JP2713885B2 - Floating transfer device - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a levitation type transport device suitable for transporting small articles. [Technical background of the invention and its problems] In recent years, as part of office automation and factory automation, it has been possible to move slips, documents, cash, samples, and the like using a transfer device between a plurality of points in a building. Is being done. The transfer device used for such a purpose must not damage the environment of the office, and is required to be free of dust and low in noise. For this reason, it is desirable that this type of transport device be configured to be able to support the transport vehicle in a non-contact manner with the guide rail. In order to support the transport vehicle in a non-contact manner, it is common to use air or magnetism.However, the method of magnetically supporting the transport vehicle is excellent in followability to guide rails and noise reduction effect. And is considered the most promising support system. A transfer device according to this method is usually equipped with a magnetic support unit mounted on a transfer vehicle that is arranged to run along guide rails formed of a ferromagnetic material, and the transfer is performed by a magnetomotive force generated by the magnetic support unit. This is to make the car magnetically levitated. The secondary conductor of the linear induction motor is mounted on the carrier, and the stator of the linear induction motor is intermittently arranged along the guide rail to drive the carrier. Among the above-mentioned magnetic levitation type transfer apparatuses, there have been proposed ones using a permanent magnet as a magnetic support unit. 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 excitation current of the electromagnet can be extremely reduced, and the power supply mounted on the carrier can be reduced. The capacity can be increased. However, even if such a device is used, the carrier will vibrate due to some external force while traveling, and when the position of the guide rail and the magnetic support device are displaced, power is consumed to restore the position. If the displacement is large, an extremely large amount of electric power is required, so that an excessive load is applied to the power supply and, in some cases, there is a problem that the control may be impossible. In particular, when the width of the ferromagnetic material on the lower surface of the guide rail and the width of the upper end surface of the electromagnet yoke placed on the transporting vehicle facing the same are aligned, the transporting vehicle moves in the left-right direction perpendicular to the traveling direction. When it starts to swing by receiving some external force, it has a pendulum motion with the equilibrium position at the lowest point, and there is a problem that the swing is connected for a long time and it is difficult to return to the equilibrium position. That is, when the transport vehicle is shifted from the equilibrium position in the left-right direction, the area of the lower surface of the ferromagnetic material on the lower surface of the guide rail and the surface of the electromagnet yoke facing the guide rail decrease. Even in this state, if so-called zero power control is performed, in which the weight of the transport vehicle is supported by the magnetomotive force of the permanent magnet, the electromagnet is replaced with the permanent magnet in response to the lack of attraction due to the decrease in the cross-sectional area of the gap. The gap length is shortened so as to be excited to the polarity and to generate an attractive force corresponding to the weight of the carrier only by the magnetomotive force of the permanent magnet. At this position, the direction of the suction force is deviated from the direction of gravity, and a force is applied to the transport vehicle in a direction to return to the equilibrium direction. With respect to the movement of the carrier in this direction, only the braking effect due to air resistance can be expected in a magnetically levitated vehicle in which no guiding electromagnet is arranged, so that the carrier continues the so-called pendulum motion for a long time, There is a problem that the power consumption increases due to the support and the load is adversely affected. [Object of the invention] The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a levitation type transfer device that can return to an equilibrium position in a short time and secure stable traveling even when an external force is applied to a transfer vehicle. [Summary of the Invention] The present invention is directed to a guide rail at least partially formed of a magnetic material, a transport vehicle arranged to run along the guide rail, and facing the guide rail via a gap. And a magnetic circuit including the electromagnet, the guide rail, and the air gap, the electromagnet being formed such that the width of a surface facing the guide rail is larger than the width of the guide rail. Based on the output of a magnetic support unit that is constituted by a permanent magnet that is provided with a permanent magnet that supplies a magnetomotive force necessary to levitate the carrier and that is mounted on the carrier, and that discharges the gap length Control means for controlling an exciting current for exciting the electromagnet and stabilizing the magnetic circuit so that the attractive force of the magnetic support unit and the weight of the carrier are balanced. It is characterized by comprising. [Effects of the Invention] According to the present invention, even when an external force in the right and left direction perpendicular to the traveling direction is applied to the carrier, the facing area between the guide rail and the electromagnet hardly changes. There is almost no change in the gap length to make the same. Therefore, the pendulum motion does not continue for a long time as in the conventional art, and the left and right swing can be calmed in a short time. For this reason, the power required to return to the equilibrium position can be reduced, vibrations applied to the load are suppressed, and safety during transport is improved. [Embodiment of the Invention] Hereinafter, a floating transfer device according to an embodiment of the present invention will be described with reference to the drawings. 1 is a plan view of the apparatus, FIG. 2 is a perspective view of the same part cut away, FIG. 3 is a sectional view taken along the line AA in FIG. 1, and FIG. 4 is FIG. BB cross-sectional view in FIG. In these figures, reference numeral 1 denotes a guide rail laid so as to avoid an obstacle in an office space, for example. On the guide rail 1 , a transport vehicle 2 is arranged so as to be able to travel along the guide rail 1 . The stator 6 of the linear induction motor 5 is disposed at a predetermined interval on the fixed portion 4 along the guide rail 1 . The guide rail 1 is configured by laying parallel members 10a and 10b at least on the lower surface of which are formed of a ferromagnetic material, and is supported on the fixed portion 4 by a support member 11. The transport vehicle 2 is configured as follows. That is,
A base 12 and a support plate 13 are arranged in parallel with the guide rail 1 so as to sandwich the guide rail 1 up and down. Both are connected by a connecting member 14. On the base 12, a container 16 for facilitating the transfer of a conveyed object such as a document is mounted. On the lower surface of the support plate 13, a secondary conductor 17, which is a movable element of the linear induction motor 5 , is attached. The secondary conductor 17 is arranged at a height opposed to the stator 6 with a slight gap during operation of the apparatus. Four magnetic support units are provided at four corners of the upper surface of the support plate 13 so as to face the lower surface of the guide rail with a predetermined gap.
21 is installed. A gap sensor for detecting a gap length between the unit 21 and the guide rail 1 is provided at a position of the support plate 13 close to the magnetic support unit 21.
22 is attached via an attachment member 23. A control device 24 for controlling the magnetic support unit 21 and a power supply 25 for supplying necessary power to the control device and the like are mounted at a central position of the support plate 13. The magnetic support unit 21 includes two yoke 31 and 32 whose upper end faces the lower surface of the guide rail 1 via a predetermined gap P, and excitation coils 33 and 34 wound around these yoke 31 and 32. It is composed of two electromagnets 35 and 36 and a permanent magnet 37 interposed between the lower side surfaces of the yoke 31, 32, and has a U-shape as a whole. The exciting coils 33 and 34 are
They are connected in series in such a direction that the magnetic fluxes formed by 36 are added together. The main part of the present embodiment is that the width of the lower surface of the guide rail 1 made of a ferromagnetic material is smaller than the width of the electromagnet yokes 31 and 32. In the embodiment, the electromagnet yoke 31, 32 of the left and right magnetic support units 21
Is configured such that the upper end surface of the guide rail 1 , that is, the center of the surface facing the guide rail 1 , is positioned in the same vertical plane with the center of the ferromagnetic material on the lower surface of the guide rail 1 in the steady floating state of the carrier 2. Is shown. Further, the control device 24 transmits a light-emitting signal to the gap sensor 22 and modulates a light-receiving signal from the gap sensor 22 by, for example, a fixed resistor that is an exciting current detecting means connected in series with the exciting coils 33 and 34. Device, an arithmetic circuit for calculating the value of the current flowing through the exciting coils 33E and 34 based on the signal from the modulator and the signal due to the voltage drop of the fixed resistor, and the exciting coils 33 and It is composed of an amplifier that supplies power to 34. On the other hand, at four corner positions of the base 12 and the support plate 13, four sets of wheels 41 that support the transport vehicle 2 on the guide rail 1 in an emergency or the like are mounted so as to sandwich the guide rail 1. ing. The wheel group 41 includes three auxiliary wheels 42, 43, and 44, respectively. The auxiliary wheel 42 is disposed above the guide rail 1 and is rotatably supported by the base 12 via a support member 45 so as to rotate about a horizontal axis orthogonal to the traveling direction of the carrier 2 as a rotation axis. . The auxiliary wheel 42, a magnetic support units 21
Transport car 2 and when the magnetic attractive force between the guide rail 1 is guided vehicle 2 has fallen drops on the upper surface of the guide rail 1
Is to run. The auxiliary wheel 43 is also disposed above the guide rail 1 , and is rotatably supported by the base 12 via the support member 46 so as to rotate about a vertical axis orthogonal to the traveling direction of the carrier 2 as a rotation axis. I have. The auxiliary wheel 43, when the transport vehicle 2 offset in the horizontal direction for some reason, so that the guide rail 1 and the magnetic support units 21 not separate more than necessary, but in contact with the side surface portion of the guide rail 1 . The auxiliary wheel 44 is disposed below the guide rail 1 and is fixed to the support plate 13 via a support member 47 so as to rotate about a horizontal axis orthogonal to the traveling direction of the transport vehicle 2 as a rotation axis. . The auxiliary wheel 44 comes into contact with the lower surface of the guide rail 1 when the guide rail 1 and the magnetic support unit 21 are too close to each other due to any cause, so that the magnetic support unit 21 is directly attracted to the guide rail 1. It is to prevent that. Next, the operation of the thus configured floating type transport apparatus according to the present embodiment will be described. When the device is started, the control device 24 applies a magnetic flux in the same direction as the magnetic flux generated by the permanent magnet 37 or in the opposite direction to the electromagnets 35 and 3.
6 and controls the current flowing through the exciting coils 33 and 34 so as to maintain a gap P of a predetermined length between the magnetic support unit 21 and the guide rail 1 . Thereby, the permanent magnet 37-the yoke 31-the gap P-the guide rail 1 -the gap P-
A magnetic circuit composed of a path from the yoke 32 to the permanent magnet 37 is formed. The gap length is set such that the weight of the supported body such as the transport vehicle 2 and the magnetic attraction between the magnetic support unit 21 and the guide rail 1 due to the magnetomotive force of the permanent magnet 37 are exactly balanced. The control device 24 controls the exciting current of the electromagnets 35 and 36 to maintain the gap length. As a result, so-called 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 energized, the secondary conductor 17 attached to the support plate 13 receives electromagnetic force from the stator 6, The transport vehicle 2 starts traveling along the guide rail 1 in a magnetically levitated state. If the stator 6 is disposed again until the carrier 2 completely stops due to the influence of air resistance or the like, the carrier 2 is re-energized and continues to move along the guide rail 1 . This movement continues to the destination. Thus, the carrier 2 can be moved at the destination in a non-contact state. By the way, as shown in FIG. 5, when the widths of the lower surfaces of the guide rail members 10a and 10b made of a ferromagnetic material of the guide rail 1 are equal to the widths of the electromagnet yokes 31 and 32 of the magnetic support unit 21. When some external force is applied from the equilibrium position in FIG. 3A and the electromagnet yokes 31 and 32 are shifted to the right as shown in FIG. 3B, the guide rail 1 and the electromagnet yokes 31 and 32 are shifted.
Area of the surface facing the decreases in W / W _0. In order to compensate for the decrease in the attraction force due to the decrease in the area without significantly increasing the power consumption of the electromagnet coil not shown in the figure, it is necessary to shorten the gap length. In the state of FIG. 5B, the guide rail members 10a and 10b and the yoke 31,
A force acting to return the carrier 2 to the equilibrium position acts between the carrier 32 and the carrier 32. In addition to this force, the difference between the gap lengths (g ₀ -g) in FIGS. 5 (a) and 5 (b), that is, the force due to the difference in the potential energy acts, and the carrier 2 continues the so-called pendulum motion. Will do. What suppresses this pendulum motion is air resistance, overcurrent loss, etc., but all of them are very small in absolute value, and almost no damping effect can be expected. In this regard, according to the levitation transfer device according to the present embodiment, as shown in FIG. 6, the width of the lower surface of the guide rail members 10c, 10d is larger than the width of the upper end surfaces of the electromagnet yokes 31, 32. Due to the narrowing, there is almost no change in the facing area, and therefore no pendulum movement occurs. In this example, when the carrier 2 is in a steady floating state, the center position of the guide rail members 10a and 10b and the electromagnet yoke 3
The center positions of 1,32 coincide. According to this example, as shown in FIG.
Even if 2 shifts to the right, if the shift is as shown in the figure, the facing area between each yoke 31, 32 and the guide rail members 10a, 10b hardly changes, so that the gap length also hardly changes. And a suction force corresponding to the weight of the transport vehicle can be generated. Figure 6 (b) the yoke 31 and the guide rail member 10a in a state, since the center of 10b are displaced, guiding force in a direction to return to the state of FIG. 5 (a) acts on the transport vehicle 2 However, unlike the conventional example shown in FIG. 5, the time required to return to an equilibrium state is greatly reduced because the movement is not a pendulum movement. In addition, as shown in FIG. 7, the guide rail members 10a, 10b are arranged so that the width of the outer edge portion thereof is equal to the width of the outer edge surface of the upper end surface of the electromagnet yoke 31, 32, As shown in FIG. 8, if the width of the inner edges of the guide rail members 10a and 10b and the width of the inner edges of the upper end surface of the electromagnet yoke 31 are arranged to be equal, the above-described example can be obtained. A larger guiding force can be obtained. Further, in the above embodiment, an example in which a member having an angled cross-sectional shape is used as the guide rail member, however, as the guide rail member, a portion facing the electromagnet yoke portion on the vehicle is a flat plate. The purpose of the present invention can be fully utilized even if a cross-sectional shape such as a flat plate or an inverted T-shape, which is easily supported and manufactured and whose installation cost is inexpensive, is selected. Further, in the above embodiment, the transport vehicle passes through the magnetic circuit composed of the magnetic support unit, the guide rail member, and the gap.
2 shows a case in which the loop of the main magnetic flux generating the attraction force supporting the carrier 2 is parallel to the traveling direction of the carrier, but the magnetic support unit is set so that the main magnetic flux loop is perpendicular to the traveling direction of the carrier. The gist of the present invention can be fully utilized even in the case of arrangement. FIG. 9 is a schematic front view showing the positional relationship according to the present invention of the permanent magnet portion, the electromagnet yoke portion, and the guide rail member of the magnetic support unit in this case. That is, FIG. 9 (a) shows that when the carrier 2 is in a steady floating state, the center positions of the left and right magnetic support units 21 and the center positions of the left and right guide rail members 10a and 10b are
Each shows a case where they are coincident in the vertical plane. In the case of such a configuration, similarly to the above description, even if the transport vehicle 2 receives a force in the left-right direction due to some disturbance and causes a lateral movement, unless the disturbance is extremely large, the flying gap length is increased. No major change occurs. Therefore, it is possible to return to the equilibrium state relatively quickly without performing the above-described pendulum movement. Also, as shown in FIGS. 9 (b) and 9 (c), the mounting positions of the left and right guide rail members 10a and 10b are determined by the width of the outer ends of the upper ends of the electromagnet yokes 31 and 32 of the magnetic support unit or the electromagnet yokes. By arranging the widths of the inner ends of the upper ends of the irons 31 and 32 and the widths of the outer edges or the inner edges of the guide rail members 10a and 10b, respectively, a greater guiding force is generated. However, the carrier 2 can run stably. In the above embodiment, the case where the transfer container portion is located above the magnetic support unit has been described. However, even when the transfer container portion is located below the magnetic unit, the gist of the present invention is sufficient. It is used for

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a floating type transport apparatus according to an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view of the apparatus, and FIG. FIG. 4 is a sectional view taken along the line AA in FIG. 4, FIG. 4 is a sectional view taken along the line BB in FIG. 1, and FIG. FIG. 6 is a schematic front view for explaining the effects of the above embodiment, and FIGS. 7 to 9 are diagrams for explaining the effects of the levitation type transport apparatus according to another embodiment of the present invention. FIG. 2 is a schematic front view of FIG. DESCRIPTION OF SYMBOLS 1 ... Guide rail, 2 ... Carrier, 4 ... Fixed part, 5
... linear induction motor, 6 ... stator, 10a, 10b ... guide rail member, 12 ... base, 13 ... support plate, 16 ... container, 17 ... secondary conductor, 21 ... magnetic support Unit, 22 ……
Gap sensor, 24 ... Control device, 25 ... Power supply, 31, 32
...... Yoke, 33, 34 Excitation coil, 35, 36 Electromagnet, 37
... permanent magnet, 41 ... wheel group, 42-44 ... auxiliary wheel, 45
~ 47: Mounting member, P: Air gap.

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References JP-A-60-16603 (JP, A)                 JP-A-55-17161 (JP, A)                 Shokai Sho 53-133313 (JP, U)

Claims (1)

(57) [Claims] A guide rail at least partially formed of a magnetic material, a transport vehicle arranged to run along the guide rail, and attached to the transport vehicle so as to face the guide rail via a gap, An electromagnet formed such that the width of the surface facing the guide rail is larger than the width of the guide rail; and interposing the carrier in a magnetic circuit including the electromagnet, the guide rail, and the gap. A magnetic support unit configured by a permanent magnet that supplies a magnetomotive force necessary for levitating and mounted on the carrier, and an excitation current that excites the electromagnet is controlled based on an output of a gap sensor that detects the gap length. And control means for stabilizing the magnetic circuit so that the attractive force of the magnetic support unit and the weight of the carrier are balanced. Levitation conveyor apparatus according to symptoms. 2. The guide rail is configured such that an outer edge of a surface facing the electromagnet in a steady floating state of the carrier and an outer edge of the guide rail are arranged in the same vertical plane. 2. The floating transfer device according to claim 1, wherein: 3. The guide rail is configured such that an inner edge of a surface facing the electromagnet and a inner edge of the guide rail in the steady floating state of the carrier are arranged in the same vertical plane. 2. The floating transfer device according to claim 1, wherein: