KR20090050569A - Piezoelcetric linear actuator - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric linear actuator, comprising: a piezoelectric element positioned between sliders, one side of which is fixed to a support surface to move the slider, and a slider and a piezoelectric element bonded to the other side of the piezoelectric element. It is characterized in that it comprises a clamper (Clamper) for transmitting the deformation force of the piezoelectric element to the slider by being contacted.

According to the present invention, since the slider can be moved left and right using one piezoelectric element, the size of the actuator can be miniaturized, and the size of the driving circuit can be reduced because the driving signal is simpler than the conventional method.

Piezoelectric Linear, Actuator, Piezoelectric Element, Clamper, Slider

Description

Piezoelce Linear Actuator

The present invention relates to a piezoelectric linear actuator, and more particularly, to a piezoelectric linear actuator capable of moving a slider using one piezoelectric element.

Recently, micronization of processing and assembly systems has become an international issue in the field of production machinery, and micro miniaturization of processing and assembly machines and systems is enabled by the development of micro technology such as MEMS (Micro-Electro Mechanical System).

In particular, a piezoelce linear actuator using a piezoelectric element is easy to move finely and is mainly used for a zoom function of a mobile phone or a pickup for an optical disk drive (ODD).

The piezoelectric linear actuator is composed of a plurality of piezoelectric elements, a displacement moving unit, a guide rail, and the like, and a displacement moving unit connected thereto by mechanical deformation of the plurality of piezoelectric elements moves in one direction in the guide rail.

1 is a view showing a general piezoelectric linear actuator.

As shown therein, the first piezoelectric element 110 and the second piezoelectric element 120 and the first piezoelectric element 110 and the second piezoelectric element 120 respectively positioned between the guide rails 100, respectively. A first clamp 131 and a second clamp 134 coupled to the first piezoelectric element 110 and the second piezoelectric element 120, wherein both sides of the first piezoelectric element 110 and the second piezoelectric element 120 are in contact with the guide rail 100. The third piezoelectric element 140 is formed between the first piezoelectric element 110 and the second piezoelectric element 120 and is surrounded by the frame 150.

The piezoelectric linear actuator configured as described above moves to the right or left along the guide rail 100 by mechanical deformation of the piezoelectric elements 110, 120, and 140 according to the applied voltage.

2A to 2F are schematic views showing a state in which a general piezoelectric linear actuator moves to the right.

First, as shown in FIG. 2A, when the first piezoelectric element 110 located on the left side expands according to an applied signal voltage, the first clamp 131 connected thereto contacts the guide rail 100.

In this state, when the third piezoelectric element 140 positioned in the center portion receives the signal voltage and expands, the second clamp 134 away from the guide rail 100 is pushed in the right direction to move by a predetermined distance. (FIG. 2B).

Next, when the second piezoelectric element 120 expands in accordance with the applied signal voltage, the second clamp 134 connected thereto contacts the guide rail 100 (FIG. 2C). At this time, the third piezoelectric element 140 allows the signal voltage to be continuously applied to maintain the expanded state.

When the expanded first piezoelectric element 110 returns to its original state by blocking the signal voltage, the first clamp 131 attached to the guide rail 100 is separated from the guide rail 100 (FIG. 2). d).

Next, when the expanded third piezoelectric element 140 returns to its original state by blocking the signal voltage, the first clamp 131 away from the guide rail 100 is moved by a predetermined distance in the right direction (FIG. 2e).

When the first piezoelectric element 110 expands according to the applied signal voltage, the first clamp 131 connected thereto contacts the guide rail 100 to complete the movement of the piezoelectric element for one cycle.

When the above-described operation is repeated sequentially, the piezoelectric linear actuator can move in a right direction by a desired distance.

The piezoelectric linear actuator is used for auto focusing of a mobile terminal or an ultra-precision positioning mechanism for positioning in units of nanometers. Therefore, miniaturization is required.

However, conventional piezoelectric linear actuators require a large number of parts, and there are limitations in miniaturization since they use three or more piezoelectric elements.

In addition, there is a problem in that the driving circuit becomes complicated because different driving signals of various steps must be applied to each of the three piezoelectric elements.

In addition, the conventional piezoelectric linear actuator has a signal line attached to each piezoelectric element, which causes inconvenience in that the signal lines move together with the movement of the actuator.

A preferred embodiment of the piezoelectric linear actuator of the present invention for solving the above problems is located between the upper slider and the lower slider spaced apart from each other, and the upper slider and the lower slider, one side is fixed to the support surface and the upper slider And a piezoelectric element for moving the lower slider and the other side of the piezoelectric element, contacted with the upper slider and the lower slider according to the deformation of the piezoelectric element, and thereby deforming the piezoelectric element to the upper slider and the lower slider. It characterized in that it comprises a clamper for transmitting (Clamper).

The clamper is made of a material having an elastic force, characterized in that the expansion or contraction according to the deformation of the piezoelectric element.

The piezoelectric element may include a plurality of stacked piezoelectric sheets, a clamping portion formed on one side of the piezoelectric sheet and expanding or contracting in the stacking direction of the piezoelectric sheet, and formed in a region other than the clamping portion, Characterized in that it comprises a displacement expansion / contraction portion that expands or contracts in the longitudinal direction.

According to the present invention, since the slider can be moved left and right using one piezoelectric element, the size of the actuator can be miniaturized, and the size of the driving circuit can be reduced because the driving signal is simpler than the conventional method.

And since the piezoelectric element which is a site | part which receives a signal is fixed, it becomes easy to locate a signal application line.

Hereinafter, the piezoelectric linear actuator of the present invention will be described in detail with reference to FIGS. 3 to 6.

In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

3 is a diagram showing an embodiment of a piezoelectric linear actuator of the present invention.

As shown therein, the upper slider 201 and the lower slider 202 are spaced apart from each other, and are located between the upper slider 201 and the lower slider 202, and one side is fixed to the support surface 200. It consists of a piezoelectric element 210 and a clamper 220 which is bonded to the other side of the piezoelectric element 210 and in contact with the upper slider 201 and the lower slider 202.

Here, the piezoelectric element 210 has a clamping part 211 and a displacement enlargement / reduction part 214 formed on a plurality of laminated piezoelectric sheets, and the clamping part 211 is a piezoelectric element according to an applied voltage. The corresponding portion of 210 is expanded or contracted in the stacking direction of the piezoelectric sheet, and the displacement expanding / reducing portion 214 expands or contracts the corresponding portion of the piezoelectric element 210 from side to side according to the applied voltage. The detailed configuration of the piezoelectric element 210 will be described later.

The clamper 220 is made of a material having an elastic force, and contracted or expanded together with the contraction or expansion of the clamping part 211 to be separated from the upper slider 201 and the lower slider 202. Contact.

In the present invention, since one side of the piezoelectric element 210 is fixed to the support surface 200, the upper slider 201 and the lower slider 202 itself move in a constant direction due to the deformation of the piezoelectric element 210. Here, the upper slider 201 and the lower slider 202 may be connected to each other to constitute a single frame.

4A to 4E are diagrams showing the operation of the piezoelectric linear actuator of the present invention. Here, the case where the slider moves to the right direction is shown.

As shown therein, first, in the state where the clamper 220 is in contact with the upper slider 201 and the lower slider 202 and is bitten (FIG. 4A), the displacement enlargement / reduction portion 214 of the piezoelectric element 210. When the signal voltage is applied to and expanded, the upper slider 201 and the lower slider 202 move to the right (Fig. 4B).

That is, since the piezoelectric element 210 is fixed to the support surface 200 in the present invention, the slider moves to the right due to the expansion of the displacement enlargement / reduction portion 214.

Next, when the clamping unit 211 is contracted by applying a signal voltage to the clamping unit 211 of the piezoelectric element 210, the clamper 220 adhered to the clamping unit 211 is also contracted together to form the upper slider 201. ) And the lower slider 202 (FIG. 4C).

Subsequently, when the signal voltage applied to the displacement enlargement / reduction section 214 is cut off, it returns to its original state in the expanded state (Fig. 4D).

Subsequently, when the signal voltage applied to the clamping unit 211 is blocked, the signal voltage applied to the clamping unit 211 is returned to its original state, and the clamper 220 contacts the upper slider 201 and the lower slider 202 to be bitten. It is in a state of being present (FIG. 4E).

Thereafter, when a signal voltage is applied to the displacement enlargement / reduction portion 214 of the piezoelectric element 210 to expand, the upper slider 201 and the lower slider 202 move to the right again, and the operation is repeated. You can move the slider the distance you want.

As described above, according to the present invention, since the slider can be moved left and right by using one piezoelectric element, the size of the actuator can be reduced, and the size of the driving circuit can be reduced because the driving signal is simpler than the conventional method.

And since the piezoelectric element which is a site | part which receives a signal is fixed, it becomes easy to locate a signal application line.

Meanwhile, the clamping unit 211 is inflated to cause the clamper 220 to come into contact with the upper slider 201 and the lower slider 202 to be bitten, and then the displacement enlargement / reduction unit 214 is expanded to expand the upper slider 201 and The lower slider 202 is moved to the right, and the clamping portion 211 is contracted so that the clamper 220 is separated from the upper slider 201 and the lower slider 202, and then the displacement expanding / reducing portion 214 is contracted. The slider can be moved back to its original state.

5 is a diagram showing the configuration of a piezoelectric element used in the piezoelectric linear actuator of the present invention.

In the piezoelectric element of the present invention, a plurality of piezoelectric sheets S are stacked, and each piezoelectric sheet S includes an electrode plate 311 or 312 on one side thereof, and spaced apart from each other by the first electrode 321 and The second electrode 322 is provided.

Each of the piezoelectric sheets S may have the electrode plates 311 and 312 stacked alternately to form a clamping part 310, and the first electrode 321 and the second electrode 322 formed in each of the piezoelectric sheets S may be formed. This displacement enlargement / reduction portion 320 is formed.

As described above, the configured piezoelectric element expands or contracts in the stacking direction of the piezoelectric sheet S according to signal voltages applied to the electrode plates 311 and 312, and the first electrode 321 and the second electrode. The portion expands or contracts in the longitudinal direction of the piezoelectric sheet S according to the signal voltage applied to the 322.

In this case, the electrode plates 311 and 312 of the clamping part 310 are electrically connected to each other by interlayer wiring, and the same codes (that is, between the 311 electrode plates and the 312 electrode plates) are separated from each other. Are electrically connected to each other.

In addition, the first electrode 321 and the second electrode 322 of the displacement expanding / reducing unit 320 are also electrically connected to each other by an interlayer wiring. That is, the first electrode 321 and the second electrode 322 formed for each piezoelectric sheet S are electrically connected through the interlayer wiring.

The electrode plates 311 and 312, the first electrode 321, and the second electrode 322 are formed by applying a metal paste. The metal may be platinum, palladium, silver-palladium alloy, or silver. And calcined ceramic powder can be used.

As the piezoelectric material used in the piezoelectric sheet S, lead zirconate ferroelectric (PbZrO3) and semiferroelectric lead zirconate titanate (PbZrO3-PbTiO3) -based piezoelectric ceramics may be used.

6 is a view showing the configuration of a displacement enlargement / reduction portion in the piezoelectric element of the present invention.

As shown therein, the first electrode and the second electrode of the displacement enlargement / reduction unit are composed of electrode pads 321-1 and 322-1 and electrode bodies 321-2 and 322-2 extending therefrom, respectively. .

Each of the first electrode and the second electrode has a stripe shape, and is spaced apart from each other by a predetermined distance.

The first electrode and the second electrode configured as described above may have voltages having different magnitudes applied to the first electrode pad 321-1 and the second electrode pad 322-1, respectively. As a result, the positive and negative charges are polarized in the piezoelectric material constituting the piezoelectric sheet, thereby causing mechanical vibration.

Although the present invention has been described in detail with reference to exemplary embodiments above, those skilled in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. I will understand.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

1 shows a general piezoelectric linear actuator.

2A to 2E are schematic views showing a state in which a general piezoelectric linear actuator moves to the right.

3 shows an embodiment of a piezoelectric linear actuator of the present invention.

4A to 4E show the operation of the piezoelectric linear actuator of the present invention.

Fig. 5 is a diagram showing the configuration of a piezoelectric element used in the piezoelectric linear actuator of the present invention.

Figure 6 is a view showing the configuration of the displacement enlarged / reduced portion in the piezoelectric element of the present invention.

Explanation of symbols on the main parts of the drawings

200: support surface 201: upper slider

202: lower slider 210: piezoelectric element

211: clamping part 214: displacement expansion / reduction

220: clamper

Claims (6)

An upper slider and a lower slider spaced apart from each other; A piezoelectric element positioned between the upper slider and the lower slider and having one side fixed to a support surface to move the upper slider and the lower slider; And And a clamper attached to the other side of the piezoelectric element, the clamper contacting the upper slider and the lower slider according to the deformation of the piezoelectric element to transfer the deformation force of the piezoelectric element to the upper slider and the lower slider. Piezoelectric linear actuator. The method of claim 1, The clamper is a piezoelectric linear actuator, characterized in that made of a material having an elastic force. The method according to claim 1 or 2, The piezoelectric element, A plurality of laminated piezoelectric sheets; A clamping part formed on one side of the piezoelectric sheet to expand or contract in a stacking direction of the piezoelectric sheet; And And a displacement enlargement / reduction portion formed in a region other than the clamping portion to expand or contract in the longitudinal direction of the piezoelectric sheet. The method of claim 3, The clamping unit, A piezoelectric linear actuator, characterized in that the first electrode plate and the second electrode plate are alternately formed alternately for each of the plurality of piezoelectric sheets. The method of claim 3, The displacement expansion / reduction unit, A piezoelectric linear actuator, characterized in that the first electrode and the second electrode are spaced apart from each other on each of the plurality of piezoelectric sheets. The method of claim 5, The first electrode and the second electrode, A plurality of piezoelectric linear actuators, which are arranged alternately, but alternately arranged.

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