JP2849611B2 - Piezo actuator and active vibration isolator - Google Patents

Description

The present invention relates to a piezo actuator and an active vibration isolator, and more particularly, to a piezo actuator using a stacked piezo element and an active vibration isolator using the piezo actuator.

[Conventional technology]

A conventional active vibration isolator using a laminated piezoelectric element of a piezo element as an actuator (piezoactuator) is basically configured as shown in FIG. That is, the piezo actuator 14 is disposed between the lower gantry 10 and the device mounting table 12, and when the vibrations are detected by the vibration detectors 16 and 17, the control device 18 controls the vibration in the opposite phase to the detected vibration. A control signal is output to the piezo actuator 14 in order to generate the following.

However, in the case of such a configuration, it is possible to insulate the vertical vibration input from the lower gantry 10, but the practical range is limited because most of the actual vibration is three-dimensional vibration. Therefore, the configuration shown in FIGS. 10 and 11 is adopted.

The active vibration isolator shown in FIG. 10 has a three-stage structure of a lower gantry 20, a middle gantry 22, and a device mounting gantry 24 in order to extend the vibration isolation effect not only vertically but also horizontally. JP-A-61-286634).

In this active vibration isolator, a ball 28 is arranged between the center mount 22 and the lower mount 26 to support the middle mount 22 so as to be movable in the horizontal direction, and the vertical vibration is caused by vibrating the piezo actuator 30. The horizontal vibration is insulated by driving the piezo actuator 32 in the horizontal direction on FIG. 10 and the piezo actuator (not shown) in the direction perpendicular to the plane of FIG. Vibration is insulated.

The active vibration isolator shown in FIG. 11 has a piezo actuator 40 between a device mounting table 41 and an upper frame 42.
Are arranged, piezo actuators 44, 44 are arranged between the upper frame 42 and the wall 43, and piezo actuators 46, 46 are arranged between the lower frame 48 and the wall 49. Have been. Then, vertical vibration isolation is performed by the piezo actuator 40 mounted in the vertical direction, and horizontal vibration isolation is performed by a combination of the piezo actuators 44 and 46.
Three-dimensional vibration is insulated by these combinations.

Further, there is a piezo actuator in which a piezo element 52 and an anti-vibration rubber member 54 are integrated or connected as shown in FIG. 12 (Japanese Patent Laid-Open No. 59-65640). The piezo actuator 50 aims at enabling vibration to be absorbed by the laminated piezo element 52 and attenuating vibration not absorbed by the laminated piezo element 52 by internal friction of the vibration-proof rubber member 54.

[Problems to be solved by the invention]

However, the active vibration isolator shown in FIG. 10 has a drawback that the ball 28 does not operate effectively when targeting micro vibrations on the order of microns.

In addition, there is a problem in that when one of the piezo actuators is driven during the vibration control in the horizontal direction, a shearing force is applied to the other piezo actuator in a direction orthogonal to this. In particular, the piezo actuator is weak to shearing force. Therefore, in order to remove the shearing force acting on the piezo actuator from the outside, it is conceivable to further incorporate another stage, but in this case, a four-stage structure is used. The disadvantage is that the device becomes too complicated.

On the other hand, the active vibration isolator shown in FIG. 11 can prevent the effect in the micro-vibration region, which is one of the above-mentioned drawbacks, but cannot solve the drawback that the structure becomes complicated.

Further, when the piezo actuator 50 shown in FIG. 12 is used as the piezo actuator of the above conventional active vibration isolator, the vibration isolating rubber member 54 provides flexibility against the force applied to the piezo actuator 50 in the lateral direction. Thus, the problem of the strength of the piezo actuator can be solved. However, the piezo actuator 50 also has flexibility in its driving direction, and there is a problem that vibration control of minute vibration cannot be performed.

The present invention has been made in view of such circumstances, and together with a piezo actuator suitable for controlling microscopic three-dimensional microvibration, it is possible to control three-dimensional microvibration well, and the structure of the device is simple. It is an object of the present invention to provide a simple active vibration isolator.

[Means for solving the problem]

In order to achieve the above object, the present invention attaches a plate material sandwiching a thin-film elastic body in a crimped state to an end face in the driving direction of the stacked piezo element, and attaches the elastic body to the driving direction of the stacked piezo element in the driving direction It is characterized by having micron-order elasticity only in the direction perpendicular to the direction.

In addition, the present invention provides a plurality of the piezo actuators, and arranges the piezo actuators between the lower gantry and the device mounting table so that the driving directions of the piezo actuators coincide with the X, Y, and Z directions. A vibration detector for detecting vibrations in the Y and Z directions is provided on the device mounting table, and the driving directions are X, Y, and X based on signals indicating the vibrations in the X, Y, and Z directions detected by the vibration detector. Each piezo actuator disposed so as to coincide with the Z direction is individually controlled to prevent three-dimensional vibration of the device mounting base.

[Action]

The piezo actuator has elasticity only in a direction orthogonal to the driving direction. That is, the piezo actuator has rigidity in the driving direction and has flexibility in a direction orthogonal to the driving direction.

Therefore, vibration control is possible even for micro vibrations on the micron order in the same direction as the driving direction, while flexibility is provided for vibration perpendicular to the driving direction, so that a large shear force is applied to the piezo actuator. Thus, the problem of the strength of the piezo actuator can be solved, and a large load does not occur when other piezo actuators arranged in an orthogonal relationship to each other vibrate.

Thus, the active vibration isolator using the piezo actuator can favorably control three-dimensional microvibration with a simple structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a piezo actuator and an active vibration isolator according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 4 is a side view showing one embodiment of the piezo actuator according to the present invention. This piezo actuator 60
Has a laminated piezo element 62, two metal plates 64 and 66, and an elastic body 68, and a metal plate 64 is attached to an end face of the laminated piezo element 62 in the laminating direction (driving direction) 70, This metal plate 64
An elastic body 68 in the form of a thin film is sandwiched between the other surface and the metal plate 66 in a pressed state.

The pre-compression force of the elastic body 68 is set to be larger than the force generated by the laminated piezo element 62, whereby the elastic body 68 has rigidity in the driving direction 70 of the laminated piezo element 62. , Has elasticity (flexibility) only in a direction (lateral direction) 72 perpendicular to the driving direction 70.

FIG. 5 is a side view of a piezo actuator 74 having the same effect as that of the piezo actuator 60 of FIG. 4. In this actuator 74, a bearing 76 is provided between metal plates 64 and 66 instead of the elastic body 68. Is different.

That is, when the laminated piezo element 62 vibrates in the driving direction 70, the elastic body 68 of the piezo actuator 60 acts as a rigid body in the driving direction 70 because the elastic body 68 is crimped as described above. In the direction 72, the elastic body 68 acts as soft under the effect of the elastic force. The use of the elastic body 68 has an effect that it works particularly effectively at the time of micro-vibration on the order of submicrons, unlike the case where a rigid body such as the bearing 76 is used.

As a result, the piezo actuator 60 is very rigid in the driving direction 70, and has a softness in which it can move freely in the lateral direction 72 perpendicular to the driving direction 70. Therefore, piezo actuators 60 mounted in the same rigid body in different directions
Can freely and independently move, and by arranging the piezo actuators 60 freely, it is possible to provide an actuator vibration isolation device capable of three-dimensionally controlling vibration.

6 to 8 are longitudinal sectional views showing other embodiments of the piezo actuator according to the present invention. The same parts as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 6, concentric cylinders 73 and 75 are arranged on the metal plates 64 and 71 so as to surround the laminated piezo element 62, respectively. The space between the cylinders 73 and 75 is expandable and contractible in the driving direction of the laminated piezo element 62, and can maintain confidentiality in the cylinder.

As a result, the humidity of the atmosphere of the stacked piezo element 62 is kept at a predetermined value (80%) or less, so that the characteristics of the piezo element do not change. Further, the cylindrical bodies 73 and 75 also have an effect of absorbing an impact force in the shear direction applied to the laminated piezo element 62.

The piezo actuator shown in FIG. 7 uses a metal cylinder 77 and a rubber cylinder 78 instead of the cylinders 73 and 75 shown in FIG. 6, and the piezo actuator shown in FIG.
In this case, the laminated piezo element 62 is moisture-proof.

1 and 2 are a plan sectional view and a vertical sectional view, respectively, showing an embodiment of the active vibration isolator according to the present invention. FIG. 1 is a sectional view taken along line AA of FIG.

As shown in these drawings, the actuator vibration isolator includes a lower frame 80, a device mounting table 82, piezo actuators 60X, 60Y, 60Z, coil springs 84X, 84Y, a vibration detector 86, and the like.

The lower mount 80 is installed horizontally on the base 90 by a height adjusting screw 88, and the device mount 82 is mounted on the lower mount 80 via piezo actuators 60X, 60Y, 60Z and coil springs 84X, 84Y. Has been established.

Here, the piezo actuators 60X, 60Y, and 60Z are each configured similarly to the above-described piezo actuator 60 (FIG. 4) or the piezo actuator shown in FIGS. 6 to 8, and the piezo actuators 60X, 60X The piezo actuators 60Y and 60Y are similarly driven in the Y direction by disposing the piezo actuators 60Y and 60Y in such a manner that their driving directions coincide with the X direction of the XY plane (horizontal plane).
Four piezo actuators 60 to match the directions
The Z is disposed between the lower frame 80 and the device mounting table 82 such that the driving direction thereof coincides with the Z direction (vertical direction).

Further, the coil springs 84X, 84X, and 84Y84Y are disposed between the lower frame 80 and the device mounting table 82 on the side facing the piezo actuators 60X, 60X, 60Y, and 60Y, respectively.
The coil springs 84X and 84Y are provided so as to always apply a pre-compression force to the piezo actuators 60X and 60Y so that the piezo elements of the piezo actuators 60X and 60Y can always be distorted in a compressive stress field. . The metal plate 6 of the piezo actuator 60 is also provided to the coil springs 84X and 84Y.
Means having flexibility only in the horizontal direction, which is composed of the elastic members 68 and 66, is provided. However, since the coil springs 84X and 84Y are originally flexible in the horizontal direction, this means is not always necessary.

The vibration isolator 86 detects a three-dimensional vibration propagated from a device (not shown) on the device mounting base 82, that is, a vibration in the X, Y, and Z directions, and outputs a signal indicating the vibration in each direction. Output to The control device controls the amount of extension of the piezo actuators 60X, 60Y, and 60Z required to stop the device mounting base 82 based on the input signal from the vibration detector 86, that is, the voltage signal to be applied to the piezo actuators 60X, 60Y, and 60Z. And obtain the voltage signal of each piezoelectric actuator 60X, 60
Output to Y and 60Z to control the vibration of the equipment mounting table 82.

Thereby, three-dimensional vibration of the device mounting base 82 can be controlled. Also, the piezo actuators 60X, 60
Y and 60Z are thin film-like elastic bodies 68 (fourth
The effect of FIG. 4 does not hinder the drive control in the direction perpendicular to each other, whereby the control can be performed simultaneously and independently.

FIG. 3 is an elevational sectional view showing another embodiment of the active vibration isolator according to the present invention. The same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. This active vibration isolating device is different from the device shown in FIG. 2 mainly in the shape of the lower frame 81 and the arrangement position of the piezo actuator 60Z.

In the above embodiment, the thin film-shaped elastic body is provided on one end surface of the piezo element, but may be provided on both end surfaces.

Also, on the opposite surface of the horizontal piezo actuator, a coil spring that can use a reaction force to create a pre-compressed state in the piezo element was used, but instead of the coil spring, a piezo actuator was installed in the same way, A method of giving both left and right vibration displacements by giving a vibration signal inverted from the facing surface may be adopted.

〔The invention's effect〕

As described above, the piezo actuator according to the present invention has rigidity in the driving direction of the piezo element, so that vibration control can be performed even in a micro-vibration region, while flexibility is provided in a direction orthogonal to the driving direction. Therefore, no shearing force is applied to the piezo actuator, and a large load does not occur when driving other piezo actuators arranged in an orthogonal relationship to each other. As a result, the active vibration isolator according to the present invention using the above-described piezo actuator can satisfactorily control three-dimensional six-degree-of-freedom fine vibration with a simple two-stage structure of the lower frame and the device mounting table.

[Brief description of the drawings]

1 and 2 are a plan sectional view and a vertical sectional view, respectively, showing an embodiment of the active vibration isolator according to the present invention, and FIG. 3 shows another embodiment of the active vibration isolator according to the present invention. 4 and 5 are side views of the piezo actuator according to the present invention and side views simulating the effects thereof, and FIGS. 6 to 8 are piezo actuators according to the present invention, respectively. FIGS. 9 to 11 are longitudinal sectional views showing another embodiment, FIGS. 9 to 11 are views showing a conventional active vibration isolator, and FIG. 12 is a side view showing an example of a conventional piezo actuator. 60, 60X, 60Y, 60Z …… Piezo actuator, 62 ……
Laminated piezo element, 64, 66 ... metal plate, 68 ... elastic body,
80… Lower frame, 82… Equipment mounting table, 86… Vibration detector.

──────────────────────────────────────────────────の Continued on the front page (73) Patentee 999999999 Patent Equipment Co., Ltd. 10-133 Minamihatsushima-cho, Amagasaki City, Hyogo Prefecture (72) Inventor Takashi Fujita 575-28 Nakano Hisagi, Naganoyama City, Chiba Prefecture (72) Inventor Murai Nobuyoshi 3-1-8 Timber Dori, Miharacho, Minamikawachi-gun, Osaka (72) Inventor Hiroshi Hayami 2-5-1-14 Minamisuna, Koto-ku, Tokyo (72) Yoshinori Takahashi 3-1 Timberdori, Mihara-cho, Minamikawachi-gun, Osaka 8 (72) Inventor Kazuki Katayama 3-1-8 Mitsudori, Mihara-cho, Minamikawachi-gun, Osaka (72) Inventor Shoji Takeshita 2-6-2 Otemachi, Chiyoda-ku, Tokyo Hitachi Construction Design Co., Ltd. (72) Inventor Koichiro Akita 2-6-2 Otemachi, Chiyoda-ku, Tokyo Inside Hitachi Construction Design Co., Ltd. (72) Inventor Akira Tsuruta 1-1-14 Uchikanda, Chiyoda-ku, Tokyo Hitachi Plant Construction (72) Inventor Itoshi Fukui 1-1-1 Uchikanda, Chiyoda-ku, Tokyo Hitachi Plant Construction Co., Ltd. (56) References JP-A-61-286634 (JP, A) 24147 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01L 41/08 H01L 41/083 H01L 41/09 B06B 1/06

Claims (2)

(57) [Claims] 1. A plate member in which a thin film-like elastic body is sandwiched in a crimped state on an end face in a driving direction of a laminated piezoelectric element, and the elastic body is attached to the elastic body only in a direction orthogonal to a driving direction of the laminated piezoelectric element. A piezo actuator characterized by having micron-order elasticity. 2. A laminated plate member in which a thin film-like elastic body is sandwiched in a press-fit state is attached to an end face of a laminated piezo element, and the elastic body has a micron order only in a direction orthogonal to a driving direction of the laminated piezo element. A plurality of piezo actuators having elasticity are arranged between the lower gantry and the device mounting base so that the driving directions of the piezo actuators coincide with the X, Y, Z directions, and X, Y, Z A vibration detector for detecting vibrations in the directions is provided on the device mounting table, and the driving directions are set in the X, Y, and Z directions based on signals indicating the vibrations in the X, Y, and Z directions detected by the vibration detectors. An active vibration isolator, wherein each of the piezo actuators disposed so as to coincide with each other is controlled to prevent three-dimensional vibration of the device mounting base.