JPH0529285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic levitation device for magnetic plates that levitates magnetic plates by magnetic attraction without contacting them.

[Prior Art] This type of magnetic levitation device for magnetic plates is used to support magnetic plates without touching them during transportation, and to hold the tip of a steel plate without touching it in a steel plate painting line. .

A conventional magnetic levitation device for a magnetic plate, for example, as shown in _FIG .
and a distance sensor 12 that detects the gap _G3 .
It is equipped with a control power source 13 for passing an excitation current through a coil 11b wound around a core 11a of an attraction electromagnet 11, and is configured to maintain a gap _G3 at a predetermined value based on an output signal from a distance sensor 12. By controlling the excitation current to the coil 11b, the magnetic plate 1
horizontally in a fixed position without touching it.

By the way, when adjusting the attraction force of the attraction electromagnet 11, as the magnetic plate 1 is attracted by the attraction electromagnet 11 and the gap _G3 becomes smaller, the attraction force F _c becomes stronger. Since the magnetic plate 1 comes into contact with the magnetic plate 11, in order to prevent this, it is necessary to control the attraction force corresponding to the gap _G3 .

[Problems to be Solved by the Invention] However, in the conventional magnetic levitation device for magnetic plates, the change in the attraction force F _c of the attraction electromagnet 11 with respect to the change in the gap G ₃ is very large, and magnetic saturation and magnetic leakage are ignored. Then, with constant excitation, it changes in inverse proportion to the square of the gap _G3 , so there is a drawback that it is troublesome to control the attractive force F _C to follow the change in the gap _G3 .

Furthermore, conventional magnetic levitation devices for magnetic plates have the disadvantage that when the magnetic plates are thin or wide, they bend due to their own weight due to their elasticity.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic levitation device for a magnetic plate that does not require control of the attractive force of a magnet to the magnetic plate and can prevent the magnetic plate from deflecting.

[Means for Solving the Problems] The present invention provides an upper magnet disposed at a predetermined interval above an end of a magnetic plate arranged so that its plane is substantially horizontal; horizontal direction side magnets arranged at predetermined intervals on the horizontal direction side.

[Function] According to the present invention, the upper magnet supports the magnetic plate material against gravity so that the plane becomes substantially horizontal, and the horizontal magnet prevents the magnetic plate material from deflecting.

[Example] Next, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, reference numeral 1 indicates a magnetic plate material. This magnetic plate 1 is arranged so that its plane 1a is substantially horizontal. Above the ends 1b, 1b on both sides of the magnetic plate 1, upper magnets ₂ , 2 are arranged with a predetermined gap G1, respectively. In the illustrated embodiment, these upper magnets 2, 2 are constituted by electromagnets consisting of a core 2a and a coil 2b.

On the horizontal sides of both end portions 1b, 1b of the magnetic plate 1, horizontal magnets ₃ , 3 are arranged with a predetermined gap G2, respectively. In the illustrated embodiment, these horizontal side magnets 3, 3 are composed of electromagnets consisting of a core 3a and a coil 3b. These horizontal side magnets 3,3
The cores 3a, 3a are connected to the cores 2a, 2a of the upper magnets 2, 2. the coil 2b,
When current is supplied to 3b, the magnetic flux exits the core 2a, enters the magnetic plate ₁ through the gap G1, then enters the core _3a through the gap G2, and then returns to the core 2a. configured.

When this magnetic circuit is configured, the upper magnets 2, 2 attract the magnetic plate 1 upward in the vertical direction with an attractive force F _u to move the magnetic plate 1 within a predetermined range on the plane 1a.
The horizontal side magnets 3, 3 attract the ends 1b, 1b of the magnetic plate 1 with an attractive force _Fs. to prevent deflection of the magnetic plate 1.

The gap _G1 is set within a range that allows the upper magnets 2, 2 to change the position of the magnetic plate 1 in the vertical direction. In addition, the end faces of the cores _3a , 3a of the horizontal side magnets 3, 3 facing the end faces of the end portions 1b, 1b of the magnetic plate 1 through the gap G2 are narrowed to an opposing area corresponding to the thickness of the magnetic plate 1. As a result, the magnetic flux density in the gap _G2 is increased, and the attraction force _Fs of the horizontal side magnets 3, 3 to the magnetic plate 1 is increased.

The reason why the deflection of the magnetic plate 1 can be prevented will be explained in detail.

When the center of the end face of the magnetic plate 1 is at the same level as the center of the end face (magnetic pole) of the cores 3a, 3a of the water direction side magnets 3, 3 (the level of the magnetic plate 1 is 0)
), the attractive force F _s of the horizontal side magnets 3 acts on the magnetic plate 1 in the horizontal direction, so the component force in the vertical direction is 0.

When the magnetic plate 1 is lowered by a distance L from the same level as the horizontal magnet 3 (when the level of the magnetic plate 1 is −L), as shown by the solid line in FIG. On the other hand, horizontal side magnet 3
Since the suction force F _s acts in an upward diagonal direction forming an angle θ with the horizontal line, an upward component force F _v (F _v =F _s ×sin θ) as shown in FIG. 3 is generated.

On the other hand, as shown by the dashed line in FIG. 2, when the level of the magnetic plate 1 is higher than the level of the horizontal magnet 3 by a distance L (when the level of the magnetic plate 1 is +L), As shown in FIG. 3, a downward component force F _v (F _v =-F _s ×sinθ) is generated.

Attraction force of the upper magnet 2 to the magnetic plate 1
F _u always acts only upwards.

Now, ignoring magnetic saturation and magnetic leakage, magnetic plate material 1
The number of effective magnetic fluxes passing through the upper magnet 2 and the horizontal magnet 3 is Φ, and the horizontal magnet 3
and the effective facing area of upper magnet 2, respectively.
Assuming Ag ₁ and Ag ₂ , F _v = Φ ² / Ag ₁ sin θ × k (k: constant) ... (1) F _u = Φ ² / Ag ₂ × k ... (2), and F _v , F _u is proportional to the square of Φ, and
Inversely proportional to Ag ₁ and Ag ₂ .

From the relationship of equations (1) and (2) above, as shown in Figure 3, when F _s acts upward, θ is +, and when F _s acts downward, θ is −. Then, the total supporting force F acting on one end of the magnetic plate 1 is
is expressed by the following formula.

F=F _u (1-Ag ₂ /Ag ₁ sinθ) ...(3) Therefore, by selecting the values of Ag ₁ and Ag ₂ , the total supporting force F can be surrounded by curves A and B in Figure 4. Since the value can be set to the value shown by the curve within the range (within the range shown by diagonal lines), the end portions 1b, 1b of the magnetic plate 1 are placed at a level corresponding to the center of the horizontal side magnet 3, that is, , the horizontal magnet 3 applies a restoring force to the magnetic plate 1 so as to prevent the magnetic plate 1 from bending.

Note that the curve C in FIG. 4 indicates the total supporting force F acting on the magnetic plate 1 in the conventional magnetic levitation device for magnetic plates shown in FIG. Curve C shows that no force is available to restore the voltage to the reference level.

As shown in FIG. 3, the attractive force _Fs of the horizontal side magnet 3 to the magnetic plate 1 is always a horizontal component force.
This horizontal component force F _h also prevents _the magnetic plate 1 from deflecting.

Note that it is not necessary to control the attractive force to the magnetic plate 1 by controlling the magnitude of the current supplied to the coil 2a of the upper magnet 2 and the coil 3a of the horizontal magnet 3. Therefore, it is not necessary to provide the core 2a of the upper magnet 2 and the core 3b of the horizontal magnet 3 in series, and the upper magnet 2 and the horizontal magnet 3 can also be made of permanent magnets.

[Effects of the Invention] The present invention does not require control of the attraction force of the magnet to the magnetic plate material, and can prevent deflection of the magnetic control plate material.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG.
The figure is a partially cutaway sectional view showing the main part of the embodiment same as above, FIGS. 3 and 4 are diagrams for explaining the operation of the embodiment same as above, and FIG. 5 shows a conventional magnetic levitation device for magnetic plate material. It is a schematic diagram. 1...Magnetic plate material, 2...Upper side magnet, 3...Horizontal side magnet.

[Claims]

1 A step of mixing raw material powder mainly composed of cobalt oxide or nickel oxide and then sifting it, and after CIP molding the sifted mixed powder,
The process of calcining, crushing, and then sieving;
A step of pulverizing the sieved calcined powder to 1 μm or less, a step of granulating the finely pulverized powder into a spherical shape of 20 μm or more, a step of CIP forming the granulated powder, a step of sintering the compact, sintering. 1. A method for producing a CoO-NiO-based nonmagnetic substrate for a magnetic head, comprising the step of subjecting the substrate to HIP treatment. 2. The method for producing a non-magnetic substrate for a magnetic head according to claim 1, wherein the molded body is sintered using pressureless sintering or hot pressing at a temperature of 1000°C or higher in an oxygen atmosphere. . 3. The method of manufacturing a nonmagnetic substrate for a magnetic head according to claim 1, wherein in the HIP treatment of the sintered body, the sintered body is treated as it is at a temperature lower than the sintering temperature. 4. A step of mixing raw material powder mainly composed of cobalt oxide or nickel oxide and then sifting it, and after CIP molding the sifted mixed powder,
The process of calcining, crushing, and then sieving;
The sifted calcined powder is finely divided to 1 μm or less.