JP2760495B2 - Floating transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a levitation type transport device for transporting small articles, and particularly when a transport vehicle is taken in and out at an end of a transport path. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a levitation type transport device that facilitates work and reduces impact applied to a transport vehicle. (Prior Art) In recent years, as a part of office automation, moving slips, documents, cash, materials, and the like between a plurality of points in a building using a transport device has been widely performed. The transport device used for such an application is required to be able to move a transported object quickly and quietly. For this reason, in this type of transfer device, a transfer vehicle is supported on a guide rail in a non-contact manner. Among them, the method of magnetically supporting the carrier in a non-contact manner
It has the advantage of being excellent in followability to the guide rail, noise, and dust prevention effects. However, in the case where the carrier is supported by magnetic force, if all of the magnetic force is to be covered by the electromagnet, the electromagnet must be constantly energized, resulting in a large current consumption. Therefore, the present applicant has previously constituted a magnetic support unit with an electromagnet and a permanent magnet, and applied most of the magnetomotive force required by the electromagnet with the permanent magnet to reduce power consumption, so-called zero power feedback. Proposed a magnetic support device using a control method (Japanese Patent Application No. 59-222702)
issue). By the way, in such a magnetic support system, the transport path must have a structure that can support the transport vehicle even if it falls due to a failure of the control device or excessive external force applied to the transport vehicle. become. Therefore, the simplest method for taking the carrier in and out of the transport path for maintenance and inspection is to pull or push the transport vehicle from the end of the transport path along the traveling direction. However, in such a magnetic support method using a permanent magnet, the magnetic force of the permanent magnet always acts on the guide rail even when the magnetic support device is not operating. If the magnetic force causes the magnetic support unit to be attracted to the guide rail while the magnetic support device is stopped, the impact at that time not only damages the guide rail and the unit, but also damages the onboard control device. It could be.
In addition, since such a strong magnetic force acts on the guide rail due to such adsorption, an excessive force is required to separate the magnetic support unit from the guide rail. Will be severely damaged. For this reason, it is necessary for the carrier to take measures to prevent adsorption, such as wheels for preventing adsorption, proposed by the present applicant (Japanese Patent Application No. 60-65207). However, it is difficult to keep the transport vehicle parallel to the guide rails due to the above-described magnetic force when the transport vehicle is taken in and out at the edge of the transport path. Also, a situation may occur in which the guide rail ends and the magnetic support unit come into contact with each other during the operation and are attracted. For this reason, the work of taking in and out the carrier becomes extremely difficult. Further, if the magnetic support unit is directly attracted to the guide rail, undesirable situations such as generation of dust and noise may occur. (Problems to be Solved by the Invention) As described above, in the conventional floating type transport apparatus using both the permanent magnet and the electromagnet, the magnetic support unit is used when the transport vehicle is taken in and out from the edge of the transport path. It has to be prevented from directly adsorbing on the guide rails, which causes a problem that the work becomes extremely difficult. Therefore, the present invention provides a floating type transport device that prevents the magnetic support unit and the guide rail from being attracted to each other at the time of loading / unloading operation of the transport vehicle at the edge of the transport path, thereby preventing generation of dust and simplifying the loading / unloading operation. The purpose is to: [Structure of the Invention] (Means for Solving the Problems) In the present invention, a guide rail at the end of a transport path serving as an entrance of a transport vehicle is made of a non-magnetic material. That is, a transport path provided with a guide rail formed of a magnetic material, a transport vehicle arranged to be able to travel along the transport path, and a lower surface of the guide rail are arranged to face each other via a gap. A magnet mounted on the carrier, comprising: an electromagnet; and a permanent magnet interposed in a magnetic circuit formed by the electromagnet, the guide rail, and the air gap, and supplying a magnetomotive force necessary to levitate the carrier. A support unit, a sensor unit attached to the carrier for detecting a change in the size of the air gap in the magnetic circuit, and controlling a magnetomotive force of the magnetic support unit based on an output of the sensor unit; Zero power control means for controlling the exciting current flowing through the electromagnet so as to make the steady value of the exciting current flowing through the electromagnet of the unit zero, thereby stabilizing each magnetic circuit; and the guide An emergency guide arranged in parallel with the guide rail, and a wheel mounted on the carrier and holding a gap between the guide rail and the magnetic support unit at a predetermined length or more when the emergency guide is in contact with the emergency guide. And a non-magnetic member attached to the end of the guide rail at the end of the conveyance path, the end position of which in the traveling direction of the conveyance vehicle is substantially equal to the end position of the emergency guide. Features. (Operation) The operation of the magnetic support unit of the transport vehicle arriving at the end of the transport path serving as the entrance is stopped when the transport vehicle is pulled out from the entrance or the transport vehicle in which the operation of the unit is stopped is taken out of the entrance. If the guide rail near the door is made of a non-magnetic material when pushing it into the vehicle, the magnetic force due to the permanent magnet of the magnetic support unit mounted on the vehicle will not act on the guide rail near the door, so the carrier Can be pulled out and pushed in smoothly. (Embodiment) Hereinafter, a floating type transport apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an end of the transport path and a transport vehicle, and FIGS. 2 and 3 are a front view and a side view showing the transport vehicle in the transport path, respectively. 1 to 3, reference numeral 11 denotes a track frame whose section is formed in an inverted U-shape and which is laid, for example, in an office space so as to avoid obstacles. Two guide rails 12a and 12b are laid in parallel on the lower surface of the upper wall of the track frame 11, and emergency guides 13a and 13b having a U-shaped cross section are provided on the inner surface of the side wall of the track frame 11, respectively. It is laid with the open side facing. These track frame 11, guide rails 12a, 12
b, The emergency guides 13a and 13b form the transport path 1 as a whole. Under the guide rails 12a, 12b, a transport vehicle 15 is disposed so as to be able to travel along the guide rails 12a, 12b. In addition, the guide rail 12 is provided on the lower surface of the upper wall of the track frame 11.
A stator 16 of the linear induction motor is disposed at a predetermined distance along the guide rail in a portion between a and 12b. The guide rails 12a and 12b are formed by painting a flat member 21 made of a ferromagnetic material in white. Further, as shown in FIG. 1 , at the end of the transport path 1 , the guide rails 12a and 12b
The transport vehicle 15 is inserted into and out of the transport path 1 through the opening B. Next, the configuration of the transport vehicle 15 will be described. That is, the flat base 25 is arranged so as to face the lower surfaces of the guide rails 12a and 12b. The base 25 includes two divided plates 26a and 26b arranged in the traveling direction, and a freezing mechanism 27 that rotatably freezes the two divided plates 26a and 26b in a plane orthogonal to the traveling direction.
It is composed of At the four corners of the upper surface of this base 25 ,
A magnetic support unit 31 is mounted on each of the vertical wheels for preventing the unit 31 from directly contacting the lower surface of the guide rail 12a (12b) when the operation of the unit 31 is stopped or the like. 45a 'is attached. The magnetic support unit 31 includes a bolt 32 and a pedestal.
It is attached to the upper surface of the base 25 using 33. These magnetic support units 31, the optical gap sensor 34 for detecting the length of the gap between the lower surface of the unit 31 and the guide rails 12a, 12b is attached. In addition, each split plate 26a, 26
On the lower surface of b, containers 37 and 38 for accommodating the conveyed articles are attached via connecting members 35a, 35b, 36a and 36b, respectively. And in these containers 37 and 38, a control device 41 for controlling the four magnetic support units 31 respectively,
A constant voltage generator 42 and a small-capacity power supply 43 for supplying electric power thereto are mounted two each, that is, four in total. Magnetic support units are provided at the four corners of the lower surface of the base 25.
The emergency guides 13a, 13
b, four vertical wheels 45a for supporting the transport vehicle 15 by contacting the inner surface of the lower wall, and four vertical wheels 45a for supporting the transport vehicle 15 by contacting the inner surface of the side wall of the emergency guides 13a, 13b. And two horizontal wheels 45b. The base 25 also serves as a conductor plate which is an operating element of the above-described linear induction motor, and is arranged at a height opposed to the stator 16 with a slight gap during operation of the apparatus. I have. As shown in FIG. 4, the magnetic support unit 31 has two electromagnets 51 and 52 arranged in a direction perpendicular to the traveling direction of the carrier 15 so that the upper end faces the lower end of the guide rails 12a and 12b. And a permanent magnet 53 interposed between the lower side surfaces of the electromagnets 51 and 52 , and has a U-shape as a whole. Each of the electromagnets 51 and 52 includes a yoke 55 formed of a ferromagnetic material and a coil 56 wound around the yoke 55. Each coil 56 is formed by the electromagnets 51 and 52 . They are connected in series such that the magnetic fluxes are added to each other. The control device 41 is configured, for example, as shown in FIG. In this figure, arrows indicate signal paths and bar lines indicate power paths. The control device 41 includes a sensor 61 for detecting a change in motion of the magnetomotive force or magnetic resistance or transport vehicle 15 in the magnetic circuit formed by the magnetic support units 31 mounted on the transport vehicle 15, the sensor unit 61 And a power amplifier that supplies power to the coil 56 based on a signal from the arithmetic circuit 62.
63, which collectively control the four magnetic support units 41, respectively. The sensor unit 61 includes the optical gap sensor 34 described above to suppress the influence of external noise.
And a current detector 65 for detecting a current value of the coil 56. Arithmetic circuit
62, on the other hand, introduces the signal from the optical gap sensor 34 through the modulation circuit 64, subtracts the gap length set value Z ₀ by the subtractor 66, and directly or differentiates the output of the subtractor 66. The feedback signal from the current detector 65 to the feedback gain compensator 70, and the signal from the current detector 65 to the feedback gain compensator 70. 0, the signal compensated by the integration compensator 72, and the three feedback gain compensators 68 to 68
The addition output of the adder 73 of 70 is compared with the subtractor 74,
The deviation is output to the power amplifier 63. Further, the constant voltage generator 42 is interposed between the power supply 43 and the controller 41, and constantly supplies a current to the modulation circuit 64, the arithmetic circuit 62, and the optical gap sensor 34 at a constant voltage. The constant voltage generator 42 removes the influence of a voltage drop caused by a load change of the power supply 43 on the control device 41. The constant voltage generator 42 includes a reference voltage generator 75 and an output signal of the reference voltage generator 75. And a current amplifier 76 for supplying a current always required at a constant voltage to the control device 41. Next, the operation of the thus configured floating type transport apparatus according to the present embodiment will be described. If the equipment is in the stopped state, the emergency guides 13a, 13
The vertical wheels 45a or 45a 'of the transport vehicle 15 are in contact with either the inner surface of the lower wall of b or the lower surface of the guide rails 12a and 12b. When the device is started in this state, the control device
41 generates a magnetic flux in the same or opposite direction as the magnetic flux generated by the permanent magnet 53 in the electromagnets 51 and 52 , and maintains a predetermined gap length between the magnetic support unit 31 and the guide rails 12a and 12b. The current flowing through the exciting coil 56 is controlled. As a result, as shown in FIG.
A magnetic circuit is formed which includes a path from the yoke 55 to the gap P to the guide rail 2a, (2b) to the gap P to the yoke 55 to the permanent magnet 53. The gap length is set such that the weight of the supported body such as the transport vehicle 15 and the magnetic attraction between the magnetic support unit 31 and the guide rails 12a (12b) by the magnetomotive force of the permanent magnet 53 are exactly balanced. Is done. The control device 41 controls the exciting current of the electromagnets 51 and 52 to maintain the gap length. As a result, so-called zero power control is performed. Now, it is assumed that the carrier 15 that is magnetically levitating is directly below the stator 16 of the linear induction motor. When a three-phase AC voltage is applied to the three-phase winding applied to the stator 16, a moving magnetic field traveling in a specific direction is generated. As a result, an eddy current flows through the base 25 . As a result, the carrier 15 receives an electromagnetic force due to the interaction between the eddy current and the magnetic field, so that the carrier 15 starts traveling along the guide rails 12a and 12b in a magnetically levitated state. If the stator 16 is disposed again until the transport vehicle 15 completely stops due to the effect of air resistance or the like, the transport vehicle 15 is re-energized and continues to move along the guide rails 12a and 12b. This movement continues to the destination. Thus, the carrier 15 can be moved to the destination in a non-contact state. According to this embodiment, a nonmagnetic material is used for the guide rails 12c and 12d in the opening B of the transport path 1. Here, the end position of the non-magnetic material and the end positions of the emergency guides 13a and 13b in the traveling direction of the carrier are set to be substantially equal as shown in FIG. Therefore, when the operation of the magnetic support unit 31 is stopped and the carrier 15 is pulled out from the opening B for maintenance and inspection, the magnetic force of the permanent magnet 53 is applied to the guide rail 12c (12).
Does not affect d). For this reason, even if the vertical wheel 45a 'is not located below the guide rail 12c (12d), the magnetic support unit 31 does not directly adhere to the guide rail 12c (12d), and the carrier 15 and the guide rail 12c do not stick. Withdrawal work can be performed with little concern for the parallelism with (12d). The same applies when returning the transported vehicle 15 to the transport path 1 . Further, the magnetic support unit 31 is connected to the guide rail 12c (12
d) Because it is not affected by the magnetic force trying to adsorb,
The magnetic force of the entire carrier 15 is reduced. for that reason,
These operations can be performed very smoothly and quickly. In addition, in the present embodiment, even when the carrier 15 is set on or taken out of the transport path at the end of the transport path, the transport path edge where the influence of the magnetic field appears particularly strong is non-magnetic. Since it is formed of a body, the magnetic support unit 31 does not stick to the guide rail. For this reason, the occurrence of dust and noise in the apparatus according to the present invention can be suppressed as much as possible, and the attracted magnetic support unit 31 is not separated from the guide rail, so that the carrier 15 is not broken. Note that the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, a non-magnetic material having the same shape as the guide rail 12a (12b) is used as the guide rail at the end of the transport path, but this restricts the shape and material of the non-magnetic material at all. For example, as shown in FIG. 6, the non-magnetic material may be air, as shown in FIG. However, in this case, the magnetic support unit 31
7 and 8, the vertical wheels 45a come into contact with the inner surfaces of the upper and lower walls of the emergency guide 13a (13b), so that the transport vehicle cannot be prevented from adhering to the guide rails 12a (12b).
It is desirable to be able to support 15 vertically. As described above, the present invention can be variously modified and implemented without departing from the gist thereof. [Effects of the Invention] As described above, according to the present invention, the magnetic force of the permanent magnet in the on-vehicle magnetic support unit is reduced when the carrier is taken in and out of the opening at the end of the transport path. Does not act on the guide rails, the total amount of magnetic attraction acting on the carrier is reduced, and the above operation can be performed easily and safely.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cut-away perspective view showing a schematic configuration at an end of a conveying path of a floating type conveying apparatus according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the apparatus. FIG. 3 is a side view of the apparatus with a part cut away, FIG. 4 is a longitudinal sectional view of a magnetic support unit in the apparatus, FIG. 5 is a block diagram showing an electrical configuration of a control device of the apparatus, FIG. FIG. 7 is a partially cut-away perspective view showing a schematic configuration at an end of a conveying path of the apparatus according to another embodiment of the present invention, FIG. 7 is a longitudinal sectional view of the same apparatus, and FIG. It is the side view which notched partially. 1. Track frame, 12a, 12b ... Ferromagnetic guide rail, 12
c, 12d: Non-magnetic material guide rail, 13a, 13b: Emergency guide, 15: Carrier, 16: Linear induction motor stator, 25: Base, 26a, 26b: Dividing plate , 27… Link mechanism, 3
1 … Magnetic support unit, 34… Gap sensor, 37, 38
…… Container, 41… Control device, 42 …… Constant voltage generator, 43
…… Power, 51,52 …… Electromagnet, 53 …… Permanent magnet, 55 ……
Yoke, 56 ... coil, A ... seam, P ... void, B ...
Opening, 45a, 45a '... vertical wheel, 45b ... horizontal wheel.

Claims (1)

(57) [Claims] A transport path including a guide rail formed of a magnetic material, a transport vehicle disposed to be able to travel along the transport path, and an electromagnet disposed to face the lower surface of the guide rail via a gap, And a magnetic support unit mounted on the carrier, comprising a permanent magnet interposed in a magnetic circuit constituted by the electromagnet, the guide rails, and the gap to supply a magnetomotive force necessary to levitate the carrier. A sensor unit attached to the carrier for detecting a change in the size of the air gap in the magnetic circuit; and controlling a magnetomotive force of the magnetic support unit based on an output of the sensor unit; Zero power control means for controlling the exciting current flowing through the electromagnet so as to make the steady value of the exciting current flowing through the electromagnet zero, thereby stabilizing each magnetic circuit; and the guide rail. An emergency guide that is arranged in parallel, a wheel that is mounted on the carrier, and that holds a gap between the guide rail and the magnetic support unit at a predetermined length or more when the emergency guide is in contact with the emergency guide; Attached to the end of the guide rail at the end of the transport path,
A non-magnetic member formed at a position where the end position of the carrier in the traveling direction is substantially equal to the end position of the emergency guide.