JPH0669852B2 - Floating carrier - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a levitation type conveyance device for conveying small articles,
In particular, the present invention relates to a levitation type transfer device capable of achieving stable control of a magnetic levitation system.

[Technical background of the invention and its problems]

In recent years, as a part of office automation and factory automation, slips, documents, cash, materials and the like have been moved between a plurality of points in a building using a carrier device.

The conveying device used for such an application should not damage the environment of the office, and is required to have low noise without generation of dust or the like. For this reason, this type of transport device is configured to support the transport vehicle in a non-contact manner with respect to the guide rail. In order to support the carrier without contact, it is common to use air or magnetism. Among them, the method of magnetically supporting the carrier is excellent in following the guide rails and reducing noise. And is considered the most promising support system.

The transfer device according to this method includes a guide rail formed of a ferromagnetic material, a transfer vehicle movably arranged along the guide rail, and a magnetic attraction between the guide rail mounted on the transfer vehicle and the guide rail. A plurality of magnetic support units that magnetically levitate the carrier vehicle by a force, a gap sensor that detects a gap length between the magnetic support unit and the guide rail, and a magnetic support unit of the magnetic support unit based on an output of the gap sensor. The control device controls the magnetomotive force. As the gap sensor, there is used an optical gap sensor which is small and inexpensive, and which is not affected by magnetic effects and has good detection accuracy.

By the way, in the levitation type conveying apparatus using such a magnetic support system, the present applicant previously proposed a magnetic support unit using a permanent magnet. According to this device, most of the magnetomotive force required to levitate the carrier can be obtained by the magnetomotive force of the permanent magnet, so that the exciting current of the electromagnet can be reduced and energy saving can be achieved.

However, the levitation type transport device configured as described above has the following problems. That is, since the magnetomotive force of the electromagnet is controlled when the device is started,
Although a predetermined gap length is maintained between the magnetic support unit and the lower surface of the guide rail, the guide rail and the magnetic support unit may be attracted by the magnetic force of the permanent magnet when the device is at rest or during a power failure, for example. When both are sucked in this way, a large number of scratches will be formed on the lower surface of the guide rail due to the shock during suction. For this reason, the light emitted from the optical gap sensor is irregularly reflected at the scratched portion, and the amount of light received by the sensor decreases, which causes the output of the sensor to fluctuate and the transportation vehicle to vibrate. It was one of the causes that made the system unstable. Also, when dirt or rust is scattered on the lower surface of the guide rail, the same problem occurs.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a levitation type conveyance device that uses a permanent magnet as a magnetic support unit and an optical gap sensor as a gearup sensor, and It is to enable stable magnetic support control of the.

[Outline of Invention]

The present invention is formed of a ferromagnetic material, a guide rail having a surface extending in the longitudinal direction, a carrier arranged so as to be free to travel along the guide rail, and a plurality of carriers mounted on the carrier,
A magnetic support including electromagnets arranged so as to face the guide rails via a gap, and interposing a magnetic circuit constituted by the electromagnets, the guide rails and the gap to float the transport vehicle. The unit and the guide rail are fixed to the carrier so as to face the extended surface, transmit light to the extended surface, and receive reflected light from the extended surface. An optical gap sensor that measures a gap length between a support unit and the guide rail, and a levitation-type transfer device that includes a control device that controls an exciting current flowing through the electromagnet based on an output of the optical gap sensor, It is characterized in that the extended surface of the guide rail is subjected to a surface treatment for promoting diffuse reflection of light.

〔The invention's effect〕

According to the present invention, since the lower surface of the guide rail is a light-colored diffuse reflection surface, even when scratches, dirt, rust, etc. are scattered, or even when scratched by adsorption of the magnetic support unit, It has little effect on the intensity of reflected light. That is, since the reflected light does not fluctuate due to the presence of scratches or the like, it is possible to stabilize the magnetic support control system and suppress vibration of the transport vehicle.

Example of Invention

Hereinafter, a levitation type conveyance device according to an embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, 1 is a guide rail in which at least the lower surface (extended surface) is made of a ferromagnetic material. On this guide rail 1, the transport vehicle 2 is traveling freely arranged along the guide rail 1. A magnetic support device 3 is mounted on the lower portion of the carrier vehicle 2 . Further, a stator 6 of a linear induction motor 5 is arranged at a predetermined interval on a base portion 4 along the guide rail 1 .

The guide rail 1 is constructed by laying angle-shaped members 11a and 11b in parallel and adhering a white vinyl tape 12 to the lower surfaces of the angle-shaped members 11a and 11b.
The vinyl tape 12 is, for example, subjected to a matting treatment so as to promote irregular reflection on the surface.

The carrier 2 includes a plate-shaped base 13, a flat container 14 placed on the base 13 for facilitating the transfer of an object such as a document, and four lower corners of the base 13. It is composed of four wheels 15 that are attached and support the base 13 in an emergency.

Further, the magnetic support device 3 is arranged at a right angle to the base 13 and a support plate 21 facing the lower surface of the base 13 via the guide rail 1 , and connects the base 13 and the support plate 21. Connecting plate
22, four magnetic support units 23 fixed to the four corners of the support plate 21 so as to face the lower surface of the guide rail 1 , and the magnetic support units 23 and the guide rail 1 fixed to the magnetic support units 23 , respectively. An optical gap sensor 24 for detecting a gap length between the base plate 13, a control device 25 mounted at a central position of the support plate 21, and a power source 26 fixed to a lower surface of the base 13.

As shown in FIG. 3, the magnetic support unit 23 is wound around the two yokes 31 and 32 whose upper end faces oppose the lower surface of the guide rail 1 with a predetermined gap P and the yokes 31 and 32. It is composed of two electromagnets 35, 36 composed of the excited coils 33, 34 and a permanent magnet 37 interposed between the lower side surfaces of the yokes 31, 32, and has a U-shape as a whole. The exciting coils 33 and 34 are connected in series in such a direction that magnetic fluxes formed by the electromagnets 35 and 36 are added to each other.

The optical gap sensor 24 is fixed to the magnetic support unit 23 via a support member 38. This optical gap sensor
A reflection type photocoupler is used for 24 as shown in FIG. 4, for example. The reflection type photocoupler is emitted from the light emitting element 41 toward the vinyl tape 12 on the lower surface of the guide rail 1 and the vinyl tape 12 is used.
The light reflected by is detected by the light receiving element 42, and the gap length is detected by the intensity of the reflected light.

Further, the control device 25 sends a light emission signal to the fixed resistor 43, which is an exciting current detection means connected in series with the exciting coils 33 and 34, and the optical gap sensor 24, and also receives a light receiving signal from the optical gap sensor 24. A modulator 44 for modulating, an arithmetic circuit 45 for arithmetically operating the value of the current flowing through the exciting coils 33, 34 based on the signal from the modulator 44 and the signal due to the voltage drop of the fixed resistor 43, and from this arithmetic circuit 45 Amplifier 46 for supplying power to the exciting coils 33, 34 based on the signal of
It consists of and.

The support plate 21 that supports these magnetic support units 23
Serves as a conductor plate that is a movable element of the linear induction motor 5 , and the stator 6 is used when the apparatus is in operation.
And are located at opposite heights through a slight gap.

Next, the operation of the levitation type transporting apparatus according to this embodiment configured as described above will be described.

When the device is stopped, the guide rail 1
The magnetic support unit 23 is attracted to the guide rail 1 by the contact between the two or the magnetic attraction force of the permanent magnet 37. When the device is started in this state, the control device 25
Is a magnetizing coil for generating a magnetic flux in the electromagnets 35, 36 in the same direction or in the opposite direction as the magnetic flux generated by the permanent magnet 37 and maintaining a gap P of a predetermined length between the magnetic support unit 23 and the guide rail 1. Controls the current flowing through 33 and 34. As a result, as shown by the dotted line in FIG. 3, the permanent magnet 37-the yoke 31-the void P-the vinyl tape 12-the angled member 11a (11b) -the vinyl tape 12-the void P-the yoke 32-the permanent magnet 37. The magnetic circuit is formed by the path of. The gap length is set such that the weight of the supported plate such as the transport vehicle 2 and the magnetic attraction force between the magnetic support unit 23 and the guide rail 1 due to the magnetomotive force of the permanent magnet 37 are just balanced. That is, zero power control is performed.

Now, assuming that the carrier 2 is on the stator 6 of the linear induction motor 5 , when the stator 6 is biased, the support plate 21 receives an electromagnetic force from the stator 6, so that the carrier 2 is in a magnetic levitation state. Start traveling along the guide rail 1 as it is. Carrier 2
If the stator 6 is disposed again until the vehicle completely stops due to the influence of air resistance or the like, the carrier vehicle 2 is urged again and continues to move along the guide rail 1 . This movement continues to the desired point. Thus, the transport vehicle 2 can be moved to the destination point in a non-contact state.

By the way, in the process of movement of the carrier 2 , the optical gap sensor
24 constantly irradiates the guide rail 1 with light and receives the reflected light to detect the distance between the magnetic support unit 23 and the guide rail 1 . Therefore, if scratches, dirt, etc. are present on the reflecting surface, the amount of light received by the optical gap sensor 24 decreases and the electromagnets 35, 36 are urged more than necessary, and the transport vehicle 2
May vibrate or the guide rail 1 and the magnetic support unit 23 may be attracted. When such a problem occurs, not only the stabilization of the control system is impaired, but also the power is wasted.

However, in this embodiment, since the reflecting surface is formed by the vinyl tape 12, the reflected light is diffusely reflected. Therefore, the amount of light received by the optical gap sensor does not fluctuate significantly even if there are some scratches or dirt on the reflecting surface. Moreover, since the irregularly reflected light is received, it is possible to increase the change in the gap length versus the received light amount at the position where the optical gap sensor 24 and the detection target are close to each other, and the detection accuracy is also improved.

Further, according to the present embodiment, when the magnetic support unit 23 and the guide rail 1 are attracted to each other, the non-magnetic vinyl tape 12 is present in the magnetic circuit, which increases the magnetic resistance of the magnetic circuit. The electromagnets 35, 36 for separating the attracted magnetic support unit 23 and the guide rail 1 from each other
Can be made smaller than the exciting current when the vinyl tape 12 is not provided. Therefore, the magnetic support device
A small-sized battery having a small capacity can be used as the power supply 26 incorporated in the device 3, which can contribute to downsizing and cost reduction of the device.

The present invention is not limited to the above embodiment. For example, in the above embodiment, white vinyl tape was used as the light-colored diffuse reflection surface on the lower surface of the guide rail, but this does not limit the color or material of the diffuse reflection surface at all, and for example, light-colored paper tape, paint, matte It may be obtained by plating, resin coating, or the like, or the metal surface may be directly formed into a matte surface by a chemical treatment. The point is that the lower surface of the guide rail may be formed so as to have a light-colored and irregular reflection surface. Especially vinyl tape, paper tape,
By forming a non-magnetic diffused reflection film such as a resin coating, it is possible to reduce the electric power required to separate the magnetic support unit and the guide rail that are attracted to each other as described above, and it is possible to save energy. It is also possible to prevent the occurrence of scratches.

Further, the present invention is not limited to an apparatus using a reflection type photocoupler as an optical gap sensor, for example, a sensor in which a light emitting element and a light receiving element are separately arranged, a sensor using an optical fiber, etc. It is also applicable to a device using. Furthermore, the present invention does not limit the number of magnetic support units, electromagnets, and permanent magnets or the method of configuring them.

As described above, the present invention can be implemented with various modifications without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a levitation type transporting apparatus according to an embodiment of the present invention, FIG. 2 is a front view of the apparatus, and FIG. 3 is a magnetic support unit and its peripheral portion in the apparatus. FIG. 4 is a sectional view showing the schematic configuration of a control device and its peripheral portion in the same device. 1 ... Guide rail, 2 ... Transport vehicle, 3 ... Magnetic support device, 4 ... Base, 5 ... Linear induction motor, 6 ... Stator, 11a, 11b ... Angle member, 12 ... Vinyl Tape, 13 ... Base, 14 ... Container, 15 ... Wheels, 21 ... Support plate, 22 ... Connecting plate, 23 ... Magnetic support unit, 24 ... Optical gap sensor, 25 ... Control device, 26 …… power supply, 31,3
2 …… yoke, 33,34 …… excitation coil, 35,36 …… electromagnet, 3
7 ... Permanent magnet, P ... Air gap.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-53-98616 (JP, A) JP-A-57-151807 (JP, A) Actually opened 51-76304 (JP, U) JP-B 57- 20185 (JP, B1) Japanese Patent Publication Sho 57-36187 (JP, B1)

Claims (7)

[Claims] 1. A guide rail which is made of a ferromagnetic material and has a surface extending in the longitudinal direction, a transport vehicle which is arranged so as to be able to travel along the guide rail, and a plurality of transport vehicles which are mounted on the transport vehicle. A magnetic support unit including an electromagnet arranged to face the guide rail via a gap, and interposing a magnetic circuit constituted by the electromagnet, the guide rail and the gap to levitate the transport vehicle. The magnetic support unit is fixed to the conveyance vehicle so as to face the extending surface of the guide rail, transmits light to the extending surface, receives reflected light from the extending surface, and receives the reflected light from the extending surface. And an optical gap sensor for measuring a gap length between the guide rail and the guide rail, and a controller for controlling an exciting current flowing through the electromagnet based on an output of the optical gap sensor, In floating type conveying apparatus wherein said extending surface of said guide rail, levitated conveyance apparatus, characterized in that it is subjected to surface treatment to promote the diffused reflection of light. 2. The levitation type conveyance device according to claim 1, wherein a non-magnetic diffuse reflection film is provided on the extending surface of the guide rail. 3. The levitating transfer device according to claim 2, wherein the irregular reflection film is a white vinyl tape or a paper tape. 4. The levitating transfer device according to claim 2, wherein the irregular reflection film is a white paint layer. 5. The levitation type conveying device according to claim 2, wherein the irregular reflection film is a resin coating layer. 6. The extension surface of the guide rail is plated with a matte coating.
Floating type carrier according to the item. 7. The levitation type conveying apparatus according to claim 1, wherein the extending surface of the guide rail is formed in a satin-like shape by a chemical treatment.