JPH10135036A - Detection coil structure for position sensor of magnetic floating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect sample position with high precision by assigning a detection coil which is plated by vapor-deposition on the surface of a tube-like member, and detecting induction current induced at a soil. SOLUTION: Around a core tube 11 acting as tube-like member, a pair of floating electromagnetic coils 12 and 13 are assigned by extrapolation. The electromagnetic coils 12 and 13 are applied with high-frequency currents, reversely directed each other to form a magnetic field, so that a sample 1 is kept in floating state at intermediate position between both the floating electromagnetic coils 12 and 13. On the outside surface of core tube 11, a detection coil 20 (Z-axis coils 21A and 21B, X-axis coils 22A and 22B, Y-axis coils 23A and 23B) of a position sensor is provided, and position of the sample 1 is detected with the detection coil for detecting an induction current. For a thin film which forms a coil pattern of the detection coil 20, such conductive material as gold, copper, etc., is coagulated on the surface core tube 11 by vapor-deposition plating such as vacuum vapor-deposition, etc. With a configuration like this, the detection coil 20 does not interfere with the floating electromagnetic coils 12 and 13 and a heating coil, so their assignment near the sample becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic levitation apparatus for holding a sample in a floating state in a tubular member by an electromagnetic levitation method, in which a change in the position of the sample is induced by a detection coil disposed around the tubular member. The present invention relates to a detection coil structure of a position sensor for detecting by induced current.

[0002]

2. Description of the Related Art FIG. 5 is a conceptual diagram showing a configuration in which a sample can be held in a floating state in order to perform a semiconductor or alloy material generation experiment under microgravity using a falling tower or an artificial satellite. Electromagnetic levitation devices have been considered.

[0003] This is constituted by disposing a pair of floating electromagnetic coils 12, 13 at a predetermined distance in the axial direction about a furnace tube 11, and applying a high frequency current in the opposite direction to the floating electromagnetic coils 12, 13. By flowing, the conductive sample 1 placed inside the furnace tube 11 is kept in a floating state. That is, an induced current is generated in the sample 1 by the magnetic field formed by the floating electromagnetic coils 12 and 13, and the magnetic field formed by the induced current repels the magnetic field generated by the floating electromagnetic coils 12 and 13, so that the sample 1 is in a floating state. Is to be held in the still,
In addition to the floating electromagnetic coils 12 and 13, a solenoid type heating coil (not shown) for heating the sample 1 at high frequency is disposed around the furnace tube 11. The sample 1 is also heated by the floating electromagnetic coils 12 and 13. However, it is mainly heated and melted by the heating coil.

In the electromagnetic levitation apparatus having the above-described configuration, when the sample is operated on the ground on which gravity acts, with the center axis of the furnace tube being vertical, the sample is stabilized at a position where the levitation force acting and the gravity are balanced.

[0005]

On the other hand, under microgravity, since there is no action of gravity, the sample is placed in the center of the floating coil system (both floating) where the repulsive force (floating force) due to the magnetic field from both floating electromagnetic coils cancels out. (In the middle of the electromagnetic coil), but in the vicinity thereof, the sample tends to rotate and vibrate because the repulsive force by the magnetic field is small. The vibration of this sample will eventually be attenuated due to the viscosity of the ambient gas, etc.
In experiments where only a short microgravity time can be obtained, such as a falling tower or a ballistic rocket, it is necessary to resolve the problem promptly. Therefore, it is desirable to detect the sample position and perform feedback control.

Here, as a method of detecting the position of the sample, a detection coil corresponding to each coordinate axis of a three-dimensional coordinate system orthogonal to the periphery of the furnace tube is provided, and the magnetic field of the sample is attached to the detection coil. It has been considered that the position of the sample is detected by measuring an induced current induced by the sample.

However, when a detection coil formed by winding an insulated wire such as an enameled wire is to be disposed around a furnace tube, it must be disposed outside a floating electromagnetic coil or a heating coil. In addition, there has been a problem that it is impossible to perform highly accurate detection because it is separated from the detected member (sample). There is also a problem that the sample is damaged by radiant heat from a sample heated to a high temperature.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a small size, so that it can be disposed near a sample and has high heat resistance. The purpose is to provide.

[0009]

According to a first aspect of the present invention, there is provided a magnetic levitation device for a magnetic levitation device, comprising: a magnetic sensor for holding a sample in a floating state in a tubular member by an electromagnetic levitation method; A position sensor that detects a change in the position of the sample by an induced current induced in a detection coil disposed around the tubular member,
The detection coil is characterized by being formed by vapor deposition plating on a surface of the tubular member or a surface of a support substrate disposed near the tubular member.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view conceptually showing a magnetic levitation electric furnace 10 to which a configuration example of a detection coil structure of a position sensor in a magnetic levitation device according to the present invention is applied.

The illustrated magnetic floating electric furnace 10 includes a pair of floating electromagnetic furnaces around a furnace tube 11 as a tubular member formed of a heat-resistant material such as quartz, alumina or sapphire at predetermined intervals in the direction of the center axis thereof. The coils 12 and 13 are arranged in an extrapolated state, and these floating electromagnetic coils 1
A heating coil (not shown) for high-frequency heating is disposed adjacent to each of the floating electromagnetic coils 1 and 2.
A magnetic field formed by flowing high-frequency currents in opposite directions to each other causes a floating electromagnetic coil 1
An induced current is generated in a direction opposite to that of the floating electromagnetic coils 1 and 2, and the magnetic field formed by the induced current repels the magnetic field generated by the floating electromagnetic coils 12 and 13.
It is held in a floating state at an intermediate position between 2 and 13, and is heated by a heating coil (not shown).

On the outer surface of the furnace tube 11, a detection coil 20 of a position sensor (Z-axis detection coils 21A and 21B, X-axis detection coils 22A and 22B, Y-axis detection coils 23A and 23) is provided.
B) is provided, and the position sensor can detect the position of the sample 1 by detecting the induced current generated in these detection coils 20 by the magnetic field of the sample 1.

Here, the detection coil 20 is formed on the outer peripheral surface of the core tube 11 directly by a thin film made of a conductive material.
Are formed on the outer surface of the core tube 11, and one pair is arranged corresponding to the coordinate axes of a three-dimensional coordinate system orthogonal to the central axis of the furnace tube 11.

That is, with the central axis of the furnace tube 11 as the Z axis,
An X-axis orthogonal to the Z-axis, a Y-axis orthogonal to the Z-axis and the X-axis are set, and a pair of detection coils 20 are arranged around these coordinate axes, respectively, and X-axis detection coils 22A and 22B are provided. And Y-axis detection coils 23A and 23B
Is formed in a substantially rectangular shape, for example, as a 10-turn swirl pattern in each region obtained by dividing the peripheral surface of the core tube 11 into four around the X axis and the Y axis.
Each of 1A and 21B is configured such that a pattern of winding the outer peripheral surface of the furnace tube 11 by, for example, 10 turns is formed at symmetrical positions with respect to the X axis and the Y axis.

The thin film forming the detection coil 20 is formed by depositing a conductive material such as gold, platinum, or copper by vapor deposition such as physical vapor deposition (PVD) such as vacuum deposition, sputter deposition, or ion plating or chemical vapor deposition (CVD). By solidifying the core pattern on the surface of the furnace tube 11, the coil pattern can be made extremely fine by forming the coil pattern using a photolithography method or the like.

Each pair of detection coils 20 is composed of the Z-axis detection coils 21A, 21 shown in FIG.
2B is a diagram (B), and Y-axis detection coils 23A and 23B are a diagram in FIG.
As shown in (C), by wiring so that the currents cancel each other, it becomes possible to detect the displacement of the sample 1 based on the direction and magnitude of the current.

As described above, since the coil pattern of the detecting coil 20 is formed on the surface of the furnace tube 11 by a thin film formed by vapor deposition, the detecting coil 20 does not interfere with the floating electromagnetic coils 12, 13 and the heating coil. In addition, a position sensor that can be disposed at a position close to the sample 1 and that can be detected with high accuracy without being damaged by radiant heat from the sample 1 can be configured. Also, the detection coil 2 may be configured such that the sample 1 is heated by an infrared lamp or the like provided outside.
0 does not hinder infrared irradiation. Thus, the position of the sample 1 can be detected with high accuracy and stability, and the feedback control that suppresses the vibration of the sample 1 can be performed by using the position detection information.

Next, FIG. 3 shows a conceptual cross-sectional view of a magnetically suspended electric furnace 10 '.

The configuration shown in the figure is the Z-axis detecting coils 21A, 21A.
B is formed on a surface of a substrate 30 as a donut disk-shaped support substrate formed of a refractory insulating material as shown in a perspective view of FIG. To the floating electromagnetic coil 12,
13 and the heating coils 14 and 15 are disposed in an interposed state. In FIG. 3, the X-axis detection coil and the Y-axis detection coil are omitted.

According to this configuration, the Z-axis detection coils 21A,
21B can be configured to be thinner in the Z-axis direction than the above configuration. The Z-axis coils 21A, 21B
Not only that, the X-axis detection coils 22A and 22B and the Y-axis detection coils 23A and 23B are formed on a substrate made of a refractory insulating material having a shape surrounding the furnace tube 11 by a thin film formed by vapor deposition and brought close to the outer surface of the furnace tube 11. It is good also as a structure arrange | positioned at the same time.

[0021]

As described above, according to the detection coil structure of the position sensor in the magnetic levitation device according to the present invention, the coil pattern of the detection coil is deposited on the surface of the tubular member or the support mounted on the tubular member. By forming a thin film by plating, the detection coil can be configured with extremely compact and high heat resistance, and can be placed close to the sample without interference with the floating electromagnetic coil or heating coil Thus, a position sensor capable of performing highly accurate detection without being damaged by radiant heat from the sample can be configured.

[Brief description of the drawings]

FIG. 1 is a perspective view conceptually showing a magnetic levitation electric furnace to which a configuration example of a detection coil structure of a position sensor in a magnetic levitation device according to the present invention is applied.

2A is a conceptual diagram showing a wiring state of a Z-axis detection coil, FIG. 2B is a conceptual diagram showing a wiring state of an X-axis detection coil,
(C) is a conceptual diagram showing a wiring state of a Y-axis detection coil.

FIG. 3 is a conceptual sectional view of a magnetically suspended electric furnace which is another configuration example of the present invention.

FIG. 4 is a perspective view of a substrate as a detection coil support.

FIG. 5 is a perspective view showing a conceptual configuration of a magnetic suspension device.

[Explanation of symbols]

 Reference Signs List 1 sample 10, 10 'magnetic floating electric furnace (magnetic floating device) 11 furnace tube (tubular member) 12, 13 floating electromagnetic coil 20 detection coil 21A, 21B Z-axis detection coil 22A, 22B X-axis detection coil 23A, 23B Y-axis Detection coil 30 Substrate (support substrate)

Claims (2)

[Claims] 1. A magnetic levitation device for holding a sample in a floating state in a tubular member by an electromagnetic levitation method, wherein a change in the position of the sample is caused by an induced current induced in a detection coil disposed around the tubular member. It is a position sensor to detect, The said detection coil is formed by vapor deposition plating on the surface of the said tubular member, The detection coil structure of the position sensor in the magnetic suspension device characterized by the above-mentioned. 2. A magnetic levitation device for holding a sample in a floating state in a tubular member by an electromagnetic levitation method, wherein a change in the position of the sample is caused by an induced current induced in a detection coil disposed around the tubular member. A position sensor for detecting, wherein the detection coil is formed by vapor deposition plating on a surface of a support substrate disposed near the tubular member, and is configured to be configured. Detection coil structure.