JPH10129585A - Anti-rolling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the damping factor of a magnetic damper along the orbit of movable mass in the dynamic vibration absorber type anti-rolling device. SOLUTION: The magnetic damper includes a belt shaped conductive member 30 and permanent magnets 32, and the conductive member 30 is changed in shape along an orbit. For example, the conductive member 30 is changed in width, and the size or density of each hole provided for the conductive member 3O is changed. Furthermore, one out of the two permanent magnets 32 can be relatively moved with respect to the other one. Magnetic fields or magnetic fluxes can be changed by changing the relative position of the two permanent magnets 32, so that damping force can thereby be changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-oscillation device for reducing the oscillation of an object to be reduced, and more particularly to a device for reducing the oscillation of an object to be reduced by a movable mass reciprocating on a track. The present invention relates to a dynamic vibration absorber type vibration reducing device. The object to be attenuated includes a suspended ship, a marine structure floating on the sea or water such as a purge, and a structure suspended in the air such as a lift and a gondola.

[0002]

2. Description of the Related Art Conventionally, as an anti-oscillation device for reducing the oscillation of an object to be reduced, an active type using an actuator and a passive type using a dynamic vibration absorber principle are known. The active type device is configured to detect the motion of the object to be reduced by a sensor and vibrate the movable mass by an actuator. The phase of the vibration of the movable mass is controlled so as to reduce the motion of the object to be reduced. Further, there is also a type in which a damping action is generated by using torque due to a gyro effect.

On the other hand, a passive device using the dynamic vibration absorber principle has a simpler structure because it does not use an actuator for driving a movable mass, and has a wide range of application because it does not consume power.

With reference to FIG. 6, an example of a conventional vibration damping device using the principle of a dynamic vibration absorber will be described. This rocking device includes a track member 510 having a track surface 511 curved in an arc shape and a track surface 5.
11 and the orbital surface 51 that can move freely on the
And a conductor member 530 curved in an arc shape in parallel with the first conductor member 530.

[0005] The movable mass 512 has a pair of wheels 513 at the front and rear, respectively. The movable mass 5 is provided at both ends of the raceway surface 511.
Stoppers 511A, 511 for defining 12 strokes
B is provided.

Referring to FIG. 7, the structure and operation of the magnetic damper provided in the rocking device shown in FIG. 6 will be described. Movable mass 51
2 has a concave portion 512A inside and has a U-shaped cross section. A pair of permanent magnets 53 is provided on the inner surface of the recess 512A.
2, 532 are mounted. Permanent magnet 5 as shown
32, 532 are spaced on both sides of the plate-shaped conductor member 530 and at a smaller interval.

The conductive member 530 and the permanent magnets 532 and 53
2 constitute a magnetic damper. Conductor member 53
0 is made of a conductive material such as copper, and the movable mass 512 is made of a metal having a small magnetoresistance such as iron. As indicated by an arrow M, a magnetic path is formed through the movable mass 512, the permanent magnets 532, 532, and the conductor member 530 having a U-shaped cross section.

[0008] The magnetic flux generated by the permanent magnets 532 and 532 passes through the conductor member 530. Movable mass 512
Moves along the raceway surface 511, the conductor member 530 moves.
The magnetic flux passing through moves, and according to Fleming's law,
An eddy current is generated in the conductive member 530 sandwiched between the permanent magnets 532, 532. This eddy current causes the permanent magnet 5
A braking force acts on the movable mass 512 that supports the movable members 32 and 532. This braking force becomes a damping force for the movable mass 512 that reciprocates.

The magnetic damper has the following features. (1) The damping force is exactly proportional to the moving speed of the movable mass 512. (2) Since there is no mechanical contact portion and unnecessary friction does not occur, the durability is good. (3) The temperature dependency of the damping force is small.

The restoring force acting on the movable mass 512 will be described with reference to FIG. The movable mass 512 is the raceway surface 51
It is assumed that, when reciprocating along 1, the center of gravity G of the movable mass 512 reciprocates on a circle having a center O ′ and a radius R.
As shown in the figure, the lowest point of the locus of the center of gravity G is set as the origin O, and the X axis is set in the horizontal direction and the Y axis is set in the vertical direction. Further, the Z axis is set so as to be orthogonal to the X axis and the Y axis (perpendicular to the paper surface). This rocking device is configured to reduce the rocking of the rocking object about a rotation axis parallel to the Z axis.

When the movable mass 512 reciprocates along the track surface 511, a tangential component of gravity acting on the movable mass 512 becomes a restoring force. For example, if the displacement of the center of gravity G of the movable mass 512 is x, and the angle between the radius O'G of the circle and the vertical line (Y axis) is α, the tangential component of gravity is mgsin α
= (Mg / R) x, which is proportional to the displacement x of the movable mass 512.

The movable mass 512 receives a restoring force (mg / R) x due to the gravity and a damping force due to the magnetic damper. Therefore, the equation of motion of the movable mass 512 is expressed as follows.

[0013]

Equation 1 m (d ² x / dt ² ) + C (dx / dt) + kx = P

Here, k = mg / R. C is a damping coefficient by the magnetic damper, and P is an external force caused by the swing of the object to be reduced.

[0015]

Generally, in order for an anti-oscillation device to generate an optimal anti-oscillation effect on an object to be reduced, the period of vibration of the movable mass 512 must be equal to the period of oscillation of the object to be anti-oscillation. And that both vibrations are deviated by a predetermined phase difference. For example, the swinging angle of the object to be reduced increases, and the movable mass 512 is moved to the stoppers 511 at both ends.
A, when colliding with 511B, the phase relationship between the two deteriorates,
The desired anti-rolling effect cannot be obtained. Therefore, the movable mass 5
The stroke of the reciprocating motion needs to be limited so that the cylinder 12 does not collide with the stoppers 511A and 511B.

The movable mass 512 is connected to the stoppers 511A, 51
In order not to collide with 1B, the damping force by the magnetic damper may be sufficiently increased to limit the stroke. However, when the damping force of the movable mass 512 is increased, there is a disadvantage that a desired anti-oscillation effect cannot be obtained when the oscillation angle of the anti-oscillation object is small.

After all, when the swing angle of the object to be reduced is large, the damping force is sufficiently large so that the movable mass 512 does not collide with the stoppers at both ends, and when the swing angle of the object to be reduced is small. It is desirable that the damping force be sufficiently small so that a sufficient anti-oscillating effect can be obtained for the object to be anti-oscillated.

Generally, the damping force of the magnetic damper is proportional to the speed of the movable mass 512 on which the permanent magnet is mounted.
Accordingly, the damping force is small at both ends of the vibration of the movable mass 512 because the speed is small, and the damping force is large near the origin O because the speed is large.

However, with the magnetic damper used in the conventional rocking device shown in FIGS. 6 and 7, the damping force cannot be adjusted depending on the rocking angle of the rocking object. For example, the damping coefficient C of the second term on the left side of Equation 1 is constant.

Further, in the passive type dynamic vibration absorber type vibration damping device, the inertia force acting on the movable mass 512 differs depending on the installation height, and therefore, the vibration damping action changes. For example, as the installation height of the anti-oscillation device with respect to the oscillation center of the object to be anticipated is higher, the inertial force acting on the movable mass 512 becomes larger,
The inertia force acting on the movable mass 512 decreases as the installation height of the vibration reduction device decreases.

Therefore, as described above, in order to prevent the movable mass 512 from colliding with the stoppers 511A and 511B, that is, in order to limit the stroke, it is necessary to provide the rocking device with respect to the rocking center of the rocking object. It is necessary to increase the damping force as the installation height increases, and to decrease the damping force as the installation height of the rocking reduction device decreases.

However, in the magnetic damper used in the conventional rocking device shown in FIGS. 6 and 7, the damping force of the magnetic damper can be adjusted even if the height of the rocking device is different. And constant.

In view of the above, the present invention provides a vibration damping device configured to have a large damping force when the swing angle is large and a small damping force when the swing angle is small. With the goal.

[0024] In view of the above, an object of the present invention is to provide a vibration damping device configured to be able to adjust a damping force by a magnetic damper.

[0025]

According to the rocking device of the present invention, a movable mass capable of reciprocating along a predetermined trajectory, a restoring force generating device for generating a restoring force of the movable mass, and the movable mass are provided. And a damper for generating the damping force of the magnetic damper, and a damping coefficient of the damping force generated by the magnetic damper is configured to change along the orbit.

According to the present invention, in the rocking device, the magnetic damper includes a conductive member extending along the track and a permanent magnet mounted on the movable mass. Further, it is configured such that a cross-sectional area of a magnetic flux passing through the conductor member among magnetic fluxes generated by the permanent magnet changes along the trajectory.

For example, the conductor member is formed of a band-shaped member, and the width of the band-shaped member is configured to change along the track. The conductor member is formed of a band-shaped member, and the band-shaped member is provided with a number of holes, and the holes are configured so that a cross-sectional area of a magnetic flux passing through the conductor member changes along the track. I have.

According to the present invention, in the vibration damping device, the magnetic damper includes a fixed permanent magnet fixed to the movable mass and a movable permanent magnet movable with respect to the movable mass, and the movable damper is movable relative to the fixed permanent magnet. The magnetic field or the magnetic flux generated by the two permanent magnets can be changed by changing the relative position of the permanent magnets.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a vibration reducing device according to the present invention will be described with reference to FIG. The rocking device according to the present embodiment includes a track member 11, a movable mass 12 that can freely move along the track member 11, and a support member 13 that supports the track member 11 on both sides.
A, 13B and a wire 15 attached to the movable mass 12. The wires 15 are rollers 17A, 17B, 17C
Has been guided by A spring 21 is mounted on the wire 15, and the other end is mounted on the support member 13B.

In the vibration reducing device of this embodiment, a restoring force is generated by the spring 21 mounted on the movable mass 12. Compared with the example of the conventional rocking device shown in FIG. 6, the rocking device of this embodiment has a track surface 511 formed in an arc shape and the gravity acting on the movable mass 12 in the rocking device of FIG. Although the restoring force is generated by the component in the tangential direction, the difference is that the restoring force is generated by the elastic force of the spring 21 in the vibration reduction device of the present example.

Referring to FIG. 2, the structure of the magnetic damper of the rocking device according to this embodiment will be described. The magnetic damper of the rocking device according to the present embodiment includes a conductor member 30 arranged to extend in parallel with the track member 11 and a permanent magnet 3 mounted on the movable mass 12.
2, 32.

The center point of the reciprocating movement of the movable mass 12 is defined as the origin O
And When the movable mass 12 is at the position of the origin O, the restoring force by the spring 21 is only the initial tension. According to the magnetic damper of the present example, the conductive member 30 is formed of a band-shaped member, and the width of the band-shaped member is small near the origin O and becomes larger as the distance from the origin O increases.

A description will be given with reference to FIG. As shown in FIG. 3A, it is assumed that a magnetic flux of magnetic flux density B is transmitted through an infinitely wide conductor member 30. The cross section of the magnetic flux is a rectangle having a vertical length of α and a horizontal length of β. When the magnetic flux moves at the speed v, the force F acting on the permanent magnet generating the magnetic flux is expressed as follows.

[0034]

## EQU2 ## F = Cv

C is a damping coefficient that defines the damping force of the magnetic damper, and is expressed as follows.

[0036]

## EQU3 ## C = C ₀ (B ² tαβ) / ρ

C ₀ is the shape factor of the magnetic field, B is the magnetic flux density, t
Is the thickness of the conductive member 30, and ρ is the specific resistance of the conductive member 30. The shape factor C _{0 of the} magnetic field is, as shown in FIG.
When the conductive member 30 is infinitely wide, it is expressed as follows.

[0038]

C ₀ = (1 / π) [2 tan ⁻¹ γ + (γ / 2)
ln (1 + γ ⁻² ) − (γ ⁻¹ / 2) ln (1 + γ ² )]

Here, γ = α / β. As shown in FIG. 3B, the conductor member 30 is not infinite, and the vertical length is a,
In the case of a rectangle having a horizontal length of b, it is expressed as follows.

[0040]

(Equation 5)

As expressed by the equations (4) and (5),
Generally, the shape factor C ₀ of the magnetic field is a function of the cross-sectional area αβ of the magnetic flux passing through the conductive member 30. When the cross-sectional area αβ of the magnetic flux is large, the shape factor C _{0 of the} magnetic field increases, and when the cross-sectional area αβ of the magnetic flux is small, the shape factor C _{0 of the} magnetic field decreases.

In order to adjust the damping force of the magnetic damper,
What is necessary is just to change the attenuation coefficient C. The damping coefficient C is a function of the shape coefficient C ₀ , which varies with the cross-sectional area αβ of the magnetic flux. After all, in order to change the damping force of the magnetic damper, it is sufficient to change the cross-sectional area αβ of the magnetic flux.

According to the present invention, two permanent magnets 32, 3
2 is configured such that the cross-sectional area of the magnetic flux passing through the conductor member 30 among the magnetic fluxes generated by 2 is changed. As shown in FIGS. 1 and 2, the width of the conductive member 30 is narrow near the origin O and becomes wider as the distance from the origin O increases. Therefore, when the movable mass 12 is near the origin O, the damping coefficient C
The damping coefficient C increases when the movable mass 12 moves to both sides from the origin O.

An example of the shape of the conductive member 30 will be described with reference to FIG. In the example shown in FIG. 4A, the conductor member 30 is confined at a central portion including the origin O. As the distance from the origin O increases, the width becomes wider. In the example shown in FIG. 4B, similarly to the example shown in FIG.
, A reinforcing portion 30A made of a non-conductive material is provided to prevent the strength from being reduced.

In the example shown in FIG. 4C, the width of the conductive member 30 is reduced in a curved shape at the central portion including the origin O.
In the example shown in FIG. 4D, the width of the conductive member 30 changes linearly on both sides of the origin O. In the example shown in FIG. 4E,
The width of the conductive member 30 changes linearly on both sides of the origin O, but one side is straight and the other side changes.

4C to 4E, similarly to the example shown in FIG. 4B, reinforcing portions 30A may be provided on both sides in a portion where the width of the conductive member 30 is reduced. In the example shown in FIG. 4F, the width of the conductor member 30 is constant, but the conductor member 3
0 is provided with a hole 30B. A hole 30B having a large diameter is provided near the origin O, and a hole 30B having a small diameter is provided away from the origin O.

Incidentally, a large number of holes having the same diameter may be provided, and the density of the holes may be changed. For example, the density of the hole 30B is increased near the origin O, and as the distance from the origin O increases,
Decrease the density of OB. Thus, the cross-sectional area of the magnetic flux substantially passing through the conductor member 30 near the origin O is small, and the cross-sectional area of the magnetic flux substantially passing through the conductor member 30 outside both sides of the origin O is large.

In this embodiment, by changing the shape of the conductive member 30, the sectional area of the magnetic flux substantially passing through the conductive member 30 is changed, and the damping coefficient C of the magnetic damper is changed. ing.

According to the present invention, the damping coefficient C of the magnetic damper is changed according to the displacement of the movable mass 12. For example, instead of using the permanent magnets 32A and 32B, an electromagnet may be used to change the magnetic field or magnetic flux by the electromagnet. For example, the magnetic field or magnetic flux generated by the electromagnet can be changed by changing the current flowing through a coil constituting the electromagnet.

A description will be given with reference to FIG. FIG. 5 shows a pair of permanent magnets 32A provided on the upper surface 12A of the movable mass 12,
32B is shown. In this example, one permanent magnet 32B is fixed to the upper surface 12A of the movable mass 12, but the other permanent magnet 32A is configured to be able to move on the upper surface 12A of the movable mass 12.

It is assumed that the two permanent magnets 32A, 32B have the same shape and the same dimensions. Two permanent magnets 32
When A, 32B are positioned parallel to each other and aligned with one another along the Z axis, the strongest magnetic field or magnetic flux is generated between them, but the two permanent magnets 32A, 32B
Are offset from the Z-axis, the magnetic or magnetic field generated between them changes, ie, decreases.

In this embodiment, a block 34 having a female screw is attached to the movable permanent magnet 32A, and a male screw 35 is inserted through the female screw of the block 34. The head 35A of the male screw 35 is rotatably supported by a support member 36. By rotating the head 35A of the male screw 35, the female screw and the male screw 35 of the block 34 move so that the screw advances relatively to each other. Since the male screw 35 cannot be moved along the axial direction by the support member 36, the block 34 moves. Therefore, the permanent magnet 32A moves on the upper surface 12 of the movable mass 12.

The movable permanent magnet 32A is a fixed permanent magnet 32B
, The magnetic field or magnetic flux generated by the two changes, and the damping force of the magnetic damper changes. Therefore, for example, when the installation height of the rocking reduction device with respect to the rocking center of the rocking reduction target is high or when the weight of the rocking reduction target is large, the two permanent magnets 32A and 32B are mutually moved along the Z axis. Maximum damping force is generated by the alignment.

Conversely, when the installation height of the rocking device with respect to the center of the rocking of the rocking object is low or when the weight of the rocking object is small, the two permanent magnets 32A and 32B are moved with respect to the Z axis. And a relatively small damping force.

The permanent magnet 32 described with reference to FIG.
A and 32B may be applied to the conductor member 30 shown in FIG.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to these examples, and various modifications can be made within the scope of the invention described in the claims. It will be understood by those skilled in the art.

[0057]

According to the present invention, since the damping coefficient of the magnetic damper is configured to change depending on the position of the movable mass, the advantage that the optimum damping effect can be achieved for the object to be damped is provided. Having.

According to the present invention, a relatively large damping force is generated when the swing angle of the object to be reduced is large, and a relatively small damping force is generated when the swing angle of the object to be reduced is small. Therefore, there is an advantage that an optimum anti-oscillation effect can be achieved for the anti-oscillation object.

According to the present invention, since the damping force of the magnetic damper can be adjusted, there is an advantage that a desired anti-rolling action can be achieved.

According to the present invention, the damping force of the magnetic damper can be adjusted. Therefore, when the installation height of the vibration reduction device with respect to the center of movement of the vibration reduction object changes, or when the weight of the vibration reduction object changes. Even in this case, there is an advantage that a desired anti-rolling action can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a rocking device according to the present invention.

FIG. 2 is a partial view for explaining a configuration of a magnetic damper of the rocking device according to the present invention.

FIG. 3 is an explanatory diagram for explaining a shape factor that generates a damping force of a magnetic damper.

FIG. 4 is a view showing an example of a conductor member according to the present invention.

FIG. 5 is an explanatory diagram for explaining another example of the magnetic damper according to the present invention.

FIG. 6 is a diagram illustrating a configuration example of a conventional rocking device.

FIG. 7 is a diagram illustrating a configuration example of a magnetic damper of a conventional rocking device.

FIG. 8 is an explanatory diagram for explaining a restoring force of the conventional rocking device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Track member 12 Movable mass 12A Top surface 13A, 13B Support member 15A, 15B Wire 17A, 17B Roller 21A, 21B Spring 30 Conductor member 32, 32A, 32B Permanent magnet 34 Block 35 Screw 35A Head 36 Support member 510 Track member 511 Track surface 511A, 511B Stopper 512 Movable mass 513 Wheel 530 Conductor member 532 Permanent magnet

Claims (6)

[Claims] A movable mass capable of reciprocating along a predetermined trajectory, a restoring force generating device for generating a restoring force of the movable mass, and a magnetic damper for generating a damping force of the movable mass. The damping device is characterized in that the damping coefficient of the damping force generated by the magnetic damper changes along the trajectory. 2. The vibration reduction device according to claim 1, wherein the magnetic damper includes a conductive member extending along the track and a permanent magnet mounted on the movable mass. apparatus. 3. The vibration reducing device according to claim 2, wherein a cross-sectional area of a magnetic flux that passes through the conductor member among magnetic fluxes generated by the permanent magnet changes along the track. An anti-rolling device, characterized in that: 4. The vibration reducing device according to claim 2, wherein the conductive member is formed of a band-shaped member, and the width of the band-shaped member is configured to change along the track. Characteristic anti-rolling device. 5. The rocking device according to claim 2, wherein the conductive member is a band-shaped member, and the band-shaped member is provided with a large number of holes, and the holes cut off the magnetic flux passing through the conductive member. A rocking device characterized in that the area is configured to change along the track. 6. The vibration reducing device according to claim 1, wherein the magnetic damper includes a fixed permanent magnet fixed to the movable mass and a movable permanent magnet movable with respect to the movable mass. By changing the position of the movable permanent magnet relative to the fixed permanent magnet.
A rocking device characterized in that the magnetic field or magnetic flux generated by the two permanent magnets can be changed.