JPH03203505A - Magnetic levitation carrier - Google Patents

Abstract

PURPOSE:To stop a carrier truck quickly regardless of trouble such as power interruption and without causing impact by providing a magnetic levitation stop means for stopping power supply to a magnetic levitation coil upon detection of displacement at a movable part and means for braking motion of the carrier truck. CONSTITUTION:Upon occurrence of a trouble, a solenoid valve 8 is turned OFF, and a light shielding board 11 is displaced and positioned at the groove part of a photosensor 13 in non-contact state. Consequently, the light from a LED 14 is shielded by the light shielding board 11 and the current of a phototransistor 15 goes to zero thus turning the photosensor 13 OFF. When a signal being held by a latch circuit 18 goes L, the content of the latch circuit 18 is read out and a judgment is made that a trouble has occurred and then the current supply to a magnetic levitation coil 20 is stopped.

Description

[Detailed Description of the Invention] [Summary] Regarding a magnetic levitation transport device, even if a failure occurs, such as a power outage, during transport of the transport vehicle, the transport vehicle can be stopped immediately without giving any impact. The purpose of the present invention is to provide a magnetic levitation conveyance device that can levitate on a conveyance rail by electromagnetic force generated in a magnetic levitation coil and move along the conveyance rail, and a conveyance cart provided at a station on the conveyance route, In a magnetic levitation conveyance device comprising a drive control means for controlling driving and stopping of a conveyance vehicle by electromagnetic force, a state of power supply to the drive control means is detected, and when the power supply state is abnormal, a predetermined a displacement means for displacing the movable part; and a displacement detection means attached to the carrier and detecting displacement of the movable part in a non-contact state;
a magnetic levitation stop means that stops energizing the magnetic levitation coil when the displacement of the movable part is detected by the displacement detection means; and a magnetic levitation stop means that stops energization of the magnetic levitation coil when the displacement of the movable part is detected; and a braking means for braking.

[Industrial application field]

The present invention relates to a magnetic levitation transport device, and more particularly to a magnetic levitation transport device that transports articles during the manufacturing process of semiconductor devices, for example.

In recent years, for example, in the manufacturing process of semiconductor devices, fine dust etc. (hereinafter referred to as
Many magnetic levitation conveyance devices have been developed that suppress dust generation and are highly reliable for conveying goods. In other words, as semiconductor devices become larger and have larger capacities, the wiring in these semiconductor devices is becoming increasingly finer.
For example, if dust is generated during the manufacturing process of a semiconductor device, care must be taken because this dust may cause problems in the wiring of the semiconductor device, leading to manufacturing defects. The causes of this dust generation are broadly divided into human factors and those generated from equipment in the manufacturing process.To prevent this dust generation, F A (F
The best means at this stage is to implement factory automation. In particular, transport equipment that transports wafers and masks between manufacturing processes requires a transport system that does not generate dust and is highly reliable for transporting items.
A magnetic levitation conveyance device using a linear motor as a drive control means is used. This magnetic levitation transport device has the excellent advantage of not generating dust and being highly reliable in transporting goods, but due to failures such as power outages, the linear motor that generates the driving force for the transport vehicle On the other hand, if the power supply is cut off, the transport cart during transport will remain floating above the transport rail unless a disturbance element is applied, as there is no mechanical friction loss between it and the transport rail. I will continue.

Therefore, there is a need for a magnetically levitated transport device that can quickly stop when a failure such as a power outage occurs.

[Conventional technology]

An example of a conventional magnetic levitation conveyance device of this type is the one shown in FIG. In this figure, l is a transport vehicle, 2 is a tray provided on the transport vehicle l, 3- is a linear motor as a drive control means for controlling the drive and stop of the transport vehicle 1, 4 is a transport rail, and 5 is a transport This mechanism unit 5 is a mechanical unit for stopping the carriage 1. This mechanism unit 5 includes a shock absorber 6, a shock absorber 6, and a seat 3.
Arrow Yl in the figure shows the quad absorber 6 fixed.

It includes a cylinder 7 that can move up and down in the Y2 direction, a solenoid valve 8 that controls the up and down movement of the cylinder 7, and a power source 9 that supplies power to the solenoid valve 8. Note that 1O indicates a predetermined stopping place (hereinafter referred to as a station) on the transport track of the transport vehicle 1, and the linear motor 3 as a drive control means is generally provided in the station 10.

In the above configuration, when the linear motor 3 and the mechanical unit 5 are normally in the energized state, power is supplied from the power source 9 of the mechanical unit 5 to the solenoid valve 8, and the cylinder 7 is Descend in the direction of arrow Y1,
As the cylinder 7 descends, the shock absorber 6 is positioned below the transport rail 4. In this case, since the shock absorber 6 does not come into contact with the carrier 6, the carrier 1 moves along the carrier rail 4, and is driven and stopped by the linear motor 3.

Here, if a failure such as a power outage occurs, the linear motor 3
The drive and stop of the transport vehicle 1 cannot be controlled by the power supply 1, and the power supply 9 of the mechanism unit 5 is temporarily cut off, and the power supply to the solenoid valve 8 is cut off. The shock absorber 6 is positioned on the front side and the rear side of the carriage l on the carriage rail 4. Then, the transport vehicle 1, which moves while floating on the transport rail 4 due to inertia, is prevented from advancing by the shock absorber 6 located on the downstream side in the transport direction, and the front surface of the transport vehicle 1 collides with the shock absorber 6. As a result, it stops on the transport rail 4.

[Problem to be solved by the invention]

However, in such a conventional magnetic levitation transport device, if a failure such as a power outage occurs, the transport vehicle 1 collides with the shock absorber 6 and is stopped within the station 10. At the moment when the cart 1 collides with the shock absorber 6 to stop the cart 1, a large impact is applied to the transport cart 1, resulting in damage to the transported object. Furthermore, if the shock absorber 6 on the downstream side in the transport direction cannot sufficiently absorb the impact of a collision and cannot stop the transport vehicle 1,
This transport vehicle 1 was thrown in the opposite direction by the reaction of the collision,
This causes vibration between the shock absorbers 6, and the impact applied to the transport vehicle 1 becomes even greater. That is, in the method of forcibly stopping the transport vehicle 1 by colliding with an obstacle, the impact applied to the transport vehicle l becomes large.
There is a problem in that wafers and masks may be damaged during transportation.

Furthermore, if a failure such as a power outage occurs in the transport vehicle 1 directly above the shock absorber 6, the transport vehicle 1 will be pushed up from below by the cylinder 7, resulting in damage to the transport vehicle 1 itself. Ta.

Therefore, an object of the present invention is to provide a magnetic levitation transport device that can quickly stop the transport vehicle without impacting it even if a failure occurs, such as a power outage, during the transport of the transport vehicle. The purpose is

[Means to solve the problem]

In order to achieve the above objectives, the magnetic levitation transport device according to the present invention has the following features:
A transport vehicle that levitates above a transport rail and moves along the transport rail by electromagnetic force generated by a magnetic levitation coil, and a drive that is installed at a station on the transport route and controls the drive and stop of the transport vehicle using electromagnetic force. A magnetic levitation transport device comprising a control means, a displacement means for detecting the state of power supply to the drive control means and displacing a predetermined movable part when the supply state is abnormal; displacement detecting means that is attached and detects displacement of the movable part in a non-contact state; and magnetic levitation stopping means that stops energizing the magnetic levitation coil when the displacement of the movable part is detected by the displacement detecting means. and a braking means for braking the movement of the transport vehicle when power supply to the magnetic levitation coil is stopped.

[Effect]

In the present invention, for example, when a failure such as a power outage occurs, the movable part of the displacement means is displaced, and the displacement of this movable part is detected by the displacement detection means of the transport vehicle in a non-contact state with respect to the movable part. When the displacement of the movable part is detected by the displacement detection means,
The magnetic levitation stopping means stops energizing the magnetic levitation coil, and the movement of the conveyance vehicle is braked by the braking means.

Therefore, even if the transport vehicle is in the middle of transport when a failure such as a power outage occurs, it is possible to quickly stop the transport vehicle without applying a shock to the transport vehicle.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

FIGS. 1 to 4(a) and 4(b) are diagrams showing a first embodiment of a magnetic levitation conveyance device according to the present invention.

First, the configuration will be explained based on FIGS. 1 to 3.

FIG. 1 is a plan view showing the main parts of this embodiment, FIG. 2 is a sectional view showing the main parts of this embodiment, and FIG. 3 is a configuration diagram showing the main parts of this embodiment. In these figures 1 to 3, l
1 is a transport vehicle, 2 is a tray provided on the transport vehicle L, and 3 is a tray provided on the transport vehicle L.
1 is a linear motor as a drive control means for driving and stopping the transport vehicle 1; 4 is a transport rail having a rectangular cross section; 5 is a mechanical unit as a movable displacement means; 7 is expandable and retractable in the directions of arrows Xi and X2 in the figure. 8 is a solenoid valve that controls the expansion and contraction operation of the cylinder 7, and 9 is a power source that supplies power to the solenoid valve 8, and this power source 9 uses a commercial power source. 10 is a station, which includes a carriage 1, a tray 2, a linear motor 3, a conveyance rail 4, a cylinder 7,
The solenoid valve 8 and the power source 9 have substantially the same configuration as the conventional example. Reference numeral 11 denotes a light shielding plate as a movable part that blocks light, and is movable in the horizontal direction while being fixed to the tip of the cylinder 7. Reference numeral 12 denotes a support column that fixes and supports the cylinder 7 in the horizontal direction, and includes the cylinder 7, the solenoid valve 8, the power source 9, the light shielding plate 11. The support column 12 constitutes a mechanism unit 5. Reference numeral 13 denotes a photosensor as a displacement detecting means, which has a roughly U-shaped cross section and is provided on the side surface of the transport vehicle l.As shown in FIG. , a constant current circuit 16 that supplies current to the light emitting eye 4
, an amplifier 17 that amplifies the output of the phototransistor 15.
It consists of

18 is a launch circuit that detects the output from the phototransistor 15 that has been amplified by the amplifier 17 and temporarily holds the state; 19 is a launch circuit that constantly reads the contents of the latch circuit 18 and is used to levitate the transport vehicle 1; A magnetic levitation control circuit 21 controls the stopping of electricity to the magnetic levitation coil 20, and 21 is a battery built into the transport vehicle l.
, and supplies power to the magnetic levitation control circuit 19, respectively. The launch circuit 18, magnetic levitation control circuit 19, magnetic levitation coil 20, and battery 21 constitute a magnetic levitation stop means 22. Reference numeral 23 denotes a wheel as a braking means, and the wheel 23 is made of urethane rubber having high viscosity and is designed to generate high resistance between it and the conveyor rail 4.

Next, the effect will be explained.

First, normally, when the linear motor 3 and the mechanism unit 5 are in a energized state, as shown in FIG. 8, cylinder 7 is indicated by arrow X2 in the figure.
shrink in the direction. When the cylinder 7 contracts, the light shielding plate 11 fixed to the tip of the cylinder 7 is
The photo sensor 13 is located opposite to the photo sensor 13 provided on the side surface of the photo sensor 13. That is, a constant current circuit 16 supplied with power from the battery 21 causes current to flow through the light emitting diode 14, and the light emitting diode 14 emits light.

The light emitted from the light emitting diode 14 is received by the phototransistor 15, and a current corresponding to the amount of the received light is caused to flow through the phototransistor 15, so that the photosensor 13 is turned on. The current passed by the phototransistor 15 is amplified by the amplifier 17 and held in the launch circuit 18 as an "H" signal. The content held in the latch circuit 18 is always read by the magnetic levitation control circuit 19, and when the photosensor 13 is in the on state, the content of the launch circuit 18 is "H", so a failure such as a power outage may occur. It is determined that this has not occurred, and the magnetic levitation coil 20 is energized. That is,
The transport vehicle l is positioned in a floating state on the transport rail 4,
The transport vehicle 1 moves along transport rails 4, and is driven and stopped by a linear motor 3.

Here, if a failure such as a power outage occurs, the power supplied to the solenoid valve 8 from the power supply 9 of the mechanical unit 5 is cut off, as shown in FIG. In the off state, the cylinder 7 displaces the light shielding plate 11 fixed to the tip of the cylinder 7 in the direction of the arrow X2 in the figure, and the light shielding plate 11 displaces the photosensor 13 provided on the side surface of the transport vehicle 1. It is located in the groove part in a non-contact state. When the light shielding plate 11 is located in the groove of the photosensor 13,
The light from the light emitting diode 14 emitted by the constant current circuit 16 supplied with power from the battery 21 is blocked by the light shielding plate 11, and the current flowing through the phototransistor 15 when the light is received becomes almost zero, and the photo The sensor 13 is turned off. That is, the current passed by the phototransistor 15 is held as an "L" signal in the latch circuit 18 via the amplifier 17. When the signal held in the launch circuit 18 becomes "L",
The contents of the launch circuit 18 (
In this case, 'L'') is read and it is determined that a failure such as a power outage has occurred, and the magnetic levitation control circuit 19
The current flowing through the magnetic levitation coil 20 is stopped.

When the current flowing through the magnetic levitation coil 20 is stopped, the carrier 1 descends onto the carrier rail 4, and the wheels 23 provided on the carrier 1 land on the carrier rail 4. The wheels 23 are made of highly viscous urethane rubber, which reduces the shock caused when the transport vehicle 1 lands on the transport rail 4, and also because high resistance is generated between the wheels 23 and the transport rail 4. , the shutdown will occur immediately.

Therefore, the transport vehicle 1 does not collide with an obstacle and is forced to stop, so no large impact is applied to the transport vehicle 1, and damage to wafers, masks, etc. during transportation can be prevented. .

Further, since the light shielding plate 11 does not directly touch the transport vehicle 1, the transport vehicle 1 itself will not be damaged.

Next, a second embodiment of the present invention is shown in FIGS. 5 and 6, and its structure will be explained.

In FIG. 5, the same numbers as in the first embodiment shown in FIG. 3 indicate the same or corresponding parts.

In this embodiment, the solenoid valve 8 is connected to the power source 9 that supplies power to the solenoid valve 8 via a relay 31, and this relay 31 is connected to the gate of a transistor 33 by a station control circuit 32. The on/off operation is controlled by applying a potential level of "H" or "L". As shown in FIG. 6, each station IOA, IOB, and
Mechanisms 5a and 5b are arranged on the upstream and downstream sides of the IOC in the transport direction, respectively.

In the above configuration, normally, when a failure such as an overrun occurs in the stop station at a predetermined station 1011 where the transport vehicle 1 is to be stopped while the linear motor 3 and the mechanism unit 5 are energized, the station IOB is immediately stopped. A control signal is output from the control circuit 32 to the transistor 33, and the sushi□-31 is turned off, and the same process as in the case of a failure such as a power outage in the first embodiment is performed, and the transport vehicle 1 stops. That is, the near motor 3 is
Even if the stop control of the transport vehicle I is not successful and an overrun occurs, the transport vehicle I will stop immediately.

Therefore, braking can be forcibly performed to prevent the transport vehicle 1 from being transported beyond the station IO where it should be stopped due to an overrun caused by a stop error of the transport vehicle 1.

Although the first and second embodiments use the solenoid valve 8 to control the cylinder 7, the cylinder 7 is not limited to the solenoid valve; for example, the cylinder 7 may be controlled by a solenoid to displace the light shielding plate 11. I do not care.

Further, it goes without saying that the material for forming the wheels 23 as braking means can be freely selected depending on the purpose.

[Effects of the Invention] According to the present invention, even if a failure such as a power outage occurs while the transport vehicle is being transported, the transport vehicle can be stopped quickly without giving any impact to the transport vehicle.

Therefore, high safety can be ensured, and articles can be transported reliably and with high reliability.

[Brief explanation of drawings]

1 to 4 are views showing a first embodiment of the magnetic levitation system according to the present invention, FIG. 1 is a plan view showing the main parts thereof, FIG. 2 is a sectional view showing the main parts thereof, and FIG. FIG. 3 is a configuration diagram showing the main parts thereof, FIG. 4 is a plan view for explaining its operation, and FIGS. 5 and 6 are diagrams showing a second embodiment of the magnetic levitation conveyance device according to the present invention. FIG. 5 is a configuration diagram showing the main parts thereof, FIG. 6 is a side view for explaining its operation, and FIG. 7 is a sectional view showing the main parts of the conventional example. 1... Transport vehicle, 2... Tray 3... Linear motor (!S [motion control means)] 4.
...Transportation rail, 5... Mechanism unit (displacement means), 7...
... Cylinder, 8 ... Solenoid valve, 9 ... Power supply, 10 ... Station, 11 ... - Light shielding plate (movable part), 12 ... ...Support column, 13... Photo sensor (displacement detection means) 14.
-...Light-emitting diode, 15...Phototransistor, 16...
・Constant current circuit, 17...Amplifier, 18...Launch circuit, 19...Magnetic levitation control circuit, 20...Magnetic levitation coil, 21... ... Battery, 22 ... Magnetic levitation stop means, 23 ... Wheels (braking means). A plan view for explaining the operation of the first embodiment.

Claims (1)

[Claims] A transport carriage (1) that levitates above a transport rail (4) by electromagnetic force generated in a magnetic levitation coil (20) and moves along the transport rail (4), and a station on the transport route. (10), and is installed on the transport trolley (1) by electromagnetic force.
A magnetic levitation transport device comprising: a drive control means (3) for controlling driving and stopping of the drive control means (3);
a displacement means (5) for displacing a predetermined movable part (11) when the supply state is abnormal;
) Displacement detection means (13) for detecting the displacement of ) in a non-contact state
and magnetic levitation stop means (22) that stops energizing the magnetic levitation coil (20) when the displacement of the movable part (11) is detected by the displacement detection means (13); (20) A magnetic levitation conveyance device, comprising: a braking means (23) that brakes the movement of the conveyance vehicle (1) when power to the conveyance vehicle (1) is stopped.