JPS6280318A - Magnetic vibration damping device - Google Patents

Abstract

PURPOSE:To aim at miniaturizing permanent magnets and at stabilizing damping force, by disposing a vibration damping member having magnetic wires embedded at a predetermined density in an electroconductive material, in a part of a magnetic flux path created between a stationary permanent magnet and a rotary permanent magnet. CONSTITUTION:A ring-like rotary permanent magnet 13 which is attached on the upper surface of a thin disc-like attaching plate 12 secured to the upper end of a rotary shaft 11, is covered with a nonmagnetic protective cover 14 having a high specific resistance so that the magnet 13 is protected. Further, a stationary permanent magnet 15 is arranged and is magnetized so that the both magnets 13, 15 attract each other, and is covered at the opposing face side thereof with a vibration damping member 16 while nonmagnetic electroconductive materials 17 are made in close contact with both sides of them. Further, the vibration damping member 16 is formed by such a manner that magnetic steel wires are embedded in a nonmagnetic electroconductive material axially at a predetermined density. Accordingly, the permanent magnets may be miniaturized, and recovery force and damping force are stabilized while magnetization exciting force may be made less.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic vibration damping device, and particularly to a magnetic vibration damping device that is compact and has stable performance.

[Background of the invention]

Magnetic vibration damping devices are widely used in bearings and the like of turbomolecular pumps. This magnetic vibration damping device is, for example, the 29th
As shown in the figure, a high magnetic permeability plate 3 is closely interposed between a permanent magnet 1 placed on the stationary side and a good conductivity plate 2, and a predetermined distance is placed between the permanent magnet 4 placed on the rotating side. I'm trying to get some damping force. As such a conventional device,
There is one described in Japanese Utility Model Publication No. 54-32133.

However, in the conventional device, in order to ensure a path for eddy current in the radial direction, it is necessary to provide a non-magnetic, highly conductive plate 2 under the high magnetic permeability plate 3, and this part is magnetically separated by an air gap. becomes. Therefore, in order to ensure bearing characteristics, the size of the permanent magnet becomes large and a large number of fixed parts are required.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a magnetic vibration damping device that is compact and has stable performance.

[Summary of the invention]

In order to achieve the above object, the present invention provides a vibration damping body in the magnetic flux path portion formed between each permanent magnet on the fixed side and the rotating side, and this vibration damping body includes a magnetic wire in a conductive material. It is characterized by being buried at a predetermined density, and the magnetic permeability μX of the damping body installation portion is extremely large.

[Embodiments of the invention]

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

As shown in FIG. 1, at the upper end of the rotating shaft 11.

A thin disc-shaped mounting plate 12 is fixed, and a ring-shaped rotating permanent magnet 13 is mounted on the upper surface of the mounting plate 12.

It is covered and protected by a protective cover 14 that is non-magnetic and has high specific resistance. The stationary permanent magnet 15 is arranged to face the rotating permanent magnet 13 so as to be attracted to each other in the axial direction, and is magnetized.

Further, the lower surface side of the stationary permanent magnet 15, that is, the side facing the rotating permanent magnet 13, is covered with a vibration damper 16, and non-magnetic conductive materials 17.
7 is closely attached.

As particularly shown in FIG. 2, the vibration damping body 16 is made by embedding iron wires 19, which are magnetic materials, at a predetermined density in a ring-shaped non-magnetic conductive material 18 so as to extend in the axial direction. . In order to create such a vibration damping body 16, as shown in FIG.
Create 1 first. Next, the composite magnetic conducting wire 21
is cut into a predetermined length, preheated to an appropriate temperature, and cast into a concave cross-sectional shape as shown in FIG. It's crowded.

Fixed side permanent magnet 15 of the vibration damping device having such a configuration
As shown in FIG.
The magnetic permeability μX (vertical axis) is increased approximately in proportion to the space factor of the iron wire 19. and.

The actual value is several to hundreds of times larger than that of air.

Furthermore, since the inner and outer portions of the vibration damper 16 are electrically connected by the non-magnetic conductive material 17, an eddy current path is ensured.

Therefore, it is possible to reduce the air gap height g between both permanent magnets 13 and 15, and thereby the magnetomotive force consumed in the air gap is suppressed to a small level, and both permanent magnets 1
It becomes possible to reduce the height of 3.15.

As shown in Fig. 6, the attractive force F (vertical axis) generated between two magnets is inversely proportional to the magnetic gap g (horizontal axis), but the magnetic bearing'! The characteristics required for the A position are to have a predetermined suction force Ft (this Ft is determined by taking into account elongation due to temperature rise of the rotating body and not more than the rotating weight W), and It is necessary to have radial restoring force and vibration damping force.

As a result of comparing the radial restoring force when both permanent magnets 13.15 are made 0.7 times that of the conventional one (see Fig. 29), as shown in Fig. 7, one of the present invention (solid line) has , was found to have a value equivalent to that of the conventional one (dashed line).

Furthermore, as shown in FIG. 8, similar values of damping force were obtained.

It is expected that a strong vibration damping force will be obtained. ' Also, in the embodiment shown in FIGS. 10 and 11, iron 4
1i! 19 are concentrated on both edges of the fixed permanent magnet, that is, on both sides of the main magnetic path. Even in this case, the same effects as in the above embodiment can be obtained.

Furthermore, as shown in FIG. 12, the iron wires 19 may be arranged in a staggered manner in the radial direction, or as shown in FIG.

The iron wires 19 may be arranged radially, or may be provided in multiple stages as shown in FIG. Also,
In the embodiment shown in FIG. 15, iron wires 19 are arranged in a grid pattern, and FIG. 16 shows an embodiment in which the iron wires 19 are directly embedded in the main body.

Furthermore, the embodiment shown in FIG. 17 has two inner and outer parts on the fixed side.
The present invention is applied to a repulsion type magnetic bearing equipped with 15.25 permanent magnets, and each fixed side permanent magnet 15.2
A damping body 16 is attached to each of the vibration absorbers 5.

Figure 18 shows how many permanent magnets 13 and stationary permanent magnets 15 per revolution.
The figure shows a repulsion type magnetic bearing in which the magnetic bearings are disposed so as to face each other in the radial direction.
6 and 16 are installed. The magnetic bearing shown in FIG. 19 uses a magnetic yoke 26 on the rotating side, and a damper 16 is provided at the tip of the magnetic body 27 connected to the fixed permanent magnet 15. Note that, as shown in FIG. 20, the iron wire 19 may be provided at the center and both sides of the magnetic yoke 26.

Next, in the embodiment shown in FIG. 21, iron wires 19 are also provided on both sides of the main magnetic path.

According to such a configuration, when there is no axis misalignment between the rotating side and the stationary side, the magnetic flux distribution is symmetrical as shown in Fig. 22, and when axis misalignment occurs on both sides, the magnetic flux distribution is symmetrical as shown in Fig. 22. As shown in the figure, the magnetic flux near the iron wire 19 changes rapidly. This generates eddy current, which generates a damping force proportional to the eddy current. As shown in FIG. 24, this damping force is larger in the present invention (actual) than in the conventional damping force (broken line).

In the embodiment shown in FIG. 25, the iron wires 9 are concentrated inside the fixed permanent magnet 5. In this way, it is possible to suddenly change the magnetic flux and obtain a large damping force.

Furthermore, as in the embodiment shown in FIG. 26, if the iron m19 provided on both sides of the stationary permanent magnet 15 is extended in the axial direction, the leakage magnetic flux is increased and a large damping force can be obtained.

Furthermore, as shown in FIG. 27, the iron wire 19 may be installed in multiple layers so as to extend in the radial direction, or as shown in FIG. 28, the iron wire 19 may be placed outside the rotating permanent magnet 13. You can also.

〔Effect of the invention〕

As described above, the magnetic vibration damping device according to the present invention has a damping body that increases magnetic permeability between the stationary permanent magnet and the rotating permanent magnet, so that the permanent magnet can be made smaller. It is possible to stabilize the restoring force and damping force.

Further, the magnetomotive force required to magnetize the permanent magnet can also be small.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a magnetic vibration damping device according to an embodiment of the present invention, Fig. 2 is a perspective view of a vibration damper, Fig. 3 is a perspective view of a composite magnetic flux conductor, and Fig. 4 is a fixed side frame. Longitudinal cross-sectional view showing the body,
Fig. 5 is a line diagram showing magnetic permeability, Fig. 6 is a vertical cross-sectional view of the fixed side frame in another embodiment of the relationship line between attractive force and magnetic gap, Figs. 11, 12, and 13. The figure is a perspective view showing another embodiment of the damping body, FIGS. 14 to 21 are longitudinal cross-sectional views showing still other embodiments of the present invention, and FIG.
23 and 23 are partially enlarged longitudinal sectional views showing changes in magnetic flux, FIG. 24 is a comparison diagram of damping force, and FIGS. 25 to 28 are longitudinal sectional views showing still other embodiments of the present invention. , 29th
The figure is a longitudinal sectional view of a conventional device. 11... Rotating shaft, 12... Mounting plate, 13... Rotating side permanent magnet, 15... Stationary side permanent magnet, 16... Vibration suppressor, 17.18... Non-magnetic electric body , 19... iron wire,
21...Composite magnetic conducting wire.

Claims (1)

[Claims] 1. In a magnetic vibration damping device that generates an eddy current at the time of axis misalignment through the interaction of permanent magnets attached to each of the fixed side and the rotating side to obtain a damper effect, the fixed side and a vibration damper is disposed in the magnetic flux path formed between each permanent magnet on the rotating side, and the vibration damper is constructed by embedding magnetic wires at a predetermined density in a conductive material. A magnetic vibration damping device featuring: 2. The magnetic vibration damping device according to claim 1, wherein the vibration damping body is installed across the main magnetic path and the vicinity of the main magnetic path.