JPH02270739A - Magnetic floating device for magnetic plate - Google Patents

Abstract

PURPOSE:To secure the follow-up property on the suction force control of an upper electromagnet by providing the first and second side magnet sections practically horizontally separated from a pair of opposite side faces of a magnetic plate, and forming magnetic poles on a pair of side faces respectively with the first and second side magnet sections. CONSTITUTION:An exciting current is fed to an upper electromagnetic coil 3 from a control power source 5 so that a gap between an upper electromagnet 2 and a steel plate 1 is kept at the preset separation distance based on the output signal from a distance sensor 4, and the steel plate 1 is floated. Both side faces of the steel plate 1 receive a component force Fv as a restoring force in the direction returning to the center level position of side magnetic poles of the first and second side magnet sections 6 and 6. The steel plate 1 is autonomously returned to the center level of the side magnetic poles by the component force Fv for the level fluctuation of the steel plate 1 from the -L size to the +L size, thus the follow-up property on the suction force control of the upper electromagnet 2 due to the fluctuation of the gap is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic levitation device for magnetic plates, and more particularly to a magnetic levitation device for magnetic plates that allows easy control of the floating position of the magnetic plates.

[Prior Art] This type of magnetic levitation device for magnetic plates is used for non-contact support during transfer of magnetic plates or for non-contact holding of the tip of a steel plate in a steel plate coating line.

For example, as shown in FIG. 3, a conventional magnetic levitation device for magnetic plates includes an upper electromagnet 2 for attracting a steel plate disposed above the plane of a steel plate 1 across a gap G1, and a distance sensor for detecting the gap G1. Based on the output signal from the distance sensor 4,
It is composed of a control section (not shown) that controls the excitation current so as to maintain the gap G1 at a predetermined distance, and supports the steel plate 1 horizontally in a fixed position without contacting it.

By the way, when adjusting the attraction force of the electromagnet, the more the electromagnet attracts the steel plate and the gap G1 becomes smaller, the stronger the attraction force Fc becomes, and if left as it is, the steel plate will come into contact with the electromagnet. In order to prevent such contact, suction force control corresponding to the gap G1 is required.

Furthermore, if magnetic saturation, magnetic leakage, etc. are ignored, the gap attraction force Fc of the electromagnet is
Since it changes in inverse proportion to the square of 1, it is necessary to control the excitation current of the electromagnet significantly and quickly, and also to suppress fluctuations in the attractive force as much as possible by reducing the rate of change of the gap G1. No.

[Problems to be Solved by the Invention] However, in the conventional magnetic levitation device for magnetic plate materials, in order to suppress fluctuations in the attractive force Fc as much as possible, it is difficult to increase the gap G1 and keep the rate of change relatively small. On the other hand, in order to counter the significant decrease in the attraction force Fc, it is necessary to increase the attraction force Fc according to the weight of the steel plate held, and the electromagnet itself must be made larger compared to general electromagnets for transporting steel materials. This goes against the demand for lighter and more compact equipment.

In addition, making the electromagnet thicker (which means making the excitation coil larger and increasing the inductance, worsens the ability to follow feedback signals from distance sensors, etc.).As a result, the attractive force of the electromagnet decreases. This has the disadvantage that the controllability of Fc deteriorates, making it difficult to control the suction force corresponding to the gap G1.

In other words, in the conventional magnetic levitation device for magnetic plate materials,
Suppression of fluctuations in the gap G1 and controllability of the suction force are in a trade-off relationship with each other, and at present no effective solution has yet been found.

Furthermore, a problem unique to steel plates that are suction-supported from above is that when the steel plate becomes thin or wide, its elasticity, along with its elasticity, causes the steel plate itself to sag due to deflection in the width direction. .

Therefore, in view of the above-mentioned drawbacks, the technical problem of the present invention is to provide a magnetic levitation device for steel plates that simultaneously improves the suppression of fluctuations in the gap G1 and the controllability of the attraction force, and also does not cause sag etc. due to the bending of the steel plate. It is to provide.

[Means for Solving the Problems] According to the present invention, an attraction electromagnet section disposed above a magnetic plate material arranged so that its plane is horizontal; a distance sensor that detects a separation distance from the magnetic plate; and excitation current control that controls an excitation current to the attracting electromagnet so as to maintain the separation distance constant based on an output signal from the distance sensor. A magnetic levitation device for a magnetic plate having a first and second side magnet parts, each of which is provided with first and second side magnet parts spaced apart in a substantially horizontal direction from a pair of mutually opposing side surfaces of the magnetic plate; A magnetic levitation device for magnetic plate material is obtained, characterized in that magnetic poles are formed on each of the pair of side surfaces by the second side surface magnet portion.

[Example] Next, one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the magnetic levitation device for steel plates according to this embodiment first includes an upper electromagnet 2 for attracting a steel plate, which is arranged above the plane of the steel plate 1 with a gap G1 in between, as in the conventional case.
Based on the output signal from the distance sensor 4 that detects the gap G1, the control power source 5 that causes an excitation current to flow through the upper electromagnetic coil 3 that winds the core of the upper electromagnet 2 for attracting a steel plate, and the distance sensor 4, The configuration includes a control section (not shown) that controls the excitation current so as to maintain the gap G1 at a predetermined distance, and the first and second side magnet sections 6, 6 according to the present invention are further provided with a level For improving control,
They are provided substantially horizontally apart from a pair of mutually opposing side surfaces of the steel plate 1 via a gap G2.

The first and second side magnet portions 6.6 will be described in detail with reference to FIG.

The first and second side magnet parts 6.6 are first composed of a core body 7 having a U-shaped cross section and a side electromagnetic coil 8 wound around the core body 7, and each of the first and second side magnet parts 6. A magnetic circuit is formed in the step.

The core body 7 includes a bottom portion 9 whose one end faces the side surface of the steel plate 1 through a gap G2, a column portion 10 extending upward from the other end of the bottom portion 9 and standing upright, and a steel plate extending from the top end of the column portion 10. The upper side 11 extending to the side and the gap G from the tip of the upper side 11
A side electromagnetic coil 8 is wound around a bottom part 9.

That is, the steel plate 1 has a side magnetic pole formed on the side surface facing the bottom portion 9 and a top surface magnetic pole formed on the top surface facing the body surface portion 12, and the steel plate 1 has the first and second side magnetic portions 6, 6. each constitute a magnetic circuit.

Here, the gap G3 is set within a range that allows the level change of the steel plate 1 in the vertical direction by the upper electromagnet 2 for attracting the steel plate.

The bottom portion 9 facing the side surface of the steel plate 1 through the gap G2 is
The end portions are narrowed to a facing area corresponding to the thickness of the steel plate 1, thereby increasing the magnetic flux density with the side magnetic poles of the steel plate 1 and increasing the attractive force against the steel plate 1.

The body surface portion 12 that extends to face the top surface of the steel plate 1 through the gap G3 is formed wide so as to have a large opposing area with the top surface of the steel plate 1. The magnetic flux density is lowered to make it easier for the magnetic flux to pass through.

Next, the operating state in this embodiment will be explained.

Referring to FIG. 2, based on the output signal from the distance sensor 4, an excitation current is passed from the control power supply 5 to the upper electromagnetic coil 3 so as to maintain the gap G1 at a predetermined distance, and the steel plate 1 is surface.

At this time, if the side surface of the steel plate 1 is at the same level as the magnetic pole centers of the first and second side magnet parts 6, 6, the gap is 0.
The attractive force between the two acts in the horizontal direction, and the force is zero.

In addition, as shown by the solid line in the figure, when the level of the steel plate is lowered by the L dimension than the side magnetic pole due to the steel plate's own weight, the attractive force F acts in an upward diagonal direction, so the upward component force F
v (Fv-FXsjnθ) is generated.

On the other hand, as shown by the broken line in the figure, when the level of the steel plate 1 rises by the L dimension from the center of the magnetic pole, the component force Fv
works downward.

That is, both side surfaces of the steel plate 1 are provided with first and second side magnet portions 6.
, 6 in the direction of returning to the center level position of the side magnetic poles,
The component force Fv will be received as a restoring force. Therefore, -
Regarding the level fluctuation of the steel plate 1 from the dimension 3 to the dimension 10, since the steel plate 1 autonomously returns to the level to the center of the side magnetic pole due to the component force FV, the attractive force of the upper electromagnet 2 due to the fluctuation of the gap G1 Followability in control is facilitated.

Note that since both side surfaces of the steel plate 1 are also subjected to horizontal tensile stress Fh at the same time, sagging in the width direction in a thin plate or a wide steel plate is prevented.

[Effects of the Invention] As described above, according to the present invention, the first and second side magnet portions are provided spaced apart from the pair of side surfaces of the magnetic material, and the magnetic material is attached to the first and second side surfaces of the magnetic material. Since the level is autonomously returned to the center of the magnetic pole of the side magnet part, followability in controlling the attractive force of the upper electromagnet can be ensured. At the same time, since the first and second side magnet parts pull the pair of side surfaces of the magnetic material in the horizontal direction, it is possible to prevent sagging in the width direction of a thin plate or a wide steel plate.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram showing an embodiment of the present invention, Fig. 2 is a partially cutaway sectional view of the side magnet portion of the embodiment shown in Fig. 1, and Fig. 3 is a conventional magnetic plate magnet. It is a levitation device. 1... Steel plate, 2... Upper electromagnet for attracting steel plate,
3... Electromagnetic coil, 4... Distance sensor 4.5...
- Control power supply, 6... First and second side magnet parts, 7.
... Core body, 8 ... Electromagnetic coil, 9 ... Bottom part,
10...Column part, 11...Upper side part, 12...Body surface part. G 0 1↑ 1-

Claims (1)

[Claims] 1) An attraction electromagnet section disposed above a magnetic plate arranged so that its plane is horizontal, and a distance between the attraction electromagnet and the magnetic plate. For magnetic plate material, comprising: a distance sensor for detecting the distance; and an excitation current control section for controlling the excitation current to the attraction electromagnet section so as to maintain the separation distance constant based on the output signal from the distance sensor. In the magnetic levitation device, first and second side magnet portions are provided, respectively, spaced apart in a substantially horizontal direction from a pair of mutually opposing side surfaces of the magnetic plate, and the first and second side magnet portions . A magnetic levitation device for a magnetic plate, characterized in that magnetic poles are formed on each of the pair of side surfaces.