JPH08135728A - Vibration resistant device - Google Patents

Abstract

PURPOSE: To reduce the number of horizontal X, Y direction piezoelectric actuator units, by making a pair of horizontal X, Y direction piezoelectric actuator units in which working direction of driving force for driving in the X, Y directions are opposite to each other arranged between a base stand and a surface plate so that rotational power is not made to work on the surface plate. CONSTITUTION: Piezoelectric actuator units 30A, 30A', 30B, 30B' by which horizontal vibration is eliminated are respectively provided in the neighborhood of vertical piezoelectric actuator unit 24 between a base stand and a surface plate 22. This piezoelectric actuator units 30A, 30A', 30B, 30B' are composed of a pair of horizontal X direction piezoelectric actuator units 30A, 30A' whose working direction of driving forces are opposite to each other while those are made driven toward the horizontal X direction and of a pair of horizontal Y direction piezoelectric actuator units 30B, 30B' whose working direction of driving forces are opposite to each other while those are made driven toward the horizontal Y direction, and these horizontal piezoelectric actuators are arranged so that rotational power does not work on the surface plate 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolation device, and more particularly to
The present invention relates to an active vibration isolator using a piezoelectric actuator unit in which a piezoelectric element and an elastic body are arranged in series as an actuator.

[0002]

2. Description of the Related Art A conventional vibration isolator of this type will be described with reference to FIGS. A rectangular base 2 having a concave cross section is fixed to a floor surface 1 of a building or the like. At the four corners between the base 2 and a surface plate 4 on which a vibration-damping device 3 such as a semiconductor manufacturing apparatus is mounted, the surface plate 4 is driven in the vertical direction to eliminate vibration in the vertical direction. The piezoelectric actuator units 5, 5, ... Are provided in the vertical direction of the base, and the side plate 2A of the base 2 is provided.
Between the and the outer surface of the surface plate 4, eight horizontal piezoelectric actuator units 6A and 6B for driving the surface plate 4 in the horizontal direction to eliminate horizontal vibration are provided. The piezoelectric actuator units 6A and 6B in the horizontal direction include four piezoelectric actuator units 6A in the horizontal X direction for damping horizontal vibrations in the horizontal X direction and four horizontal Y for damping horizontal vibrations in the horizontal Y direction. Direction piezoelectric actuator unit 6B. In each of the vertical and horizontal piezoelectric actuator units 5, 6A, 6B, a piezoelectric element 7 as an actuator and an elastic body 8 such as laminated rubber are provided in series. The elastic body 8 can absorb a force applied to the piezoelectric element 7 in the shearing direction (direction orthogonal to the axial direction of the piezoelectric element 7) to prevent the piezoelectric element 7 from being broken. Further, on the surface plate 4, a plurality of vertical vibration detectors 9 for detecting vibrations in the vertical direction,
A plurality of horizontal vibration detectors 10 for detecting horizontal vibrations
And are installed. And these detectors 9, 1
The vibration signal obtained at 0 is sent to the controller 12 via the amplifier 11. Controller 12 that received the signal
Then, a control signal for controlling vibration is sent to the drive amplifier 13 based on a preset program,
Then, the vertical and horizontal piezoelectric actuators 5,
A drive voltage is applied to 6A and 6B, whereby the piezoelectric actuators 5, 6A and 6B are driven to drive the surface plate. By repeating this operation, the vibration is damped, and the vibration is prevented from being transmitted to the vibrating device 3 mounted on the surface plate 4.

[0003]

However, the conventional vibration isolator having the above structure has the following drawbacks. When the piezoelectric actuator units 6A and 6B in the horizontal direction are driven for vibration isolation and a driving force is applied to the surface plate 4, a reaction force of the driving force is applied to the side plate 2A of the base 2. As a result, the side plate 2A needs to have rigidity to withstand the reaction force, and it is necessary to make the side plate 2A thick and to provide a reinforcing member (not shown). Therefore, there is a drawback in that the vibration isolator becomes heavy. Since the side plate 2A of the base 2 is provided around the surface plate 4 and the horizontal piezoelectric actuator units 6A and 6B are provided between the side plate 2 and the outer periphery of the surface plate 4, the surface plate 4 is provided.
The bottom area of the base 2 is larger than the area of the base, and a large floor area is required to install the vibration isolation device. Since the number of piezoelectric actuator units 6A and 6B installed in the horizontal direction is as large as eight, there are drawbacks that the control becomes complicated and the number of drive amplifiers 13 increases and the price of the vibration isolation device becomes expensive. Further, as a result of experiments, the present inventors have found that when the piezoelectric element 7 and the elastic body 8 are arranged in series to form an actuator, a predetermined load is applied in advance in the driving direction of the piezoelectric actuator units 5, 6A, 6B (hereinafter, This load is called preload)
It was found that if not done, the vibration isolation performance is poor and that the controllability of the vibration isolation depends on the method of applying the preload. However, in the conventional vibration isolator, the vertical piezoelectric actuator unit 5 is loaded with a load equivalent to a preload due to the weight of the surface plate 4 and the vibration isolator 3, but the horizontal piezoelectric actuator unit 6A. 6B has the drawback that no preload is applied.

Against this background, in order to reduce the number of horizontal piezoelectric actuator units 6A and 6B and reduce the cost of the vibration isolator, the number of horizontal piezoelectric actuator units 6A and 6B is set to eight. Therefore, a vibration isolator in which the elastic body (compression spring or rubber column) is reduced to four and the vibration isolator is also omitted, as shown in FIG. 15, is being studied. However, the vibration isolation device in which the piezoelectric element actuator units 6A and 6B are replaced with elastic bodies has a drawback that it is difficult to balance the preloads applied to the horizontal actuator units 6A and 6B because the elastic bodies have different rigidity. On the other hand, in the case of the vibration isolation device of FIG. 15, the piezoelectric actuator unit 6 in the horizontal direction is used.
When a preload is applied to A and 6B, a rotational force in the direction of the arrow 15 in the drawing acts on the surface plate 4, so that there is a disadvantage that a predetermined preload cannot be applied. Therefore, these vibration isolation devices do not solve the above-mentioned drawbacks.

The present invention has been made in view of the above circumstances, and it is possible to reduce the size and weight of the apparatus and reduce the number of piezoelectric actuator units in the horizontal direction.
An object of the present invention is to provide a vibration isolation device capable of accurately and reliably applying a predetermined preload to a horizontal piezoelectric actuator unit.

[0006]

In order to achieve the above-mentioned object, the present invention interposes between a base fixed on the floor surface of a building or the like and a surface plate on which an anti-vibration device is mounted. A plurality of vertical piezoelectric actuator units that drive the board in the vertical direction to eliminate vertical vibrations, and a plurality of horizontal piezoelectric actuator units that drive the platen in the horizontal direction to eliminate horizontal vibrations. In a vibration isolator comprising an actuator unit, wherein the piezoelectric actuator unit is configured by arranging piezoelectric elements and elastic bodies in series, the plurality of horizontal piezoelectric actuator units are driven in the horizontal X direction and A pair of horizontal X-direction piezoelectric actuator units whose driving force acts in the opposite direction, and a pair of horizontal Y-direction piezoelectric actuator units which drive in the horizontal Y direction and whose driving force acts in the opposite direction. And Tayunitto, characterized in that it is arranged so as not to act a rotational force to the surface plate between the base and the platen.

[0007]

According to the present invention, a plurality of horizontal piezoelectric actuator units constituted by arranging a piezoelectric element and an elastic body in series are mounted on a base fixed to a floor surface of a building or the like and an anti-vibration device. It was provided between the surface plate. As a result, it is not necessary to provide the side plate of the base around the surface plate as in the conventional vibration isolator, so that a flat base can be used and the area of the base can be smaller than that of the conventional vibration isolator. Furthermore, by installing the horizontal piezoelectric actuator unit between the base and the surface plate, the reaction force of the driving force applied to the surface plate when the horizontal piezoelectric actuator unit is driven is parallel to the driving direction. It can be supported in terms of a base. As a result, the plate thickness of the base can be reduced as compared with the conventional vibration isolator in which the reaction force is supported by the side plates of the base perpendicular to the driving direction.

Further, the piezoelectric actuator unit in the horizontal direction is driven in the horizontal X direction, and a pair of piezoelectric actuator units in the horizontal X direction in which the driving force acts in the opposite direction, and in the horizontal Y direction are driven. The piezoelectric actuator unit is composed of a pair of horizontal Y-direction piezoelectric actuator units whose forces act in opposite directions, and these horizontal piezoelectric actuator units are arranged so that no rotational force acts on the surface plate. As a result, the number of horizontal piezoelectric actuator units can be reduced as compared with the conventional vibration isolator using eight horizontal piezoelectric actuator units, and the preload (piezoelectric element drive direction) of the horizontal piezoelectric actuator units can be reduced. The surface plate can be prevented from rotating when a load is applied in advance in the driving direction. Therefore,
Since it is possible to accurately and reliably apply a predetermined preload to the piezoelectric actuator unit in the horizontal direction, it is possible to improve vibration isolation performance.

Further, according to the present invention, since the horizontal piezoelectric actuator unit is provided with the load means for applying a preload and the load to be applied can be varied, a predetermined preload can be easily applied to the piezoelectric element. Can be loaded.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a vibration isolator according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a plan view showing an arrangement of piezoelectric element actuators of a vibration isolator according to the present invention, and FIG. 2 is a perspective view showing an arrangement of piezoelectric element actuators by cutting out a part of the vibration isolator. As shown in FIGS. 1 and 2, a rectangular plate-shaped base 20 fixed to a floor surface (not shown) of a building or the like, and a rectangular plate-shaped surface plate 22 on which a vibration-damping device such as a semiconductor device is mounted. A plurality of vertical piezoelectric actuator units 24 that drive the surface plate 22 in the vertical direction (Z direction in FIG. 1) to eliminate vibrations in the vertical direction are provided at four corners between them. The vertical piezoelectric actuator unit 24 includes a piezoelectric element 26 that is driven in the vertical direction and a shearing direction (piezoelectric element 26) applied to the piezoelectric element 26.
And a laminated rubber 28 that prevents the piezoelectric element 26 from being broken by absorbing a force in a direction orthogonal to the driving direction of the.

In the vicinity of the vertical piezoelectric actuator unit 24 between the base 20 and the surface plate 22, a horizontal piezoelectric element for driving the surface plate 22 in the horizontal direction to eliminate horizontal vibrations. Actuator units 30A, 30
A ', 30B, 30B' are provided respectively. This horizontal piezoelectric actuator unit 30A, 30
A ', 30B and 30B' are the piezoelectric element 26 and the laminated rubber 28 similar to the piezoelectric actuator unit 14 in the vertical direction.
Composed of and. The horizontal piezoelectric actuator units 30A, 30A ', 30B, 30B' are a pair of horizontal X-direction piezoelectric actuator units 30A, 30A 'that are driven in the horizontal X direction (X direction in FIG. 1), and a horizontal Y direction. It is composed of a pair of horizontal Y-direction piezoelectric actuator units 30B and 30B 'that are driven (Y direction in FIG. 1). The piezoelectric actuator units 30A and 30A 'in the horizontal X direction have a driving force acting direction (arrows a and a'in the figure) at one substantially diagonal position on one of the four corners between the base 20 and the surface plate 22. Are placed in the opposite direction. In addition, a pair of horizontal Y-direction actuator units 30B, 30
B'is arranged at the other substantially diagonal position between the base 20 and the surface plate 22 with the driving force acting directions (arrows b and b'in the figure) reversed.

At the four corners of the lower surface of the surface plate 22, a plurality of vertical vibration detectors 32 for detecting vibrations in the vertical direction and a plurality of horizontal X direction vibration detectors 34 for detecting vibrations in the horizontal X direction are provided. And a plurality of horizontal Y-direction vibration detectors 36 for detecting vibrations in the horizontal Y-direction. The vibration signals obtained by these detectors 32, 34 and 36 are
As described in FIG. 13, the control signal sent to the controller 12 via the amplifier 11 and controlling the vibration based on a preset program is sent to the drive amplifier 13, and the drive amplifier 13 operates in the vertical and horizontal directions. Piezoelectric actuator units 24, 30A, 30A ', 30B, 30
A drive voltage is applied to B'to drive the surface plate 22, and the vibration is thus isolated. Application of this drive voltage and piezoelectric actuator units 24, 30A, 30A ', 30B, 30
In the displacement driven by B ′, since the piezoelectric element 26 has a hysteresis characteristic as shown in FIG. 3, the amount of displacement generated differs when the applied voltage increases and when the applied voltage decreases. Therefore, a bias voltage is applied and used in a range where the characteristics can be kept linear.

Next, an attachment structure for attaching the horizontal piezoelectric actuator units 30A, 30A ', 30B, 30B' to the base 20 and the surface plate 22 will be described with reference to an example of the piezoelectric actuator unit 30A. 4 is a side view in which the horizontal piezoelectric actuator unit 30A is attached to the base 20 and the surface plate 22, and FIG. 5 is an upper plan view of FIG. 4 with the base 20 and the surface plate 22 omitted. As shown in FIG. 4 and FIG. 5, the piezoelectric element 26 side of the piezoelectric actuator unit 30A is coupled to the vertical surface 38B of the base mounting jig 38 having the horizontal surface 38A and the vertical surface 38B by the bolts 42 and the horizontal surface 38A. Are connected to the base 20 with bolts 44. On the other hand, the laminated rubber 28 side is joined to the vertical surface 40B of the surface plate mounting jig 40 having the horizontal surface 40A and the vertical surface 40B by the bolts 46, and the horizontal surface 40A is fixed to the surface plate 22.
Are connected with bolts 48. In addition, the base mounting jig 38
The bolt holes 50 formed at the four corners of the horizontal surface 38A are long holes having a long diameter in the driving direction of the piezoelectric element actuator 30A. When the bolt 44 is loosened, the piezoelectric element actuator 30A can move. In addition, a horizontal plane 52A and a vertical plane 52B are provided near the base mounting jig 38.
Is provided with a preload pressing jig 52, the horizontal surface 52A of which is connected to the base 20 by a bolt 54, and the preload bolt 56 is screwed into a female screw drilled at substantially the center of the vertical surface 52B. The tip of the preload bolt 56 is in contact with the base mounting jig 38. As a result, when the preload bolt 56 presses the base mounting jig 38 with the bolts 44 of the base mounting jig 38 loosened, the base mounting jig 38 is pressed.
Moves in the direction A in the figure and compresses the laminated rubber 28 via the piezoelectric element 26. Then, a preload is applied to the piezoelectric element actuator unit 30A by the reaction force of the compressed laminated rubber 28. The degree of the preload can be adjusted by changing the rotation speed of the preload bolt 56, that is, the movement amount of the base mounting jig 38.

Next, the detailed structure of the piezoelectric actuator units 30A, 30A ', 30B, 30B' in the horizontal direction will be described with an example of the piezoelectric actuator unit 30A. Here, the horizontal piezoelectric actuator unit 30A
In the case of the piezoelectric actuator unit 24 in the vertical direction, the driving direction is basically the same as the above. As shown in FIG. 6, a casing 60 having a U-shaped cross section having an opening 58 on the left side in the figure is coupled to the above-described base mounting jig 38 with bolts 42. Also,
A leaf spring 62 is held in the opening 58 of the casing 60 by a pressing ring 64, and the casing 60 and the leaf spring 6 are
2. The pressing ring 64 is connected by a bolt 66. Further, the leaf spring 62 is sandwiched between a mounting flange 68 and a holding jig 70, and is joined by a bolt 72. Further, a ring-shaped projection 74 for aligning the piezoelectric element 26 is formed on the casing 60, and a ring-shaped projection 76 is also formed on the holding jig 70. The piezoelectric elements 26 are formed on both the projections 74, 76. Both ends of are fitted. Further, the flanges 7 are provided on both ends of the laminated rubber 28, respectively.
8, the flange 78 on one side is connected to the mounting flange 68 with a bolt 80, and the funnel radiator 78 on the other side is connected to the above-described platen mounting jig 40 with a bolt 46. Further, an electric connector 84 of the wiring 82 of the piezoelectric element 26 is attached to the casing 60. In the horizontal piezoelectric actuator unit 30A thus configured, the driving force of the piezoelectric element 26 is transmitted to the surface plate attachment jig 40 via the laminated rubber 28 to drive the surface plate 22. Further, the shearing direction applied to the piezoelectric element 26 (the piezoelectric element 2
A force in a direction orthogonal to the axial direction of 6) can be prevented from being transmitted to the piezoelectric element 26 by the laminated rubber 28 and the leaf spring 62.

According to the vibration isolator of the present invention constructed as described above, a plurality of horizontal piezoelectric actuator units 30A, 30A ', 30B, 30B' are provided in the space between the base 20 and the surface plate 22. Are arranged so that the driving direction is horizontal, and both ends thereof are attached to the base mounting jig 38 and the surface plate mounting jig 4.
It was fixed to the pedestal 20 and the surface plate 22 via 0. As a result, it is not necessary to provide the base side plate (see FIG. 13) around the surface plate 22 as in the conventional vibration isolator, so that the flat base 20 can be used and the area of the base 20 can be reduced. The area required for the surface plate 22 on which the shaking device is mounted can be made as small as possible. Further, the horizontal piezoelectric actuator units 30A, 30A ', 30B, 30B' are attached to the base 2
Since it is provided between 0 and the surface plate 22, the reaction force of the driving force applied to the surface plate 22 when the piezoelectric actuator units 30A, 30A ', 30B, and 30B' are driven is set by the base mounting jig 38. It can be supported by the surface of the base 20 parallel to the driving direction. As a result, the plate thickness of the base 20 can be made smaller than in the case where the reaction force is supported by the base side plates that are perpendicular to the driving direction as in the conventional vibration isolator. Therefore, the base 20 can be downsized and the weight can be reduced, so that the vibration isolation device can be made smaller and lighter.

Further, the piezoelectric actuator units 30A, 30A ', 30B, 30B' in the horizontal direction are driven in the horizontal X direction, and a pair of piezoelectric actuator units 30A in the horizontal X direction, in which the driving force acts in the opposite direction,
30A 'and a pair of horizontal Y-direction piezoelectric actuator units 30B and 30B' which are driven in the horizontal Y direction and in which the driving force acts in opposite directions. The piezoelectric actuator units 30A and 30A 'are arranged in the horizontal X direction. Is arranged at one of the four corners between the base 20 and the surface plate 22 at almost diagonal positions with the driving force acting in the opposite direction, and a pair of horizontal Y-direction actuator units 30B, 30B 'are installed. The driving force was applied in the opposite direction between the 20 and the surface plate 22 at a substantially diagonal position. This allows horizontal X
The piezoelectric actuator units 30A and 30A 'in the horizontal direction exert a rotational force E (see FIG. 1) on the surface plate 22, while the piezoelectric actuator units 30B and 30B in the horizontal Y direction,
30B 'applies rotational force D (see FIG. 1) to the surface plate 22 to cancel each other. Therefore, even if the number of piezoelectric actuators in the horizontal direction is reduced to half that of the conventional vibration isolator using eight horizontal piezoelectric actuator units, the horizontal piezoelectric actuator unit 30
It is possible to prevent the surface plate 22 from rotating when a preload is applied in the driving direction of A, 30A ', 30B, 30B'. Furthermore, the horizontal piezoelectric actuator units 30A, 3A
The structure of the base mounting jig 38 is formed so that 0A ′, 30B and 30B ′ can move in the driving direction, and a preload pressing jig 52 is provided in the vicinity of the base mounting jig 38. By rotating the preload bolt 56, the base mounting jig 38 can be accurately moved by a predetermined amount. As a result, a predetermined preload can be accurately and reliably applied to the horizontal piezoelectric actuator units 30A, 30A ', 30B, 30B', so that vibration isolation performance can be improved.

Here, the relationship between the preload and the vibration isolation performance will be described with reference to FIGS. 7 (a), (b), (c)
Is a horizontal piezoelectric actuator unit 30A, 3
The behavior of the piezoelectric element 26, the laminated rubber 28, and the platen mounting jig 40 with respect to the base mounting jig 38 when a preload is applied to 0A ', 30B, and 30B' is shown in FIG.
(A), (b) and (c) are the cases where no preload is applied. Further, (a) shows the initial state, (b) shows the time when the drive voltage is applied to the piezoelectric element 26, and (c) shows the time when the applied voltage is lowered. Note that, in FIGS. 7 and 8, in order to make the behavior of the laminated rubber 28 easy to understand, it is shown in a spring-like shape.

As can be seen from FIG. 7, when a preload is applied, when a driving voltage is applied to the piezoelectric element 26, the piezoelectric element 26 expands and the platen mounting jig 40 becomes the base mounting jig 3.
Move away from 8. Further, when the applied drive voltage is lowered, the piezoelectric element 26 contracts and the surface plate mounting jig 40 moves in a direction approaching the base mounting jig 38. That is, when a preload is applied, the platen attachment jig 40 moves in response to the application of the drive voltage to the piezoelectric element 26, so that the piezoelectric actuator units 30A, 30A ′, 30B, 3
When 0B 'is driven, the surface plate 22 can be driven. Further, in the vibration isolator of the present invention, as described above, the piezoelectric actuator units 30A, 30 in the horizontal direction are arranged.
A device 52 for preloading A ', 30B, 30B',
Since 56 is provided and the magnitude of the preload can be changed, a predetermined preload for obtaining the best vibration isolation performance can be easily applied.

On the other hand, as can be seen from FIG. 8, when the preload is not applied, when a driving voltage is applied to the piezoelectric element 26, the piezoelectric element 26 expands, but the laminated rubber 2 is correspondingly expanded.
8 shrinks. Further, when the applied drive voltage is reduced, the piezoelectric element 26 contracts, but the laminated rubber 28 extends correspondingly. That is,
When no preload is applied, even if a drive voltage is applied to the piezoelectric element 26, the surface plate mounting jig 40 and the base mounting jig 3
The distance from 8 is constant. Therefore, even if the piezoelectric actuator units 30A, 30A ', 30B, 30B' are driven, the surface plate 22 is not driven.

Further, FIG. 9 shows the piezoelectric actuator units 24, 30A, 30A 'and 3 in the horizontal and vertical directions.
Fig. 10 shows the vibration isolation performance of the vibration isolation device when an appropriate preload is applied to 0B and 30B ', and Fig. 10 shows the vibration isolation performance of the vibration isolation device when no preload is applied. is there.
9 and 10, (a) shows the vibration isolation performance in the horizontal X direction, (b) shows the horizontal Y direction, and (c) shows the vibration isolation performance in the vertical direction.

As is apparent from FIGS. 9 and 10, the piezoelectric actuator units 24, 30A, 30A ', 30.
Vibration isolation performance is obviously poor unless a proper preload is applied to B and 30B ', whereas vibration is about 10 when a preload is applied.
0% vibration isolation is possible. Incidentally, the vibration isolation performance of FIG. 10C is better than that of FIGS. 10A and 10B.
The piezoelectric element actuator unit 24 in the vertical direction,
This is because a load equivalent to the preload is applied due to the weight of the surface plate 22 and the vibration-improving device.

In this embodiment, the horizontal piezoelectric actuator units 30A, 30A ', 30B, 30B'.
Although it is arranged at four corners of the base 20 and the surface plate 22 diagonally, they may be arranged as shown in FIG. 11 or 12. In the piezoelectric actuator unit, the piezoelectric element 26 and the laminated rubber 28 are arranged in series.
Instead of 8, rubber columns may be used.

[0023]

As explained above, according to the vibration isolator of the present invention, a plurality of horizontal piezoelectric actuator units are mounted on a base fixed to the floor of a factory and a vibration isolator. It was installed between the board and the board. As a result, the area of the base can be made smaller and the weight can be made lighter than that of the conventional vibration isolator.
Therefore, it is possible to reduce the size and weight of the vibration isolation device.

Further, the piezoelectric actuator unit in the horizontal direction is driven in the horizontal X direction, and a pair of piezoelectric actuator units in the horizontal X direction in which the driving force acts in the opposite direction, and in the horizontal Y direction, are driven. The piezoelectric actuator unit is composed of a pair of horizontal Y-direction piezoelectric actuator units whose force acting directions are opposite to each other, and these horizontal piezoelectric element actuators are arranged so that no rotational force acts on the surface plate. As a result, the number of piezoelectric actuator units in the horizontal direction can be reduced, and when a predetermined preload is applied to the piezoelectric actuator units, the piezoelectric actuator units can be accurately and reliably loaded, so that the vibration isolation performance can be improved.

Further, according to the vibration isolator of the present invention, the piezoelectric actuator unit in the horizontal direction is provided with the load means for applying the preload, and the load to be applied can be varied. A predetermined preload can be easily applied.

[Brief description of drawings]

FIG. 1 is a plan view showing an arrangement of piezoelectric actuator units of a vibration isolation device according to the present invention.

FIG. 2 is a perspective view showing a disposition of a piezoelectric actuator unit by cutting out a part of a vibration isolation device according to the present invention.

FIG. 3 is a characteristic diagram showing a voltage-displacement characteristic of a piezoelectric element.

FIG. 4 is a side view showing a horizontal piezoelectric actuator unit mounting structure of the vibration isolator according to the present invention.

5 is a plan view of FIG. 4 with the substrate and surface plate omitted.

FIG. 6 is a sectional view showing a detailed structure of a piezoelectric actuator unit.

7A and 7B are diagrams showing the behavior of the piezoelectric element, the laminated rubber, and the platen mounting jig when a preload is applied to the piezoelectric actuator unit. FIG. 7A is an initial state, and FIG. When a drive voltage is applied to the piezoelectric element 26, (c) shows the time when the applied voltage is lowered.

8A and 8B are diagrams showing the behavior of the piezoelectric element, the laminated rubber, and the platen mounting jig when no preload is applied to the piezoelectric actuator unit. FIG. 8A is an initial state, and FIG. When a drive voltage is applied to the piezoelectric element 26, (c) shows the time when the applied voltage is lowered.

9A and 9B are diagrams showing vibration isolation performance when a preload is applied to the piezoelectric actuator unit. FIG. 9A is a horizontal X direction, FIG. 9B is a horizontal Y direction, and FIG. 9C is a vertical direction. The results of vibration isolation are shown below.

FIG. 10 is a diagram showing the vibration isolation performance when a preload is not applied to the piezoelectric actuator unit.
Shows the horizontal X direction, (b) shows the horizontal Y direction, and (c) shows the vertical vibration isolation result.

FIG. 11 is a plan view showing another arrangement of the piezoelectric actuator unit of the vibration isolation device according to the present invention.

FIG. 12 is a plan view showing another arrangement of the piezoelectric actuator units of the vibration isolation device according to the present invention.

FIG. 13 is an explanatory diagram of a conventional vibration isolation device.

FIG. 14 is a plan view showing an arrangement of piezoelectric actuator units of a conventional vibration isolation device.

FIG. 15 is a plan view of an example in which a piezoelectric actuator unit is omitted in a conventional vibration isolation device.

[Explanation of symbols]

20 ... Base 22 ... Surface plate 24 ... Vertical piezoelectric actuator unit 26 ... Piezoelectric element 28 ... Laminated rubber 30A, 30A '... Horizontal X direction piezoelectric actuator unit 30B, 30B' ... Horizontal Y direction piezoelectric actuator unit 32 ... Vertical vibration detector 34 ... Horizontal X direction vibration detector 36 ... Horizontal Y direction vibration detector 38 ... Mounting jig for base 40 ... Mounting jig for surface plate 52 ... Preload pressing jig 56 ... Preload bolt

Claims (2)

[Claims] 1. A vibration isolation device for vertically oscillating by interposing a base fixed to a floor surface of a building or the like and a surface plate on which an anti-vibration device is mounted to drive the surface plate in the vertical direction. A plurality of vertical piezoelectric actuator units, and a plurality of horizontal piezoelectric actuator units that horizontally drive the surface plate to eliminate horizontal vibrations. In a vibration isolation device configured by arranging a body and a body in series, the plurality of horizontal piezoelectric actuator units are driven in a horizontal X direction, and a pair of horizontal X directions in which driving force acts in opposite directions. Of the piezoelectric actuator unit and a pair of piezoelectric actuator units in the horizontal Y direction that are driven in the horizontal Y direction and in which the acting directions of the driving force are opposite to each other. Anti-vibration apparatus is characterized in that it is arranged so as not to act a rotational force to the surface plate. 2. The horizontal piezoelectric actuator unit is provided with load means for applying a load in the driving direction of the piezoelectric actuator unit, and the load to be applied is variable. Vibration isolation device.