JPH0327705A - Magnetic levitation carrier apparatus - Google Patents

Abstract

PURPOSE:To enable a smooth high-speed movement, also when an instantaneous acceleration is applied, by providing a magnetic levitation truck with a correction magnet for correcting the imbalance of the attraction of a magnet for a guide rail generated at the time of moving the magnetic levitation truck. CONSTITUTION:A correction magnet 7 equipped with a gap sensor 13 is provided at the lower part of a magnetic levitation truck 15 and a correction guide rail 8 facing the magnet is provided too. An electromagnet having no attraction normally and operating only when connected with a battery 2 is used as the correction magnet 7. That is, the correction magnet 7 for correcting the imbalance of the attraction of a magnet 1 for a guide rail 4 generated at the time of moving the magnetic levitation truck 15 by application of acceleration in the direction of the guide rail 4 is provided at the magnetic levitation truck 15. Therefore, the imbalance of the attraction of the correction magnet 7 is corrected and the variation of a gap between the composite magnet 1 of the magnetic levitation truck 15 and the guide rail 4 is decreased. Thus, also when an instantaneous acceleration is applied, it is possible to conduct a high-speed movement.

Description

[Detailed Description of the Invention] [Summary] Regarding the prevention of failures that occur when moving a magnetically levitated cart of a magnetically levitated conveyance device at high speed, the present invention aims to ensure smooth high-speed movement even when instantaneous acceleration is applied. The purpose of the present invention is to provide a lightweight magnetically levitated conveyance device that allows the magnetically levitated carrier to move the magnetically levitated carrier to the In a magnetically levitated transport device that moves along the guide rail without contacting the guide rail, the magnet against the guide rail occurs when the magnetically levitated cart is moved by applying acceleration in the direction of the guide rail. The magnetic levitation vehicle is provided with a correction magnet for correcting the imbalance in the attraction force.

[Industrial application field]

The present invention relates to a magnetically levitated transport device, and particularly to prevention of failures that occur when a magnetically levitated cart is moved at high speed.

In recent years, in the manufacturing process of semiconductor devices, with the miniaturization of semiconductor elements and the automation of manufacturing equipment, dust, lubricant mist, etc. generated from the mechanical parts of the manufacturing equipment have a large impact on the manufacturing yield of semiconductor elements. Therefore, there is a demand for dust-free manufacturing processes.

In order to meet these demands, efforts have been made to reduce dust generation by robotizing manufacturing equipment and reducing the number of sliding parts by simplifying mechanisms, but dust generation due to friction in mechanical parts has yet to be eliminated. It has not been. For this purpose, a completely non-contact conveying device is required.

Under the above circumstances, there is a need for a lightweight magnetically levitated transport device that can move at high speed in a completely non-contact manner.

[Conventional technology]

A conventional magnetic levitation transfer device for wafers will be explained in detail with reference to FIGS. 3 and 4.

As shown in FIG. 3, the general structure of a conventional magnetically levitated transfer device for transferring a single wafer is as follows: A wafer chuck 9 is provided on the upper surface of a U-shaped magnetically levitated carrier 15, and a wafer chuck 9 is provided on the upper surface of a U-shaped magnetically levitated carrier 15. Inside the guide rail 4 and composite magnet 1
It is equipped with two composite magnets 1 each equipped with a gap sensor 3 that detects the gap between the two. As shown in the figure, the magnetic levitation truck 15 is placed so that the guide rail 4 made of ferromagnetic material is located between the upper part of the magnetic levitation truck 15 and this composite magnet 1, and the gravity acting on the magnetic levitation truck 5 is balanced. When the composite magnet l is given an attractive force of 1, the magnetically levitated vehicle 15 becomes in a floating state without contacting the guide rail 4.

When the wafer 10 is mounted on the wafer chuck 9 in this state, the wafer 10 can be moved along the guide rail 4 without the magnetic levitation cart 15 coming into contact with the guide rail 4.

As the composite magnet 1, two types of structures as shown in FIGS. 4A and 4B can be used.

The one shown in Figure 4 (al) uses a permanent magnet 1a, with the permanent magnet 1a as the main
A control permanent magnet 6 that influences the magnetic field of a is provided, and a stepping motor 6a is used to rotate the control permanent magnet 6 around the center of the control permanent magnet 6 to place it in a predetermined position, thereby controlling the attraction force of the main permanent magnet ia. It is a composite magnet that performs the following, and when the control permanent magnet 6 is located at a position where both magnetic fields match, the attraction force is maximum, and when the control permanent magnet 6 is located at a position where both magnetic fields are exactly opposite. The adsorption force is minimized.

Although a large force is required to move a permanent magnet within its magnetic field, rotation of a permanent magnet can be performed with a relatively small force compared to movement.

The one shown in FIG. 4(b) is a composite magnet consisting of a permanent magnet and an electromagnet.A permanent magnet 1a is the center, and a coil lc is wound around an iron core 1b provided on both sides of the permanent magnet 1a, which is supplied from a battery 2. The permanent magnet 1 is adjusted by adjusting the power with the variable resistor 2a.
It is a composite magnet that controls the attraction force of permanent magnet 1a.
When the magnetic field of the coil 1c matches the magnetic field of the electromagnet, the attraction force is maximized, and when the current flowing through the coil 1c is reversed to make both magnetic fields exactly opposite, the attraction force is the minimum.

[Problem to be solved by the invention]

In the conventional magnetic levitation transport device described above, when an attempt is made to apply instantaneous acceleration to the magnetic levitation cart to make it move at high speed, if the direction in which the acceleration is applied does not completely coincide with the center of gravity, the acceleration will increase. A rotational moment corresponding to the direction of Even if you control it so that it is maximized and the attraction force of the composite magnet with a narrow gap is minimized,
It becomes impossible to correct the imbalance in the attraction forces of both composite magnets, making it impossible to move the magnetically levitated cart smoothly, making it impossible to apply instantaneous acceleration to achieve high-speed movement. In addition, if the guide rail has large undulations, the weight of the magnetic levitation cart must be increased in order to improve the ability of the magnetic levitation cart to follow the guide rail, which requires a large driving force. The problem was that it was necessary.

In view of the above-mentioned circumstances, the present invention aims to provide a light-weight magnetic levitation type conveyance device that is capable of smooth high-speed movement even when instantaneous acceleration is applied.

[Means to solve the problem]

The magnetic levitation type conveyance device of the present invention balances the own weight of the magnetic levitation truck and the attraction force of the magnets built into the magnetic levitation truck to the guide rail, so that the magnetic levitation truck does not come into contact with the guide rail. A correction magnet that corrects the imbalance in the attraction force of the magnet to the guide rail that occurs when applying acceleration in the direction of the guide rail to move the magnetically levitated vehicle along the guide rail. is configured to be included in the magnetically levitated vehicle.

[Effect]

That is, in the present invention, the magnetic levitation cart is prevented from rotating due to the rotational moment about the center of gravity of the magnetic levitation cart, which occurs when an instantaneous acceleration is applied to the magnetic levitation cart to cause it to move at high speed. A correction magnet is installed on the magnetically levitated cart to correct the imbalance in the attraction force between the composite magnet and the guide rail due to variations in gas pressure between the composite magnet and the guide rail. This correction reduces the dispersion of the gas flow between the composite magnet of the magnetically levitated truck and the guide rail, making it possible to move at high speed even when instantaneous acceleration is applied.

〔Example〕

Hereinafter, first and second embodiments of the present invention will be explained in detail with reference to FIGS. 1, 2, and 4.

FIG. 1 is a diagram showing a first embodiment according to the present invention, and in the diagram, the same parts as in the prior art are given the same numbers.

Composite magnet 1 and gap sensor 3 of this first embodiment,
The guide rail 4, magnetic levitation cart 15, and wafer chuck 9 are the same as those explained in the conventional technique, and the composite magnet 1 is the same as that shown in FIG. 4(a) explained in the conventional technique.
Alternatively, one of the composite magnets shown in (b) is used.

In this embodiment, the gap sensor 13 is used to correct a change in the gap between the guide rail 4 and the composite magnet l due to a moment about the center of gravity that occurs when an instantaneous force is applied to the magnetically levitated vehicle 15. As shown in the figure, a correction magnet 7 is provided at the bottom of the magnetically levitated truck 15, and a correction guide rail 8 is provided opposite thereto.

As shown in the figure, the correction magnet 7 uses an electromagnet that normally does not have an attractive force and is activated only when connected to the battery 2.

In such a structure, for example, if the gap between the composite magnet 1 on the left in the figure and the guide rail 4 becomes narrow, the attraction force of the correction magnet 7 on the left with respect to the correction guide rail 8 is increased. By widening the gap, it becomes possible to make the gap between the composite magnet l and the guide rail 4 equal on both the left and right sides.

FIG. 2 is a diagram showing a second embodiment according to the present invention, and in the diagram, the same parts as in the prior art are given the same numbers.

Composite magnet 1 and gap sensor 3 of this second embodiment,
The guide rail 4 and wafer chuck 9 are the same as those explained in the conventional technique, and the composite magnet 1 is one of the composite magnets shown in FIG. 4(a) or (bl) explained in the conventional technique. I am using it.

In this embodiment, unlike the first embodiment, the correction guide rail 8 is not provided, and the conventionally used guide rail 4 is also used for correction.

Therefore, in order to provide two sets of magnets, the composite magnet 1 and the correction magnet 7, inside the magnetic levitation truck 5, it is larger than the conventional magnetic levitation truck 15, and the gap sensor 3 of the composite magnet 1 and the gap sensor l3 of the correction magnet 7 are opposed to each other, and the guide rail 4 is disposed between them.

As shown in the figure, the correction magnet 7 uses an electromagnet that normally does not have an attractive force and is activated only when connected to the battery 2.

In such a structure, for example, if the gap between the composite magnet l on the left in the figure and the guide rail 4 becomes narrow, the attraction force of the left correction magnet 7 to the guide rail 4 is increased to close the gap. By widening the gap between the composite magnet 1 and the guide rail 4, it is possible to make the gap between the composite magnet 1 and the guide rail 4 equal on both the left and right sides.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by providing the magnetically levitating truck with a correction magnet that corrects the imbalance in the attraction force of the composite magnet that levitates the magnetically levitating truck with respect to the guide rail, This has the advantage that even when instantaneous acceleration is applied to the magnetically levitated bogie, it is possible to move the magnetically levitated bogie smoothly and at high speed along the guide rail, and it is expected to have significant economic and reliability effects. It becomes possible to provide a magnetic levitation type transport device that can

[Brief explanation of drawings]

FIG. 1 is a diagram showing a first embodiment according to the present invention, FIG. 2 is a diagram showing a second embodiment according to the present invention, and FIG. 3 is a diagram showing a schematic structure of a conventional magnetically levitated iron feeding device. , FIG. 4 is a diagram showing the configuration of a composite magnet. In the figure, 1 is a composite magnet, 1a is a permanent magnet, lb is an iron core, lc is a coil, 2 is a battery, and 3 and 13 are gap sensors. 4 is a guide rail, 5 is a magnetic levitation trolley, 6 is a permanent magnet for control, 6a is a stemming motor, 7 is a correction magnet, 8 is a correction guide rail, 9 is a wafer chunk, 10 is a wafer, according to the present invention Figure 1 illustrating the first embodiment - Figure 2 illustrating the second embodiment of the present invention Figure ta+ Front view ~) Side view

Claims (1)

[Claims] The own weight of the magnetic levitation vehicle (5) and the magnetic levitation vehicle (5)
The attraction force of the built-in magnet (1) to the guide rail (4) is balanced, and the magnetically levitated vehicle (5) is not brought into contact with the guide rail (4).
In a magnetically levitated conveyance device that moves along the guide rail (4), the magnet ( A magnetically levitated conveyance device characterized in that the magnetically levitated carriage (5) is equipped with a correction magnet (7) for correcting the imbalance in attraction force as described in (1) above.