JPH0120341Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention is a magnetic attraction suitable for magnetic materials, especially steel plates, which utilizes the attraction force of an electromagnet against a steel plate as a levitation force, and the thrust of a linear motor as a conveying force. The present invention relates to a floating conveyance device.

[Prior art]

A conventionally known magnetic suction levitation conveyance device of this type is shown in FIGS. 1 and 2. In these figures, a plurality of attraction electromagnets 2 are attached to the bottom surface of the pedestal 1, and the pedestal 1
A plurality of linear motors 3 are attached to the lower surface near the center. A gap sensor 4 is attached very close to the attraction electromagnet 2. Below the suction electromagnet 2, linear motor 3, and gap sensor 4 attached to the lower surface of the pedestal 1, a steel plate 5 to be transported is placed with a constant gap. The arrangement of the linear motor 3 is independent of the suction electromagnet 2, and depends on the length of the transported material, the thrust per linear motor 3,
It is determined based on the relationship of force required for transportation, etc.

Next, the operation will be explained. When a current is applied to the attraction electromagnet 2 , a magnetic attraction force acts between the attraction electromagnet 2 and the conveyed steel plate 5 , and the steel plate 5 is attracted toward the electromagnet 2 . At this time, if the output of the gap sensor 4 that measures the distance between the steel plate 5 and the electromagnet 2 indicates that the measured gap length is shorter than the set gap length, an electromagnet current control device (not shown) controls the electromagnet. The gap is kept constant by controlling the magnetic attraction force by decreasing the current in the magnet and controlling the electromagnet current until the measured gap length becomes equal to the set gap length. If the output of the gap sensor 4 indicates that the measured gap length is wider than the set gap length, the electromagnetic current is controlled by the reverse operation as described above. Due to these operations, the steel plate 5 is always suspended in the air with a constant gap relative to the attraction electromagnet 2. When the linear motor 3 is energized in this state, a thrust force acts between the linear motor 3 and the steel plate 5, and the steel plate 5 is conveyed in a predetermined direction while floating.

However, in such a conventional magnetic suction levitation conveyance device, the size and arrangement of the linear motor 3 for conveyance are independent of the levitation electromagnet 2, and the length of the steel plate 5 and the thrust per linear motor 3 are This is determined based on the relationship between the forces required for transportation, etc., and since the control systems of the electromagnet 2 and linear motor 3 are independent, the suction force generated by the linear motor 3 (this is 10 times the normal thrust) (This is often more than that.)
However, this has a large effect on the magnetic levitation system, and when the steel plate 5 is being conveyed, the levitation state becomes unstable, and the conveyed steel plate 5 may fall or come into contact with the surface of the core of the suction electromagnet 2 or the linear motor 3. The downside is that there are things you can do. Furthermore, as shown in FIG. 5, since the gap is not controlled near the linear motor 3, depending on the rigidity of the conveyed steel plate 5, the conveyed steel plate 5 may bend, causing the portion of the suction electromagnet 2 to bend. Even if the gap δ was sufficiently controlled, there were cases in which the steel plate 5 to be conveyed came into contact with the linear motor 3 and became unable to be conveyed.

[Summary of the idea]

The purpose of this invention is to eliminate the above-mentioned drawbacks and to provide a magnetic suction levitation conveyance device that can stably levitate and convey a steel plate to be conveyed.

This idea consists of a levitation electromagnet, a transportation linear motor, and a gap sensor, and a control system that controls the attraction force of the electromagnet using the linear motor's thrust and the gap sensor's detection signal. This is an attempt to reduce the instability of the state.

[Example of idea]

An embodiment of this invention will be described below based on the drawings. In FIGS. 3 and 4, the attraction electromagnet 6
are arranged in a staggered manner, and this attraction electromagnet 6
A linear motor 7 is placed directly adjacent to the attraction electromagnet 6 in a one-to-one relationship. Furthermore, a gap sensor 8 is disposed between the suction electromagnet 6 and the linear motor 7, so that the average value of each gap length of the suction electromagnet 6 and the linear motor 7 with respect to the steel plate 5 to be transported can be measured. It's summery. Note that the other configurations are the same as those of the prior art, so explanations will be omitted. According to this embodiment, as described above, the suction electromagnet 6 and the conveyance linear motor 7 are arranged in one-to-one correspondence, and the gap between the electromagnet 6 and the conveyed steel plate 5 is determined by the average gap length of the two gap lengths. Therefore, even if the primary voltage of the linear motor 7 is changed in order to control the thrust of the linear motor 7, and thereby the suction force of the linear motor 7 changes, the linear motor 7 By controlling the attraction electromagnet 6, the electromagnet 6 and the conveyed steel plate 5
It becomes possible to always keep the gap constant.

That is, as shown in FIG. 7, the set gap value and the output of the gap sensor are input to the control system of the control device, the suction force of the suction electromagnet 6 is determined, and the suction force is input to the suction force control section. On the other hand, the conveyance command of the linear motor 7 is input to the control system to control the thrust of the linear motor 7, and this thrust is converted into suction force that the linear motor 7 gives to the steel plate 5 to be conveyed, and the feed forward is used to control the thrust of the linear motor 7. Input to the suction force control section.
Then, the attraction force control section controls the attraction force of the attraction electromagnet 6 based on the above-mentioned input signals so that the gap δ becomes a set value. Therefore, the gap δ can be controlled more stably by inputting the disturbance of the suction force caused by changing the thrust of the linear motor 7 to the suction force control section before the gap δ fluctuates.

In addition, a device (linear motor) that generates a suction force without controlling the gap δ by pairing the suction electromagnet 6 and the linear motor 7 and measuring the average gap length between them.
Therefore, even if the steel plate 5 to be conveyed has a low steel property, the steel plate 5 to be conveyed is less likely to come into contact with the linear motor 7 as shown in FIG.

In this embodiment, the attraction electromagnets 6 and the conveyance linear motors 7 are made to correspond one-to-one, but one conveyance linear motor may be made to correspond to a plurality of attraction electromagnets. In this case, due to the size and rigidity of the steel plate to be transported, it is possible to do so under the condition that the steel plate to be transported stably floats even if multiple suction electromagnets are controlled by one gap sensor. be.

[Effect of idea]

As described above, in the magnetic suction levitation conveyance device, the electromagnet for suction levitation, the linear motor for propulsion, and the gap sensor are combined into one control system, and the electromagnet is activated based on the detection signal of the gap sensor and the thrust of the linear motor. By controlling the suction force, the suction force of the linear motor can also be used as part of the levitation force to levitate the steel plate, making it possible to reduce the capacity of the levitation electromagnet, and even if the suction force of the linear motor changes. Since the electromagnets in the same control system can correct changes in the attraction force, there is an effect that the conveying steel plate can be stably floated and propelled.

[Brief explanation of the drawing]

1 is a plan view showing a conventional magnetic suction levitation conveyance device, FIG. 2 is a front view of FIG. 1, FIG. 3 is a plan view showing a magnetic suction levitation conveyance device according to an embodiment of the invention, and The figure is a front view of FIG. 3, FIG. 5 is a diagram showing an example of a state in which a steel plate to be transported is being transported by a conventional magnetic suction levitation transport device, and FIG. 6 is a diagram of an embodiment of the present invention. A diagram showing an example of a state in which a steel plate to be transported is being transported by the magnetic suction levitation conveyance device, and FIG. 7 is a diagram showing an example of a control system of the control device of the magnetic suction levitation conveyance device according to the present invention. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is a frame, 5 is a steel plate to be transported, 6 is an electromagnet for suction levitation, 7 is a linear motor for transport propulsion, 8
is a gap sensor.

Claims (1)

[Scope of utility model registration request] In a magnetic suction levitation conveyance device that has an electromagnet for suction levitation, a linear motor for propulsion, and a gap sensor on a pedestal disposed above the conveyed member, the suction levitation is determined based on the difference between the output of the gap sensor and the set gap value. an attractive force requesting unit that obtains the attractive force that the electromagnet should generate; a linear motor propulsion control unit that outputs a current that causes the propulsion linear motor to generate a propulsive force in accordance with a conveyance speed command; and a linear motor propulsion control unit that converts the propulsive force into an attractive force. Generates attraction force data based on the output signals of the thrust/attraction force calculation unit to be converted, the attraction force request unit, and the thrust/attraction force calculation unit, and applies a current corresponding to the attraction force data to the attraction levitation unit. a control device comprising a suction force control unit outputting to the electromagnet for suction and levitation, the suction levitation electromagnet, the propulsion linear motor, and the gap sensor as a set, and the gap sensor is connected to the conveyed member. The set is installed at a position to detect the average gap length of the gap length between the suction levitation electromagnet and the gap length between the conveyed member and the propulsion linear motor, and the set is installed along the conveyance line of the conveyed member. A magnetic suction levitation conveyance device characterized in that a plurality of sets are attached.