]

The ultrasonic linear motor according to the present invention is configured to drive a polygonal ring-shaped base body with a rectangular cross section on each side at least on the top and bottom surfaces of each side so that the sides of the same polarity face each other and drive in the same phase. A piezoelectric element that vibrates in an ultrasonic range is fixed to one of the inner and outer surfaces, and a slider is inscribed or circumscribed in the base body.

[Effect]

In this invention, when a signal in the ultrasonic range is applied to the piezoelectric elements excavated on the side surface of the base and the 10,000 piezoelectric elements on the bottom surface, the opposing vibrating pieces form a pair and alternately tighten and move relative to the slider. Repeat this to give the slider one-axis movement.

By switching the piezoelectric elements on the upper and lower surfaces to the other, the direction of movement of the slider can be reversed.

〔Example〕

FIGS. 1 and 2 show an embodiment of the present invention. In the figures, a base body (20) made of an elastic material selected from nickel steel, carbon glass, etc. The pieces (1), (2), (3) and (4) are joined together in a square shape to form an integrated quadrangular ring shape. Plate-shaped piezoelectric elements (5a), (5b), (5C), and (5d) are fixed to the outer surface of each of the vibrating pieces (1) to (4), and a plate-shaped piezoelectric element ( 6a) ~ (6d
), plate-shaped piezoelectric elements (7a) to (7d) are respectively fixed to the lower surface. The polarization direction is indicated by ■△. Furthermore, the state in which the piezoelectric element is fixed to the base (20) is symmetrical about the center.

The columnar or cylindrical slider (8) is attached to the base (20).
It is inscribed in the rectangular ring formed by the ring and is in pressure contact with each inner circumferential surface to be movably engaged in the axial direction.

The base body (20) has mounting holes (9a) to (9) for fixing the assembly.
d) is provided.

Note that connection lead wires led out from each piezoelectric element are omitted.

Next, the operation will be explained with reference to FIGS. 3 and 4. First, when a voltage in the ultrasonic range is applied to the piezoelectric elements (5a) to (5d), the piezoelectric elements of the vibrating pieces facing each other are polarized with the same polarity, and the piezoelectric elements of the orthogonal imaging pieces are polarized with different polarities. Therefore, as shown in Figure 3, when the base (20) is deformed from the state of (a) as shown in (b) and (C) and an alternating voltage is applied to it, the It operates in the opposite way to Figure 3. In this way, each of the vibrating pieces (1) to (4) performs bending vibration toward the center.

Next, when a voltage is applied to the piezoelectric elements (6a) to (6d), the piezoelectric elements on opposite sides have the same polarity, and the piezoelectric elements on orthogonal sides are polarized to different polarities, so the fourth figure(
It is deformed as shown in a) to (C), and each opposing side is bent in opposite directions in the direction of the arrow shown in FIG.

Now, piezoelectric elements (5a) to (5d) and piezoelectric element (6a)
) to (6d) in parallel and apply an alternating voltage in the ultrasonic range to them, the above-mentioned distortion will occur in combination, so the slider (8) inscribed in the base (20) 2
It will move in the direction of the arrow in the figure, that is, in the axial direction of the slider (8).

Furthermore, the behavior during this time will be explained in detail.

First, in a positive cycle of the applied voltage, the slider (
8) is in a state where it is tightened by the vibrating pieces (1) and (2), and the polarization direction of the piezoelectric element of the other vibrating piece (3) and (4) is the same as that of the vibrating pieces (1) and (2). The slider (8) is the opposite of the piezoelectric element in 2), so the slider (8) is the vibrating element (3), (4).
Some are in a state of freedom. Then, the holding left pieces (1) and (2), which are in the tightened state, tighten and clamp the slider (8), and at the same time are moved in the axial direction. On the other hand, the pair of vibrating pieces (3) and (4) in the open state are connected to the slider (
At the same time as loosening 8), the shaft is moved back in the negative direction in preparation for the next moment.

In the next negative cycle, the behavior is completely opposite to that described above, and the tightening is performed at the same time as the vibrating pieces (1) and (2), which were in the current state, begin to loosen and prepare for the next one. The vibrating pieces (3) and (4), which had been loosened and waiting, start moving in the same axial direction as before while being tightened.

Now, if we keep the axial resonance and the tightening direction resonance close to each other and apply an alternating voltage at the resonant frequency to this, the above operation will be repeated, so the slider (8
) will move rapidly in the axial direction and act as a -axis actuator.

Also, if you want to reverse the moving direction of the slider (8),
By reversing the phase of the axial direction and tightening, the purpose can be easily achieved. That is, specifically, the piezoelectric elements (7a) to (7d) bent in the axial direction are fixed to the back sides of the piezoelectric elements (6a) to (6d) with the same polarity, and the piezoelectric elements (5a) to By connecting the group (5d) and the group of piezoelectric elements (7a) to (7d) in parallel, the axis movement can be reversed.

For those that do not require reversing the direction of movement, a pressure element (
It goes without saying that it is sufficient to have either one of 6a) to (6d) or (7a) to (7d).

As for the material of the slider (8), it is desirable that the material be non-slip and less likely to generate audible sounds. For example, a material obtained by mixing and molding a phenol resin with about 15% metal powder is suitable for this purpose.

A material such as AI%Cu is suitable for this metal powder.

Since the cylindrical slider (8) has a reduced self-weight, it is effective in shortening the start-up time of movement.

Further, the cross-sectional shape of the slider (8) is not limited to a circular shape, but may be rectangular as shown in FIG. 5 in order to prevent rotation. In other words, the figure (a) shows a rectangular slider (8).
A protrusion (8a) is formed on each side of the slider (8a), and the protrusion (8a) is inscribed in the base body (20). FIG. (8b) is formed and inscribed in the base body (20) by the plane portion (8b).

Note that the above embodiment describes the case where the slider (8) is inscribed in the base (20), but as shown in FIG.
The slider (8) is shaped like a square ring, and a protrusion (8C) is formed on each inner wall surface of the slider (8).
20) may be a structure circumscribed.

In this case, the piezoelectric element fixed to the outer peripheral surface of the base (20) may be attached with a contact member as is, or the piezoelectric element may be fixed to the inner peripheral surface of the base (20). Good too.

Moreover, the slider (8) and the base body (20) only need to move relative to each other, and it goes without saying that either of them may be moved for use.

FIG. 7(a) shows another modification of the base (20), in which eight vibrating pieces are combined to form a regular octagonal ring-shaped base (20) consisting of four pairs of opposing sides, and a slider is attached to this. It is formed by inscribing (8).

With this configuration, the vibration phases of the vibrating pieces facing each other are the same, and the vibration phases of the vibrating pieces adjacent to each other are opposite to each other, so that 9M (sharpness) at the time of resonance can be increased. The operation is exactly the same as in the case of a rectangular ring-shaped base, where every other two opposing sides behave in the same way, so at the moment when the inscribed slider (8) is clamped, four vibrations occur simultaneously. It will be clamped at four points on each piece. This type of structure has the advantage of being able to meet the requirements for a large thrust without lowering the frequency.

FIG. 7 shows a case of a regular dodecagonal ring-shaped substrate (20) with six pairs of opposing sides, and its operation and effect are similar to those of FIG. 7(a).

FIG. 8 shows a case where the ultrasonic linear motor of the present invention is used as a control valve, in which a gas or liquid flow path (12) is provided in the main body (10), and (12a) is the inlet; 12b) is the exit. Main body (10)
The above-mentioned ultrasonic linear motor consisting of a base body (20), a slider (8), etc. is housed in the housing section (13) surrounded by a lid body (11) and a lid body (11). An opening/closing valve (14) integral with the slider (8) at the midpoint of the flow path (12) is adapted to control the fluid flow.

With the above configuration, stepless and continuous control is possible, and such a control valve exhibits highly accurate functions for use in automobiles and other general industries.

It should be noted that great efforts are being made to incorporate position detection means into the slider (8) described above to make it into a composite component.

〔Effect of the invention〕

As explained above, the present invention includes a polygonal ring-shaped base by integrally bonding a plurality of vibrating pieces each made of a rod-shaped elastic body with a rectangular cross section, and forming a polygonal ring-shaped base body on the upper and lower surfaces of each vibrating piece. Alternatively, a piezoelectric element is fixed to each outer surface so that the opposite sides of the base body vibrate in the same phase, and a structure in which a slider is inscribed or circumscribed on the base body can be made thin and small, and high torque can be obtained.

It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a side view, FIGS. 3 and 4 are schematic diagrams for explaining the operation of the embodiment, and FIGS. Figure and 7th
8 is a side sectional view showing an application example of the embodiment, and FIG. 9 is a front view of the main part of a conventional ultrasonic linear Tanabata. (1) to (4)... Vibration piece, (5a)-L(sa)
, (6a) ~ (6d), (7a) ~ (7d) ,,
, piezoelectric element, (8) ... slider, (20) ...
Base.

Claims (1)

[Scope of Claims] A polygonal ring-shaped base integrated with a plurality of vibrating pieces each side of which is a rod-shaped elastic body with a square cross section, and the vibrating pieces facing each other are driven in the same phase. a plurality of piezoelectric elements fixed to at least one of the upper and lower surfaces of the vibrating element and one of the inner and outer surfaces thereof, to which an electric signal in the ultrasonic range is applied; An ultrasonic linear motor comprising: a slider movably engaged in the axial direction by either;