JPH0823690A - Non-contact fixing device - Google Patents

Abstract

PURPOSE:To achieve positioning without any contact and at the same time suppress the displacement of a vibration-elimination stand etc., by connecting either a magnet or oxide superconductor to the vibration-elimination stand and installing the other at a base for device. CONSTITUTION:A surface plate 2 of a device is fixed on an installation floor 3 by an air spring 9 and a trestle 4, non-circular permanent magnet 6 is laid out at the tip of a surface plate fixing post 8 as a floating body, and the permanent magnet 6 is linked to the surface plate 2 in a form where the surface plate 2 mounting a precision equipment 1 can be balanced by the surface plate fixing post 8. On the other hand, a superconductive bulk body 5 is provided in a liquid nitrogen container 7 for cooling which is installed on the installation floor 3 and is cooled to a superconductive critical temperature or less in a magnetic field by the permanent magnet 6 by loading liquid nitrogen which is a refrigerant for lifting the floating body for generating pinning force, thus suppressing the displacement which is generated by enabling the precision equipment 1 to travel on the surface plate 2 and hence fixing the displacement of a stand due to the move of an object on the vibration-elimination stand without any contact and with a simple structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact fixing device utilizing superconducting magnetic levitation. Particularly in non-contact fixing devices that suppress self-generated displacement, such as displacement of the vibration isolation table position due to object movement on the vibration isolation table, in equipment such as semiconductor manufacturing lines where vibration affects product yield Is.

[0002]

2. Description of the Related Art Conventionally, in an LSI manufacturing apparatus such as a stepper, when a circuit is overlaid on the same place, it becomes impossible to perform alignment due to vibrations such as floor vibrations and processing time. In order to prevent it from becoming long, it has been used by mounting it on a vibration isolation device. As the degree of integration of LSI increases, the required vibration isolation characteristics also increase. In particular, as a problem that has become a problem in recent years in a semiconductor manufacturing line or the like, there is a problem that the position of the vibration isolation table is displaced by the movement of the silicon wafer or the like in the manufacturing equipment on the vibration isolation table. In a highly integrated LSI line in the future, it is necessary to minimize the displacement of the vibration isolation table position that occurs when an object moves in equipment on the vibration isolation table. That is, there is a demand for a fixing device that suppresses self-generated displacement of a vibration isolation table or the like. In addition, there is a demand for a non-contact fixing device that makes it difficult for the fixing device to transmit vibrations.

As a non-contact type which can be used for a position fixing device such as a vibration isolation table, non-contact fixing by magnetic attraction between permanent magnets and permanent magnets and electromagnets can be considered. . However, the magnetic attraction force between these magnets gives a force to return to the original position when the positions between the magnets are slightly separated, but gives a restoring force when the positions between the magnets approach each other. Absent.

Further, as a system which suppresses the instability of the magnetic attraction force and is similar to the non-contact fixing device, there is an active damper in which a position displacement sensor and a displacement suppressing electromagnet are combined with a magnetic levitation type vibration isolation table. It requires a large electronic control circuit and is very expensive. For the above reasons, there is no fixing system so far that can be used in a non-contact and inexpensive anti-vibration table or the like.

Therefore, an object of the present invention is to provide an inexpensive non-contact fixing device which can be positioned in a non-contact manner and which suppresses displacement of a vibration isolation table or the like.

[0006]

The present inventors have earnestly promoted research in order to develop an oxide superconducting material having a critical temperature higher than the liquid nitrogen temperature and excellent in critical current density characteristics. . In particular, by manufacturing a YBCO-based oxide superconducting material by a melting method, it has succeeded in developing a material having a critical current density higher than that of a conventional sintering method by two digits or more.

In the course of the research, we developed Y
It was revealed that the molten oxide superconducting materials have very strong pinning properties. As a result of vigorous research paying attention to the pinning force, we succeeded in developing a material that has a very strong attracting and fixing force with a magnet when the superconducting material is cooled in a magnetic field. Furthermore, it has been clarified that the superconducting material has the property of always staying in a stable position when cooled in a magnetic field. It has been found that the above problems can be solved by combining these, and the present invention has been completed based on this finding.

That is, the object of the present invention is, specifically,
(1) A levitation body and a means for levitating the levitation body are provided, and a magnetic member such as a non-circular permanent magnet or an electromagnet is arranged on one of the levitation body and the levitation body, and the other is arranged. REBa ₂ C which is a superconducting phase in an oxide superconductor composed of RE (one kind of rare earth element including Y or a combination of those elements), Ba and Cu.
RE ₂ BaCuO ₅ which is a normal conducting phase in the u ₃ O _7-x crystal
Is provided with an oxide superconductor having a finely and uniformly dispersed structure, one of the magnet and the oxide superconductor is connected to an anti-vibration table, and the other one is installed on the equipment installation base. It is achieved by the structure of the non-contact fixing device.

Another object of the present invention is (2) that two or more combinations of a magnetic member such as a non-circular permanent magnet or electromagnet and an oxide superconductor are arranged in a horizontal direction and a vertical direction. This is achieved by adopting the configuration of the non-contact fixing device as described in (1), which is a characteristic feature.

[0010]

The non-contact fixing device according to the present invention will be described in more detail based on its principle.

First, in the superconductor according to the present invention having a strong pinning force as produced by the melting method, the superconductor and a magnetic member such as a permanent magnet or an electromagnet (hereinafter, simply referred to as a permanent magnet) are fixed. When cooled in a magnetic field at a distance of, the magnetic attraction between the permanent magnets is very different from the ordinary magnetic attraction, and the distribution of the external magnetic field is inherited.

Therefore, for example, when a permanent magnet or the like is cooled with a spacer or the like at a distance of 1 cm from the superconductor, a part of the magnetic field distribution of the permanent magnet or the like is stored in the superconductor. Even if the spacer is removed, the permanent magnet and the like can be fixed in the space at a distance of 1 cm. This is because the superconductor according to the present invention, which is produced by the melting method provided as a means for levitating the levitating body, has strong pinning and therefore tries to retain the magnetic field distribution introduced by cooling in the magnetic field. is there. Electromagnetic force acts on the disturbance that tries to change this magnetic field distribution, and tries to restore it. That is, the magnetic field distribution given when cooled in a magnetic field by a permanent magnet or the like becomes the basic position, and the permanent magnet or the like is fixedly placed in the space as a floating body at a certain distance so that the magnetic field distribution is always maintained. . In addition, the distance between the superconductor and the permanent magnet, etc., should have sufficient restoring force against self-generated displacement such as displacement of the vibration isolation table position due to object movement on the vibration isolation table, and external vibration from the floor. It may be set so that it can be expressed, and is appropriately determined according to the type, size, shape, etc. of the magnet or superconductor used.

In the above case, when a permanent magnet is used as the magnetic member, if the permanent magnet has a disk shape or a spherical shape, the magnet can rotate with extremely low resistance. This seems to be inconsistent with the fact that the pinning holds the magnet, but in the part of the unquantized magnetic flux between the magnet and the superconductor, its dissociation and recombination can occur with almost no resistance. It can be understood by thinking. Therefore, by degrading the symmetry of the magnetic flux density distribution, the symmetry of the magnetic flux density distribution in the superconductor is disturbed, and resistance is generated against rotation. That is, if a non-disc-shaped or non-spherical magnet such as a quadrangle is used, a restoring force is generated not only in the vertical direction but also in the surface direction,
It can act as a non-contact fixing device such as an ideal vibration isolation table.

In addition to this, the superconductor produced by the melting method used in the present invention has damping characteristics to some extent by itself. That is, in the non-contact fixing device of the present invention, when a permanent magnet or the like that is a floating body vibrates due to external vibration from the floor or the like, the magnetic flux tends to vibrate from the equilibrium point where the superconductor is pinned. When the magnetic flux is displaced, an electric field is formed in the superconductor.
Corresponding to this electric field, normal conduction electrons in the quantized magnetic flux form a flow, the normal conduction electrons interact with the crystal lattice, and are emitted as thermal energy. As a result, the external vibration is absorbed as heat energy loss in the superconductor, and the vibration is damped.

In the above non-contact fixing device, the permanent magnet or the like is cooled in a magnetic field at a constant distance, whereby the magnet is floated and fixed by the pinning force, and this is connected to the vibration isolation table or the like. The position cooled in the magnetic field becomes the initial position,
The force that tends to displace from this point is suppressed without electronic control. Further, external vibrations from the floor installed in the non-contact fixing device are absorbed as energy loss in the superconducting material and the like, so that the vibration isolation characteristics of the vibration isolation table are not impaired.

Further, in the non-contact fixing device according to the present invention, it is desirable that two or more combinations of the permanent magnets and the oxide superconductors are arranged in the horizontal direction and the vertical direction. This is because the fixing force of the non-contact fixing device is generated by the magnetic flux pinning, so that a large force is generated when the amount of magnetic flux captured in the superconductor is changed. That is, in the direction parallel to the applied magnetic field when cooled in a magnetic field,
A large fixing force can be obtained because the magnetic field changes greatly in the direction of moving the magnet closer to or further from the superconductor. However, when the magnet is displaced in the horizontal direction, the magnetic field change given to the magnetic flux supplemented by the superconductor is not so large, so that the fixing force is weak as compared with the direction parallel to the applied magnetic field. Therefore, when it is necessary to apply a sufficiently strong fixing force to a three-dimensional displacement, not only in the z-axis direction (direction parallel to applied magnetic field = vertical direction) but also in x-axis and y-axis directions (horizontal direction). Also in (), a fixing force is added by arranging a permanent magnet or the like and an oxide superconductor in combination.

The non-contact fixing device of the present invention having the above principle will be described in detail.

First, the superconductor used in the present invention is R
An oxide superconductor composed of E (one kind of rare earth elements including Y or a combination of those elements), Ba, and Cu, which is a superconducting phase in a REBa ₂ Cu ₃ O _7-x crystal in a normal conducting phase. Any oxide superconductor having a structure in which RE ₂ BaCuO ₅ is finely and uniformly dispersed may be used. In the oxide superconductor, the critical temperature (Tc) of the boiling point temperature of liquid nitrogen (77 K) or higher, usually 80 to 95 K (for example, QM according to Japanese Patent Publication No. 4-40289 of Example 1 described later).
The oxide superconductor manufactured by the G method has Tc = about 93 K), and the oxide superconductor according to the present invention has the conventional sintering method (T
c = 90K, Jc = several 10 A / cm ^{2 at} 1T), an excellent critical current density (Jc) higher by 2 digits or more, usually 1 ×
10 ⁴ to 4 × 10 ⁴ A / cm ² (at 77Kand at 1T)
(For example, Jc = 3 × 10 ⁴ manufactured by the QMG method according to Japanese Patent Publication No. 4-40289 of Example 1 described later.
A / cm ² ) and very strong pinning force (F
p), usually 1 × 10 ⁸ to 4 × 10 ⁸ N / m ³ (at 77K
and at 1T) (for example, Japanese Patent Publication No.
Fp produced by the QMG method according to Japanese Patent No. 40289
= 2.5 × 10 ⁸ N / m ³ ), when the oxide superconductor is cooled in a magnetic field, it is a very strong permanent magnet or the like, for example, a permanent magnet having a surface magnetic flux density of 3000 to 5000 gauss. For example, in the case of a bulk body having a diameter of 8 cm, it has a suction fixing force of about 5 to 20 kgf and has the property of always staying in a stable position.

In the above oxide superconductor, the normal conducting phase R is contained in the REBa ₂ Cu ₃ O _7-x crystal which is the superconducting phase.
The structure having a structure in which E ₂ BaCuO ₅ is finely and uniformly dispersed means that a normal-conducting phase having a diameter of 20 μm or less, preferably 5 μm or less in the REBa ₂ Cu ₃ O _7-x crystal that is the superconducting phase. RE ₂ BaCuO ₅ is 5 to 60
It has a structural structure in which it is uniformly dispersed in a weight ratio of 20 to 40% by weight.

As a method for producing the above oxide superconductor, for example, RE (rare earth element containing Y), Ba, C
In an oxide superconductor consisting of an oxide of u, the RE
(Rare earth element including Y), Ba, Cu oxide superconductor structure REBa ₂ Cu ₃ O _{7- x} phase having a structure in which a RE ₂ BaCuO ₅ phase having a diameter of 20 μm or less is dispersed As a material for obtaining an oxide superconducting bulk material, RE (rare earth element containing Y), which is manufactured by the melting method as described in the above-mentioned principle,
Rapidly solidifies a melt containing Ba and Cu elements, or RE
Semi-molten by once heating a plate or linear compact having a thickness of 5 mm or less obtained by mixing ₂ O ₃ (RE: rare earth element including Y) and BaCu oxide to a high temperature of 1000 ° C. to 1350 ° C. After being brought into a state, it is slowly cooled at a rate of 200 ° C./hr or less to obtain a superconductor having a high critical current density, and a method for producing an oxide superconducting bulk material (Japanese Patent Publication No.
40289, QMG (Qench and Me)
lt Growth method), or RE (one kind of rare earth element including Y or a combination of those elements) in an oxide body containing Ba and Cu elements whose ratio of Ba element is 25 mol% to 75 mol% in terms of metal element ratio). A precursor in which RE ₂ O ₃ having 5 to 50% by volume is dispersed is once heated in an oxidizing atmosphere in a temperature range from 950 ° C. to 1350 ° C. to bring the precursor into a semi-molten state, then cooled 900 ° C. in the region of 1100 ℃, REBa ₂ Cu ₃ O of RE composition having a forming temperature higher than the RE composition of the product temperature of REBa ₂ Cu ₃ O _7-x phase in the precursor
_{A 7-x} phase single crystal seed crystal is brought into contact with a precursor to form a superconducting phase having an arbitrary orientation same as that of the seed crystal from 800 ° C. to 10 ° C.
REBa ₂ Cu ₃ O can be obtained by gradually cooling or retaining the temperature within a temperature range of 60 ° C. in a uniform temperature or a temperature gradient.
Method for producing high temperature oxide superconductor characterized by continuously growing _7-x (JP-A-5-301797,
Improved QMG method), etc., but the method for producing an oxide superconductor according to the present invention is not limited to the above method, and may be one obtained by using another conventionally known method. Good. Regarding the shape of the oxide superconductor,
Since the shape of the permanent magnet to be combined is an asymmetric non-circular shape, it is not particularly limited, and any shape can be used.

As the magnetic member such as the permanent magnet or electromagnet used in the present invention, as shown in the above principle, an asymmetric non-circular permanent magnet and electromagnet can be used. In addition, the magnitude of the magnetic flux density of the permanent magnet or the like used is obtained by combining the above-mentioned oxide superconductor with the force applied when the object moves and gives a displacement on the vibration isolation table on which the device of the present invention is installed. It is appropriately selected so that the fixing force by the generated magnetic flux pinning force becomes larger.

Next, the levitation body according to the present invention may be any one in which any one of the above-mentioned oxide superconductor and the above-mentioned permanent magnet is arranged, and the levitation body can be connected by a suitable connecting method, For example, when using a permanent magnet or the like for the levitation body, a connecting member such as a cylinder or a prism is fixed to the lower surface of the vibration isolation table so that the entire vibration isolation table is balanced, and the permanent member is provided near the tip of the connection member. There is a method of mounting magnets and the like vertically and horizontally with respect to the upper surface (lower surface) of the vibration isolation table, and also when an oxide superconductor is used for the levitation body, as with permanent magnets, a connecting member. There is a method of fixedly disposing near the tip of the connecting member by using
Since the oxide superconductor which is the levitation body needs to be cooled in a magnetic field using a coolant such as liquid nitrogen as a means for levitation of the levitation body described below, it is necessary to fix the oxide superconductor. Is preferably fixed by a mechanical method such as sandwiching, instead of a chemical method such as adhesion.
The method for connecting the floating bodies according to the present invention is not particularly limited to the above method, and other conventionally known methods can be used so as to be suitable for actual equipment.

Next, as means for levitating the levitating body according to the present invention, one of the above-mentioned oxide superconductor, the above-mentioned permanent magnet and the like other than the one used as the above-mentioned levitating body is provided.
It may be installed on the base for installing the device. For example, when the levitation body side is a connecting method using the permanent magnet or the like and an oxide superconductor is provided as a means for levitating the levitation body, By cooling the oxide superconductor in a magnetic field, a strong magnetic flux pinning force is generated, which allows the levitation body to levitate.Therefore, in order to perform the cooling in the magnetic field, the cooling installed on the base for installing the device. In the apparatus, the oxide superconductor is supported and fixed by using an appropriate supporting and fixing member so as to have a fixed distance from the floating magnet such as a permanent magnet. As a result, the oxide superconductor is placed in a magnetic field at room temperature by an external magnetic field such as a permanent magnet.
Subsequently, the cooling device is operated to introduce a refrigerant having a boiling point equal to or lower than the superconducting critical temperature, for example, liquid nitrogen (boiling point 77K) directly from outside the system, or directly cools the nitrogen gas in the device to liquefy. In this way, there is a means for levitating the levitation body by cooling to a superconducting critical temperature or lower in a magnetic field to cause superconducting transition, and the levitation side is connected as a connecting method using the oxide superconductor. Even when a permanent magnet or the like is provided as means for levitating the body, a strong magnetic flux pinning force is generated by cooling the oxide superconductor, which is the levitator, in the magnetic field, and thus the levitator can be levitated. First, in order to perform cooling in a magnetic field, first, the permanent magnet is attached to an appropriate supporting and fixing member installed on the base for installing the apparatus so that the levitation body has a constant distance from the oxide superconductor. Providing a stone such as support fixed to. Also,
The cooling device is installed on the vibration isolation table or the equipment installation base so as to enclose the levitation body connected to the vibration isolation table. In this case, a suitable sealing member is used at the boundary between the floating member and the connecting member so that liquid nitrogen does not leak out. As a result, the oxide superconductor is placed in a magnetic field at room temperature by an external magnetic field such as a permanent magnet. Subsequently, the cooling device is operated to introduce a refrigerant having a boiling point equal to or lower than the superconducting critical temperature, for example, liquid nitrogen (boiling point 77K) directly from outside the system, or directly cools the nitrogen gas in the device to liquefy. By doing so, there is a means for cooling to a superconducting critical temperature or lower in a magnetic field to cause a superconducting transition to levitate the levitation body. The means for levitating the levitating body according to the present invention is not particularly limited to the above method, and is appropriately designed by using other conventionally known means so as to be suitable for actual equipment. Is.

The anti-vibration table according to the present invention is not particularly limited, and is an anti-vibration in a very broad sense including an anti-vibration device used for preventing external vibration such as an LSI manufacturing apparatus such as a stepper. It is a table. Further, in the present specification, a mounting board provided on a general vibration isolation table is referred to as an isolation table for convenience. As this type of mounting plate, for example, honeycomb surface plate, stone surface plate, damping steel plate surface plate, cast iron surface plate,
Alternatively, a ceramic surface plate or the like is generally known.

Furthermore, the base for installing the device according to the present invention is
It is not particularly limited, as long as it is a floor of a building that secures these manufacturing facilities, such as an installation floor that secures the above-mentioned vibration isolation table, etc., but preferably from the foundation for installing the device. In order to reduce the external vibrations, it is desirable to use a base for installing a device or the like, which is provided with an appropriate vibration-damping member such as a vibration-proof rubber on the installation floor surface.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the non-contact fixing device of the present invention will be described below with reference to FIGS. FIG. 1 shows a set of a magnet and a superconductor (vertical direction;
FIG. 2 is a schematic configuration diagram of an embodiment in which a non-contact fixing device using (z-axis direction) is used, and FIG. 2 shows another example of the present invention in an air isolation table facility equipped with precision equipment having a moving device mounted therein. As one embodiment, a non-use using five sets of magnets and a superconductor (one set in the z-axis direction, two sets in each of the x-axis direction and the y-axis direction, of the horizontal direction, the moving direction of the moving device; the x-axis direction) It is a schematic block diagram of the Example which uses a contact fixing device, Comprising: It is a partial cross section figure which shows the vicinity of this non-contact fixing device.

Example 1 In FIG. 1, a surface plate 2 on which a precision device 1 having a moving device mounted therein is mounted is a honeycomb surface plate for a normal air vibration isolation table, and the surface plate 2 is an air spring 9 It is fixed on the installation floor 3 by the gantry 4. The surface plate 2 is composed of a superconducting bulk body 5, which has a superconducting transition at a liquid nitrogen temperature or higher, which constitutes the present invention, a permanent magnet 6, a cooling liquid nitrogen container 7, and a surface plate fixed column 8 which connects the permanent magnet 6 and the surface plate 2. It is fixed by the non-contact fixing device.

That is, the non-contact fixing device of this embodiment is
A non-circular permanent magnet 6 is placed as a floating body at the tip of the surface plate fixing column 8, and the permanent magnet 6 is further attached to the surface plate fixing column 8.
An apparatus in which a superconducting bulk body 5 is provided in a cooling liquid nitrogen container 7 installed on an installation floor 3 while the superconducting bulk body 5 is connected to the surface plate 2 in such a manner that the whole surface plate 2 carrying the precision equipment 1 can be balanced. And has means for levitating a levitation body that puts liquid nitrogen as a cooling medium in the cooling liquid nitrogen container 7 and cools it to a superconducting critical temperature or lower in a magnetic field by the permanent magnet 6 to generate a pinning force. It is a thing.

With this configuration, the displacement caused by the movement of the precision instrument 1 on the surface plate 2 is suppressed. .

In this embodiment, the boiling point of liquid nitrogen (7
7K) Superconducting transition above temperature, and as the superconducting bulk body 5 having a strong pinning force, the above-mentioned Japanese Patent Publication No. 4-40
QMG (Qench and Me) disclosed in Japanese Patent No. 289
lt Growth) method, that is, after a plate-shaped compact having a thickness of 5 mm or less obtained by rapidly solidifying a melt containing Y, Ba, and Cu elements is heated to a high temperature of 1150 ° C. to be in a semi-molten state, In an oxide superconductor made of an oxide of Y, Ba, Cu produced by a method of gradually cooling at a rate of 1 ° C./hr, a texture of an oxide superconductor of Y, Ba, Cu YBa ₂ Cu ₃ O _7- Y with diameter less than 20 microns in _x phase
An oxide superconductor having a structure in which ₂ BaCuO ₅ phase is uniformly dispersed at a ratio of 30 wt%, and is a superconducting bulk material (Tc = 80 mm in diameter and 20 mm in thickness) formed.
92K, Jc = 2 × 10 ⁴ A / cm ² ) was used. The magnetic attraction force characteristic of this superconducting bulk body 5 has a diameter of 60 mmφ and a thickness of 20 mm in an Instron type tensile tester.
When an Nd-Fe-B permanent magnet having a surface magnetic flux density of 4500 gauss was attached and measured, an attraction force characteristic of about 10 kgf was shown.

Further, in this embodiment, in order to select the magnet shape, an Sm-based permanent magnet having a thickness of 1 cm and each of a disk shape, a square shape, and a rectangular shape was used to investigate the fixing force with respect to the rotational freedom. Magnet In the case of a disk-shaped magnet, there is no resistance to rotational force, and a square (2 cm x 2 cm) magnet with a vertical and horizontal aspect ratio of 1: 1 and a rectangular (2
The resistance to rotation was about 0.5 kgf and about 1 kgf, respectively. From this, in order to increase the fixing force in the rotation direction, it is desirable that the shape of the rectangular magnet has a vertical and horizontal aspect ratio of the magnet shape or that the magnetic field distribution in the magnet is nonuniform. On the other hand, in order to obtain a strong fixing force, it is necessary to increase the amount of magnetic flux supplemented by the superconducting bulk body 5, and a strong magnet having a large area is desirable. From the above, in this embodiment, a magnet having an aspect ratio of about 1: 2 was used.

A superconducting bulk body 5 having a diameter of 80 mm and a thickness of 20 mm and manufactured by the QMG method is fixed to a cooling liquid nitrogen container 7, and Nd-Fe having a surface magnetic flux density of 4500 gauss.
-B type square permanent magnet 6 (width: 4 cm x length: 6 cm x
(Thickness: 2 cm) was fixed at a distance of 5 mm from the surface of the superconducting bulk body 5, and then liquid nitrogen was put into the cooling liquid nitrogen container 7, cooled in a magnetic field, and operated as a non-contact fixing device. In the present embodiment, it is 10 k with respect to the displacement in the vertical direction (z-axis direction).
Indicates gf tensile force, horizontal direction (x-axis and y-axis direction)
The tensile strength was 3 to 5 kgf. This few kg
The value f was a sufficient fixing force because the force applied when an object moves and gives a displacement on an air vibration isolation table of a general size is several hundred gf or less.

Further, vibration of 100 Hz was applied from the outside to the non-contact fixing device manufactured in this example, and the vibration damping characteristic was examined. Vibration damping coefficient is 1N · sec /
The external vibration of 100 Hz is reduced to 1/100 or less by the non-contact fixing device, and the surface plate 2 serving as a vibration isolation table
It became clear that the vibration transmission to the is suppressed.

In this embodiment, the magnet 6 is Nd-.
Although the Fe-B type or Sm-Co type permanent magnet is used, it goes without saying that the same effect can be obtained by using an electromagnet instead of the permanent magnet.

Example 2 In addition to the fixing force of the set of permanent magnets 6 and the superconducting bulk body 5 as shown in FIG. 1 described in Example 1, the side surface of the surface plate fixing column 8 as shown in FIG. A combination of the permanent magnet 6 and the superconducting bulk body 6 was added in order to improve the fixing force in the direction. Similar to the z-axis direction, the x-axis direction and the y-axis direction (in the present embodiment, the moving direction of the moving device mounted in the precision instrument 1 is defined as the x-axis direction, and the z-axis direction and the x-axis direction are perpendicular to each other. In the y-axis direction) and a diameter of 80
The superconducting bulk body 5 having a thickness of 20 mm and a thickness of 20 mm and manufactured by the QMG method was fixed in the cooling liquid nitrogen container 7. An Nd-Fe-B system square permanent magnet 6 (width: 4 cm x length: 6 cm x thickness: 2 cm) having a surface magnetic flux density of 4500 gauss is fixed to a surface plate fixing column 8 and x, y and z axes are fixed. It was separated from the surface of the superconducting bulk body 5 by about 5 mm and cooled in a magnetic field. As a result, a tensile force of 10 kgf similar to that in the vertical direction was obtained as the fixing force in the x, y, and z directions, and the three-dimensional fixing force was increased.

In addition, it goes without saying that the magnets and the superconductors in Examples 1 and 2 can be arranged in reverse (that is, the arrangement as a floating body is opposite).

For the non-contact fixing device, in order to reduce vibration transmission from the installation floor 3, the lower part of the non-contact fixing device,
For example, as shown in FIG. 2, a simple vibration isolator having a vibration isolating ability such that the vibration isolating rubber itself is not largely displaced by a tensile force between the installation floor 3 and the cooling liquid nitrogen container 7. By using the member 10 in combination, it operates more effectively.

[0038]

As is apparent from the above description, according to the non-contact fixing device of the present invention, the displacement of the table due to the movement of the object on the vibration isolation table can be fixed with a simple structure. Furthermore, it is not necessary to perform complicated control unlike the conventional vibration sensor displacement control device using a displacement sensor or an electromagnet, and it is inexpensive. Therefore, the present invention makes it possible to realize an epoch-making non-contact fixing device in the vibration isolation table field.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment in which a non-contact fixing device using a set of magnets and a superconductor is used as an embodiment of the present invention in an air vibration isolation table equipment equipped with a precision device having a moving device mounted therein. It is a block diagram.

FIG. 2 is an example in which a non-contact fixing device using five sets of magnets and superconductors is used as another embodiment of the present invention in an air isolation table equipment equipped with a precision device having a moving device mounted therein. FIG. 3 is a schematic configuration diagram of FIG. 3, which is a partial cross-sectional view showing a portion near the non-contact fixing device.

[Explanation of symbols]

1 ... Precision equipment that moves on a vibration isolation table, 2 ... surface plate, 3 ...
Installation floor, 4 ... Stand, 5 ... Superconducting bulk body, 6 ... Permanent magnet, 7 ... Liquid nitrogen container for cooling, 8 ... Plate fixed column, 9 ...
Air spring, 10 ... Simple vibration isolation member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiichi Teshima 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Inside Nippon Steel Corporation Advanced Technology Research Institute (72) Inventor Katsuyoshi Miyamoto 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Address Nippon Steel Co., Ltd. Advanced Technology Research Laboratory (72) Inventor Misao Hashimoto 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Nippon Steel Co., Ltd. Advanced Technology Research Laboratory (72) Inventor Keita Noguchi Yokohama, Kanagawa Prefecture 16-18 Sakaemachi, Kanagawa-ku, Kanagawa, Meiji Seiki Co., Ltd. (72) Inventor Katsumi Hinata 16-18, Sakaemachi, Kanagawa-ku, Yokohama, Kanagawa Prefecture 16-18 Meiritsu Seiki Co., Ltd. (72) Inventor Tsutomu Tohara 16-18 Sakaemachi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Meiritsu Seiki Co., Ltd.

Claims (2)

[Claims] 1. A levitation body and a means for levitating the levitation body, wherein a magnetic member such as a non-circular permanent magnet or an electromagnet is arranged on one of the levitation body and the levitation body. On the other hand, RE (a rare earth element including Y or a combination of those elements), Ba, and Cu, which is a superconducting phase in the oxide superconductor REBa
RE ₂ BaCu which is a normal conducting phase in ₂ Cu ₃ O _7-x crystal
An oxide superconductor having a structure in which O ₅ is finely and uniformly dispersed is provided, and either one of the magnet and the oxide superconductor is connected to a vibration isolation table, and the other one is installed on a base for device installation. A non-contact fixing device characterized by being provided. 2. A combination of a magnetic member such as the non-circular permanent magnet or electromagnet and the oxide superconductor,
The non-contact fixing device according to claim 1, wherein two or more sets are arranged in a horizontal direction and a vertical direction.