JP3015566B2 - AC magnetic levitation transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is applied to a field in which an object needs to be transferred in a non-contact manner, for example, a wafer transfer apparatus in a semiconductor manufacturing apparatus which dislikes dust generation, a vacuum transfer apparatus which dislikes scattering of lubricating oil, and the like. And a suitable AC magnetic levitation transfer device.

[0002]

2. Description of the Related Art Conventionally, dust and lubricating oil are disliked.
For example, a so-called magnetic bearing using a permanent magnet or an electromagnet is used as a bearing of a mechanism for carrying or moving an object such as a semiconductor wafer in a semiconductor manufacturing process line or the like. This type of bearing utilizes magnetic attraction or repulsion acting between magnets or between a magnet and a magnetic material,
The object to be transported or the object to be supported is levitated in a non-contact manner through a gap. Various inventions and inventions have been made for the magnetic levitation transfer device, and many of them have already been put to practical use.

[0003] Of these, magnetic bearings using electromagnets have the advantage of requiring less power, but inherently have to stabilize the unstable attractive force by electrical control, so that a high-performance control device is required. Etc.
There are drawbacks such as the necessity of a large number of additional components such as a gap sensor required for this.

In particular, when a magnetic bearing using an electromagnet is used to carry a long distance, it is necessary to provide these control devices all over the carrying line, which is often difficult in terms of structure and cost.

As means for avoiding such a problem,
In general, a method is employed in which a necessary control circuit and a sensor are mounted on the side of an object to be conveyed. However, in this case, it is necessary to provide a power source such as a battery on the object side, and when used for a long time, a charging system or a power supply system is newly required, which causes another problem in facilities.

On the other hand, a magnetic bearing utilizing a magnetic repulsive force does not need the above-described control device in principle, and has a great advantage as a long-distance transport mechanism. However, a repulsion levitation mechanism combining only permanent magnets is practically impossible to realize, and it is said that it is necessary to stabilize at least one or more axes of freedom by the above-described control device.

On the other hand, it has been confirmed in principle that an induction repulsion type magnetic levitation mechanism using an AC electromagnet can stably support the levitation by devising the shape of a levitation body made of a conductive material.

FIGS. 7 and 8 show an example of a magnetic levitation mechanism (AC magnetic levitation transport device) of the above-mentioned repulsion system. In the figure, reference numeral 1 denotes an AC electromagnet (a floating electromagnet). In the configuration shown in the figure, a plurality of AC electromagnets 1 are installed in two rows. 2
Is a floating body which is conveyed on a row of AC electromagnets 1. For the floating body 2, a light and highly conductive material such as aluminum is suitable, and the object to be transferred is usually mounted on the floating body 2.

In the configuration shown in FIGS. 7 and 8, the AC electromagnet 1
When a single-phase AC current indicated by reference numeral 4 in FIG. 9 is applied, an alternating magnetic field is generated above the single-phase AC current. Then, since the floating body 2 is in the magnetic field, an alternating current called an eddy current flows in the aluminum material of the floating body 2.

The magnetic field generated by the eddy current is formed in a direction repelling the magnetic field generated by the AC electromagnet 1. For this reason, due to the above-described repulsive force, a floating force indicated by reference numeral F1 in FIGS. 7 and 8 acts on the floating body 2, and the floating body 2 floats.

In the configuration shown in FIGS. 7 and 8, a row of three-phase AC electromagnets (running electromagnets) 3 is provided between two rows of the AC electromagnets 1. When a three-phase AC current indicated by reference numerals 5, 6, and 7 in FIG. 10 is applied to the three-phase AC electromagnet 3, a traveling force indicated by reference F2 in FIGS. The body 2 is transported.

[0012]

The above-mentioned conventional magnetic levitation mechanism (magnetic levitation transport device) of the induction repulsion method has an advantage that it does not require a control device for stabilizing the levitation over the entire transport line. It is necessary to configure the apparatus by using the electromagnet for levitation and the electromagnet for traveling separately, so that the entire mechanism becomes large and the cost is high.

SUMMARY OF THE INVENTION An object of the present invention is to provide a conventional low-cost levitation mechanism using an AC electromagnet while applying the induction repulsion method, thereby enabling conveyance without using a special conveyance mechanism. Another object of the present invention is to provide an AC magnetic levitation transfer device which can be manufactured by using the method.

[0014]

Means for Solving the Problems In order to solve the above problems and achieve the object, the present invention takes the following means as basic means.

That is, according to the present invention, as shown in FIGS. 1 to 4, for example, the floating body 2 made of a conductive paramagnetic or non-magnetic metal material is levitated and conveyed using an alternating magnetic field of an alternating current electromagnet 10. In the magnetic levitation transport device, as the above-described AC electromagnet 10 provided in the transport direction, a levitation coil 10-1 for applying a single-phase AC current for levitation of the levitation body 2, and the levitation body 2 for traveling. The present invention is characterized in that a two-winding electromagnet having a structure in which a running coil 10-2 for supplying a multiphase alternating current and a traveling coil 10-2 are wound around a common iron core 10-3 is used.

[0016]

The following effects are obtained as a result of taking the above measures.

First, the levitation coil 10 of the AC electromagnet 10
When the single-phase AC current is applied to the −1, the floating body 2 is moved in the same manner as when the single-phase AC current is applied to the AC electromagnet (floating electromagnet) 1 of the conventional transfer device shown in FIGS. Surface. Also, the traveling coil 10-2 of the same AC electromagnet 10
When the multi-phase AC current is supplied to the floating body 2, the floating body 2 travels in the same manner as when the three-phase AC current is supplied to the three-phase AC electromagnet (running electromagnet) 3 of the conventional transfer device shown in FIGS. .

As described above, the alternating current electromagnet 10 is constituted by a two-winding electromagnet, and one electromagnet is used for both levitation and traveling, so that the electromagnet for traveling and the electromagnet for traveling are conventionally used. There is no need to separately install the transfer line, and the transfer line can be realized in a simple form, so that the cost can be significantly reduced.

[0019]

FIG. 5 is a block diagram showing a specific embodiment of the present invention, and the same parts as those in FIGS. 1 to 4 are denoted by the same reference numerals.

In FIG. 5, reference numeral 10 denotes an AC electromagnet which is used both for levitation and for traveling. A plurality of AC electromagnets 10 are arranged in a row to form a transport line for transporting the levitation body 2. . Each of the legs of the row of the AC electromagnets 10 has levitation coils A1, A2,... (Represented by the levitation coil 10-1) and traveling coils U1, U2 (represented by the traveling coil 10-2). , ..., V1, V2, ..., W
1, W2, ... are wound.

The levitation coils Ai (i = 1, 2,...) Are connected in series so that the polarities are N, S, N, S,. The running coils Ui, V
i, Wi have a three-phase star connection such that the polarities are U, V, W, U, V, W,... and are connected to a three-phase AC power supply 9.

The single-phase AC power supply 8 generates a single-phase AC current 14 required for floating the levitation body 2 as shown in FIG. 3 and supplies power to the respective levitation coils A1, A2,. Further, the three-phase AC power supply 9 generates three-phase AC currents 15, 16, 17 as shown in FIG. 4 necessary for running the levitating body 2, and causes the respective running coils U1, V1, W1,. Supply power.

In the row of the AC electromagnets 10 configured as described above, the traveling coils U1, V1, W1,... Are generated by the single-phase AC current 14 flowing through the levitation coils A1, A2,.
Are all in the same phase. Therefore,
Single-phase alternating current 14 flowing through levitation coils A1, A2, ...
In some cases, the star-connected running coils U1, V1,
No current flows through W1,.

The running coils U1, V1, W1,...
Are induced in the levitation coils A1, A2,... By the three-phase AC currents 15, 16, 17 flowing through
It has a phase difference of 0 °, and becomes zero when three phases are connected in series. Therefore, the running coils U1, V1,
Due to the three-phase AC currents 15, 16, 17 flowing through W1,..., No current flows through the levitation coils A1, A2,.
From the above, the outputs of the single-phase AC power supply 8 and the three-phase AC power supply 9 can be arbitrarily changed without interfering with each other.

Next, the levitating operation of the levitating body 2 in the apparatus constructed as described above will be described. First, a single-phase AC current 14 as shown in FIG. 3 is applied to a row of the AC electromagnets 10 arranged in the transport direction as shown in FIG. ..), And the three-phase AC currents 15, 16, 17 as shown in FIG.
To the running coil 10-2 (the running coils U1, V1,
, W1,...) Are energized repeatedly in the order of 15, 16, 17.

Then, an eddy current is generated in the aluminum material of the floating body 2 by the single-phase alternating current 14, and the floating body 2
Repels the AC electromagnet 10. Thus, a floating force as shown by F1 in FIGS. 1 and 2 acts on the floating body 2, and the floating body 2 floats.

On the other hand, a moving magnetic field is generated on the AC electromagnet 10 by the three-phase AC currents 15, 16, and 17. Due to the moving magnetic field and the eddy current flowing in the floating body 2 due to the moving magnetic field, a running force indicated by F2 in FIGS. 1 and 2 acts on the floating body 2, and the floating body 2 is arranged in the transport direction. On the row of the AC electromagnets 10.

FIG. 6 shows a single-phase AC current 14 (single-phase excitation current) and a three-phase AC current 1 according to the traveling mode of the levitating body 2.
It is a figure which shows the current intensity pattern of 5, 16, 17 (three-phase excitation current). In the figure, A indicates the single-phase excitation current intensity for levitation, and B indicates the three-phase excitation current intensity for traveling. Usually, the running friction force is small in the floating state, so that the three-phase excitation current intensity B
A level much smaller than the single-phase exciting current intensity A is used.

In order to levitate the levitation body 2 in the configuration shown in FIG. 5, first, as shown in FIG. 6, the three-phase exciting current intensity B (of the three-phase alternating currents 15, 16, 17) is set to zero. When the single-phase exciting current intensity A (of the single-phase AC current 14) is gradually increased to a set value, the floating body 2 enters a floating state.

In this state, when the three-phase excitation current intensity B is gradually increased, a running force acts on the floating body 2 and the floating body 2
Levitation. When the floating body 2 is stopped, the three-phase exciting current intensity B may be gradually reduced, contrary to the above. To reverse the traveling direction, the phase rotation of the output of the three-phase AC power supply 9 may be reversed, or the connection of two of the three phases may be switched. It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

[0031]

As described above in detail, according to the present invention, in an induction repulsion type AC magnetic levitation transfer device using an AC electromagnet, the AC electromagnet is constituted by a two-winding electromagnet, and is used for levitation and traveling. Is also used by one electromagnet,
Unlike the related art, there is no need to separately install a levitation electromagnet and a traveling electromagnet, so that a transfer line can be realized in a simple form, and a low-cost AC magnetic levitation transfer device can be manufactured.

[Brief description of the drawings]

FIG. 1 is a front view showing a basic configuration of a magnetic levitation transfer device according to the present invention.

FIG. 2 is a plan view showing a basic configuration of a magnetic levitation transfer device according to the present invention.

FIG. 3 is a waveform diagram of a single phase alternating current for levitation applied to the configurations of FIGS. 1 and 2;

FIG. 4 is a waveform diagram of a traveling three-phase AC current applied to the configurations of FIGS. 1 and 2;

FIG. 5 is a diagram showing a configuration of a magnetic levitation transfer device according to one embodiment of the present invention.

FIG. 6 is a view for explaining the operation in the embodiment.

FIG. 7 is a front view showing a basic configuration of a conventional magnetic levitation transfer device.

FIG. 8 is a plan view showing a basic configuration of a conventional magnetic levitation transfer device.

FIG. 9 is a waveform diagram of a single-phase alternating current for levitation applied to the configurations of FIGS. 7 and 8;

FIG. 10 is a waveform diagram of a traveling three-phase AC current applied to the configurations of FIGS. 7 and 8;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... AC electromagnet (electromagnet for levitation), 2 ... Floating body, 3 ... Electromagnet for three phases (electromagnet for traveling), 4,14 ... Single-phase alternating current (single-phase alternating current for levitation), 5,6,7, 15, 16,
17: three-phase AC current (running three-phase AC current), 8: single-phase AC power source (floating single-phase AC power source), 9: three-phase AC power source (running three-phase AC power source), 10: AC electromagnet ( A two-winding electromagnet), 10-1: a floating coil, 10-2: a traveling coil, 10-3: an iron core.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Motomi Nakajima 4-22, Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (56) References JP-A-52-43214 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B60L 13/03-13/10

Claims (1)

(57) [Claims] 1. An AC magnetic levitation transfer device for levitation transfer of a levitation body made of a conductive paramagnetic or non-magnetic metal material using an alternating magnetic field of an AC electromagnet, comprising: a first winding as an AC electromagnet; A two-winding electromagnet having a second winding is used. A single-phase alternating current for causing the floating body to float is applied to the first winding of the electromagnet, and the second winding is driven by the second winding. An AC magnetic levitation transfer device characterized in that a multi-phase AC current for running a levitation body is supplied.