JPS597858B2 - Eddy current damping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration damping device for a high-speed rotating shaft, and more particularly to an eddy current type vibration damping device that utilizes eddy currents.

A rotating shaft that is relatively thin and rotates at a very high speed is prone to whirling vibration.

In order to prevent such whirling vibrations, an eddy current vibration damping device as shown in FIG. 1 has conventionally been used.

In Fig. 1, a nearly disk-shaped magnetic rotating body 2 is attached to the rotating shaft 1.
is installed.

This magnetic rotating body 2 has a plurality of concentric annular ribs 2a and 2b on its seven surfaces and its lower surface.

Annular ribs 2a are located above the magnetic rotating body 2, respectively.
and 2b in a downward annular groove 3a, 3b that accommodates the grooves 3a and 2b in a non-contact manner.
An annular non-magnetic conductor 3 having a diameter is disposed.

Furthermore, an annular non-magnetic conductor 4 having annular grooves 4a and 4b for receiving annular ribs 2a and 2b protruding from the lower surface of the magnetic rotating body 2 in a non-contact manner is disposed below the magnetic rotating body 2. There is.

The non-magnetic conductor 3 further has an annular protrusion 3A that enters between the annular ribs 2a and 2b in a non-contact manner between the annular grooves 3a and 3b, and the annular ribs 2a and 2b.
It has annular protrusions 3B and 3C extending adjacent to the periphery thereof.

Similarly, the lower non-magnetic conductor 4 has annular grooves 4a and 4b that receive annular ribs 2a and 2b protruding from the lower surface of the magnetic rotating body 2 without contact, and extends adjacent to these annular grooves. It has annular projections 4A, 4B, and 4C.

On the other hand, the non-magnetic conductor 3 is provided with annular recesses 3R and 3S aligned with the annular ribs 2a and 2b of the magnetic rotating body 2.

Similarly, annular recesses 4R and 4S that are aligned with the annular rib of the magnetic rotating body 2 are provided on the lower surface of the lower non-magnetic conductive hole 4.

A cylindrical magnet 5 having an inner diameter larger than the outer diameter of the nonmagnetic conductors 3 and 4 is arranged outside the annular nonmagnetic conductors 3 and 4, and both end surfaces of the magnet 5 are nonmagnetic. It is designed to be at the same height as the ends of the magnetic conductors 3 and 4.

The above-mentioned annular recesses 3R and 3S are provided on the upper surface of the non-magnetic conductor 3.
An annular yoke 6 having annular teeth 6R and 68 inserted therein is provided, and this yoke 6 is attached to the magnet 5.

A yoke 7 having a structure similar to that of the yoke 6 is a non-magnetic conductor 4.
An annular tooth 7R provided on the lower surface and protruding from the upper surface.
and 7S are annular recesses 4R and 4 on the lower surface of the nonmagnetic conductor 4.
S and the yoke T is inserted into the magnet 5.
It is attached to the lower end surface of.

In the vibration damping device constructed as described above, the magnetic circuit is constructed as shown by the dotted line in FIG.

That is, from the magnet 5, it passes through the annular teeth 6S and 6R of the yoke 6, passes through the annular ribs 2a and 2b on the upper and lower surfaces of the magnetic rotating body 2, and then returns to the magnet 5 through the annular teeth 7R and 7S of the lower yoke 7. A magnetic circuit is constructed.

Therefore, in the magnetic rotating body 2 and the non-magnetic conductors 3 and 4, eddy currents are generated in a right-handed screw direction relative to this magnetic flux, and a braking force is applied to the magnetic rotating body 2 by this.

If a whirling vibration occurs in the rotating shaft 1 and the rotating shaft 1 vibrates in the left-right direction in FIG. 1, and the magnetic rotating body 2 accordingly vibrates in the left-right direction in FIG. This causes a sudden change in the magnetic flux of the magnetic circuit as shown by , which generates eddy currents in the magnetic rotating body 2 and the non-magnetic conductors 3 and 4, and as a result, a large braking force is applied to the magnetic rotating body 2. It will be done.

Therefore, even if whirling vibration occurs, a correspondingly large damping force is applied to the rotating shaft 1.

However, in the conventional vibration damping device shown in FIG. 1 and FIG. Because of this, the magnetic flux is not widely dispersed within the nonmagnetic conductors 3 and 4, resulting in a disadvantage that a very large damping force cannot be obtained.

Furthermore, since the magnetic flux is concentrated only in a specific narrow portion, residual magnetism is likely to occur in the annular ribs 2a and 2b of the magnetic rotating body 2, and this residual magnetism also has the disadvantage of causing a whirling phenomenon during low speed rotation. Ta.

The present invention provides an improved eddy current type control device that eliminates the drawbacks of the known eddy current type vibration damping devices as described above and can obtain an even greater vibration damping effect.

In order to improve the known eddy current damping device as described above, the inventor of the present invention tried various experiments, and as a result, it was found that the annular rib of the rotating body 2 and the annular teeth of the yokes 6 and 7 were aligned as in the conventional method. In addition to arranging the annular ribs 2a and 2b, the vibration damping effect can be greatly improved by providing the yoke with annular teeth that do not align with the annular ribs 2a and 2b, or by providing the rotating body with an annular rib that does not align with the annular teeth of the yoke. I discovered that.

The present invention is based on this fact.

The eddy current damping device improved by the present invention will be explained below with reference to Figure 3 and subsequent figures of the attached drawings. Portions indicated by reference numerals are the same as those shown in FIG. 1, so explanations of these portions will be omitted unless necessary.

The feature of the first embodiment shown in FIGS. 3 and 4 is that annular grooves 3Y and 4Y that are not aligned with the annular ribs 2a and 2b are provided on the back surfaces of the upper and lower nonmagnetic conductors 3 and 4, respectively. The annular teeth 6Y and 7Y of the upper and lower yokes 6 and 7 are inserted and fixed into this.

According to this configuration, the annular teeth 6Y and 7 are additionally provided.
Since a magnetic flow path is created through Y as shown by the dotted line in FIG.
Since the magnetic flux is dispersed within the non-magnetic conductors 3 and 4, the number of eddy currents generated within the non-magnetic conductors 3 and 4 increases, and as a result, when the rotating shaft 1 vibrates, a larger damping force is generated compared to conventional devices. can be done.

As in the embodiment shown in FIGS. 3 and 4, the annular rib 2
The control effect is increased as described above by providing ring teeth that are not aligned with a and 2b on the upper and lower yokes 6 and 7, but such additional ring teeth may be provided at any position. For example, as in the second embodiment shown in FIG.
If Z, 7X, and 7Z are further added, the nonmagnetic conductor 3
, 4 is dispersed over a wider area, and therefore when the rotating body 2 vibrates in the left-right direction as shown in FIG. More eddy currents are generated in the bodies 3 and 4, and the rotation of the rotating body 2 is slowed down due to these eddy currents, so that a greater vibration damping effect is obtained.

An embodiment in which the basic principle of the present invention as described above is further expanded is shown in FIG.

In FIG. 6, instead of providing additional annular teeth that are not aligned with the annular ribs as in the previous embodiment, an additional annular rib that is not aligned with the annular teeth is provided on the rotating body to achieve the same effect as described above. A damping device is shown that can move around the area.

In the embodiment shown in FIG. 6, the rotating body 2 is provided with an additional annular rib 2c.

This additional annular rib serves as the annular tooth 6 of the upper and lower yokes 6 and 7.
8, 7S, 6R, and 7R, respectively.

The upper and lower non-magnetic conductors 3 and 4 each have annular grooves 3 for accommodating the additional annular ribs 2C in a non-contact manner.
c and 4c are provided.

It is clear from the above description that in this embodiment as well, the magnetic flux flow paths in the non-magnetic conductors 3 and 4 are dispersed, and therefore the number of eddy currents generated in the upper and lower non-magnetic conductors 3 and 4 increases. Will.

The embodiment shown in FIG. 7 shows another embodiment based on the above-mentioned principle, and in this embodiment, the yoke 6 is divided into two halves in the same circular shape, and the yoke 6 is divided into two halves. A magnet 5 is placed between them.

Each yoke 6 has several annular teeth 6T and 68 for each of the annular ribs 2a and 2b of the rotating body 2.
, 6U and 6V, 6R, 5W are annular rings 7, respectively.
'2a and 2b are arranged so as to correspond to each other.

Therefore, the rotor 2 passes from the yoke 6 through the non-magnetic conductor 3.
The flow of magnetic flux flowing through the annular ribs 2a and 2b is dispersed in the radial direction of the rotating shaft 1 in the non-magnetic conductor 3. Therefore, when a transverse vibration occurs in the rotating shaft 1, the flow of magnetic flux flows through the annular ribs 2a and 2b of the non-magnetic conductor 3.
This produces more eddy currents within the damper, thus significantly improving the damping effect compared to conventional damping devices.

The embodiment shown in FIG. 8 is a further development of the above-mentioned principle, and in this embodiment, the axial length h2 of the pocket 2d at the center of the rotating body 2 is set to the axial length h2 of the annular rib 2a. Furthermore, as in the embodiment shown in FIGS. 3 and 4, an additional annular tooth 6Y that is not aligned with the annular rib is provided between the annular tooth 6R and the annular tooth 6S. It is characterized by having the following.

According to the configuration shown in FIG. 8, the flow path of the magnetic flux flowing from the yoke 6 to the rotating body 2 through the nonmagnetic conductor 3 is formed by the annular ribs 2a, 2
Not only the magnetic flux toward b but also the boss 2 at the center of the rotating body 2
A flow path for the magnetic flux flowing toward d is also created, so that the magnetic flux is widely dispersed within the non-magnetic conductor 3. Therefore, when vibration occurs in the rotating shaft 1, the magnetic flux is distributed more widely within the non-magnetic conductors 3 and 4. Eddy currents are generated and a large damping force is obtained.

As explained below, according to the present invention, the lack of damping force caused by the small dispersion of magnetic flux in the non-magnetic conductors 3 and 4 can be improved, and a larger damping force can be obtained. An improved eddy current gland device is provided.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a conventionally known eddy current damping device.
FIG. 2 is an enlarged vertical cross-sectional view of a part of FIG. 1 for explaining the flow path of magnetic flux, and FIG. 3 is a vertical cross-sectional view similar to FIG. 1 showing the first embodiment of the present invention. FIG. 4 is an enlarged vertical sectional view of a part of FIG. 3, FIG. 5 is a vertical sectional view showing a second embodiment of the present invention,
FIG. 6 shows a third embodiment of the invention, FIG. 7 shows a fourth embodiment of the invention, and FIG. 8 shows a fifth embodiment of the invention. 1...Rotating shaft, 2...Magnetic rotating body, 3
, 4... Non-magnetic conductor, 6, 7... Yoke, 5... Magnet, 2a, 2b, 2c-...
"Annular rib, 3a, 3b, 3c... annular groove, 4a, 4b, 4c... annular groove, 3A, 3B
, 3C... annular projection, 4A, 4B, 4C...
...Annular projection, 3R, 3S, 3Y...Annular recess, 4R, 48, 4Y...Annular recess, 6
R, 68, 6Y...Annular tooth, 7R, 78.7Y
・・・・・・Ring teeth.

Claims (1)

[Scope of Claims] 1. A circular magnetic rotating body whose center portion is fitted onto a rotating shaft extending in the vertical direction, and whose annular ribs concentric with the rotating shaft protrude from both upper and lower surfaces, and the magnetic rotating body. The lower surface is provided with an annular groove that opens downward so as to receive the annular rib on the upper surface of the body without contact, and the upper surface has a plurality of annular recesses that are aligned with the annular rib and the annular groove and open upward. a first annular non-magnetic conductor placed stationary with a predetermined gap between the upper surface of the magnetic rotating body; and an annular ring opening upward so as to receive the annular rib on the lower surface of the magnetic rotating body without contact. An annular shape having a groove on the upper surface and an annular concave portion aligned with the annular groove and the annular rib and opening downward on the lower surface, and resting at a predetermined gap with respect to the lower surface of the magnetic rotating body. a second non-magnetic conductor, a magnet having an inner diameter larger than the outer diameter of the first and second non-magnetic conductors and arranged to surround the outer periphery of the non-magnetic conductor; a pair of circular yokes having annular teeth inserted into the annular recesses of first and second non-magnetic conductors and fixed to the magnet; The eddy current vibration damping device configured to form a circuit is characterized in that, in addition to the aligned annular ribs and annular teeth, either the annular ribs or the annular teeth that are not aligned are provided. Eddy current double gland device. 2. The eddy current vibration damping device according to claim 1, characterized in that several groups of annular teeth are provided for one of the annular ribs. Shaking device. 3. In the eddy current type vibration damping device according to claim 1, additional annular teeth are provided between the annular teeth aligned with each of the annular ribs, and additional annular teeth are provided between the annular teeth aligned with each of the annular ribs, and the rotation shaft is inserted through the annular teeth. The axial length of the center collar of the magnetic rotating body is longer than the length from the tip of the annular rib on the upper surface of the magnetic rotating body to the tip of the annular rib on the lower surface of the magnetic rotating body. Eddy current vibration damping device.