JPS61165043A - Magnetic vibration absorbing device - Google Patents

Abstract

PURPOSE:To make it possible to absorb vibration which is extremely slight, by disposing, between a support member and a movable member, a magnetic means for effecting magnetic force in the opposite direction of recovery force, between the support member and the movable member, which increases as they come to close together. CONSTITUTION:Both support member 10 and movable member 12 are made of feromagnetic materials, and the movable member 12 is supported to a support member 10 through an air spring 13 into which compressed air is fed from a supply port 15 through a pipe line 16 and a leveling valve 17. Further, a magnet 25 is secured to the support member 10 through the intermediary of a member 16 made of feromagnetic materials. As a result, it is possible to sufficiently lower the natural frequency of the movable member 12, and therefore, it is possible to absorb even slight vibration of 1 Hz.

Description

[Detailed description of the invention] Industrial applications This invention relates to a magnetic vibration isolator.

BACKGROUND OF THE INVENTION Vibration isolators have been widely used which apply a restoring force to a movable member using, for example, a spring when the movable member is displaced relative to a support.

Problems to be Solved by the Invention Conventional vibration isolators can only isolate vibrations transmitted from the outside at frequencies of 2 to 3 Hz or more, and the amplitude of the movable member is usually on the order of several hundred microns or more. I was only able to prevent vibrations. However, there is a demand for vibration isolation against frequencies transmitted from around 1 Hz, so that the amplitude is at least several tens of microns or less, for example, several microns.

The present invention solves these problems and provides a magnetic vibration isolator that can sufficiently isolate vibrations even when the frequency transmitted from the outside is about I Hz, and the amplitude can be extremely small, less than several tens of microns. .

Means for Solving the Problems This invention provides a movable member that can be displaced in a predetermined direction with respect to a support, and restoring force means that provides a larger restoring force as the displacement increases when the movable member is displaced in a predetermined direction. The device is characterized in that it includes magnetic force means having portions disposed on the support side and the movable member, respectively, and exerting a magnetic force in a direction opposite to the restoring force between the movable member so as to increase as the movable member approaches the support body side. The present invention provides a magnetic vibration isolator.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In one embodiment of the invention shown in FIGS. 1 to 5, 10
12 is a support made of a ferromagnetic material such as mild steel, and 12 is a movable member made of a ferromagnetic material such as mild steel that is supported by the support via four air springs 13 serving as restoring force means. When an attempt is made to feed the pipe 16 and leveling pulp 17 into the air spring 13 through the supply port 15, the leveling pulp 17 operates and is evacuated from the pipe 18 to maintain a predetermined height. 20 is an adjustment screw for finely adjusting the operating point of the leveling pulp. A repel ring 7 is provided for each of the two air springs 13, and one is provided in common for the other two air springs 13, so that the movable member 12 can be moved at three points. to keep it horizontal.

A magnet 25, such as a permanent magnet or an electromagnet, has a polarity as shown in the figure. 26 is a member made of ferromagnetic material such as mild steel that fixes the magnet 25 to the support 10 and forms a magnetic path. Therefore, the movable member 12 has a magnet 25
It will be subject to a strong magnetic force. Reference numeral 27 denotes a locking member made of a non-ferromagnetic material such as copper 2 synthetic resin, which is provided between adjacent magnets 25 so that their magnetic poles slightly protrude. It is designed to prevent you from getting close and being sucked in with great force. FIGS. 4 and 5 show some of the magnetic flux generated in this case. The portion through which this magnetic flux passes, including the magnet 25 and the movable member 12, constitutes magnetic force means.

The present invention will be described in detail as follows with reference to FIG. That is, in this figure, X is the movable member 12
The position where the movable member 12 moves downward from the reference position X-, where the leveling pulp 17 is to be exhausted, is shown as a positive value. The total elastic force exerted on the movable member 12 with respect to this position
The magnetic force exerted on 2 is expressed as Fm and is a negative value.

F represents the sum of the elastic force Fs and the magnetic force Fm. In this case, Xl indicates the position where the movable member 12 is stopped by the locking member 27 when it vibrates, and Xz indicates the position where the movable member 12 is stopped by the locking member 27 when vibrating.
2 shows a state in which the number 2 is in contact with the magnetic pole of the magnet 25.

Here, the following formula holds true.

F = Fs + Fm (1) K is a spring constant when the movable member 12 makes minute vibrations, and it changes depending on the position of the movable member. The first term on the right side of equation (8) is a positive value, and the second term is a negative value. If the value of X becomes larger than the position indicated by X+ in FIG. 6, the spring constant will have a negative value and elastic vibration will not be possible. Therefore, the engaging member 27 is provided so that at least the value of xl is not exceeded. The mass of the movable member 12 is M
Then, the natural frequency f is expressed by equation (4), and in a range where the spring constant K is small, the natural frequency is very low. When vibrations in the vertical direction with a frequency f are transmitted from the outside to the support 10, the vibration transmission rate T, which is the proportion of the amplitude transmitted to the movable member 12, is expressed by equation (5), where the natural frequency f is small. The smaller the value becomes. By adjusting the set position xo of the movable member 12 using the adjustment screw 20, the spring constant K is made small and the natural frequency f becomes sufficiently small. Therefore, it is possible to prevent vibrations even from vibrations of about I Hz.

In this invention, instead of using attractive force as the magnetic force, as shown in FIG. 7, the downward force may be applied to the movable member 12 using magnets 25 that provide a larger repulsive force as they approach each other. good. Further, the present invention can be applied to a device that performs vibration isolation using a steel spring or a rubber spring in addition to an air spring.
can be applied even if it is elastically supported in any direction other than vertically, such as horizontally. FIG. 8 shows magnet 32.
A state in which the present invention is applied when supporting the movable member 12 using the repulsive force of 33 is shown, 35 is a member made of a ferromagnetic material, and 36 is a member made of a material other than ferromagnetic material.

Effects of the Invention As described above, the present invention uses magnets to significantly lower the natural frequency of the vibration isolator by magnetic force, and even if low frequency vibrations are transmitted, the transmission to the movable member 12 is significantly reduced. It has the effect of making it possible.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the main part showing one embodiment of the present invention, Fig. 2 is a front view thereof, Fig. 3 is a plan view showing the movable member removed, and Figs. 4 and 5 are An explanatory diagram showing the magnetic flux when the cross section is taken in the direction of the A-A line and the B-B line in FIG. 3, respectively,
FIG. 6 is a characteristic diagram, and FIGS. 7 and 8 are front views showing different embodiments of the present invention. 10 is a support body, 12 is a movable member, 13 is an air spring serving as restoring force means, 25 is a magnet for configuring magnetic force means, 2
6 is a locking member. Agent Patent Attorney Akira Katsube Naga-1- No. 5 8

Claims (1)

[Claims] a movable member that can be displaced in a predetermined direction with respect to the support;
When the movable member is displaced in a predetermined direction, the restoring force means provides a larger restoring force as the displacement becomes larger, and the restoring force means has portions disposed on the support side and the movable member respectively, and the portions increase as the movable member approaches the movable member. 1. A magnetic vibration isolator comprising magnetic force means configured to exert a magnetic force in a direction opposite to the restoring force between the two.