JPH0585355A - Branch mechanism for magnetically levitated conveyor device - Google Patents

Abstract

PURPOSE:To enable free branching and joining by disposing yoke like magnetic poles not only in the travel direction of a carrier base but also in the direction of a branched carrier path in a specified branch place. CONSTITUTION:In a specified branch place X, yoke like magnetic poles 12, 12a are disposed not only in the carrier base travel direction M but also in the direction of a branched carrier path. Accordingly, when a current is applied to a unit including the yoke like magnetic poles 12a disposed also in the direction of the branched carrier path, a carrier base 18-2 moves in the branch direction B by the resiliency following the Lenz's law. That is, the shifting magnetic field is generated to a primary fixed iron core by making a three-phase alternating current flow to a primary coil, and the carrier base 18-2 performs non- contact levitated movement receiving the driving force of the shifting magnetic field and upward levitating force by the electromagnetic force between the induced current flowing therein and the shifting magnetic field of the primary fixed iron core. The carrier base 18-2 proceeds without branching off by applying a current to a unit including yoke like magnetic poles 12 extended in the rectilinear direction M of the carrier base.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a carrier for accommodating an object, which is housed in a partition wall, shielded from the external atmosphere, and made of a non-magnetic and good conductor material, and a track. Is a transfer path of a magnetic levitation transfer device that floats and travels above the track and partition while maintaining a non-contact state (a path surrounded by a partition, in which a transfer platform floats and moves. The same applies hereinafter) to a branch mechanism used in a magnetic levitation transport device.

[0002]

2. Description of the Related Art A magnetic levitation transport device of this type is
It is preferably used in the field of precision engineering such as semiconductor manufacturing equipment. For example, in an environment where the prevention of dust generation is an absolute requirement, such as in a clean room, if the carriage can float and move without contacting the track,
It is very convenient because dust is prevented from being generated from the carrier. For this reason, various magnetic levitation-type transport devices have been proposed in the past, which allow the transport base to float on an orbit.

On the other hand, when used as a transfer device in a clean room of a semiconductor manufacturing facility, the transferred object is often a wafer. Then, if impurities such as dust adhere to the wafer during the transfer, the yield will be deteriorated. To prevent this, it is also proposed that the track and the transfer base be housed in a partition wall to be shielded from the external atmosphere.

Here, in the magnetic levitation transfer device of the type in which the track and the transfer base are housed in the partition wall and shielded from the external atmosphere, conventionally, due to its structure, the transfer path cannot be branched or joined. It was Therefore, conventionally, for example, FIG.
The transport devices were arranged in the layout shown in.

In FIG. 8, two clean rooms C are provided.
1 and C2 are connected by the transport device 1. In the clean rooms C1 and C2, the carrier device 1 collects and distributes the collection means 2-1, 2-2, the auxiliary carrier devices 3-1, 3-2, and
Via branching / merging means 4-1 and 4-2, they are respectively connected to processing-step transporting devices 5-1 ... 5-2, which form various lines. Adjacent room clean room C1 or C
The objects (workpieces) transported by the transporting device 1 from the auxiliary transporting device 3 are collected by the collecting and distributing means 2-1 and 2-2.
-1, 3-2 are appropriately allocated to the branch and merge means 4-
1, 4-2, a predetermined processing process transfer device 5-1 ...
It is distributed to 5-2 ... and necessary processing is performed. Alternatively,
The workpieces that have been subjected to the predetermined processing by the transporting devices 5-1 ..., 5-2 ... Collective distribution means 2-
It is transported to 1, 2-2, where it is arranged in a predetermined order,
It is transported to another clean room via the transport device 1.

The arrangement shown in FIG. 8 is designed for batch processing using cassettes.

[0007]

However, even in the case of semiconductor products, when it is required to manufacture a large amount of various products represented by ASIC, the layout shown in FIG. 7 is often inadequate. Also, since the floor area of the clean room is relatively small, it is desirable that the layout can be designed freely, but it is impossible to freely design the layout because the transfer path cannot be branched or merged. There was a problem.

The present invention has been proposed in view of the above-mentioned problems of the prior art. The transfer path of a magnetic levitation transfer device of the type in which the transfer table is housed in a partition wall and shielded from the external atmosphere is freely branched. Or, the purpose is to provide a branching mechanism that can merge.

[0009]

A branching mechanism of a magnetic levitation carrier according to the present invention is a carrier which is housed in a partition wall and shielded from an external atmosphere, and which is made of a non-magnetic and good conductor material and on which an object is placed. In the branching mechanism of the magnetic levitation transfer device, the transfer base includes a track, and the transfer base branches the transfer path of the magnetic levitation transfer device that floats above the track while maintaining a non-contact state with the track and the partition wall. The track is composed of a plurality of yoke-shaped magnetic poles having a substantially U-shaped cross section, and the carrier has a cross-sectional shape such that at least the lower surface thereof is flat, and the track is located above the yoke-shaped magnetic pole. A coil is provided in the protruding portion, and a flat plate made of a magnetic material or a non-magnetic material is provided below the coil. A plurality of the yoke-shaped magnetic poles are arranged as a unit in series in the traveling direction of the carrier. , In the constant of bifurcation is also arranged in the direction of the transport path yoke-shaped magnetic poles branched not carrying table travel direction only.

Here, it is preferable that the carrier is formed in a flat plate shape.

Further, in the magnetic levitation transport device to which the branching mechanism of the present invention is applied, the yoke-shaped magnetic poles are provided in two rows, and three pairs of yoke magnetic poles form one unit and are serially arranged in the traveling direction of the transport platform. It is preferably arranged. In this case, the flat plate made of the magnetic material may be common to the two rows of yoke-shaped magnetic poles, or two rows may be provided below each yoke-shaped magnetic pole.

Further, in the magnetic levitation transfer device to which the branching mechanism of the present invention is applied, in order to improve the levitation force, a plate-shaped member made of a magnetic material is provided at a position corresponding to the yoke-shaped magnetic pole above the partition wall. Is preferably provided.

In addition to this, in the magnetic levitation transport device to which the branching mechanism of the present invention is applied, the length of the transport base in the traveling direction is three times the pitch of the yoke-shaped magnetic poles in the transport base traveling direction. It is set to the above integer multiple, and it is particularly preferable to be 3 times.

The cooling mechanism of the magnetic levitation transport apparatus of the present invention comprises:
A lead-in point is formed in a part of the feed path of the magnetic levitation conveyer device in which the feed table is housed in a partition wall and shielded from the external atmosphere, and the above-described branching mechanism is configured in the feed path where the lead-in point is formed. The cooling means is provided at the drawing-in place.

[0015]

According to the branching mechanism of the magnetic levitation transporting apparatus of the present invention constructed as described above, the yoke-shaped magnetic poles are arranged not only in the traveling direction of the transporting platform but also in the direction of the branched transporting path at a predetermined branching point. Therefore, when a current is supplied to the unit including the yoke-shaped magnetic poles arranged also in the direction of the branched transport path, the transport base moves in the branch direction by the repulsive force according to Lenz's law. That is, if a three-phase alternating current is applied to the primary coil, a moving magnetic field is generated in the primary fixed iron core, and the carrier is driven by the electromagnetic force of the induced current flowing therethrough and the moving magnetic field of the primary fixed iron core in the direction of the moving magnetic field. Then, the non-contact floating movement is performed by receiving the upward floating force.

If it is not necessary to invade the carrier table into the branched carrier path, a current is supplied to the unit including the yoke-shaped magnetic poles extending in the straight direction of the carrier table so that the carrier table proceeds without branching. To do.

Here, the carrier is heated by an induced current flowing, but since it is levitating and moving in a non-contact state, its heat is not conducted to anywhere, but only accumulated.
Therefore, it is necessary to cool the carrier. Here, if the cooling mechanism of the present invention is further provided, by the branching mechanism described above,
The transfer table is moved to a drawing-in position formed in a part of the transfer path, and the transfer table is cooled together with the drawing-in position by the cooling means provided at the drawing-in position. This solves the problem of heat storage in the carrier.

[0018]

Embodiments of the present invention will be described below with reference to FIGS.

First, a magnetic levitation transfer apparatus to which the branching mechanism of the present invention is applied will be described with reference to FIGS.

In FIG. 2, a partition 10 whose inside (reference numeral I) is in a vacuum state is provided. Then, it is placed on the U-shaped yoke-shaped magnetic poles 12, 12. Coils 16 and 16 are respectively wound around the portions 14 and 14 protruding above the magnetic pole 12. A base 22 made of a magnetic material or a non-magnetic material is provided below the magnetic pole 12. Here, the partition wall 10 is made of a non-magnetic material.

In the partition wall 10, a flat plate-shaped carrier, that is, a floating plate 1 made of a non-magnetic material such as aluminum.
8 is accommodated in the floating plate 18, and an object 20 to be conveyed such as a wafer is placed on the floating plate 18. As described below,
The levitation plate 18 energizes the coils 16, 16 to energize the magnetic poles 12.
When it is excited, it levitates, and by generating a moving magnetic field, it moves in a direction perpendicular to the paper surface of FIG.

FIG. 3 shows the magnetic levitation transport device of FIG. 2 seen from another angle. As is clear from FIG.
A plurality of magnetic poles 12 are arranged in series in the traveling direction of the carrier (indicated by an arrow M in FIG. 3). The base 22 also extends in the traveling direction M of the carrier. In FIG. 3, reference numeral 24 indicates an openable / closable door portion for a robot hand handling the wafer 20 to enter and leave.

Although not clearly shown in FIG. 3, the length L of the levitation plate 18 in the carrier traveling direction M is set to be three times the pitch P between the magnetic poles 12. Further, as is clear from FIG. 2, the width of the levitation plate 18 in the horizontal direction H is 2 rows of the coils 1
It corresponds to the length in the width direction from the end of 6 and 16 to the end.

The operation of the magnetic levitation transport device shown in FIGS. 2 and 3 is mainly shown in FIG.

When the coil 16 is energized to excite the yoke-shaped magnetic pole 12, the levitation plate 18 is operated according to the same principle as the prior art.
(In FIG. 4, the wafer 20 is shown mounted)
Float above the bottom of the partition wall 10. That is, the coil 16
When the yoke-shaped magnetic pole 12 is excited by energizing, the force in the direction of the arrow T acts and the levitation plate 18 rises. Then, if a moving magnetic field is generated, the levitation plate 18 travels in a floating state accompanying it.

In the magnetic levitation transport apparatus shown in FIGS. 2 to 4, magnetic fields 26 and 26 in FIG. 4 are generated. By this magnetic field, the stabilizing force, that is, the horizontal direction H
A force is added to try to maintain an equilibrium state for.
As a result, although the levitation plate 18 has a flat plate shape, the levitation plate 18 floats and runs in the horizontal direction H without shaking.

When the floating plate 18 is run, the plurality of magnetic poles 12 arranged in series may be excited by a three-phase alternating current. In the magnetic levitation transport device of FIG. 5, a plurality of magnetic poles 1
2 ... is divided into three indicated by U, V and W, and the magnetic poles 12 indicated by _U are excited by passing a current I _U ,
The magnetic poles 12 indicated by reference numeral V are excited by passing a current I _V, and the magnetic poles 12 indicated by reference numeral W are excited by passing a current I _W , thereby generating a moving magnetic field.

Next, a mechanism for branching the transfer path in the magnetic levitation transfer device described with reference to FIGS.

FIG. 1 shows a state in which the partition wall 10 is removed from the magnetic levitation transport device of FIGS. Here, with respect to the yoke-shaped magnetic pole 12 having a U-shape, only the portions 14 and 14 projecting upward are shown, and the coils 16 ... Are not shown. The carrier table 18 that floats along the carrier path when the partition wall 10 is provided is shown by a chain line, and the carrier table 18 advances along the moving magnetic field according to the above-described operating principle.

A base 22 made of a magnetic material or a non-magnetic material extending in parallel with the transport path of the magnetic levitation transport device branches downward in FIG. 1 at a branch point X, and the branch path 22a. Indicated by. Then, the branch point X
Are arranged in a branch direction, that is, in a direction (arrow B) orthogonal to the traveling direction of the carrier (arrow M), and a plurality of U-shaped yoke-shaped magnetic poles 12a are arranged.

The carrier platform 18-1 that has levitated from the upstream side (left side in FIG. 1) reaches the branch point X and is designated by reference numeral 18.
When it is located at the position indicated by the alternate long and short dash line indicated by -2, the control means (not shown) judges whether the carrier table can be levitated in the traveling direction M or branched in the branching direction B. If you want to levitate in the traveling direction M as it is,
The corresponding magnetic poles 12 are excited to generate a moving magnetic field in the direction of arrow M. As a result, the carriage moves in the direction of arrow M as indicated by reference numeral 18-3. When branching,
The yoke-shaped magnetic poles 12a extending in the branch direction B are appropriately excited to generate a moving magnetic field in the branch direction. As a result, the carriage is levitated in the direction of arrow B, as shown by reference numeral 18-4, and the branch is made.

On the other hand, the same applies to the case where the branch path is merged with the transport path.
Will be described.

The carrier 18 which has moved in the direction of the arrow BM from the branch path 22a of the base 22 made of a magnetic material or a non-magnetic material.
-4 is located at the confluence (reference X) as indicated by reference numeral 18-2. In this state, when the appropriate magnetic poles 12 ... Are excited to generate a moving magnetic field in the direction of arrow M, the carrier moves along the moving magnetic field in the direction of arrow M as indicated by reference numeral 18-3. The merging is completed.

Thus, by using the branching mechanism shown in FIG. 1, it is possible to freely branch or join the transfer path in the magnetic levitation transfer device of the type in which the transfer table is housed in the partition wall and shielded from the external atmosphere. I can. Therefore, as shown in FIG. 6, it is possible to provide a branch path BR in parallel with the transport path R or branch the transport path R into three transport paths R1, R2, and R3. As a result, the degree of freedom in layout of the magnetic levitation transport device is dramatically improved.

FIG. 7 shows a cooling mechanism to which the above branching mechanism is applied. This cooling mechanism has a lead-in portion 48 which is obtained by shortening the branch path of the branch mechanism shown in FIG. 1, a yoke-shaped magnetic pole 12a ..., And a cooling means 50. The cooling means 50 is configured to cool the bottom surface of the partition wall above the drawing-in place 48 when the partition wall not shown in FIG. 7 is attached.

When cooling the carrier table 18-1 which is levitating in the traveling direction M, the branching mechanism described with reference to FIG. And a portion (reference numeral 18) where the carriage constitutes the branching mechanism.
2), the magnetic poles 12a are sequentially excited appropriately as in the case of the branching mechanism, and a moving magnetic field is generated so as to move the heated carrier table to the retracted portion 48. Then, when the carrier is located directly above the cooling means 50 (position indicated by reference numeral 18-4) across the partition wall (not shown), the current supply to the magnetic poles 12a ...
The partition wall portion (the partition wall bottom surface) cooled by 0 is contacted. As a result, the carrier is cooled by heat transfer.

After the carrier table has been cooled, current is supplied to the magnetic poles 12a to levitate the carrier table so that it can join the carrier path.
As indicated by reference numeral 18-4, it again floats in the direction of arrow M.

The illustrated embodiment is merely an example, and the contents of the claims are not intended to be limited thereto. In other words, it should be noted that various modifications other than those shown in the drawings are possible according to the description of the claims.

[0039]

According to the branching mechanism of the magnetic levitation transfer device of the present invention described above, the transfer path of the magnetic levitation transfer device of the type in which the transfer base is housed in the partition wall and shielded from the external atmosphere is freely branched. You can join and join. Therefore, the degree of freedom in layout of the transfer device or the transfer path is increased, and an optimum layout can be achieved according to the shape of the clean room, the arrangement of equipment, and the arrangement of equipment. Furthermore, by branching into a plurality of processing lines or by arranging a plurality of processing lines in parallel, it can be used as a multi-product manufacturing line. As a result, the area occupied by semiconductors and other manufacturing equipment is reduced, and an efficient layout is designed, which also contributes to a reduction in manufacturing cost.

Further, according to the cooling mechanism of the magnetic levitation transfer apparatus of the present invention, the transfer table can be cooled even if it is heated, so that the reliability of the transfer apparatus is improved. In particular,
It is convenient when the transported object is easily affected by heat.

[Brief description of drawings]

FIG. 1 is a plan view of a main part for explaining a branching mechanism of the present invention.

FIG. 2 is a front view of a magnetic levitation transfer device to which the branching mechanism of the present invention is applied.

FIG. 3 is a side view of the magnetic levitation transport device of FIG.

FIG. 4 is a front view illustrating the operation of the magnetic levitation transport device of FIG.

FIG. 5 is a side view illustrating a means for generating a moving magnetic field in the magnetic levitation transport device of FIG.

FIG. 6 is a schematic diagram showing an example of a layout of a conveyance path using the branching mechanism of the present invention.

FIG. 7 is a plan view of a main part for explaining a cooling mechanism of the present invention.

FIG. 8 is a schematic diagram showing a layout according to a conventional technique.

[Explanation of symbols]

 10 ... Partition wall 12, 12a ... Yoke-shaped magnetic pole 16, 16a ... Coil 18, 18a ... Floating plate (conveyance table) 20 ... Wafer 22, 22a ... Base 26, 48 ... Magnetic flux 30, 32 ... AC power supply 38U, 38V, 38W ... Gain controller 48 ... Pull-in location 50 ... Cooling means B ... Branching direction H ... Horizontal direction T ... Vertical direction M: Direction of carriage movement

Claims (2)

[Claims] 1. A carrier, which is housed in a partition wall and shielded from an external atmosphere, is made of a non-magnetic and good conductor material, and on which an object is placed, and a track, and the carrier table is provided on the track and the partition wall. On the other hand, in a branching mechanism of a magnetic levitation transporting device that branches a transporting path of a magnetic levitation transporting device that floats and travels above it while maintaining a non-contact state, the orbits are a plurality of yoke-like cross-sectional shapes that are approximately U-shaped. The carrier has a cross-sectional shape such that at least its lower surface is flat, and a coil is provided at a portion protruding above the yoke-shaped magnetic pole, and a magnetic material is provided at a lower portion thereof. Alternatively, a flat plate made of a non-magnetic material is provided, and a plurality of the yoke-shaped magnetic poles are arranged in series in the traveling direction of the carrier as a unit. A branch mechanism of a magnetic levitation transport device, which is also arranged in the direction of a branched transport path. 2. A lead-in point is formed in a part of a feed path of a magnetic levitation conveyer device in which a carrier is housed in a partition wall and shielded from an external atmosphere, and a charge path is provided in the place where the lead-in point is formed. A cooling mechanism for a magnetic levitation transporting device, comprising the branching mechanism according to the item 1, wherein a cooling means is provided at the drawing-in portion.