JPH0479702A - Carrier - Google Patents

Abstract

PURPOSE:To stop a truck at a target position in short time by providing the truck, for carrying an object while being levitated magnetically from fixed part, with stopping means for generating magnetic force reversely from the moving direction in order to brake the truck. CONSTITUTION:A carrier 1 comprises a truck 3 for carrying an object mounted on a mounting table 14. The truck 3 is bent in C-shape at the opposite ends in order to wrap a rail 13 constituting a T-type fixed part 2 at the opposite sides thereof. A linear motor 11 and salient poles 12a, 12b are disposed, respectively, on the top and rear faces of the rail 13. The truck 3 is provided with guide magnets 15a, 15b at the opposite insides and levitation electromagnets 16a, 16b comprising U-shaped cores 17a, 17b applied with coils 18a, 18b at the end thereof. Stop position of the truck is determined by a slit board 22 on the truck 3 and an encoder 23 arranged at the fixed side. Permanent magnets 20a, 20b on the truck side and an electromagnet 21 on the fixed side produce magnetic force in the direction reverse from the traveling direction of the truck. According to the constitution, the truck 3 can be stopped at a predetermined position in a short time.

Description

[Detailed Description of the Invention] [Summary] Regarding a conveyance device that moves a cart to a predetermined position by magnetic levitation, the purpose is to stop the cart at a target position in a short time. In the conveying device which levitates and moves from a fixed part, the moving trolley is configured to be provided with a stopping means that generates a magnetic force in a direction opposite to the moving direction to brake the moving trolley.

Further, the stopping means is provided with a pair of magnetic poles on the cart and the fixed part side, and drives one of the magnetic poles, or controls the generation of magnetic force of the one magnetic pole by the control means according to the position of the cart by position detection. Then, the cart is stopped at a predetermined position.

[Industrial application field]

The present invention relates to a transport device that moves a cart to a predetermined position using magnetic levitation.

In recent years, as LSIs have become more highly integrated, LSI manufacturing factories are required to have a higher degree of cleanliness, and dust-free transport devices are required for transporting wafers and the like. For this reason, it is necessary to provide a transport device using a linear motor as a drive source, or to stop the transport vehicle without contact in order to prevent generation of dust.

[Conventional technology]

FIG. 5 shows a partial schematic diagram of a conveyance device using a conventional linear motor as a drive source. FIG. 5(A) shows a case where the cart side is in an unstable position, and FIG. 5(B) shows a case where the cart side is in a stable position.

In FIGS. 5(A) and 5(B), the conveyance device is composed of a magnetic body 50 having a U-shaped cross section at the lower part (truck side) of a trolley on which an object is placed and transported. A coil 52 is wound around a plurality of protrusions of a U-shaped core 51 fixed on the side. Then, the magnetic body 50 on the cart side is magnetically levitated by an electromagnet constituted by a core 51 and a coil 52, and moves in the vertical direction on the drawing (paper surface).

Generally, the magnetic flux generated by the electromagnet is stabilized at the shortest position relative to the magnetic body 50, so the trolley is as shown in FIG. 5(A).
In FIG. 5(B), it is in an unstable position, and in FIG. 5(B), it is in a stable position. Therefore, when stopping the cart at the target position, the magnetic body 5 is placed at a stable position as shown in FIG.
It was stopped by the electromagnetic attraction force between 0 and the electromagnet.

However, when stopping the truck, the restraining force against the traveling direction of the truck is weak, so a spring system is configured around the stop position to assist in braking.

[Invention or problem to be solved]

However, the spring system described above is slow at damping vibrations, and it takes time for the vibrations to converge and for the truck to come to a complete stop. In other words, even if the cart is transported at high speed to near the stop position, it vibrates near the stop position, making it impossible to take out the transported object from the cart, resulting in the problem that it takes a long time to transport as a whole. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a transport device that can stop a cart at a target position in a short time.

[Means to solve the problem]

The above-mentioned problem is solved in a conveying device in which a cart carrying an object to be transported is levitated from a fixed part by magnetic force and moved, and the moving cart is stopped by generating a magnetic force in a direction opposite to the moving direction. This can be solved by providing a means.

Further, the stopping means is provided with a pair of magnetic poles on the cart and the fixed part side, and drives one of the magnetic poles, or controls the generation of magnetic force of the one magnetic pole by the control means according to the position of the cart by position detection. and stops the truck at a predetermined position.

[Effect]

As mentioned above, a stopping means is provided, and this stopping means is composed of a pair of magnetic poles, and when one of the magnetic poles is driven, a magnetic force is generated in a direction opposite to the moving direction of the truck, thereby braking the truck. As a result, compared to a spring system, vibrations in the traveling direction near the target stop position are damped more quickly, making it possible to stop the truck at the target position in a short time.

Further, the one magnetic pole is controlled by the position detecting means according to the position of the truck. That is, when the truck deviates from the target stop, one of the magnetic poles is controlled according to the amount of displacement of the truck from the stop position.

This makes it possible to quickly damp the vibrations of the truck and position and stop it in a short time.

〔Example〕

FIG. 1 shows a longitudinal sectional view of an embodiment of the present invention.

The conveying device l shown in FIG. 1 includes a fixed part 21, a cart 3. Stopping means 4
and position detection means 5.

The fixed part 2 is made up of a linear motor 11, and has a plurality of protrusions 12a, 12b or a rail 13 integrally provided below the left and right upper parts of the "T" shape.

The trolley 3 is provided with a mounting table 14 on the upper surface on which an object to be transported is placed, and a linear motor 11. It is formed into a curved shape so as to cover the rail 13. Inside this truck 3, guiding magnets 15a are placed close to both ends of the rail 13.
15b is provided. The guiding magnets 15a and 15b are electromagnets having a coil wound around a core, and prevent lateral vibration when the cart 3 moves. Furthermore, levitation magnets 16a and 16b are provided at the inner end of the truck 3. These levitation magnets 16a, 16b have U-shaped cores 17a, 1.
Coils 18a and 18b are wound around core 1
Tips of 7a, 17b and protrusions 12a, 12b of rail 13
are facing each other. That is, the rail 13 and the levitation magnet 16a
, 16b acts to levitate the cart 3 and move the cart 3 in a direction perpendicular to the plane of FIG. Further, the trolley 3 is provided with the guide magnets 15a, 15b and the levitation magnet 16a.

A battery 19 is also provided to drive the components 16b and the like.

The stopping means 4 has a pair of magnetic poles formed by permanent magnets 20a and 20b and an electromagnet 21 having a coil 21b wound around a core 21a (horizontal to the plane of the paper). In this case, the electromagnet 21, which is one magnetic pole, is provided on the fixed part 2 side, and the permanent magnet 20a, which is the other magnetic pole.

20b is provided on the trolley 3. Note that the permanent magnet 20a,
The arrangement of the electromagnet 20b and the electromagnet 21 may be reversed. Here, in the electromagnet 21, the coil 21b is wound horizontally on the paper as described above, and when electromagnetic power is supplied to the coil 21b, an electromagnetic force is generated perpendicular to the paper, and the electromagnetic force is generated depending on the polarity of the current. can change the front direction or the depth direction.

The position detection means 5 is a slit plate 22 provided on the trolley 3.
and an encoder 23 provided on the fixed part 2 side. Here, FIG. 2 shows a partial perspective view of this position detection means 5. The slit plate 22 has slits 22 at predetermined intervals.
A is formed, and this slit plate 22 is sandwiched between the encoder 23 and the slit plate 22.

The encoder 23 is composed of a light emitting part and a light receiving part (not shown), and the number of pulses that detect the slit 22a is used to control the trolley 3.
Detect the position of.

Here, the electromagnet 21 of the stopping means 4 and the encoder 23 of the position detecting means 5 are provided at the target stopping position of the truck 3.

In the transport device 1 as described above, first, the trolley 3 is floated by attracting the rail 3 of the fixed part 2 by magnetic force using the floating magnets 16a and 16b. Then, the trolley 3 moves along the rail, and the permanent magnets 20 a, 20 b of the stopping means 4
A current is supplied to the coil 21b of the electromagnet 21 with a polarity such that a magnetic force is generated in the direction opposite to the moving direction of the truck 3 when the electromagnet 21 is located at the electromagnet 21. As a result, braking force is applied to the truck 3, and the position detection means 5 and control means (to be described later)
(see FIG. 4) to stop the truck 3 at the target stop position in a short time.

Here, FIG. 3 shows a diagram for explaining the above-mentioned operating principle, and will be explained. In FIG. 3, permanent magnets 20a, 20
An electromagnet 21 having a coil 21b wound around a core 21a is arranged between the N poles of the magnet 21b. In this case, when a current I (A) is passed through the coil 21b in the direction of the arrow, an electromagnetic force F is generated in an upward direction according to Fleming's left hand rule. The magnitude of the electromagnetic force F (N) in this case is as follows: The magnetic field acting on the coil 21b is B[T], the width of the core 21a is f(m), and the coil 21
When the number of turns of b is N (turn), it is expressed by the following formula (1). In this case, when the current I flows in the opposite direction, an electromagnetic force is generated in the downward direction.

Next, FIG. 4 shows a configuration diagram of a control means for controlling the stop means. FIG. 4(A) is a control loop of the control means, and FIG. 4(B) is a block diagram of the control means.

When the trolley 3 reaches near the target stop position, the control means 6 controls the
As shown in FIG. 4(A), the electromagnetic force F, which is the braking force, is controlled by feeding back the output from the position detection means 5 and controlling the current (or voltage) applied to the coil 21b. .

This control means 6 includes a CPU, as shown in FIG. 4(B).
(Central processing unit) 30. 'It is composed of a D/A converter 31, a servo amplifier 32, and a counter 33. Fourth
In Figure (B), the number of pulses of the encoder 23 is input to the CPU 30 via the counter 33, and the displacement, speed, acceleration, etc. of the truck 3 from the stop position are read out to the CPU 30. Then, the CPU 30 calculates the amount of current (voltage) to be applied to the coil 21b, and the command amount is applied to the D/A converter 3.
1 is converted into an analog signal and supplied to the coil 21b via the servo amplifier 32 to control the force (electromagnetic force F) that drives the truck 3. That is, the force F is strong when the cart 3 is displaced largely from the stop position, and becomes weaker as it approaches the stop position. Also, for example, if the truck 3 goes too far from the target stop position, the direction of the force F is controlled in the opposite direction by reversing the polarity of the current (voltage) supplied to the coil 21b depending on the direction of displacement. be. This makes it possible to position the cart 3 in a short time.

〔Effect of the invention〕

As described above, according to the present invention, the stopping means generates a magnetic force in the opposite direction to the moving direction of the cart, and the position detecting means controls the coil that generates the magnetic force at the position of the cart, thereby achieving a target stop. It is possible to attenuate vibrations in the traveling direction near the position, stop the cart at the target position in a short time, and position the cart in a short time.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a partial perspective view showing the position detection means, Fig. 3 is a diagram for explaining the operating principle of the stop means, and Fig. 4 is FIG. 5 is a block diagram showing a control means, and is a partial conceptual diagram of a conventional conveyance device. In the figure, l is a transport device, 2 is a fixed part, 3 is a trolley, 4 is a stopping means, 5 is a position detection means, 6 is a control means, 16a, 16b are levitation magnets, 20a, 20b are permanent magnets, 21 is a 21a is a core, 21b is a coil, 22 is a slit plate, and 23 is an encoder. Andei Wholesale Japanese Fire (A) (B) Control order dead 1 loading diagram Figure 4 (A) (B) Handling solicitation 1st position diagram

Claims (3)

[Claims] (1) In a conveyance device that levitates and moves a cart (3) on which an object is placed on a fixed part (2) by magnetic force, the cart (3) to be moved is moved in a direction opposite to the moving direction. A conveying device characterized by being provided with a stopping means (4) that generates magnetic force and performs braking. (2) The stopping means (4) includes a pair of magnetic poles (20a, 20
b, 21), each of which is connected to the trolley (3) and the fixed part (2).
2. The conveying device according to claim 1, wherein the magnetic force for braking is generated by driving the one magnetic pole (21). (3) A position detecting means (5) is provided for detecting the position of the moving cart (3), and one of the magnets (21) is moved according to the position of the cart (3) from the position detecting means (5). 3. The conveying device according to claim 2, further comprising a control means (6) for controlling generation of magnetic force to stop the trolley (3) at a predetermined position.