JPS597211A - Displacement element - Google Patents

Abstract

PURPOSE:To change the direction and voltage value of potential and to enable free displacement, by using two pieces a set of laminated piezo-electric elements which are respectively joined to the inside circumferential surface and outside circumferential surface positioned opposite to each other on one side of a displacement member. CONSTITUTION:Two pieces a set of laminated piezo-electric elements 21 and 22, 23 and 24 are provided to a cylindrical displacement member 1 made of spring steel. The elements 21, 22 are laminated with rectangular or plate-shaped piezo- electric elements 211 along the outside circumference of the displacement member and provided with electrodes 212 between the elements 211 and 211. The electrodes 212 are connected alternately +, -, +, - to each other, and the elements 211 are laminated with the crystal directions reversed to each other. The displacement member is thus displaced if a voltage is applied in the direction where the elements 22 and 23 joined on the inside circumferential surface of the displacement member elongate, and conversely if the voltage is applied in the direction where the elements 21, 24 contract.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a displacement element that uses a piezoelectric element to obtain a displacement amount. It is known that a piezoelectric element (+) ZT element) expands, contracts, or covers itself in the direction of the voltage when a voltage is applied. Using this property, piezoelectric elements are laminated,
A laminated piezoelectric element in which electrodes are formed between them is known. Since this laminated piezoelectric element has an extremely small amount of displacement when a voltage is applied to one piezoelectric element, a large number of piezoelectric elements are stacked to ensure a certain amount of deformation as a whole. For example, if a voltage of 1.6 kV is applied to the top and bottom surfaces of a piezoelectric element having a diameter of 32+11111 mm and a thickness of 1 mm, a displacement of 0.1 to 1 μ can be obtained without a load. By applying a voltage of 1.6 kV to each piezoelectric element, this laminated piezoelectric element in which 100 piezoelectric elements are laminated can obtain a displacement amount of 50 to 100 microns, which is 100 times that amount. Conventional laminated piezoelectric elements are expected to be used in pulse motors, high-speed valves, vibration sources, and the like.

In addition, as a displacement element published in the literature, laminated piezoelectric elements are laminated on both sides of a plate-shaped elastic material, and the displacement of one laminated piezoelectric element is set in the direction of extension, and the amount of displacement of the other piezoelectric element is set in the direction of contraction. Displacement elements have been announced that bend a V1 plate-shaped elastic member in one direction by applying electric current.

Such a displacement element has a function similar to that of a bimetal.

The displacement element of the present invention uses a laminated piezoelectric element to provide a displacement element that can take a large amount of displacement. That is,
The displacement element of the present invention is made of spring steel or the like. Each set consists of a cylindrical displacement member made of U material, and four laminated piezoelectric elements cut in at least two pairs of two in one phase, bonded to the outer and inner peripheral surfaces of the displacement member. the two laminated piezoelectric elements are joined to corresponding outer and inner peripheral surfaces of one side of the displacement member, the two sets are located axially symmetrically to each other of the displacement member, The lamination direction of all laminated piezoelectric elements is parallel to the circumferential direction of the displacement member.

A cylindrical displacement member made of an elastic material C such as spring steel, which is a component of the displacement element of the present invention, constitutes the main body of the wooden displacement element, and displacement is extracted by deforming the displacement member. A pair of laminated piezoelectric elements bonded to the outer circumferential surface and the inner circumferential surface of one side of the displacement member are arranged to have a displacement amount r using laminated piezoelectric elements corresponding to the conventionally known bimetal described above.
It has the same effect as . That is, by extending the laminated piezoelectric element bonded to the inner circumferential surface and contracting the laminated bielectric element bonded to the outer circumferential surface, the radius of curvature of the side of that portion of the displacement member becomes human. If the displacement of the laminated piezoelectric system r is reversed,
The radius of curvature of the side of that part becomes small.

The two-phase laminated piezoelectric element of the displacement element of the present invention is located axially symmetrical to the displacement member. Therefore, the voltage is applied in the direction in which the two laminated piezoelectric elements bonded to the inner peripheral surfaces of the two sets of laminated piezoelectric elements extend, and in the opposite direction to the two laminated piezoelectric elements laminated on the outer peripheral surfaces to contract. By applying a force, for example, a perfectly circular displacement member is deformed into a circular shape that is elongated in the direction in which the laminated piezoelectric elements are laminated. Conversely, the laminated piezoelectric elements are stacked by applying a voltage in the direction in which the two laminated piezoelectric elements bonded to the inner circumferential surface contract and in the direction in which the laminated piezoelectric element bonded to the outer circumferential surface extends. It deforms into a circular shape with shorter directions. Due to this movement of the displacement member in substantially the same direction, one small displacement can be avoided.

The displacement element of the present invention requires the two sets of laminated piezoelectric elements described above, but by using four sets of laminated piezoelectric elements, a displacement element with a larger displacement and deformation force of 4+1 can be obtained. . In this case, one set of laminated piezoelectric elements are joined to each other so that they are positioned at equal intervals around the circumference of the cylindrical displacement member. Specifically, two-phase laminated piezoelectric elements that are axially symmetrical are applied a voltage in the same direction of expansion or contraction, and two sets of laminated piezoelectric elements located adjacent to these two sets of laminated piezoelectric elements are A reverse voltage is applied to the laminated electric element. This causes the displacement member to deform into a circular shape.

Since there are 4 laminated 11 electrolytic elements that cause deformation,
The deformation force is large, and the radius of curvature changes at four points, so the amount of displacement also becomes large.

This will be further explained in Examples.

Example 1 A cross-sectional view of a displacement element according to a first example of the present invention is shown in FIG. This displacement element consists of a cylindrical displacement member 1 made of spring steel, and two pieces each connected to the corresponding inner and outer peripheral surfaces of one side of the displacement member. 1st layer Tsujiden holiday prefecture 21
．． 22, and two one-phase laminated piezoelectric elements 23 and 24 bonded to corresponding inner and outer peripheral surfaces of the dark blue and axially symmetrical sides, respectively. In other words, the W4-layer piezoelectric elements 21 and 22 and 23 and 24 each form one phase. The set consisting of laminated piezoelectric elements 21 and 22 is l#lI
The layer is located at a symmetrical position with respect to the central axis of this displacement member with respect to the set made up of the power resting element bodies 3 and 24. 1st
FIG. 2 shows an enlarged view of a part of the displacement element shown in FIG.
Mechanical piezoelectric elements 211 are stacked along the outer peripheral surface of a displacement member, and electrodes 212 are provided between each piezoelectric element 211.211. The electrodes 212 are alternately connected to +, -1, -
1... are connected alternately. And piezoelectric element P
211 are alternately stacked with their crystal directions reversed. -), alternately move the electrodes l-1-1 (-1-1...
By applying a voltage of
'' is reversed, both parts are displaced in the direction of contraction.

Note that the laminated piezoelectric coupling r is covered with a cover 213 to ensure that each piezoelectric element 211 is held on the outer peripheral surface of the displacement member 1. Note that the laminated piezoelectric elements 22, 23, and 24 also have the same configuration as the laminated piezoelectric element 21. Using this displacement element, a voltage is applied in the extending direction of the laminated piezoelectric elements 22 and 23 bonded to the inner peripheral surface of the displacement member 1, and vice versa By applying a voltage in the direction of contracting the front members 21 and 24, the displacement element is deformed into the state shown in its cross section in FIG. For this reason, if we focus on point Q (a point located between each laminated piezoelectric element of the displacement member), we can see that the line segment P in FIG. 1 to which no voltage is applied is the line in FIG. 3 to which a voltage is applied. 1) Q is getting larger.

Furthermore, in the displacement element of this embodiment, a voltage is applied in a direction to shrink the laminated piezoelectric elements 22 and 23 bonded to the inner circumferential surface of the displacement member, and conversely, the laminated piezoelectric elements 21 and 23 bonded to the outer circumferential surface of the displacement member are compressed. By applying a voltage in the direction in which 24 extends,
Contrary to FIG. 3, it is deformed into approximately the same shape that is longer in the left-right direction in the figure.

In such a case, line segment 1) Q will be smaller than PQ in FIG. Therefore, by applying the voltages of the laminated piezoelectric elements 21, 22, 23, and 24 in the opposite direction, the position of point 1 Q can be changed significantly, and a displacement amount comparable to that of humans can be obtained.

Therefore, for example, if Q is a fixed point and P is a displacement point, then
By changing the voltage of the laminated piezoelectric element to + or - or changing the magnitude of the voltage, the position of the displacement point 1 can be set to an arbitrary position, and the line segment PQ can be changed significantly.

In addition to J3, points P, and Q, the position of point R1 and point S, which is the intermediate point of point P1Q on the displacement member 1, also has a large displacement distance of 1q, similar to points P and Q.

In addition, when a large angle change is required, the angle in the tangential direction of the intermediate point between adjacent points P and R, R, QlQ, SSS, etc.] on the displacement member 1, for example, the position of point T. changes greatly, so this displacement element can also be used as a variable angle element.

Embodiment 2 A displacement element according to another embodiment of the present invention is shown in FIGS. 4 and 55. This displacement element uses four sets of laminated piezoelectric elements, whereas the displacement element of the first embodiment uses two sets of laminated piezoelectric elements. That is, the displacement element of this example is
Cylindrical displacement member 1 and eight laminated piezoelectric elements 21 and 22
．． 23.2/1.25.26.27.28 is used. Here, the displacement member 1 is similar to the displacement member 1 of the first embodiment. Also, laminated piezoelectric element 21.22.23.2
4, the laminated piezoelectric element 21 of the displacement element of Example 1
．． There is a C similar to 22.23.24.

In this example, four laminated piezoelectric elements 25, 26, 2
7.28 are respectively joined to the displacement portion 1tA1 located between the piezoelectric elements of each phase.

Also in the displacement element of this embodiment, two
A voltage is applied to the laminated piezoelectric elements so that the displacements are opposite to each other, for example, when a negative laminated piezoelectric element expands, the other laminated piezoelectric elements contract.

In the relationship between the pairs and the navy blue, voltage is applied in the direction of displacement of the pairs that are axially symmetrical to the displacement member 1, but in the case of adjacent pairs, voltage is applied in the opposite direction so that when one expands, the other contracts. be done. For example, the laminated piezoelectric elements 21 and 22
Regarding silk, when a voltage is applied in the direction in which the laminated piezoelectric element 21 extends, a weight is applied in the direction in which the other laminated piezoelectric element 22 contracts.

Two sets of axially symmetrical elements, for example, laminated piezoelectric elements 21 and 2
In the set No. 2 and the set of laminated piezoelectric elements 23 and 24, the laminated piezoelectric elements 21 and 24, which are connected to the outer peripheral surface of the displacement member and correspond to n, are applied with voltage in the same displacement direction, for example, in the direction in which they extend together. is applied.

A voltage is also applied to the other corresponding laminated piezoelectric elements 22 and 23 in the same -ti direction, for example, in a direction in which they both contract.

Two adjacent sets, for example, laminated piezoelectric elements 21 and 22
In the pair of laminated piezoelectric elements 25 and 26, the corresponding one-layer piezoelectric elements 21 and 25 connected to the outer peripheral surface of the displacement member are moved in different directions, for example, the laminated piezoelectric elements 21
When a voltage is applied to the laminated piezoelectric element 25 in the direction of extension, a voltage is applied to the laminated piezoelectric element 25 in the direction of contraction. Similarly, for other corresponding laminated piezoelectric elements 22 and 2 (5), when a voltage is applied in the direction in which the laminated Lt electrically conductive body r-22 contracts,
A voltage is applied in the opposite direction. Figure 5 shows the shape of the displacement element when voltage is applied in this state. This displacement element has a long circular shape in the vertical direction. J3, if the direction of voltage application to each laminated piezoelectric element is reversed, it deforms into a horizontally elongated circular shape. The displacement element of this second embodiment is compared with the displacement element of the first embodiment as shown in FIGS.
Since the laminated piezoelectric elements 25, 26 and 27, 28 of the upper and lower sub-base groups are added, the deformation of the applied fft layer piezoelectric elements is added, and the displacement member 1 is pushed more forcefully. Avoid deformation. Therefore, it is thought that the deformation force is approximately twice that of the displacement element of the first embodiment. Also, since the deformation in the downward direction is forced by the laminated piezoelectric element, In addition, the amount of displacement is slightly larger than that of the displacement element of the first embodiment.

This displacement element can also be used as a variable angle element in the same way as the displacement element of the first embodiment.

[Brief Description of the Drawings] Figures 1, 2, and 3 are shown in Embodiment 1 of the present invention] Regarding the displacement element, Figure 1 is a cross-sectional view, and Figure 2 is the displacement of Figure 1. A partially enlarged view of the element, FIG. 3, shows the state when a constant voltage is applied to the first embodiment, and a cross-sectional view, FIGS. 4 and 5, relate to the displacement element of the second embodiment of the present invention. , FIG. 4 is a sectional view thereof, and FIG. 5 is a sectional view of the displacement element shown in FIG. 4, showing a state when a constant voltage is applied to the displacement element. 1...Displacement member 21.22.23.24.25.26.27゜28...
...Laminated piezoelectric element 211...Piezoelectric element 212...Electrode 213...Cover patent applicant Toyota Motor Corporation agent Patent attorney Hirodo Okawa Patent attorney Shudo Fujitani Patent Attorney Akio Maruyama Figure 5

Claims (2)

[Claims] (1) A cylindrical displacement member made of an elastic material such as spring steel, with at least 2 sets of 814 laminated piezoelectric elements joined to the outer and inner circumferential surfaces of the displacement member. The two laminated piezoelectric elements constituting each set are one of the displacement members.
They are joined to corresponding outer and inner circumferential surfaces of the side portions, the two sets are located axially symmetrically of the displacement member, and the stacking direction of all laminated piezoelectric elements is aligned with the circumference of the displacement member. A displacement element characterized by being parallel in direction. (2) The displacement element according to claim 1, wherein the laminated piezoelectric element is composed of four sets, and each set is positioned at equal intervals in the circumferential direction of the cylindrical displacement member.