JPS5865321A - Magnetic bearing - Google Patents

Abstract

PURPOSE:To safely absorb shock force of a rotary body in touch down operation at high speed rotation, by providing a shock absorbing device to a touch down bearing. CONSTITUTION:Shock absorbing devices 13a, 13b, 13c, 13d are provided in touch down bearings 3a, 3b. In this way, in case of performing touch down at high speed rotation, shock force of a rotary body 2 can be dispersedly absorbed by the shock absorbing devices 13a, 13b and 13c, 13d respectively in the thrust direction and the radial direction, and safe touch down operation can be performed, then mechanical accuracy of a magnetic bearing after touch down can be obtained repeatably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bearing used in high-speed rotating equipment. FIG. 1 is a longitudinal sectional view showing an example of a conventional magnetic bearing. In FIG. 1, the rotating body 2 is attracted upward or downward due to the attractive force generated by the upper and lower permanent magnets sa and sh. To eliminate this unbalanced force,
The position of the rotating body is detected by the position detector 10, and a control current corresponding to the position is passed through the coils 7α and 7b, so that the thrust direction is always maintained at a constant position. Furthermore, by making the shape of the blades into a mutually concentric annular tooth shape, when the rotating body 2 moves in the radial direction, a magnetic restoring force acts to return it to the original position concentric with the fixed body. The magnetic bearing of FIG. 1 thus produces a axial and radial bearing effect.

Magnetic bearings are usually equipped with ball bearings 3α and 3b, as shown in Figure 1, as a safety measure against abnormal vibrations at the resonance point of the shaft, power outages, and unexpected car accidents. This ball bearing is called a touchdown bearing because it is dropped onto a bearing (touchdown) to apply braking force. However, with conventional touchdown bearings, if a touchdown occurs during high-speed rotation, the impact force cannot be absorbed very well, and the rotating body and stationary body receive a large blow, causing the rotating body's balancer to collapse and mechanical precision before touchdown to deteriorate. There were drawbacks such as the fact that it was impossible to reproduce.

The purpose of this invention is to eliminate such drawbacks, absorb the impact force of the rotating body when touching down during high-speed rotation, and make it possible to reproduce the mechanical accuracy after touchdown. .

2nd wJ is a vertical cross-sectional view showing an embodiment of the present invention, in which upper and lower touchdown bearings 5a and sb are provided with shock absorbers (
Sodium absorber) 13g, 1! IA, 15c, 1
By providing 3d, the impact force of the rotating body 2 when touched down during high speed rotation is transferred to the shock absorbers 13a and 15 in the thrust direction by 15C and ISd.
can be dispersed and absorbed in the radial direction, allowing for safe touchdown. This has great practical effects, such as making it possible to reproduce the mechanical precision of the bearing before touchdown. Furthermore, although this invention has been described with respect to a single-axis controlled magnetic bearing, it goes without saying that the same effect can be obtained even when the present invention is used in a multi-axis controlled magnetic bearing.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal section 1Δ showing an embodiment of a conventional magnetic bearing, and FIG. 2 is a longitudinal section showing an embodiment of a magnetic bearing according to the present invention. In the figure, 1 is a fixed body, 2 is a rotating body, and 3a. 3 is the upper and lower touchdown bearing, 4α is the upper and lower yoke of the rotating body, 5a and 5h are the upper and lower permanent magnets, 6α, 6
7a and 7b are the excitation coils of the fixed body, 8 is the stator of the motor, 9 is the rotor of the motor, 10 is the position detection device, 11 is the position control device, 12 is the amplifier, 13α, 13b 15c and 13d are vertical thrust shock absorbers, and 15c and 13d are vertical radial shock absorbers. Note that the same reference numerals in the figures indicate the same or corresponding parts. Applicant Daini Seikosha Co., Ltd. Agent Patent Attorney Tsutomu Mogami Figure 1 Figure 2

Claims (1)

[Claims] In magnetic bearings that perform bearing action using magnetic force, the touchdown bearing is equipped with a shock absorption device to reduce the risk of abnormal events and reproduce the mechanical accuracy of the magnetic bearing after touchdown. A magnetic bearing characterized by making it possible.