JPS63133803A - Conveyer utilizing magnetic levitation - Google Patents

Abstract

PURPOSE:To simplify the control of the title conveyer without necessitating massive electromagnet, by a method wherein a suspending body, to which permanent magnets are attached, is arranged in a vessel while a movable guide piece, to which electromagnets are attached, and a driving mechanism for moving the guide piece are provided at the outside of the vessel. CONSTITUTION:When an exciting current is conducted through an electromagnet 17 under a condition that a permanent magnet 12 is opposed to the electromagnet 17, a suspending body 11 is suspended by the mutual magnetic effect of the permanent magnet 12 and the electromagnet 17. When a guide piece 15 is moved by a driving mechanism 16, the suspending body 11 is moved while being suspended so as to follow the movement of the guide piece 15. A position sensor 10 is provided on the guide piece 15 so as to be opposed to the downward projection 14 of the suspending body 11 through an insulative window 20 in order to detect the suspended position of the suspending body 11. The position sensor 19 is connected to the current circuit of the electromagnet 17 through a control means to generate a position signal in accordance with the upward and downward displacement of the suspending body 11 whereby the exciting current is controlled so as to increase the flux of the electromagnet, which is reverse to the direction of the displacement. Accordingly, the suspending body 11 may be maintained at a predetermined reference suspended position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magnetic levitation transport device suitable for transporting an article such as a semiconductor wafer in a non-contact manner in a container, such as a vacuum container.

(Prior Art) In such a conventional magnetic levitation conveyance device, a levitation body to which a permanent magnet is attached is placed inside a container, and a floating body attached to a permanent magnet is placed outside the container.
There are provided stones arranged along the entire length of the article conveyance path, and a linear motor stator which is also arranged along the entire length of the conveyance path and extends along the rear side of the linear motor together with the floating body. In a floating conveyance system, when the electromagnet is energized, the floating object levitates due to the mutual gi action between the electromagnet and the permanent magnet, and at the same time, when the linear motor stator is energized, this happens. Due to the interaction with the floating body constituting the linear motor mover, the floating body moves in a non-contact state within the container. Therefore, if the article is attached to the floating body, the article is conveyed in a container without contact.

(Problems that BA is supposed to solve) In such a magnetic levitation conveyance device, electromagnets are arranged along the entire length of the conveyance path, so if the conveyance path becomes long, a large amount of electromagnets will be required. A magnet is required, and its control becomes complicated. The main purpose of this invention is to solve such conventional drawbacks.

(Means for solving the problem) In order to achieve this object, according to the magnetic levitation conveyance device of the present invention, a floating body to which a permanent magnet f is attached is arranged inside a container, and outside the container, A movable guide to which an electromagnet is attached and a drive mechanism for moving the guide are provided, and the floating body is levitated by the alternating magnetic action of the permanent magnet and the Mar. 1 stone, and at the same time, The floating body follows the movement of the inner core, and a position sensor is attached to the guide which detects the floating height 1 of the floating body and emits a number representing the detected value. Between the sensor and the electromagnet, a control means 1 is connected to control the excitation chamber 1 of the 'xi stone according to No. 3.

(Function) In the magnetic levitation conveyance device 1 having such a configuration, when the electromagnet is energized, the floating object levitates due to the alternating magnetic action of this one magnet and the permanent magnet, and then the guide element is moved by the driving machine field 1. When it is moved, the floating body remains in a floating state and moves following the movement of the guide due to the alternating magnetic action of the electromagnet and the permanent magnet. By means of a position sensor and control means, the levitator is adjusted to Kf such that it is equilibrated at the desired height.
! ! I can move up.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 7 showing an embodiment of the magnetic levitation transfer device, a vacuum container io, for example a container made of a non-magnetic material, contains:
A floating body /l also made of non-magnetic material is arranged.

The floating body // has an upper part /la and a lower part / /b
: 25. The four corners of the upper and lower surfaces of the upper part 1/a are arranged with permanent magnets/2 as shown in Figure 1.
and two magnetic members arranged to sandwich this n/
J is fixedly attached. In the V diagram, the symbol /,
? -12-i and y indicate a combination of a permanent magnet and one magnetic member. At the four corners of the lower surface of the lower portion lλa, downward protrusions/da are provided for the purpose described later.

The guide/S attached to the outside of the container IO can be moved in a direction perpendicular to the plane of the paper by a drive mechanism constituted by a linear motor. Guide element /S is a total of g permanent magnets of floating object 1/! - It has a total of S electromagnets/7 that can be positioned so as to face each other, and each of the two t magnets 17 is bent on two sides by a magnetic member 1g. AI rod member 7g both legs are floating body // one electromagnet 121! −
They can each face the two sandwiched magnetic members 13.

When the floating body /I and mud inner core /3 are moving as shown in Figure tk-7, that is, when the permanent magnet L- and the electromagnet L-1 are facing each other, the electromagnet L-1 is energized. In other words, when an excitation current is applied to this, a magnetic flux flow occurs, or a magnetic circuit in the opposite direction as shown by the broken line arrow in Figure 3 is generated, and this magnetic circuit causes a permanent magnet l and an electromagnet l. Due to the mutual magnetic action of Moving.

The guide lS further has a first drum sensor/qf.

This position sensor lde is detected through an insulating window made of glass or the like provided on the bottom wall of the container IO when the guide element /3 and floating body and is positioned so as to face the downward protrusion /Q of the floating body //. The window O° extends in the moving direction of the guide ls, that is, in the direction perpendicular to the paper surface.

The position sensor /9 is configured to detect the levitation level of the floating body //, that is, the height position of the downward protrusion LD, and emit an @ symbol at a position representing the detected value.

The position sensor 19 is connected to the current circuit of the electromagnet 17 via a control means (not shown). According to this control means, when the floating body 11 is displaced in the vertical direction Tlc, the tM signal emitted from the 1st position sensor 19 changes by the amount t'LJ/
Accordingly, the excitation current for one electromagnet changes so that the magnetic flux on the electromagnet side in the direction opposite to the displacement direction increases. By this control, the displacement of the floating body l is canceled out, and this floating body l
l is maintained at a predetermined reference flying height &. Of course, this reference floating position can be arbitrarily set by the control means. The positional vortex sensors l9 are installed at four locations approximately below Jn of the combination of permanent magnets and magnetic members shown as 13-i2-i3 in FIG. The control is
This can be achieved with great precision.

In the above-mentioned more outdated magnetic levitation conveyance device, the electromagnetic levitation device is excited 6. When a current is applied, the floating body 7/ floats up and the child/S is roughly moved by the drive mechanism 16.
The floating object ll is in a floating state, that is, in a non-contact state,
It moves following the movement of the guide IS. n1 If the control means described above performs the f''!-movement to change the reference floating height, the floating body II can be vertically displaced both in the stopped state and in the moving state.

For example, a combination of a stepping motor and a ball screw can also be used as an example of a machine frame other than the above-mentioned near motor.

For example, as shown in Figure ii', the floating body // has
A conveyor table for supporting articles (not shown) to be conveyed can be fitted. The transport platform 1 may have any shape, may be fixed to the floating body 1, or may be attached to the floating body 1.

(Effects of the Invention) According to this invention, since the guide element with the stones attached to it is made to move, a large number of stones can be transported along the entire length of the conveyance path unlike the conventional method. There is no need to arrange
Therefore, a barrel-made coffin? The price will be low since the only investment is VC. It also becomes easier to control.

[Brief explanation of the drawing]

FIG. 17 is a schematic vertical sectional view of one embodiment of the magnetic levitation conveyance device according to the present invention, taken along the conveyance direction. FIG. 1 is a schematic plan view of a floating body used in the apparatus of FIG. 1. Figure 3 shows the entire magnetic circuit of the system consisting of permanent magnets, heavy magnets/stones, and magnetic &IX materials in the apparatus shown in Figure 7. The mlxq diagram shows the conveyance table attached to the floating body in the apparatus shown in Figure 7. In the drawings, IO is a container, 1 is a floating body, /, 2 is a permanent stone, 1S is a guide, /6 is a liS!

Claims (1)

[Claims] A floating body to which a permanent magnet is attached is disposed in a container, and a movable guide to which an electromagnet is attached and a drive mechanism for moving the guide are provided outside the container, and a floating body to which a permanent magnet is attached is provided. The mutual magnetic action of the electromagnets levitates the floating body and causes the floating body to follow the movement of the guide element, and the guide element further detects the floating position of the floating body. , a magnetic levitation conveyance device is provided with a position sensor that emits a signal representing a detected value thereof, and a control means for controlling an excitation current of the electromagnet in accordance with the signal is connected between the position sensor and the electromagnet.