JPH0744858B2 - Actuator using piezoelectric element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an actuator using a piezoelectric element, and more specifically, a mechanical displacement is amplified by combining three or more piezoelectric element groups that expand and contract when a voltage is applied, and bending is performed. The present invention relates to an actuator using a piezoelectric element configured to avoid the generation of a moment.

2. Description of the Related Art Hydraulic cylinders and pneumatic cylinders are widely used as devices that perform 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 in order to control the fluid. However, in order to open and close the valve by the electromagnetic action as described above, it is necessary to always supply a current. Further, there is a problem that a desired power cannot be obtained even when trying to energize and the frequency response is not good. In particular, in recent years, unmanned systems such as articulated robots, which have begun to be widely used in factories and the like, are strongly desired to have actuators with good frequency characteristics in order to perform work quickly and reliably.

Therefore, as a result of earnest studies and ingenuities, the present inventors have focused on a piezoelectric element that expands or contracts by applying a voltage, forms a multilayer of this kind of piezoelectric element, and contracts by applying a voltage on one side. If the piezoelectric element group which is expanded by the application of the voltage is combined with the other piezoelectric element group and the extension and contraction action lines of the first piezoelectric element group and the last piezoelectric element group are set and arranged on the same line, a predetermined Due to the applied polarity of the voltage, one piezoelectric element group expands and the other piezoelectric element group contracts, so the displacement amount is strong in one direction, it is suitable for miniaturization, and the bending moment is suppressed. It has been found that an actuator having an extremely good frequency response can be obtained and the above-mentioned inconvenience can be eliminated.

Therefore, an object of the present invention is that the displacement amount is strong and large, the frequency response is good, the operation is reliable and strong, the mounting space is small, and it is suitable for downsizing, and the bending moment during expansion and contraction is suppressed. Another object of the present invention is to provide an actuator using a piezoelectric element that can be manufactured at low cost and can be easily stored and managed.

In order to achieve the above-mentioned object, the present invention is composed of a plurality of piezoelectric element groups capable of expansion and contraction configured by laminating piezoelectric elements and an operator, and the first piezoelectric element group to be fixed is The last piezoelectric element group to be displaced is arranged so as to be spaced apart from each other so that the extension and contraction action lines thereof are on the same line, and the intermediate piezoelectric element is interposed between the first piezoelectric element group and the last piezoelectric element group. At least one element group is connected and arranged so that the extension / contraction action line deviates from the same line, and the operator is further connected to the last piezoelectric element group, and a voltage is applied with a predetermined polarity to apply the first piezoelectric element. It is characterized in that the element group and the last piezoelectric element group are expanded and contracted, and the intermediate piezoelectric element group is expanded and contracted to move the operator forward and backward.

Next, a preferred embodiment in which an actuator using a piezoelectric element according to the present invention is incorporated in a fluid control valve will be described in detail below with reference to the accompanying drawings.

In the embodiment shown in FIGS. 1 and 2, a space 102 is defined inside the poppet type fluid control valve 100, and a supporting member 106 is fixed to a fixing portion 104 formed by bulging a part of the space 102.
A rectangular parallelepiped first piezoelectric element group 108 is attached to the support member 106. Further, a second piezoelectric element group 112 is attached in parallel to one end of the first piezoelectric element group 108 via a first connecting member 110, and hereinafter, as shown in the figure, a rectangular parallelepiped second piezoelectric element group 11 is formed.
2 to the second connecting member 114-third piezoelectric element group 116-third
Connecting member 118-Fourth piezoelectric element group 120-Fourth connecting member 122-
Fifth piezoelectric element group 124-Fifth prismatic 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 136-Eighth connecting member 13
The eighth-ninth piezoelectric element group 140, the ninth connecting member 142, the tenth piezoelectric element group 144, and the rod engaging member 146 are connected in series. As can be seen from FIG. 1, in the above arrangement, the first
The piezoelectric element group 108 and the tenth piezoelectric element group 144 are arranged on the same line. Therefore, a rod 148 is connected to the tip portion of the rod engaging member 146, and a poppet type valve body 150 as an operator is attached to the tip portion of the rod 148. The valve body 150 can be seated on the valve seat 152 by being displaced. At that time, as easily understood from FIG. 2, the expansion and contraction actions of the first piezoelectric element group 108 and the tenth piezoelectric element group 144 are performed on the same straight line. Therefore, it is possible to control the flow rate of the fluid that flows into the control chamber 154 in the direction of arrow A and is discharged in the direction of arrow B by the amount of displacement of the valve body 150.

When a voltage is applied with a predetermined electric polarity in the above configuration, in this embodiment, the piezoelectric element groups 108, 116, 12
4, 128, 136 and 144 arrange the piezoelectric elements that make it stretch, while the piezoelectric element groups 112, 120, 132
And 140 are arranged so that the piezoelectric elements forming them contract. Therefore, each of the piezoelectric element groups has a displacement amount of 10 times ΔX when a voltage is applied to the rod engaging member 146.
Will be brought to the tip of. As described above, since the first piezoelectric element group 108 and the tenth piezoelectric element group 144 are on the same straight line, the bending moments generated by the respective piezoelectric element groups are offset and the piezoelectric element group is destroyed. Alternatively, occurrence of a malfunction of the device is avoided.

As a result, the rod 148 moves the valve body 150 to ΔX × 10 as described above.
Then, the valve seat is seated on the valve seat 152 and the port 156 is closed. On the other hand, if the applied polarity of the voltage to the piezoelectric element group is converted, a displacement amount of −ΔX × 10 times is obtained, and the fluid is
It will be derived from port 156 to port 158. That is, it is possible to obtain the fluid control valve in which the valve can be freely opened and closed by controlling the applied polarity of the voltage.

FIG. 3 shows a modified example of the fluid control valve 100, and in the figure, the same reference numerals as those in the above-mentioned embodiment indicate the same constituent elements.

That is, in this embodiment, an actuator composed of a piezoelectric element group is incorporated in a spool / sleeve type fluid control valve instead of the poppet type, and therefore, the spool 160 as an operator is attached to the tip of the rod 148. Has been done.
When the piezoelectric element group is urged in the same manner as described above, a displacement amount corresponding to the number of the piezoelectric element group is brought to the rod 148, whereby the spool 160 is displaced, and the first to fifth ports 162, The opening portions 164, 166, 168, 170 are controlled to open and close according to the arrangement 7.

FIG. 4 shows an embodiment in which the actuator according to the present invention is applied to a nozzle flapper. Also in this embodiment, the same reference numerals as those in the above-mentioned embodiment indicate the same constituent elements. In this case, the first piezoelectric element group 108 and the tenth piezoelectric element group 1
The flapper 182 connected to 44 is arranged on the same straight line.

Therefore, by displacing the rod 148 by urging the piezoelectric element group, the nozzle 180 can be opened / closed by the flapper 182, which is an operator, and the throttle valve 184 can be opened to control the intervening fluid. Also here, the bending moment generated by the bias of the piezoelectric element group can be suppressed.

Further, FIG. 5 shows an example in which the actuator according to the present invention is used for switching an optical signal transmitting circuit.

In this embodiment, the optical cable 190 for transmission is held by the rod 148, while a plurality of optical cables 192, 194 for reception are opposed to the end face of the optical cable 190. Since the optical cable 190 is displaced in the direction of the arrow due to the bias of the piezoelectric element group, one of the optical cables 192 and 194 is the optical cable 190.
Will be able to receive signals from. That is, the optical cable for reception can be selected depending on the polarity of the voltage applied to the piezoelectric element group. The generation of the bending moment by the piezoelectric element group can be suppressed as in the above-described embodiment.

According to the present invention, since the actuator that is displaced by the piezoelectric element group that expands and the piezoelectric element group that contracts depending on the polarity of the voltage applied as described above is configured, the displacement amount is extremely large, and the operation can be performed electrically. Bending moments are also canceled each other, the piezoelectric element group can be avoided from destruction, the frequency response is good, the operation is stable and quiet, and there is no need to consider inertia etc. compared to conventional actuators. The fluid control valve has various effects such as being compact and inexpensive to manufacture.

[Brief description of drawings]

FIG. 1 shows an embodiment according to the present invention, and FIG. 1 is a perspective view of an actuator configured to increase displacement by connecting three or more piezoelectric element groups in series, FIG. 1 is an explanatory view of a state in which the actuator shown in FIG. 1 is incorporated in a poppet type fluid control valve, and FIG. 3 is a spool / sleeve type fluid control system in which three or more piezoelectric element groups are connected in series. FIG. 4 is an explanatory view of a state in which the actuator is incorporated in a valve, FIG. 4 is an explanatory view in the case where an actuator is used as a drive source of a nozzle flapper, and FIG. 5 shows a selecting operation of a receiving optical fiber by attaching the actuator to a transmitting optical fiber. FIG. 3 is an explanatory diagram of a state in which it is configured to do so. 100 ... Fluid control valve, 102 ... Space part 104 ... Fixed part, 106 ... Support member 108, 112, 116, 120, 124, 128, 132, 136, 140, 144 ...
... Piezoelectric element group 110, 114, 118, 122, 126, 130, 134, 138, 142 ... connecting member 146 ... rod engaging member, 148 ... rod 150 ... valve body, 152 ... valve seat 154 ... … Control room 156, 158, 162, 164, 166, 168, 170 …… Port 160 …… Spool, 180 …… Nozzle 182 …… Flapper, 184 …… Throttle valve 190,192,194 …… Optical cable

Claims (4)

[Claims] 1. A final piezoelectric element group, which is composed of a plurality of piezoelectric element groups capable of expansion and contraction formed by laminating piezoelectric elements and an operator, and which is displaced with respect to a first fixed piezoelectric element group. At least one intermediate piezoelectric element group is extended and contracted by arranging them apart from each other so that their extension and contraction action lines are on the same line, and interposing a connecting member between the first piezoelectric element group and the last piezoelectric element group. The connecting lines are arranged so that the lines of action deviate from the same line, and the operator is connected to the last piezoelectric element group, and a voltage is applied with a predetermined polarity to apply the voltage with a predetermined polarity to the first piezoelectric element group and the last piezoelectric element group. An actuator using a piezoelectric element, wherein the actuator is expanded and contracted, and the intermediate piezoelectric element group is expanded and contracted to move the operator forward and backward. 2. The actuator according to claim 1, wherein the object is a piezoelectric element including a fluid control valve. 3. The actuator according to claim 1, wherein the object is a piezoelectric element including a nozzle flapper. 4. The actuator according to claim 1, wherein the object is a piezoelectric element composed of one transmission optical fiber facing at least two reception optical fibers.