JPH05118334A - Magnetic bearing device - Google Patents

Abstract

PURPOSE:To converge and stabilize a passive stability axis of low characteristic frequency by converging freedom of a magnetic force generation means in the direction of the passive stability axis by a spring force and a damping force. CONSTITUTION:Teflon sheets 10a, 10b are adhered on facing surfaces of a yoke 5 and a stator 3 and Teflon sheets 10c, 10d are adhered on facing surfaces of a presser washer 9 of the stator 3 and a bolt 8. Additionally, a rubber piece 11 is tightly adhered on both sides of the yoke 5 in the (y) axial direction, and both sides of the rubber piece 11 are adhered on the stator 3. Freedom in the axial direction on which a magnetic centripetal force FY works on an electromagnet 4 is converged by a passive spring force and a damping force of the rubber piece 11 and a passive damping force due to small friction of the Teflon sheets 10a-10d, and when a rotation axis (1) moves in the (y) direction, its movement is converged and stabilized. Freedom around a (z) axis is converged in the same way, and when a supported body 1 moves around the (z) axis, its movement is converged and stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing device for supporting a supported body by a magnetic force in a non-contact manner.

[0002]

2. Description of the Related Art In a conventional magnetic bearing device, a non-contact-supported passive stable shaft has its axial movement controlled by a spring force, that is, a restoring force by a magnetic centripetal force and an eddy current damper.

[0003]

However, the conventional eddy current damper is effective in the case of giving a high-frequency motion or changing the magnetic flux at a high frequency, and it is effective for a relatively low-frequency motion. Not suitable. The passive stable shaft has a small magnetic centripetal force as compared with the magnetic attractive force, and therefore has low rigidity and a low natural frequency.

An object of the present invention is to provide a magnetic bearing device which converges and stabilizes a passive stable shaft having a low natural frequency.

[0005]

According to the present invention, in a suction type magnetic bearing device for supporting a supported body by a magnetic force in a non-contact manner, the degree of freedom in the passive stable axial direction of the magnetic force generating means is defined as a spring force. Restraint means for restraining the damping force is provided.

The magnetic force generating means is composed of an electromagnet or a permanent magnet.

The electromagnet or permanent magnetic force is attached to the support by bolts orthogonal to the axial direction, and a Teflon sheet is interposed between the electromagnet or permanent magnet and the support and between the bolt and the support. It is preferable that the axial side portion of the electromagnet or the permanent magnet is constrained by a piece fixed to the support, the spring force and the damping force are generated by the piece, and the damping force is generated by minute friction of the Teflon sheet. .

[0008]

In the magnetic bearing device configured as described above, the degree of freedom in the axial direction on which the magnetic centripetal force of the electromagnet or the permanent magnet acts is determined by the passive spring force and damping force of the piece and the small amount of the Teflon sheet. It is restrained by passive damping force due to friction. Therefore, when the supported body moves in the axial direction, its movement is converged and stabilized.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a magnetic material 2 is attached to a supported body 1.
On the fixed side, that is, on the stator 3, the magnetic body 2 is provided.
Facing each other, the yoke 5 and the coil 6, which are magnetic force generating means,
An electromagnet 4 composed of 6 and 6 is vertically restrained by a bolt 8. Teflon sheets 10a and 10b which are in close contact with each other are adhered to the surfaces of the yoke 5 and the stator 3 which face each other. Also, the stator 3 and the bolt 8
Teflon sheets 10c and 10d, which are in close contact with each other, are adhered to the surfaces facing the holding washers 9.
On both sides of the yoke 5 in the y-axis direction, pieces 11, 11 fixed to the stator 3 are in close contact with both sides of the yoke 5, and both sides of the piece 11 are fixed to the stator 3 as shown.
Is glued to. The piece 11 is made of rubber or sponge-like rubber.

With this structure, the coils 6, 6 are energized to generate a magnetic force to support the supported body 1 in a non-contact manner.

Further, in the electromagnet 4, a magnetic centripetal force Fy
The degree of freedom in the axial direction in which the force acts on the Teflon sheets 10a to 1 is the passive spring force and damping force of the rubber pieces 11, 11.
It is restrained by a passive damping force due to a minute friction of 0d. Therefore, when the rotary shaft 1 moves in the y direction, the motion is restrained and stabilized.

Further, as shown in FIG. 2, the degree of freedom around the z-axis is the same as the above-mentioned, that is, the passive spring force and damping force of the pieces 11 and the passive force due to the slight friction of the Teflon sheets 10a to 10d. It is restrained by the dynamic damping force. Therefore, when the supported body 1 makes a motion around the z axis, the motion is restrained and stabilized.

FIG. 3 shows another embodiment of the present invention, which is an example in which the magnetic force generating means is constituted by the permanent magnet 7 and the others are constituted similarly to FIG. The permanent magnet 7 has a minute gap C formed between magnets adjacent to each other in the axial direction, and the magnets of the surfaces of the adjacent magnets are arranged to have the same magnetism. This embodiment also has the same effects as the above-mentioned embodiment.

[0015]

Since the present invention is configured as described above, it is possible to provide a good magnetic bearing device in which a passive stable shaft having a low natural frequency is used as a convergent stable shaft.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a rear view of the electromagnet shown in FIG.

FIG. 3 is a side sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 Fy ... Magnetic centripetal force Fz ... Magnetic attraction force 1 ... Supported body 2 ... Magnetic body 3 ... Stator 4 ... Electromagnet 5 ... Yoke 6 ... Coil 7 ... Permanent magnet 8 ・ ・ ・ Bolt 9 ・ ・ ・ Holder washer 10a-10d ・ ・ ・ Teflon sheet 11 ・ ・ ・ Piece

Front page continued (72) Inventor Masato Eguchi 4-2-1 Honfujisawa, Fujisawa City, Kanagawa Prefecture EBARA Research Institute

Claims (3)

[Claims] 1. A suction type magnetic bearing device for supporting a supported body by a magnetic force in a non-contact manner, wherein restraining means for restraining a degree of freedom of a magnetic force generating means in a passive stable axial direction by a spring force and a damping force is provided. A magnetic bearing device characterized in that 2. The magnetic bearing device according to claim 1, wherein the magnetic force generating means is constituted by an electromagnet. 3. A magnetic bearing device characterized in that the magnetic force generating means comprises a permanent magnet.