JP3480127B2 - Stacked actuator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated actuator composed of a laminated body of thin plates formed by using a deformable member such as a piezoelectric unimorph or a bimetal and extracting an actuating force to the outside in the form of a bending operation.

[0002]

2. Description of the Related Art As a telescopic actuator whose length is expanded and contracted and a rotary actuator which outputs a rotational force, a laminated piezoelectric actuator is known together with an electromagnetic motor. However, such expansion and contraction actuators and rotation actuators are basically limited to movement in one direction. Therefore, for example, when a moving mechanism in a bent pipe is to be configured, it is necessary to configure an actuator mechanism that is a combination of a plurality of expansion / contraction actuators and a rotary actuator, in order to realize a particularly fine mechanism. Moreover, it is desired to develop an actuator that performs two-dimensional and three-dimensional operation.

In Japanese Patent Application No. 5-331679 filed earlier, a plurality of thin plates, each of which is bent and controlled in the direction of its surface, are formed by laminating a plurality of connecting portions, and the connecting portions associated with the bending deformation of the thin plates are stacked. We have proposed an actuator that performs bending motion in multiple directions by utilizing the displacement difference of. However, in the actuator configured as described above, the connecting surface of the connecting portion may hinder the deformation operation of the thin plate, and therefore it is desirable to make the connecting portion as thin as possible.

However, as the structure of the actuator mechanism is further miniaturized in this way, it becomes difficult to make the size of the connecting surface remarkably small from the viewpoint of strength in terms of the process, and it is necessary to increase the size of the connecting portion. As a result, the deformation of the thin plate is hindered by the plurality of connecting portions, and the operating range of the actuator is restricted.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a two-dimensional or three-dimensional operation can be smoothly performed without being restricted by the operation range, and further miniaturization can be achieved. It is an object of the present invention to provide a laminated actuator that can be easily manufactured.

[0006]

In the laminated actuator according to the present invention, the outer peripheral portions of a pair of thin plates that are bent and deformed in the direction of the surface based on a control signal from the outside are set to face each other in a parallel state. A plurality of actuator units having central portions connected to each other by a central connecting member are provided, the plurality of actuator units are sequentially stacked at predetermined intervals, and a pair of thin plates facing each other of the stacked actuator units. The outer peripheral portions are joined together, and the end face joint portion of the central connecting member is inclined with respect to the surface of the thin plate as the thin plate is bent and deformed.

Here, the thin plate is a piezoelectric unimorph composed of a metal plate, a piezoelectric element bonded to the surface of the metal plate, and an electrode plate segmented into regions on the surface of the piezoelectric element.
Alternatively, it is configured to include a bimetal formed by joining a plurality of metal materials having different thermal expansion coefficients, and a heater member which is divided into areas on the surface of the bimetal and set.

[0008]

In the laminated actuator constructed as above, a plurality of actuator units in which the central portions of a pair of thin plates whose displacement and bending are controlled in the surface direction are connected by the central connecting member are formed as a laminated body. Then, for example, by bonding a piezoelectric element to the surface of a thin plate constituting these laminated bodies, dividing the piezoelectric element into a plurality of regions and setting electrodes, and controlling the applied voltage to these electrodes, It is bent and deformed in the direction. Due to the bending of the thin plate, the joint surface of the central connecting member with respect to the thin plate is inclined and the axis of the connecting member is inclined. Such an operation occurs on both surfaces of a pair of thin plates constituting the actuator unit, and therefore, the axis of the laminated body formed by laminating such actuator units is arbitrarily bent and controlled to perform a two-dimensional or three-dimensional operation. Is easily realized. In this case, a pair of thin plates forming a plurality of actuator units is composed of a pair of thin plates connected only by the central connecting member, and a predetermined actuator operation can be realized by the inclination of the axis of the central connecting member with respect to the thin plates. The restriction of movement by the member is effectively removed, and the miniaturization is facilitated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional structure of a laminated actuator, which includes a plurality of actuator units 111, 112,
It is configured by sequentially stacking. Actuator unit
111, 112, ... are the first thin plates 121, 122 ,.
And the second thin plates 131 1, 132, ..., Which are set to face each other, the first thin plates 121 (122, 123, ...).
, And the second thin plates 131 (132, 133, ...) Are connected to each other by central connecting columns 141, 142 ,. Here, the outside of the first actuator unit 111, which is one end portion of this laminated body, and the end portion on the opposite side of this laminated body, are respectively 1
A number of thin plates 120 and 12n are arranged.

2 to 4 explain the basic structure for forming each of the actuator units 111, 112, ... First, FIG. 2 shows a basic structure for forming the first thin plate 121. The basic structure is composed of a circular metal plate 20. A ring-shaped connecting member is arranged on the outer peripheral edge of the metal plate 20. For example, at a three-divided position (not shown) radially extending from the center point of the metal plate 20 at the same angle, the ring is joined by brazing. The plate-like connecting member and the metal plate 20 are joined together.

With respect to this ring-shaped connecting member, cut into the metal plate 20 at a position such that its brazed portion is sandwiched.
Electrical discharge machining is performed so that 211 to 213 are formed, and the ring-shaped member is cut to form outer peripheral connection columns 221 to 223. That is, the outer peripheral connection columns 221-223.
Is formed by cutting out a part of a metal ring, and is set at a position divided into three at an equal angle from the center point of the metal plate 20. Further, wiring notches 231 to 233 are formed on the outer peripheral edge of the metal plate 20 by electrical discharge machining, and are located between the connecting columns 221 to 223, respectively.

Each of the actuator units 111, 112, ... Has a first thin plate 121, 122, as shown in FIG.
, And second thin plates 131 1, 132, ... And the same as the first thin plates 121 1, 122 ,. Therefore, as shown in FIG. 3, the metal plates 20 constituting each of the first thin plates 121, 122, ... Shown in FIG.
, And the metal plates 24 constituting the second thin plates 131, 132, ... Are set parallel to each other, and the central portions of the pair of metal plates 20 and 24 are respectively connected to the central connecting column 14.
, 142 are connected to each other to form a basic structure of the actuator unit 111.

Similarly to the metal plate 20, the metal plate 24 combined with the metal plate 20 is also constructed by forming outer peripheral connecting columns 251-253 on the outer periphery. Are set at positions corresponding to the positions of the outer peripheral connection columns 221 to 223, and the respective connection columns 221 to 223 are provided so as to project on the outer surfaces of the metal plates 20 and 24 that are placed opposite to each other.

That is, the metal plates 20 for forming the first thin plates 121, 122, ..., And the second thin plates 131, 13 are formed.
2, ... The metal plates 24 for forming each of them are set in parallel with each other, and the combination of the thin plates 121 and 131 composed of the pair of metal plates 20 and 24 respectively forms a set of actuator units 111. Is formed.
Here, the pair of metal plates 20 and 24 are integrally connected to each other by the cylindrical central connecting column 141 at the central axis portion thereof as described above. The metal plates 20 and 24, which form the thin plates 121 and 132, respectively, are joined by solder paste or the like to the surfaces corresponding to the central portions of the metal plates 20 and 24, respectively.

Here, the metal plates 20 and 24 forming each of the actuator units 111, 112, ... Forming the laminated body are in a uniform plane, and the axes of the connecting columns 141 are perpendicular to the planes. The metal plates 20 and 24 are set parallel to each other.

Disc-shaped piezoelectric elements 15 and 16 are concentrically joined to the outer surfaces of the metal plates 20 and 24, respectively. In this case, the metal plates 20 and 24 are connected to the piezoelectric element 15 respectively.
And 16 on the opposite side of the piezoelectric elements 15 and 16 from the metal plates 20 and 24, respectively, and an electrode divided into three regions by lines extending radially from the center point. The plates 261 to 263 are installed opposite to each other.

That is, the first thin plates 121, 122, ... And the second thin plate 131 are formed by the metal plates 20 and 24, respectively.
, 132, ..., respectively, forming piezoelectric unimorphs 27 and 28 corresponding to the pair of piezoelectric unimorphs 27 and 27, respectively.
A set of actuator units is constituted by. Then, each actuator unit 111, 112, ...
The corresponding electrode plates 261 to 263 of the piezoelectric unimorphs 25 and 26, respectively, are connected by lead wires 291 to 293 arranged via wiring notches 251 to 253.

Here, the metal plates 20 and 24 forming each of the actuator units 111, 112, ... Forming the laminated body are arranged in a uniform plane with respect to the metal plates 20 and 24. Make sure that the axes of the center connecting columns 141 are set vertically,
1 is joined and the metal plates 20 and 24 are set parallel to each other.

The actuator units 111, 112, including the pair of metal plates 20 and 24 connected by the central connecting columns 141, 142, ... In this way are sequentially laminated as shown in FIG. In each of the stacked actuator units 111 1, 112, ..., Adjacent actuator units 111 1, 112 ,. That is, the first and second thin plates 121 1, 122, ...
Corresponding electrodes of 131, 132, ... (Piezoelectric unimorphs 20, 24) are commonly connected.

Although not shown in detail, each thin plate 121
, 122, ... and 131, 132, .., and the metal plates 20 and 24 respectively constituting them are commonly connected, and the common connection point is connected to one pole of the point source 31. Further, at the other pole of the power source 31, the connection points of the respective electrode plates 261 to 263 of the respective thin plates 121, 122, ... And 131, 132 ,.
The electrode plates are connected through switches 301 to 303, respectively, and the electrodes 301 to 303 are selectively scanned to form an electrode plate.
The voltage from the power supply 31 is selectively applied to the capacitors 261 to 263.

FIG. 5A shows a model of a single-plate piezoelectric unimorph 27, which is the basis of the actuator operation. In this example, a circular piezoelectric plate 36 is provided for a circular metal plate 35. Electrode plates 37 and 38, which are joined to each other and are divided into two semicircular regions, are joined to the surface of the piezoelectric element 36. Although not shown in detail, the control voltage is selectively applied between the metal plate 35 and the electrode plates 37 and 38.

In this model, the diameter of the metal plate 35 is 12 m.
m, the diameter of the piezoelectric element 36 is 9 mm, and the plate thicknesses of the metal plate 35 and the piezoelectric element 36 are each 0.1 mm.
A voltage of 250 V is selectively applied to the electrodes 37 and 38. When the displacement of the metal plate 35 is measured from the surface of the metal plate 35 where the piezoelectric element 36 is not joined in the state where the control voltage is applied to the electrode plate 37 or 38 in this manner, (B) in FIG. The result is as shown in.

That is, one electrode plate (for example, the electrode plate 38
When a voltage is applied to the metal plate, the metal plate is deformed so that the portion corresponding to the electrode plate 38 protrudes, as shown by A in FIG.
The central part of 35 tilts. Since the end faces of the central connecting columns 141, 142, ... Are joined to this inclined portion, the axes of the connecting columns 141, 142 ,. In a laminated structure such as No. 1, the inclination is enlarged and the axis is bent as a whole. Further, when the same voltage is applied to the electrode plates 37 and 38, the metal plate 35 is displaced as shown by B in FIG.

As can be understood from the characteristic of this displacement, if the size (diameter) of the connecting column at the center is too large, the deformation of the piezoelectric unimorph cannot be effectively utilized. The deformation of the piezoelectric unimorph can be more effectively utilized when the size of the connecting surface of the central connecting column 141 with respect to the metal plate is equal to or less than 1/2 the outer diameter of the piezoelectric element 36 (the central region of the displacement characteristic diagram). .

In the above-mentioned embodiments, one actuator unit is constituted by a combination of a pair of piezoelectric unimorphs, but this is not limited to the piezoelectric unimorph, but is modified by controlling a signal from the outside such as a piezoelectric bimorph. It can also be appropriately configured by a combination of thin plates.

FIG. 6 shows a bimetal 41 which can be used as a thin plate which is deformed by the control of a signal from the outside.
The disc-shaped bimetal 41 is configured by joining the first metal plate 42 and the second metal plate 43 having different thermal expansion coefficients. Then, heater wirings 451 to 453 are provided on the surface of the disc-shaped bimetal 40 so as to be divided into three first to third regions with an insulating layer 44 interposed therebetween. ~ 453), a thin plate whose arbitrary surface is displaced and bent is constructed by selectively supplying a heating current. The use of shape memory alloy instead of bimetal is also conceivable.

In the above-described embodiments, the pair of thin plates that are bent and displaced are combined by the three outer peripheral connecting columns that are set at the positions where the outer peripheral portions are evenly divided to form the actuator unit. The number of the outer peripheral connecting columns can be appropriately selected, and it is also possible to configure the outer peripheral connecting columns by a single ring-shaped member that joins the entire outer periphery. Further, the central connecting column 141 is not limited to the columnar shape, as shown in FIG.
It is also possible to configure it with a ring-shaped member as shown in, and it is also possible to directly connect only the central portions of the pair of thin plates and make this connecting portion function as the central connecting member.

[0028]

As described above, according to the laminated actuator according to the present invention, an actuator capable of expanding and contracting and bending can be constructed by a simple process, and a combination of thin plates such as a pair of piezoelectric unimorphs can be used. When configuring the actuator unit, it is possible to surely reduce the influence of the connecting member that connects the thin plates on the deformation operation of the thin plates. Therefore, it is possible to obtain a sufficiently large displacement amount even if the device is miniaturized.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration of a laminated actuator according to an embodiment of the present invention as viewed from a side surface direction.

FIG. 2 is a diagram illustrating a metal plate that constitutes one thin plate of an actuator unit that constitutes the actuator.

FIG. 3 is a view for explaining a combined state of a pair of metal plates.

FIG. 4 is a view for explaining a combined state of piezoelectric unimorphs similarly composed of the pair of metal plates.

FIG. 5 is a diagram illustrating a displacement characteristic model of a piezoelectric unimorph.

FIG. 6A is a diagram illustrating another example of a thin plate that constitutes an actuator unit, and FIG. 6B is a cross-sectional configuration diagram thereof.

7A and 7B show another example of the central connecting column, where FIG. 7A is a plan view and FIG. 7B is a side view.

[Explanation of symbols]

111, 112, ... Actuator unit, 121, 122,
..., 131, 132, ... first and second thin plates, 141, 142
..., central connection column, 15, 16 ... Piezoelectric element, 20, 24 ... Metal plate, 211, 212, ... Notch, 221-223, 231-23
3… Wiring notch, 251 to 253… Perimeter connection post, 261
~ 263 ... Electrode plate, 27, 28 ... Piezoelectric unimorph, 291 ~ 29
3 Lead wire, 41 ... Bimetal, 42, 43 ... Metal plate, 44 ... Insulating layer, 45, 451-453 ... Heater wiring.

─────────────────────────────────────────────────── --- Continued from the front page (72) Inventor, Koji Idagaki, 1-1, Showa-cho, Kariya city, Aichi, Japan, Denso Co., Ltd. (56) Reference JP-A-7-193289 (JP, A) JP-A-5 -304324 (JP, A) JP-A-1-235288 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 41/09

Claims (7)

(57) [Claims] 1. A plurality of thin plates that are bent and deformed in the direction of a surface based on a control signal from the outside are set to face each other in a parallel state, and a plurality of central connecting members for connecting the central portions of the thin plates to each other are included. Actuator unit and at least one peripheral connecting member forming a laminated structure by sequentially arranging a plurality of actuator units at predetermined intervals and connecting the outer peripheral portions of a pair of thin plates set to face each other. According to the bending deformation of the thin plates constituting the actuator unit, the connecting surface with the central connecting member is tilted with respect to the surface of the thin plate, and the axis of the stacked body of the plurality of stacked actuator units is A laminated actuator characterized by being bent. 2. The laminated actuator according to claim 1, wherein the peripheral connecting member is constituted by an annular member set corresponding to an outer peripheral portion of the thin plate. 3. The support member according to claim 1, wherein the peripheral connecting member is composed of a plurality of pillar members configured by dividing an annular member set corresponding to an outer peripheral portion of the thin plate into a plurality of parts. Multilayer actuator. 4. The laminated actuator according to claim 1, wherein the central connecting member is constituted by a cylindrical body having an end surface joined to the thin plate surface. 5. The thin plate includes a metal plate, a piezoelectric element bonded to a surface of the metal plate, and a plurality of regions formed by dividing the surface of the piezoelectric element into a plurality of regions. Composed of a piezoelectric unimorph including an electrode plate,
The laminated actuator according to claim 1, wherein a control voltage is selectively applied between the electrode plate and the metal plate. 6. The thin plate is set to correspond to a bimetal, which is a joined body of a plurality of plate materials made of a plurality of metal materials having different thermal expansion coefficients, and a plurality of regions divided into the bimetal surfaces. 2. The laminated actuator according to claim 1, further comprising a heater member, wherein heating current is selectively controlled to be supplied to each of the heater members so that the heater member is bent and deformed in a direction of a surface. 7. The laminated actuator according to claim 1, wherein the central connecting member has a connecting surface with respect to the thin plate that is set to have a dimension that is ½ or less of a dimension of a portion of the thin plate that is bent and deformed.