JPH04338030A - Non-contact carrying machine - Google Patents

Abstract

PURPOSE:To improve the yield of product by eliminating generation of dust. CONSTITUTION:Multiple closed coils and 8-shape closed coils 3 inside of the closed coils are provided in the lower surface of a float table 1, and multiple exciting coils 11 for changing a phase of the excited current at a constant pitch to generate the shifting magnetic filed are provided on the top surface of a fixation side structure 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact conveyor used, for example, in semiconductor manufacturing processes where dust generation is a concern.

0002

2. Description of the Related Art Conventionally, such conveying machines have used a combination of rolling bearings and linear motors.

0003

[Problems to be Solved by the Invention] In the above-mentioned conventional conveying machine, abrasion powder is generated from the rolling bearings, and as a result, there is a problem that the yield of the product is poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a non-contact conveyor that eliminates dust generation and improves product yield.

[0005]

[Means for Solving the Problems] A non-contact conveyor according to the present invention has a floating table made of a non-magnetic and non-conductive material that floats and moves without contacting the fixed structure, and has a A plurality of rectangular closed coils are provided along the movement direction, and closed coils are provided in a figure 8 shape inside the closed coils, and the coils are arranged at a constant pitch on the upper surface of the fixed side structure along the movement direction of the floating table. A large number of excitation closed coils are provided to generate a moving magnetic field for the levitation table by changing the phase of an excitation current, and a resonance capacitor is connected to each of the excitation closed coils.

[0006] The frequency of the excitation current and the resonant frequency of the circuit consisting of the excitation closed coil and the resonant capacitor of the stationary structure are made to almost match, thereby increasing the repulsive force and thrust due to electromagnetic induction. preferable.

[0007] It is also preferable that every two of the excitation closed coils be connected to separate high-frequency power sources, and the phases of the output currents of these three power sources are shifted by 120°.

[0008]

[Operation] In the non-contact conveyor configured as described above, when the frequency of the excitation closed coil of the fixed side structure exceeds a predetermined frequency at a constant pitch, electromagnetic induction causes a gap between the excitation closed coil of the floating table and the closed coil of the floating table. Then, a repulsive force and a thrust in the direction of movement are generated in sequence, and the floating table levitates and moves without contact.
Transport loaded products. Therefore, dust generation from conventional bearings and the like is eliminated, and product yield is improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

In FIG. 1, a floating table 1 is formed into a rectangular flat plate made of a non-magnetic, non-conductive material. A repulsive levitation coil 2 and a figure-of-eight closed coil 3 are attached to the lower surface of the levitation table 1. On the other hand, fixed side structure 1
A large number of fixed-side excitation coils 11 are provided on the top surface of 0.

Referring also to FIG. 2, the repulsion levitation coil 2 is
They are formed of rectangular closed coils, and a plurality of them are arranged along the moving direction X of the levitation table 1. Further, the figure-of-eight closed coils 3 are provided inside the repulsion levitation coils 2, respectively.

Referring also to FIG. 3, the plurality of fixed excitation coils 11a to 11f are formed of rectangular closed coils, and are arranged along the moving direction X of the levitation table. Among the coils 11a to 11f, two coils 11a, 11d, etc. from the top are connected in parallel to a high frequency power source 13a via resonance capacitors 12, 12. Similarly, the coils 11b, 11e... are connected to the high frequency power source 13b, and the coils 11c, 11f...
... are connected to the high frequency power source 13c. The phases of the output currents of the high frequency power supplies 13a to 13c are shifted at a constant pitch (120° in the illustrated example). Further, the excitation current frequency and the resonance frequency of the circuit including the coils 11a to 11f, . . . and the capacitor 12 are approximately the same.

[0013] Therefore, the excitation coils 11a to 11f.
When the frequency of the excitation current exceeds a predetermined frequency at a constant pitch, the repulsive levitation coil 2,
2... and the excitation coils 11a to 11f...
A repulsive force and a thrust in the direction of movement are generated sequentially. As a result, the floating table 1 floats and moves in a non-contact manner to convey the loaded products (not shown). At this time, the resonant capacitor 12 is provided, and the excitation current frequency and the resonant frequency of the circuit consisting of the resonant capacitor and coils 11a to 11f are made to almost match, so that large repulsive force and thrust are generated. , conveyance capacity is improved.

Further, as shown in FIG. 4, when the floating table 1 is displaced horizontally by a distance ΔY in a plane perpendicular to the moving direction・A restoring force F due to an induced repulsion force in the direction opposite to the displacement is generated, and the floating table 1 is returned to its normal position.

Furthermore, as shown in FIG.
When the flying height Z0 of is displaced by the height ΔZ, the magnetic flux density by the primary coil 11a... decreases, and the induced current
o decreases by Δi. Therefore, the repulsive levitation force is reduced and the levitation table 1 is passively returned to the neutral position of the original levitation height Z0.

[0016]

[Effects of the Invention] Since the present invention is constructed as described above, it is possible to eliminate dust generation from bearings, etc., and improve the yield of products.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view perpendicular to the moving direction showing an embodiment of the present invention.

FIG. 2 is a bottom view of the floating table.

FIG. 3 is an electric circuit diagram of a fixed excitation coil.

FIG. 4 is a perspective view illustrating restoring force in a plane perpendicular to the movement direction.

FIG. 5 is a perspective view illustrating restoring force in the height direction.

[Explanation of symbols]

1... Levitation table 2... Repulsive levitation coil 3... Figure-of-eight closed coil 10... Fixed side structures 11a to 11f... Fixed side excitation coil 12... Resonance capacitor 13a to 13c...High frequency power supply

Claims (1)

[Claims] Claim 1: A plurality of rectangular closed coils are provided along the movement direction on the underside of a flat floating table made of non-magnetic, non-conductive material that floats and moves without contacting the fixed side structure. At the same time, closed coils are provided in a figure 8 shape inside the closed coils, and the moving magnetic field of the levitation table is applied to the upper surface of the fixed side structure by changing the phase of the excitation current at a constant pitch along the moving direction of the levitation table. 1. A non-contact conveyance machine, comprising: a large number of excitation closed coils, each of which is connected to a resonance capacitor.