JP3147452B2 - Magnetic levitation transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic levitation type transport apparatus in which a slider travels while floating along a transport path to transport articles and the like.

[0002]

2. Description of the Related Art In recent years, as a semiconductor integrated circuit has become highly integrated and miniaturized, a clean room for manufacturing the same has been required to have a high degree of cleanliness. In such a clean room, a transfer device for transferring a silicon wafer or the like includes:
Since it is necessary to minimize the generation of dust, a magnetically levitated transfer device that travels in a state in which the bogie floats on the transfer path, that is, in a non-contact manner, has attracted attention as an ideal.

FIGS. 4 to 8 are views each showing an example of a conventional magnetic levitation type transport apparatus. In these figures, reference numeral 1 denotes a box-shaped frame provided along the transport path, and an opening 1a extending along the transport path is formed on the upper surface thereof.

[0004] A pair of guide rails 3L and 3R made of steel are provided on the ceiling surface of the frame 1, respectively. 5 is a slider that travels on the transport path,
As shown in FIG.
L, and four floating / guide electromagnets M ₁ ~M ₄ to the lower surface of each opposite 2R, guide rails 3L, and four guide electromagnet m ₁ ~m ₄ of which each side and each opposing 3R Is provided.

The slider 5 floats by the magnetic attraction of the lower surfaces of the flying rails 2L and 2R by the flying / guide electromagnets M _{1 to} M ₄ , and furthermore, the range of the width dimension of the flying rails 2L and 2R. Within, the movement in the width direction is restricted.
Further, the guide electromagnet m ₁ ~m ₄ is guiding rails 3L,
By magnetically attracting each side of the 3R, the slider 5
Is firmly regulated in the width direction.

A slider 5 is provided with a rechargeable battery (not shown) and a floating / guide electromagnet M as shown in FIG.
For ₁ flying rails 2L of ~M _4, the gap sensor S ₁ to S ₄ for detecting the position in the vertical direction with respect to each lower surface of the 2R, guide rails 3L guide electromagnet m ₁ ~m _4, each side of the 3R gap sensors S ₅ ~ for detecting a horizontal position
And S ₈ are respectively provided.

Further, based on the detection signals of the gap sensors S _{1 to} S ₈ , the electromagnet M ₁ for floating / guiding from the battery is used.
And controlling the excitation current to be respectively supplied to ~M ₄ and guide electromagnet m ₁ ~m _4, the current control circuit 6 always constant the position and horizontal position of the vertical direction (FIG. 8) is provided .

Here, the slider 5 has Z ₁ , Z ₂ ,.
A total of five control axes x, Y ₁ and Y ₂ are set, and the control system of each axis is as shown in FIG. in this case,
This control system shows a case of Z ₁ axis, after the sum of the outputs of the gap sensors S _1, S ₄ is compared with gap command value RZ _1, the result is supplied to the current control circuit 6,
It is output as a current command value. The current supplied to each electromagnet is controlled by the current command value, and the slider 5 is controlled to a constant flying height. FIG. 9 shows the relationship between other control axes and their feedback inputs.

Returning to FIG. 6, primary coils 7, 7,... Of a linear induction motor are mounted on the inner bottom surface of the frame 1 at a predetermined interval. Secondary side conductors 8 facing up and down with a gap therebetween are attached.

In this case, the secondary conductor 8 may or may not have an iron core. Further, a loading platform 10 is attached to the upper surface of the slider 5 via a support 9, and a load 11 is loaded on the loading platform 10.

[0011] In this arrangement, when the exciting current is supplied to the air bearing / guide electromagnets M ₁ ~M ₄ and guide electromagnet m ₁ ~m _4, the slider 5 floats, whereas, the linear induction motor When an alternating current is supplied to the primary coil 7, the arrow F shown in FIG.
A traveling magnetic field is generated in the direction, so that the slider 5 is accelerated in the direction of arrow F each time it passes above the primary coil 7, and travels by inertia in other sections. As a result, the slider 5 travels continuously while alternately repeating acceleration and coasting while flying.

[0012]

By the way, in the above-mentioned conventional magnetic levitation type transport apparatus, the gap sensor S
_1, so as to have the respective outputs of the output and the gap sensor S _2, S ₃ from S ₄ equal control is performed in the vertical direction of the slider 5. However, the lifting rail 2L,
When the 2R is inclined with respect to the horizontal direction, the slider 5 also inclines in accordance with this inclination, so that there is a problem that the slider 5 shifts in the inclined direction when stopping.

The present invention has been made in view of the above circumstances, and does not cause displacement of the slider 5 when the slider 5 stops even if the flying rails 2L and 2R are inclined with respect to the horizontal direction. It is an object of the present invention to provide a magnetic levitation transfer device.

[0014]

According to a first aspect of the present invention, there is provided a magnetic levitation type transfer device, comprising: a levitation rail having a predetermined width dimension provided along a conveyance path; A vertical gap between the guide rail provided along the guide rail and the slider running on the conveyance path is detected to detect a vertical gap between the lower surface of the floating rail and the floating rail according to the vertical gap. Floating / guide force generating means for lifting the slider while restricting movement of the slider in the width direction within the range of the predetermined width dimension, and a side surface of the guide rail provided on the slider. And a guide force generating means for restricting movement of the slider in the width direction by magnetically attracting the guide rail according to the horizontal gap. Detecting means provided on the slider, for detecting an inclination angle of the flying rail with respect to the horizontal direction, and provided on the slider, so that the slider faces in the horizontal direction based on a detection result of the detecting means. Control means for controlling the levitation / guide force generation means.

According to a second aspect of the present invention, there is provided a magnetic levitation type transfer device, wherein a levitation rail having a predetermined width dimension erected along a conveyance path, a guide rail erected along the levitation rail, and A slider is provided on a slider that travels on a road, detects a vertical gap between the slider and a lower surface of the lifting rail, and magnetically attracts the lifting rail in accordance with the vertical gap. To control the movement of the slider in the width direction and to float the slider.
Detecting a horizontal gap between the guide force generating means and a side surface of the guide rail provided on the slider, magnetically attracting the guide rail in accordance with the horizontal gap, and detecting a width direction of the slider; A magnetic levitation type transport device having a guide force generating means for restricting movement to the ground, a detecting means provided on the ground side for detecting an inclination angle of the levitation rail with respect to a horizontal direction, and a detection result of the detecting means. Transmitting means for transmitting to the slider, and control means for controlling the flying / guide force generating means such that the slider is oriented in the horizontal direction based on the detection result transmitted by the transmitting means. And characterized in that:

[0016]

According to the configuration of the first aspect, the inclination angle of the flying rail with respect to the horizontal direction is detected by the detecting means provided on the slider, and based on the result of the detection, the flying / flying rail is moved so as to face the horizontal direction. The guide force generating means is controlled. Therefore, even if the flying rail is inclined, the slider is maintained in the horizontal direction, so that no displacement occurs when the slider is stopped due to the inclination of the flying rail.

According to the second aspect of the present invention, the inclination angle of the levitating rail with respect to the horizontal direction is detected by the detection means provided on the ground, and the detection result is transmitted to the slider by the transmission means and transmitted. The flying / guiding force generating means is controlled based on the detection result so that the slider is oriented in the horizontal direction. Accordingly, the slider is maintained in the horizontal direction even when the flying rail is inclined as described above, so that no displacement occurs when the slider is stopped due to the inclination of the flying rail.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a block diagram illustrating the Z ₁ axis control system of the magnetic levitation conveyor apparatus according to one embodiment of the present invention. As shown in this figure, flying rails 2L, a tilt sensor 10 for detecting an inclination angle with respect to the horizontal direction of the 2R, an arithmetic circuit 11 for calculating the horizontal deviation amount [Delta] Z ₁ based on the output of the inclination sensor 10, the horizontal a switching circuit 12 for setting control mode, different from the flat deviation amount [Delta] Z ₁ and the gap command value RZ ₁ and the conventional Z ₁ axis control system described above is that it has an adding circuit 13 for adding the I have. In this case, the tilt sensor 10, the arithmetic circuit 11, the switch circuit 12, and the adding circuit 13 are provided on the main body of the slider 5. Note that the same configuration as the other Z ₂ axis control system Again Z ₁ axis control system.

The switching circuit 12 is controlled to open and close based on a signal supplied from the outside. This signal is output from an opening / closing control circuit (not shown) when the slider 5 is stopped or when traveling at a high level is required.

The tilt sensor 10 is configured as shown in FIG. 2, for example, and an output corresponding to the displacement of the pendulum is obtained from a pendulum position detector. The tilt sensor 10 is attached to the slider 5 so that the output becomes zero when the slider 5 is horizontal.

Here, FIG. 3 shows a levitation rail 2L (2R).
FIG. 4 is a side cross-sectional view showing a positional relationship between the floating rail 2 and the slider 5, and the flying rail 2 </ b> L (2 </ b> R) is inclined with respect to the horizontal direction. This inclination angle is detected by the inclination sensor 10.
Then, a signal corresponding to the detected inclination angle is calculated by the arithmetic circuit 1.
1 to calculate a horizontal deviation amount ΔZ ₁ . Then, the flat deviation amount ΔZ ₁ is added to the gap command value RZ ₁ . Thereafter, the signal is compared with the feedback input as in the related art, and the comparison result is input to the current control circuit 6.

[0022] Thus, flying rails 2L, obtains the horizontal deviation amount [Delta] Z ₁ with respect to the horizontal direction of the 2R, it was added to the gap command value by feedback control, to the slider 5 is maintained in a horizontal direction Become.

In the above embodiment, the inclination angle of the floating rails 2L, 2R with respect to the horizontal direction is detected by the inclination sensor 10 provided on the slider 5. The inclination may be detected by a laser displacement meter. In this case, transmission devices for transmitting the detection result to the slider 5 are provided on the ground side (transmitter) and the slider 5 side (receiver).

In the above embodiment, the switch circuit 12 is provided to select whether the horizontal control is valid or invalid. However, the horizontal control may be always valid. That is,
It is not always necessary to provide this switch circuit 12. Next
Then, the arithmetic circuit 11 determines the control stability (from the tilt sensor
Slider vibrates according to the frequency of the output and disappearance of the
It is desirable to provide a PI element to prevent the above.

[0025]

As described above, according to the present invention, the slider is maintained in the horizontal direction by determining the horizontal deviation of the flying rail in the horizontal direction, adding this to the gap command value and performing feedback control. Therefore, it is possible to prevent the displacement of the slider when stopping. Further, since control of the position in the transport direction is not required as compared with the related art, the control system can be simplified. In addition, since it is not necessary to accurately determine the level of the floating rail, the work required for installing the rail can be reduced.

[Brief description of the drawings]

1 is a block diagram illustrating the Z ₁ axis control system of the magnetic levitation conveyor apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a tilt sensor and an electric circuit used for the tilt sensor.

FIG. 3 is a side sectional view showing a positional relationship between a flying rail and a slider.

FIG. 4 is a partially cutaway side view showing an external configuration of a conventional magnetic levitation type transport apparatus.

FIG. 5 is a plan view showing an external configuration of the magnetic levitation transfer device.

FIG. 6 is a front sectional view showing an external configuration of the magnetic levitation transfer device.

FIG. 7 is a perspective view showing an external configuration of a slider of the magnetic levitation transfer device.

8 is a block diagram illustrating the Z ₁ axis control system of the magnetic levitation conveyor apparatus.

FIG. 9 is a diagram showing a relationship between a control axis and a feedback input of the magnetic levitation transfer device.

[Explanation of symbols]

1 frame 2R, 2L flying rails 3R, rail for 3L guide 5 slider 6 the current control circuit 10 tilt sensor (detecting means) 11 operation circuit 12 switching circuit 13 the adding circuit (11, 13 control means) M ₁ ~M ₄ levitation / Guide electromagnet (floating / guiding force generating means) m _{1 to} m ₄ Guiding electromagnet (guiding force generating means) S _{1 to} S ₈ Gap sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/68 H01L 21/68 A

Claims (2)

(57) [Claims] 1. A flying rail having a predetermined width dimensioned along a transport path, a guide rail extended along the floating rail, and a slider running on the transport path, A vertical gap between the lower surface of the flying rail is detected, and the floating rail is magnetically attracted in accordance with the vertical gap, thereby restricting the movement of the slider in the width direction within the predetermined width. And detecting a horizontal gap between a floating / guide force generating means for floating the slider and a side surface of the guide rail provided on the slider, and magnetically moving the guide rail in accordance with the horizontal gap. And a guide force generating means for restricting the movement of the slider in the width direction. Detecting means for detecting an oblique angle, and control means provided on the slider, for controlling the flying / guide force generating means such that the slider is oriented in the horizontal direction based on the detection result of the detecting means. Characteristic magnetic levitation transfer device. 2. A levitation rail having a predetermined width provided along a transport path, a guide rail provided along the levitation rail, and a slider traveling on the transport path. A vertical gap between the lower surface of the flying rail is detected, and the floating rail is magnetically attracted in accordance with the vertical gap, thereby restricting the movement of the slider in the width direction within the predetermined width. And detecting a horizontal gap between a floating / guide force generating means for floating the slider and a side surface of the guide rail provided on the slider, and magnetically moving the guide rail in accordance with the horizontal gap. And a guide force generating means for restricting movement of the slider in the width direction. The magnetic levitation type transfer device, wherein the inclination angle of the levitation rail with respect to the horizontal direction is provided on the ground side. Detecting means, a transmitting means for transmitting a detection result of the detecting means to the slider, and a slider provided in the slider, wherein the slider is oriented in the horizontal direction based on the detection result transmitted by the transmitting means. And a control means for controlling the levitation / guide force generation means.