JP3876018B2 - Active vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, for example, vibrations caused by an earthquake or traveling of an automobile are propagated to a device mounting base equipped with various devices installed in a semiconductor manufacturing factory or a laser application product manufacturing factory, and the equipment mounting base vibrates. In detail, the vibration isolation device removes the vibration of the mounted equipment by controlling the piezoelectric actuator from the outside so as to interfere with the vibration of the equipment mounting base. The present invention relates to an active vibration isolator capable of removing vibration and the like.
[0002]
[Prior art]
As this type of active vibration isolator, a device disclosed in Japanese Utility Model Publication No. 6-58254 has been proposed. The active vibration isolator disclosed in the publication basically includes a piezo actuator, and a mechanism for transmitting drive displacement of the piezo actuator using two piston members having different diameters and a working fluid. A rubber-like elastic body is bonded between one or both of the two piston members having different diameters and a housing member surrounding the piston member and having a side surface substantially parallel to the side surface of the piston member. It is made to intervene.
[0003]
In the conventional active vibration isolator having the above-described configuration, since the rubber-like elastic body interposed between the two piston members and the housing member prevents leakage of the working fluid, both the piston members and the housing member The piston members are operated smoothly, and the drive displacement of the piezo actuator is efficiently transmitted through the two piston members and the working fluid to reliably exhibit the predetermined vibration isolation performance. Making it possible.
[0004]
[Problems to be solved by the invention]
However, in the conventional active vibration isolator having the above-described configuration, the rubber-like elastic body interposed between the two piston members and the housing member shares and loads the mounted equipment load. When the load on the mounted equipment is large, such as equipment installed in a manufacturing factory or laser application product manufacturing factory, the rubber-like elastic body that is bonded and interposed between the small-diameter piston member and the housing member is strain-deteriorated. Therefore, in order to prevent the distortion of the rubber-like elastic body from being deteriorated, it is necessary to increase the spring constant of the rubber-like elastic body. There is a problem that the vibration isolation performance of the area is deteriorated. Further, since the pre-compression force to the piezo actuator is increased, there is a problem that the driving efficiency of the piezo actuator is deteriorated, and further, there is a problem that the rigidity of the apparatus constituent members is low.
[0005]
The present invention has been made in view of the above circumstances, and it is possible to set the resonance frequency low even when the load on the mounted device is large, and to solve the disadvantage of limiting the driving range of the piezo actuator. The main object of the present invention is to provide an active vibration isolator capable of reliably and stably exhibiting predetermined vibration isolation performance and vibration suppression performance over a wide range of vibrations including a low frequency range.
[0006]
Another object of the present invention is to ensure the above-described excellent vibration isolation performance and vibration suppression performance while reducing the size of the active vibration isolation device and increasing the buckling strength. It is in.
[0007]
[Means for Solving the Problems]
In order to achieve the main object described above, an active vibration isolator according to the first aspect of the present invention includes an air spring that elastically supports a device mounting base, a piezo actuator that can be driven and controlled from the outside, A working fluid that transmits the displacement of the piezo actuator to the air spring via a piston member mounted on at least one end side in the driving direction, and the air spring and the piezo actuator are sealed by sealing the working fluid. A storage passage for the piezo actuator is configured in a sealed state, and the internal space of the air spring is connected to the internal space of the sealed storage case. It is.
[0008]
According to the invention described in claim 1 having the above-described configuration, the load on the mounted device is large by combining the air spring, the piezoelectric actuator, and the working fluid that directly transmits the driving displacement of the piezoelectric actuator to the air spring. Even in this case, it is possible to lower the spring constant and set the resonance frequency to be low, and to exhibit predetermined vibration isolation performance and vibration suppression performance against vibrations in a wide frequency range and load range including the low frequency range. it can. In addition, since the air spring and the piezo actuator operate in series via the working fluid, the vibration input source is reduced compared to the case where the air spring and the piezo actuator are arranged in parallel. Can be demonstrated. Furthermore, the storage case of the piezo actuator is configured in a sealed state, and the internal space of the air spring is connected to the internal space of the sealed storage case, so the storage case functions as an auxiliary tank for the air spring, It is possible to set the spring constant of the air spring even lower, further improving the vibration isolation performance and vibration suppression performance, expanding the applicable range, and achieving a cooling effect for the piezoelectric actuator. is there.
[0009]
An active vibration isolator according to a second aspect of the present invention is the active vibration isolator according to the first aspect of the present invention, wherein the piezo actuator has a drive direction of the piezo actuator in the storage case. The air spring is arranged so as to be orthogonal to the elastic main axis direction of the device mounting base, and the air spring is directly connected and integrated with the storage case. According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the overall height of the device can be reduced to achieve a compact size, and the buckling strength can be increased to further increase the mounting. It can correspond to the equipment load.
[0010]
In addition, the number of piezoelectric actuators and the number of piston members in the active vibration isolator as described above may be either one or a plurality, and in particular, as described in claim 3, for one of the piezoelectric actuators It is preferable that one piston member be mounted. Furthermore, as described in claim 4, by using a plurality of piezo actuators, it is possible to optimally adjust the precompression force applied to one piezo actuator even when the load on the mounted equipment is large. Drive efficiency can be improved. In addition, when using a plurality of piezo actuators, the arrangement means may be arranged in parallel or radially so that the driving directions of the piezo actuators are parallel to each other. Is appropriately selected according to the form of the mounted device, the load distribution, and the like.
[0011]
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall perspective view showing a first embodiment of an active vibration isolator according to the present invention, FIG. 2 is a half vertical side view of the active vibration isolator, and FIG. 3 is a diagram of the active vibration isolator. It is a half-longitudinal front view, roughly divided, and an air spring 2 that elastically supports the device mounting base 1 and parallel so that their driving directions (arrow x direction) are parallel to each other at a certain interval along a horizontal plane. A plurality of piezoelectric actuators 3 such as stacked piezoelectric elements, an actuator housing case 7 that houses the plurality of piezoelectric actuators 3 arranged in parallel, and is installed on the floor; The piston members 4 respectively fixed to one end in the driving direction x of the piezoelectric actuators 3... And the displacement of the piezoelectric actuators 3. A working fluid 5 such as an ethylene glycol aqueous solution that is transmitted to the air spring 2 through a piston-like bush 9 disposed in the center position directly below the screw 2 with its axial direction facing up and down, and this working fluid 5 is sealed in a sealed state And a fluid passage 6 is provided.
[0013]
The actuator storage case 7 is generally formed in a box shape having a substantially square shape in plan view. The actuator storage case 7 is driven by the air spring 2 in the driving direction x of the piezoelectric actuators 3. The bush 9 is vertically displaced via a cylindrical rubber seal 10 at a position directly above the housing case 7 in the center portion of the housing case 7. A bush holder 11 that can be fitted and supported is fixed, whereby the air spring 2 is directly connected and integrated with the actuator housing case 7.
[0014]
The actuator storage case 7 is configured in a hermetically sealed state, and an air pipe 8 is provided to connect the internal space 7a and the internal space 2a of the air spring 2 to communicate with each other. 7 a is an auxiliary tank for the air spring 2.
[0015]
A rubber ring 12 is fitted on the outer peripheral surface of each piston member 4. A plurality of operations formed on one end side wall portion 7 b of the actuator housing case 7 corresponding to each piston member 4. The fluid passage 6 from one end where the fluid passages 13 are gathered to the other end directly below the bush 9 is formed within the thickness of the one end side wall portion 7b and the upper wall portion 7c of the actuator housing case 7. .
[0016]
The air spring 2 is formed by sealing pressurized air in a flexible bag made of an expandable / shrinkable material such as a ply cord in which a reinforcing bead wire is sandwiched between inner and outer rubber layers. The spring constant can be appropriately changed by adjusting the enclosed air pressure in accordance with the weight of the mounted device and the operating conditions.
[0017]
In the active vibration isolator having the above-described configuration, the load of the mounted device and the device mounting base 1 is received by being shared by the plurality of piezo actuators 3 through the air spring 2 and the working fluid 5. Therefore, even when the load on the mounted device is large, the load ratio shared by the piezo actuators 3 is small, and it is possible to eliminate the inconveniences such as limitation of the drive range of the piezo actuators 3 and interference of control force. The resonance frequency can be set low by lowering the spring constant, and predetermined vibration isolation performance and vibration suppression performance can be exhibited against vibrations in a wide frequency range including the low frequency range. Further, the air spring 2 and the piezo actuators 3... Operate in series via the working fluid 5. Compared with the case where the air springs 2 and the piezo actuators 3. Therefore, it is possible to exhibit a high vibration isolation effect and vibration suppression effect.
[0018]
Further, the actuator storage case 7 is arranged so that the driving direction x of the piezoelectric actuators 3... Stored therein is orthogonal to the elastic main shaft direction y of the device mounting table 1 by the air spring 2. Since the air spring 2 is directly coupled and integrated on the upper surface 7, the overall height of the vibration isolator can be reduced to achieve a compact size, and the buckling strength can be increased to cope with a larger load on the mounted equipment. Further, the actuator storage case 7 is configured in a sealed state, and the internal space 2a of the air spring 2 is connected to the internal space 7a of the sealed actuator storage case 7, so that the actuator storage case 7 It can function as an auxiliary tank for the spring 2 and the spring constant of the air spring 2 can be set even lower. With attained is further improved damping performance, that increased coverage, and it is also possible to achieve cold effect of piezoelectric actuators 3 ....
[0019]
FIG. 4 is an overall plan view showing a second embodiment of the active vibration isolator according to the present invention. A plurality of piezo actuators 3 are radially arranged and stored on the same plane in the actuator storage case 7. The drive displacement of the plurality of piezo actuators 3 is transmitted to the air spring 2 via the piston member 4 fixed for each piezo actuator 3, the working fluid 5 and the bush 9 described above. The other configurations are the same as those of the first embodiment shown in FIGS. 1 to 3, and thus detailed description thereof is omitted.
[0020]
Also in the case of the active vibration isolator according to the second embodiment shown in FIG. 4, the same vibration isolation performance and vibration suppression performance as those in the first embodiment can be ensured, and the entire apparatus can be made compact and buckled. The strength can be increased.
[0021]
In each of the above-described embodiments, a plurality of the piezoelectric actuators 3 are used. However, only a single piezoelectric actuator 3 may be used. In the above embodiments, one piston member 4 is mounted on one of the piezo actuators 3. However, one piston member 4 is shared by a plurality of piezo actuators 3. You may comprise. Furthermore, the actuator storage case 7 is not limited to a box shape, and may be a cylindrical shape or a star shape.
[0022]
【The invention's effect】
As described above, according to the first aspect of the present invention, an air spring, a piezo actuator, and a working fluid that directly transmits the drive displacement of the piezo actuator to the air spring are combined to share the load on the mounted equipment. Therefore, it is possible to reduce the shared load of the piezo actuator even when the load of the mounted equipment is large, and eliminate the disadvantages of limiting the drive range of the piezo actuator and interference of control force. Since the resonance frequency can be set low by lowering the constant, the specified vibration isolation performance and damping performance can be reliably and stably exhibited against vibrations in a wide frequency range and load range including the low frequency range. be able to. In particular, since the air spring and the piezo actuator operate in series via the working fluid, the vibration input source is reduced and the vibration isolation effect is higher than when the air spring and the piezo actuator are arranged in parallel. In addition, an effect that the vibration control effect can be exhibited is achieved. In addition, the storage case of the piezo actuator is configured in a sealed state, and the internal space of the air spring is connected to the internal space of the sealed storage case, so the vibration constant is reduced by setting the spring constant of the air spring even lower. In addition, it is possible to further improve the vibration damping performance and also achieve a cold insulation effect for the piezoelectric actuator housed in the case.
[0023]
Further, according to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the overall height of the device can be reduced to achieve compactness, and the buckling strength can be increased. Further, it is possible to cope with a larger load of the mounted device, and it is possible to achieve a remarkable expansion of applicability.
[0024]
According to the invention described in claim 4, by using a plurality of piezo actuators, it is possible to optimally adjust the precompression force applied to one piezo actuator even when the load on the mounted equipment is large. The driving efficiency of the actuator can be improved.
[0025]
[Brief description of the drawings]
FIG. 1 is an overall external perspective view showing a first embodiment of an active vibration isolator according to the present invention.
FIG. 2 is a half vertical side view of the active vibration isolator.
FIG. 3 is a half vertical front view of the active vibration isolator.
FIG. 4 is an overall plan view showing a second embodiment of the active vibration isolator according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Equipment mounting base 2 Air spring 2a Internal space of air spring 3 Piezo actuator 4 Piston member 5 Working fluid 6 Fluid passage 7 Actuator storage case 7a Internal space of actuator storage case

Claims (4)

An air spring that elastically supports the device mounting base;
Piezo actuators that can be driven and controlled externally,
A working fluid that transmits the displacement of the piezo actuator to the air spring via a piston member mounted on at least one end side in the driving direction of the piezo actuator;
A fluid passage for sealing the working fluid in a sealed state and connecting the air spring and the piezoelectric actuator ;
An active vibration isolator comprising a housing case for the piezo actuator that is hermetically sealed, and an internal space for the air spring is connected to the internal space of the sealed housing case .   The piezo actuator is disposed in the storage case so that the driving direction of the piezo actuator is orthogonal to the elastic main shaft direction of the device mounting table by the air spring, and the air spring is directly coupled to the storage case. The active vibration isolator according to claim 1, wherein   3. The active vibration isolator according to claim 1, wherein one piston member is attached to one of the piezo actuators.   4. The active vibration isolator according to claim 1, wherein a plurality of the piezo actuators are arranged in parallel or radially so that their drive directions are parallel to each other. .

Images