JPH01307543A - Rotary magnetic damper - Google Patents

Abstract

PURPOSE:To obtain a damping characteristic relying on the rotation angle position of a disk in a rotary magnetic damper having a nonmagnetic conductor disk and a magnetic circuit by varying the wall thickness on the same circumference of the conductor disk in the circumferential direction. CONSTITUTION:A nonmagnetic disk 13 is joined to the end of the shaft 10 of a rotary body. When the disk 13 which is normally/reversely rotated integrally with the shaft 10 accompanying the drive of the rotary body cuts a magnetic flux in the void 16 of a magnetic circuit 14, an eddy current flows in the disk 13. The wall thickness on the same circumference of the conductor disk 13 is varied in the circumferential direction, to make a damping force larger in the rotation angle zone in the vicinity of the neutral position while making it smaller in other zones. Thereby, a damping characteristic relying on the rotation angle position of the disk can be obtained.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to improvements in rotating magnetic dampers.

(Prior Art) A rotating magnetic damper is attached to a rotating body to damp its rotational vibration, and is configured as shown in FIG. 4.5, for example. 1 is a sleeve of a rotating body, and this pongee 1 is rotatably supported by a bracket 2 via a bearing 3. At the tip of the pongee 1 is a disc 4 made of a non-magnetic conductor (aluminum, #1, etc.). be combined. Reference numeral 5 denotes a yoke constituting a magnetic circuit made of permanent magnets 6. The yoke 5 is fixed to the non-magnetic bracket 2 with the outer periphery of the disk 4 positioned within the air N7 of the magnetic circuit.

When the disc 4 rotates together with the pongee 1 due to the drive of the rotating body, this cuts the magnetic flux within the gap 7 of the magnetic circuit, causing an eddy current to flow in the disc 4. This electromagnetic action generates a damping torque (electromagnetic force) proportional to the rotational speed of the disc 4, suppressing speed fluctuations and rotational vibrations of the rotating body.

(Problem to be solved by the invention) By the way, in such a rotating magnetic damper, the damping coefficient (damping torque/rotational angular velocity) is uniquely determined, but the damping coefficient can be varied depending on the vibration condition of the rotating body. For example, if the rotating body is used in a rotation range of ±172 rotations and reversible rotation angle of 180 degrees, the damping coefficient should be increased in the rotation angle region near the neutral position, and other A small (or vice versa) damping characteristic is required in the region of

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary magnetic damper that can obtain damping characteristics that depend on the rotational angular position of a disc.

(Means for Solving the Problems) Therefore, the present invention includes a non-magnetic conductor disk and a magnetic circuit that forms a magnetic field across the conductor disk at a position offset from the center of rotation of the conductor disk. In a rotating magnetic damper that generates damping torque based on the electromagnetic action of eddy currents generated as the disc rotates, the thickness of the conductor disc on the same circumference is varied in the circumferential direction.

(Effect) According to this, the volume of the disk that cuts magnetic flux in a magnetic field (area exposed to magnetic flux x plate thickness) changes depending on the rotational angular position of the disk, so the generated damping torque depends on the rotational angular position of the disk. This results in a damping characteristic that varies and depends on the rotational angular position.

(Example) In FIG. 1, reference numeral 10 denotes the shaft of a rotating body supported by a bracket 11 through a bearing 12 for free rotation.
A disc 13 made of a non-magnetic conductor is coupled to the tip of the disc. 14 is a yoke that constitutes the magnetic circuit 14 made by the permanent magnet 15;
The disc 13 is fixed to the non-magnetic bracket 11 with the outer circumference of the disc 13 positioned inside.

The disk 13 is formed such that the volume (area exposed to magnetic flux x plate thickness) of the active portion that passes through the air gap 16 of the magnetic circuit 14 changes in the circumferential direction.

Specifically, when it is assumed that the rotating body rotates within ±172 rotations, the thickness of the disk 13 is large in the rotation angle region near the neutral position of the rotating body, and in other regions, as shown in Fig. 2. It is set so that it gradually becomes smaller as it moves away from the neutral position.

In the disk 13, which rotates forward and backward together with the pongee 10 as the rotating body is driven, an eddy current flows through the disk 13 by cutting the magnetic flux in the empty IFJI 6 of the magnetic circuit 14, and the rotation of the disk 13 is caused by the electromagnetic action. A damping force proportional to the speed acts. This damping force is also proportional to the volume of the actuating part passing through the air gap 16 of the magnetic circuit 14 of the disk 13, so as shown in FIG. A damping coefficient change characteristic that is large in the corner region and becomes smaller in other regions as the distance from the neutral position is obtained is obtained, and therefore it is possible to effectively reduce the rotational vibration of a rotating body that moves after rotation within ±172 rotations. becomes.

(Effects of the Invention) - In summary, according to the present invention, a non-magnetic conductor disk is provided with a magnetic circuit that forms a magnetic field across the conductor disk at a position offset from the center of rotation of the conductor disk. In a rotating magnetic damper that generates damping torque based on the electromagnetic action of eddy currents generated as the disk rotates, the thickness of the conductor disk on the same circumference is changed in the circumferential direction, so the rotation angle of the disk is A position-dependent damping characteristic is obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a developed shape diagram of the disc operating section, FIG. 3 is a diagram of the change characteristics of the damping coefficient, and FIG. 4 is a sectional view of a conventional device. FIG. 5 is an explanatory diagram of its operation. 10... Axis, 13... Disk, 14... Magnetic circuit,
16...Void. Figure 1: Figure 3

Claims (1)

[Claims] 1.Equipped with a non-magnetic conductor disk and a magnetic circuit that forms a magnetic field across the conductor disk at a position offset from the center of rotation, the electromagnetic field of eddy current generated as the conductor disk rotates. A rotary magnetic damper that generates damping torque based on action, characterized in that the thickness of a conductor disk on the same circumference is varied in the circumferential direction.