JPH04337114A - Damping mechanism - Google Patents

Abstract

PURPOSE:To effectively damp vibration in the radial direction by constituting a damping mechanism, mounted to a passive magnetic bearing of a magnetic bearing, in such a manner that fixed and movable members are connected to each other through a lamination type damper in which a damping material of plate-shaped rubber or the like and a metal are alternately laminated into a plurality of layers. CONSTITUTION:A rotor 2 is supported to a fixed part 1 by passive magnetic bearings 10, 10a in lower and upper parts and also an active type magnetic bearing 20 for controlling a position in the axial line direction of the rotor 2 is provided in a top part of this fixed part 1. A damping mechanism 30 against vibration in the radial direction is provided in the passive magnetic bearing 10 in the lower part. In the magnetic bearing thus obtained, a lamination rubber type damper 40 is interposed between movable and fixed members 32, 31, relating to an axial direction Z, to fix upper and lower surfaces of this damper 40 to the movable and fixed members 32, 31. This lamination rubber type damper 40 is constituted by respectively laminating three annular rubber plates 41 and metal plates 42 by adhesion or vulcanization so that axial diametric directional rigidity of the damper is made larger than radial directional rigidity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping mechanism for damping radial vibrations occurring in a magnetic bearing.

0002

2. Description of the Related Art A rotating machine equipped with such a magnetic bearing will be explained with reference to FIG.

A rotor 2 is supported on the fixed body 1 by lower and upper passive magnetic bearings 10, 10a so as to stabilize translational movement and tilting movement in the radial direction. Also,
An active magnetic bearing 20 for controlling the axial position of the rotor 2 is provided at the top of the rotor 2 . Furthermore,
The lower passive magnetic bearing 10 is provided with a damping mechanism 30 for radial vibration. In addition, the code|symbol 3 in a figure is an emergency bearing.

[0004] Taking the lower passive magnetic bearing 10 as an example, the fixed body side permanent magnet 11 is provided on the fixed body 1 side, which in the illustrated example is composed of four annular permanent magnets with mutually different magnetic poles. . On the rotor 2 side, a permanent magnet 12 similar to the permanent magnet 11 is provided with a deviation amount ΔZ (FIG. 1) from the neutral position.
This is offset upward in the axial direction. Therefore, the repulsive force of the permanent magnets 11 and 12 generates an axial force FZ that urges the rotor 2 upward.

The active magnetic bearing 20 consists of an electromagnet 21 provided on the fixed body 1 and a magnetic body 23 provided on the rotor 2. The electromagnet 21 attracts the magnetic body 23 downward, thereby moving the magnetic body 23 in the axial direction. resist force. Therefore, the axial force FZ can be compensated by controlling the current to the coil 22. Note that the magnetic bearing device shown in FIG. 4 is called a "single-axis control type."

[0006]

[Problems to be Solved by the Invention] In the above-mentioned single-axis control type magnetic bearing, the radial motion is stabilized by the magnetic force of the permanent magnets, but the permanent magnets are stabilized by the magnetic force of the permanent magnets. It does not have the effect of damping vibrations. Therefore, even if abnormal vibration occurs in the radial direction due to resonance of the rotor 2, it cannot be suppressed, and the rotor 2 may come into contact with the fixed body 1.

[0007] Therefore, in order to ensure that the rotor and/or rotating shaft supported by the single-axis controlled magnetic bearing rotate stably and at high speed, it is necessary to provide a radial damper with good performance. Here, a radial damper with good performance is one that has good damping of vibrations in the radial direction R and has the property of not being displaced in the axial direction or thrust direction.

However, conventional mechanical dampers have complicated structures and are difficult to assemble. There are also some that use eddy current dampers, but they have drawbacks such as poor damping characteristics against low frequency vibrations.

The present invention was proposed in view of the problems of the prior art described above, and aims to provide a simple damping mechanism for the structure of a magnetic bearing that effectively damps the radial vibration of a rotating body. The purpose is

0010

[Means for Solving the Problems] The damping mechanism of the present invention is a damping mechanism that damps vibrations of an object in a specific direction, and the damping mechanism is attached to at least one passive magnetic bearing, and the damping mechanism is fixed to a fixed direction. It includes a fixed member that is fixed to the body, and a movable member that is fixed in the axial direction but movable in the radial direction, and is made by alternately laminating multiple layers of damping material such as plate-shaped rubber and metal. The fixed member and the movable member are connected via a shaped damper.

Here, the damping mechanism of the present invention includes, for example, a passive magnetic bearing that stabilizes the radial translational movement of the rotating body;
Preferably, the present invention is used as a damping mechanism for damping radial vibrations occurring in a magnetic bearing including an active magnetic bearing that stabilizes the axial movement of a rotating body.

In carrying out the present invention, it is preferable that the layer of the laminated rubber type damper connected to the movable member is made of rubber, and that the connection with the movable member is integrated by adhesion or vulcanization. Further, the layer of the laminated rubber type damper connected to the fixing member is metal, and the connection with the fixing member is not particularly limited as long as it is a metal-to-metal connection method.

Note that the laminated rubber damper has relatively low strength in the direction separating the layers, so it is not only installed between the fixed member and the movable member of the damping mechanism, but also used as a fixed member of the rotating machine. It is preferable to interpose it between the movable member of the damping mechanism and the movable member of the damping mechanism.

[0014]

[Operation] In the damping mechanism of the present invention constructed as described above, the laminated rubber damper has much greater axial rigidity than radial rigidity. Therefore, the relative positions of the movable member and the fixed member of the damping mechanism are easily displaced in the radial direction, but hardly displaced in the axial direction.

Furthermore, since it has a plurality of layers made of rubber, an elastic repulsive force acts against displacement in the radial direction, thereby exerting an effective damping effect. That is, when radial vibration occurs in the rotating body, the laminated rubber damper deforms only in the radial direction, and generates a radial restoring force in the rubber layer to damp the radial vibration. Then, at the resonance point, it deforms to the maximum and generates the maximum radial restoring force, effectively damping radial vibration.

[0016]

Embodiments An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, a laminated rubber damper 40 is interposed between the movable member 32 and the fixed member 31 in the axial direction Z, and its upper and lower surfaces are fixed to the movable member 32 and the fixed member 31. There is.

The laminated rubber damper 40 is shown in detail in FIGS. 2 and 3.

In FIG. 2, each laminated rubber damper 40 is formed by laminating three annular rubber plates 41 and three metal plates 42 by bonding or vulcanizing. Note that the number of annular rubber plates 41 and metal plates 42 or the number of layers is not limited to three.

This laminated rubber type damper 40 has extremely high rigidity in the axial direction compared to the rigidity in the radial direction. Therefore, it is hardly deformed by the force FZ in the axial direction Z. In contrast, the radial force Fr due to radial vibration
is modified as shown in FIG. In the illustrated embodiment, the rectangular cross-section A of FIG. 2 is replaced by the rectangular cross-section A of FIG.
Transforms into 1. As a result of this deformation, the laminated rubber damper 40
A restoring force in the radial direction is generated due to the elasticity of the rubber plate or the rubber layer 41, and the radial vibration is attenuated by the restoring force.

Here, since the repulsive force due to elasticity is proportional to the amount of deformation, the greater the radial displacement or deformation due to vibration, the greater the radial restoring force.
Damping effect is improved. Therefore, this radial restoring force is at its maximum especially at the resonance point, effectively damping radial vibrations.

Note that in FIG. 1, the laminated rubber damper 40
is interposed between the movable member 32 and the fixed member 31, but it may also be interposed between the movable member 32 and the portion of the fixed body 1 above it.

[0023]

Effects of the Invention Since the present invention is constructed as described above, when radial vibration occurs in the rotating body, the laminated rubber damper deforms only in the radial direction, and the rubber layer reduces the radial restoring force. is generated to damp the radial vibration. In particular, at the resonance point, it deforms to the maximum and generates the maximum radial restoring force, effectively damping radial vibration.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a radial cross-sectional view showing a laminated rubber damper.

FIG. 3 is a radial cross-sectional view showing a deformed state of the laminated rubber damper.

FIG. 4 is a side sectional view showing a rotating machine equipped with a magnetic bearing device in which the present invention is implemented.

[Explanation of symbols] 1...Fixed body 2...Rotor 10, 10a...Passive magnetic bearing 11, 12...Permanent magnet 20... Active magnetic bearing 30... Damping mechanism 31...Fixing member 32...Movable member 40...Laminated rubber damper 41...Rubber plate 42...Metal plate FZ...Axial force ΔZ... bias amount

Claims (1)

[Claims] Claims: 1. A damping mechanism for damping vibrations of an object in a specific direction, the damping mechanism being attached to at least one passive magnetic bearing, and the damping mechanism having a fixed member fixed to a fixed body and an axis The fixed member and the movable member are fixed in one direction but movable in the radial direction. A magnetic bearing damping mechanism characterized by connecting.