JPS60113673A - Actuator using piezoelectric element - Google Patents

Abstract

PURPOSE:To increase the displaced amount of an actuator and to improve the frequency response by displacing a piezoelectric element group which elongates by the polarity of the applied voltage and a piezoelectric element group which shrinks. CONSTITUTION:A bearing 4 is secured to a support 2, and a piezoelectric element group 8 which is formed by laminating a piezoelectric element 6 is engaged with the end of the bearing 4. Then, a U-shaped bearing 10 is engaged with the end of the group 8, and a piezoelectric element group 14 formed by laminating a piezoelectric element 12 is engaged with the end of the bearing 10, and a rod 16 is secured to the end. A voltage for shrinking the element 6 is applied to the element 6 of the group 8, and a voltage for elongating the elemet 12 for forming the group 14 is applied to the element 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an actuator using piezoelectric elements, and more specifically, to an actuator that amplifies mechanical displacement by combining a piezoelectric element group that expands and a piezoelectric element group that contracts by applying an electric field. , relates to a reciprocating actuator configured to open and close a valve, etc.

Hydraulic cylinders and pneumatic cylinders are widely used as devices that perform Ia mechanical work using fluid energy such as hydraulic pressure or pneumatic pressure, that is, as actuators. In this case, a solenoid valve is generally incorporated to control the fluid. However, in order to open and close the valve using electromagnetic action in this way, it is necessary to keep current flowing at all times. Furthermore, when attempting to energize, it is difficult to obtain the desired power, and furthermore, there are disadvantages such as poor frequency response. Particularly in recent years, in unmanned systems such as articulated robots that have begun to be widely adopted in factories, etc., there is a strong desire for actuators with good frequency characteristics to perform operations quickly and reliably.

Therefore, as a result of intensive research and efforts, the present inventors focused on piezoelectric elements that expand or contract when an electric field is applied, and formed a multilayer piezoelectric element of this type so that one side contracts when an electric field is applied. If the piezoelectric element group and the other piezoelectric element group are configured by connecting and connecting at least one piezoelectric element group, one piezoelectric element will expand and the other piezoelectric element will expand depending on the polarity of application of a predetermined voltage. Because the piezoelectric element contracts, the amount of displacement is strong and large, and because it moves electrically back and forth, it is possible to obtain an actuator that is suitable for miniaturization and has extremely good frequency response.
It has been found that the above-mentioned inconveniences can be eliminated.

Therefore, an object of the present invention is to obtain an actuator that has good frequency response, is reliable and powerful, has a small installation space, is suitable for downsizing, and can be manufactured at low cost and easy to maintain. .

In order to achieve the above object, the present invention connects at least one piezoelectric element group, one of which contracts and the other expands, through a connecting member, and connects an object to the tip of one of the piezoelectric element groups. It is characterized by being equipped with a member that displaces.

Next, preferred embodiments of an actuator using a piezoelectric element according to the present invention will be described in detail with reference to the accompanying drawings.

Therefore, the basic principle of the actuator of the present invention is shown in FIGS. 1 and 2. That is, according to FIG. 1, a first piezoelectric element group is constructed by fixing a first support body 4 to a support part 2 and stacking a piezoelectric element 6 on the tip of the first support body 4. Attach 8. Next, an inverted U-shaped second support 10 is attached to the tip of the piezoelectric element group 8.
A second piezoelectric element 12 is laminated on the tip of the support 10.
The piezoelectric element group 14 is engaged, and the rod 16 is fixed to the tip thereof.

In the above configuration, a voltage is applied to the piezoelectric elements 6 of the first piezoelectric element group 8 so that they contract, that is, in the direction of arrow B, while the second piezoelectric element group 14 A voltage is applied to the piezoelectric element 12 constituting the piezoelectric element 12 so that it expands as a whole, that is, in the direction of arrow A. As a result, the first piezoelectric element IJ'f8
Due to the contraction, the end of the second support 10 moves to the position shown by the broken line. Therefore, since the biasing of the second piezoelectric element group 14 is a displacement based on the broken line position, the rod 1
6 will move by a distance Δx1.

On the other hand, if the voltage application to the first piezoelectric element group 8 and the second piezoelectric element group 14 is stopped, or if a voltage is applied to these piezoelectric element groups 8 and 14 with the opposite polarity, the displacement in the negative direction by Δx1 will occur. It will come to you.

That is, the rod 16 performs a reciprocating motion depending on the polarity of voltage applied to the piezoelectric element group, thereby providing a reciprocating actuator.

FIG. 2 shows the basic principle of an actuator which is a reciprocating actuator as described above, but is configured to change the direction of displacement. In this case, a first support 22 is fixed to the other end of the rod 20 with one end fixed, and a first piezoelectric element group 24 is fixed to the first support 22. Furthermore, a second support 2 is attached to the tip of the first piezoelectric element group 24.
Keep 6 attached. On the other hand, the second piezoelectric element group 28 is held between a third support 30 and a fourth support 32, and a rod 34 and a ring 36 are disposed at the tip of the fourth support 32. The ring 36 is made slidable relative to the guideline 38.

In this case, the second support 26 and the third support 30
A hinge member 40 is interposed between the two.

In the above configuration, similarly to the above, a voltage is applied to the first piezoelectric element group 24 in a direction that causes it to contract, that is, to displace it in the direction of arrow B, and on the other hand, a voltage is applied to the second piezoelectric element group 28 so that it is displaced in the direction of arrow B. A voltage is applied so that it is displaced in the direction in which it expands, that is, in the direction indicated by the arrow. As a result, ring 36
is displaced by a distance ΔX on the guideline 38. However, in this example, unlike the above, a hinge member 4 is provided between the first piezoelectric element group 24 and the second piezoelectric element group 28.
Since 0 is inserted, there is an advantage that a displacement state can be obtained by an angle without causing a simple reciprocating motion.

Therefore, an embodiment of the present invention based on the basic principle of exhibiting the above-described operation will be described next. First, in the actuator shown in FIGS. 3 and 4, a total of eight piezoelectric element groups are connected in series. That is, a first piezoelectric element group 54 that contracts in an applied electrode state is attached to a first support part 52 fixed to a fixed part 50, and a tip of the first piezoelectric element group 54 is attached to a first support part 52. A letter-shaped first connecting member 56 is engaged. A second piezoelectric element group 58 that expands in one polarity state of the applied electrode is attached to the connecting member 56, and the second piezoelectric element group 5
A second U-shaped connecting member 60 is attached to the tip end of the connecting member 8 .

Similarly, the third piezoelectric element group 72 and the fourth piezoelectric element group 74 are connected via the connecting members 62, 64, 66, 68, and 70.
, the fifth piezoelectric element group 76, the sixth piezoelectric element group 78, the seventh piezoelectric element group 801, and the eighth piezoelectric element group 82 are connected in series.

In this case, the third piezoelectric element group 72, the fifth piezoelectric element group 76, and the seventh piezoelectric element group 80 contract in one polarity state of the applied electrode, and the fourth piezoelectric element group 74, the Sixth piezoelectric element group 78 and eighth piezoelectric element group 82
Arrange them so that they grow in the opposite direction.

Therefore, in the above configuration, when a voltage is applied with a predetermined polarity from the power supply line 86 that is wired using the hole 84 that passes through the fixing part, the connecting member, and the piezoelectric element group, each piezoelectric element group It works like this: That is, the first
Piezoelectric element group 54 (contraction) - second piezoelectric element group 58 (expansion)
- Third piezoelectric element group 72 (contraction) - Fourth piezoelectric element group 74 (
expansion) - fifth piezoelectric element group 76 (contraction) - sixth piezoelectric element group 78 (extension) - seventh piezoelectric element group 80 (contraction) - eighth piezoelectric element group 82 (extension). Therefore, in each piezoelectric element group, Δ
Even if the rod 88 is displaced by χ, the rod 88 fixed to the tip of the eighth piezoelectric element group 82 will be displaced eight times ΔX.

On the other hand, by changing the polarity of the voltage applied from the power supply line 86, the piezoelectric element group as a whole can obtain a displacement amount that is 18 times ΔX. In other words, it is possible to obtain an actuator capable of displacement eight times as large as Δχ. This embodiment has the advantage that not only a large amount of displacement can be obtained, but also that the overall shape can be square and compact.

Next, FIGS. 5 to 7 show another embodiment of the actuator according to the present invention.

In this embodiment, a first piezoelectric element group 9o constituted by annular piezoelectric elements and a second piezoelectric element group 92 arranged concentrically with the piezoelectric element group 90 and having a larger diameter than the piezoelectric element group 90 are arranged in an annular shape. They are connected by a connecting member 94. In the figure, reference numeral 96 is a circular member attached to the first piezoelectric element group 90. That is, this circular member 96
The first piezoelectric element group 90 is held between the connecting member 94 and the first piezoelectric element group 90 .

In such a configuration, the circular member 96 is fixed at the fixing point 9
8, the first piezoelectric element group 90 and the second piezoelectric element group 92
A voltage with a predetermined polarity is applied to both through a power supply line (not shown). By arranging the piezoelectric elements constituting these piezoelectric elements in advance so that the first piezoelectric element group 90 is displaced in the direction of contraction according to the polarity, and the second piezoelectric element group 92 is displaced in the direction of expansion, The amount of displacement ΔX shown in the figure can be obtained. Of course, when a voltage opposite to the above voltage is applied, a displacement amount of -ΔX can be obtained.

In this case, since the actuator itself is cylindrical, there is an advantage that it can be easily replaced with a conventional actuator.

An embodiment in which the actuator that performs the displacement operation as described above is actually incorporated into a fluid control valve is shown in FIGS. 8 to 10. In this case, a support member 106 is fixed to a fixing part 104 that defines a space 102 inside the poppet type fluid control valve 100 and a part of the space bulges out, and the first piezoelectric element group is attached to this support member 106. 108 is attached. Furthermore, a first connecting member 110 is attached to one end of the first piezoelectric element group 106, and the second piezoelectric element group 112-second
Connection member 114 - third piezoelectric element group 116 - third connection member 118 - fourth piezoelectric element group 120 - fourth connection member 122 -
Fifth piezoelectric element group 124 - prismatic fifth connecting member 126 -
Sixth piezoelectric element group 128 - Sixth connecting member 130 - Seventh piezoelectric element group 132 - Seventh connecting member 134 - Eighth piezoelectric element group 1
36 - Eighth connecting member 138 - Ninth piezoelectric element group 140 - Ninth connecting part +A142 - Tenth piezoelectric element group 144 - Connected in series with rod engaging member 146. Therefore,
A rod 148 is provided at the tip of the rod engaging member 146.
A poppet-shaped valve body 150 is connected to the tip of the rod 148. The valve body 150 can be seated on the valve seat 152 by being displaced, and depending on the amount of displacement, it is possible to control the flow rate of fluid flowing into the control chamber 154 from the six directions of arrows and being discharged in the direction of arrow B. be.

Now, when applying a voltage at a predetermined electrical polarity with the above configuration, in this embodiment, the piezoelectric element group 108.
In the piezoelectric element groups 116, 124, 128, 136 and 144, the piezoelectric elements constituting them are arranged so as to expand, while in the piezoelectric element groups 112, 120, 132 and 140, the piezoelectric elements constituting them are arranged so as to contract. put. Therefore, each piezoelectric element group changes by 10 of ΔX depending on the amount of voltage displacement.
Double the amount of displacement will be provided to the tip of the rod engagement member 146.

As a result, the rod 148 moves the valve body 150 as Δ
It moves a distance of X×10, lands on the valve seat 152, and closes the boat 156. On the other hand, if the polarity of the voltage applied to the piezoelectric element group is changed, a displacement amount of -ΔX×10 is obtained, and the fluid is led out from the boat 156 to the boat 158. That is, a fluid control valve that can freely open and close the valve by controlling the voltage application polarity is obtained.

FIG. 10 shows a modification of the fluid control valve 100,
In the drawings, the same reference numerals as in the above embodiment indicate the same components.

That is, in this embodiment, an actuator consisting of a group of piezoelectric elements is incorporated in a spool-sleeve type fluid control valve instead of a poppet type, and therefore, a spool 160 is attached to the tip of the rod 148. When the piezoelectric element groups are energized in the same manner as described above, a displacement amount corresponding to the number of the piezoelectric element groups is brought to the rod 148, and this causes the spool 160 to be displaced, so that the first to fifth baubles 62 to 5
The opening of the boat 170 is controlled to open or close depending on its location.

FIG. 11 shows an embodiment in which the actuator according to the present invention is applied to a nozzle flapper. In this embodiment as well, the same reference numerals as in the previous embodiment indicate the same components.

Therefore, by displacing the rod 148 by the bias of the piezoelectric element group, the nozzle 180 can be opened and closed by the flapper 182 to control the fluid introduced through the throttle valve 184.

Further, FIG. 12 shows an example in which the actuator according to the present invention is used for switching an optical signal transmission circuit.

In this embodiment, the optical cable 1 for transmission is attached to the rod 148.
90 is held, while a plurality of receiving optical cables 192 and 194 are made to face the end face of the optical cable 190. The biasing of the piezoelectric element group causes the optical cable 190 to be displaced in the direction of the arrow, so that either one of the optical cables 192 and 194 can receive a signal from the optical cable 190. That is, the receiving optical cable can be selected depending on the polarity of the voltage applied to the piezoelectric element group.

According to the present invention, since the actuator that generates displacement is configured by the piezoelectric element group that expands and the piezoelectric element group that contracts depending on the polarity of the applied voltage, the amount of displacement is extremely large (the operation is also electrical). It has good frequency response, stable and quiet operation, and there is no need to consider inertia etc. compared to conventional actuators. It has various effects.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments. It goes without saying that various improvements and design changes, such as increasing the number of parts, can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

The figures relate to the present invention. Figures 1 and 2 are principle explanatory diagrams showing the basic operation of the actuator of the present invention, and Figure 3 is a perspective view of the actuator having a rectangular parallelepiped shape as a whole. An explanatory diagram, FIG. 4 is an explanatory diagram disclosing the relationship between the directly connected member of the actuator shown in FIG. 3 and the piezoelectric element group, and FIG. 6 is a plan view of the actuator shown in FIG. 5, FIG. 7 is a bottom view of the actuator shown in FIG. 5, and FIG. FIG. 9 is a perspective view of an actuator configured to increase
Figure 0 is an explanatory diagram of a state in which a large number of piezoelectric element groups are connected in series and assembled into a spool-sleeve type fluid control valve, and Figure 1I is an illustration of a state in which an actuator is used as the drive source for the nozzle flapper. The explanatory diagram, FIG. 12, is an explanatory diagram of a state in which the actuator is attached to a transmitting optical fiber and is configured to select a receiving optical fiber. 2... Support part 4... Support body 6... Piezoelectric element 8... Piezoelectric element group 10... Support body 12... Piezoelectric element 14... Piezoelectric element group 16... Rod 20... Rod 22... Support body 24... Piezoelectric element group 26... Support 28... Piezoelectric element group 30. 32... Support 34... Rod 36... Ring 38... Guideline 40... Hinge member 50... Fixed part 52... Support Part 54...Piezoelectric element group 56...Connection member 58...Piezoelectric element group 60.62.64.66.68.70...Connection part 72
．． 74.76.78.80.82...Piezoelectric element group 84.
- Hole 86... Power line 88... Rod 90.92... Piezoelectric element group -94...
Connecting member 96...Circular member 98...Fixing point 100...
-Fluid control valve 102...Space 104...Fixing part 106...Support member 108...Piezoelectric element group 110.1
14.118.122.126...Connecting member 130.
134.13B, i42...Connecting member 112.11
6.120.124.128 . . . Piezoelectric element group 132.
136.140.144...Piezoelectric element group 146...Rod engaging member 148...Rod 150...Valve body 152
... Valve seat 154 ... Control room 156.158 ... Boat 160
... Spool 162 ... Boat 170 ... Boat 18
0... Nozzle 182... Flapper 184... Throttle valve 190.192
．． 194 ... Optical cable patent applicant Sintered Metal Industry Co., Ltd. Nb z4 /l Fig, 4 66

Claims (1)

[Claims] (11) At least one piezoelectric element group, one of which contracts and the other of which expands, is connected via a connecting member, and an object is displaced to the tip of one of the piezoelectric element groups. An actuator using a piezoelectric element mounted with a member. (2. In the actuator according to claim 1, the piezoelectric element group has a rectangular parallelepiped shape. The actuator according to claim 1, in which the piezoelectric element group is cylindrical. (4) The actuator according to claim 1, in which the object is a fluid control valve. (5) Claims In the actuator according to claim 1, the object is an actuator comprising a nozzle flapper. (6) In the actuator according to claim 1, the object is formed from one transmitting optical fiber facing at least two receiving optical fibers. actuator.