JPH02271126A - Vibration shielding device - Google Patents

Abstract

PURPOSE:To shield the vibration in the vertical and horizontal directions by installing a damper which moves in the horizontal direction between a load carrying platform and a base and setting the damping coefficient of the damper in a specific relation between the equipment weight, effective length of a suspending member, and the acceleration of free fall. CONSTITUTION:A vibration shielding device 30 consists of a vibration shielding device body 3 and a damper 9. The device 30 is installed between the load carrying platform 2 of a transport vehicle and the base 1 of a precision machine 8. Four-five is set as the number of bodies 3 and dampers 9. Then damping coefficient C of the damper 9 is set so as to satisfy the equation C>=W/2(lg)<1/2>. Here, the equipment weight is W, the effective length of a suspending member is l, and the acceleration of free fall is (g). With this constitution, the vibration in the vertical and horizontal directions of the load carrying platform 2 can be shielded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vibration isolating device that protects equipment from vibration during transportation of precision equipment.

(Prior Art) Conventionally, there is a vibration isolating device known from Japanese Patent Publication No. 56-1.31724 as a device for protecting buildings, precision instruments, etc. from vibrations caused by earthquakes and the like. This vibration isolator is based on 2
A hanging member 23, a floating body 24. They are successively connected using hanging members 25. This configuration prevents horizontal vibrations acting on the foundation 21 from being transmitted to the building during an earthquake.

By the way, in this conventional vibration isolating device.

When it is excited vertically at a frequency twice the natural frequency, it is excited horizontally.

In the case of an earthquake, the excitation acceleration in the vertical direction is about 172 times the excitation acceleration in the horizontal direction, and no excitation due to vertical motion occurs.

However, when using this vibration isolator, the horizontal acceleration and vertical acceleration are about the diameter of IG.
When used as a vibration isolating device for transportation, which has a frequency of 10 Hz to several tens of Hz, vibration in the vertical direction causes excitation in the horizontal direction.

(Problems to be Solved by the Invention) As described above, conventional vibration isolating devices cannot insulate horizontal vibrations excited by vertical vibrations, and therefore cannot be used for transportation.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a vibration isolating device capable of insulating vertical and horizontal vibrations.

[Structure of the invention]

(Means for Solving the Problem) In order to achieve the above object, in the present invention, horizontal movement is performed especially between the loading platform and the base, the weight of the equipment is W, the effective length of the hanging member is Q, and the gravitational acceleration is reduced to g. When the damping constant C is C≧
] Two dampers are provided to satisfy the load.

(Function) With this configuration, horizontal vibrations caused by vertical vibrations of the loading platform and horizontal vibrations of the loading platform can be insulated by the damper.

(Example) An example of the present invention will be described below with reference to the drawings. 1st
As shown in the figure and FIG.
A vibration isolating device 30 consisting of a vibration isolating device main body 3 and a damper 9 is mounted between the bases 1 of the vibration isolating device 30. Five vibration isolating device bodies 3 and four dampers 9 are provided, respectively.

Here, using FIG. 3 and FIG.
The configuration of is explained. That is, a cylindrical outer case 4 having a flange 41 and a flange 51 inside this outer case 4.
A cylindrical inner case 5 in which the sides are stored, and an outer case 4
between the flange 41 of the inner case 5 and the flange 51 of the inner case 5.
As shown in the figure, the main body 3 of the vibration isolating device is constituted by a series of hanging members 6 having low bending rigidity that engage alternately and connect the two cases 4 and 5. Further, the outer case 4 and the inner case 5 are fixed to the loading platform 2 and the base 1 with bolts 7, respectively. Note that 6I is a connecting fitting for the hanging member 6.

The hanging member 6 is formed into a cylindrical shape with a diameter d and a length Q.

Next, the effect of the configuration of this embodiment will be explained. When no damper is attached, the natural frequency f of the system is expressed by the following equation, where Q is the effective length of the hanging member 6 and g is the gravitational acceleration.

In other words, the natural frequency f of the system does not depend on the weight of the equipment and is determined only by the effective length of the hanging member 6. Therefore, the hanging member 6
By simply adjusting the length of the system, the natural frequency of the system can be shifted from the frequency of vibrations caused by earthquakes, etc. In other words, vibration isolation can be easily performed.

For example, when f=IHz, vibration isolation can be achieved by setting fl=about 250 mm.

On the other hand, the system when the damper 9 is attached is modeled as shown in FIG. The equation of motion at this time is expressed by the following equation.

book “0°+cQ8 +1(K-a cosωt)sil
lθ20Here, if sinθ valve θ, then θ10−〇+ω. (1--cosωt)020m
It becomes g.

However, 5m: mass of the equipment, t: time, C: overall damping constant, e: input acceleration in the vertical direction, ω. =4tt-107 circular vibration frequency.

In other words, the system becomes unstable when ω=2ω0.

However, by providing a horizontally operating damper 9, the unstable region is reduced. That is, when the damping rate ζ satisfies the following equation, the system becomes stable.

Therefore, by providing the damper 9 that satisfies the following equation, horizontal vibration can be isolated.

For example, if the acceleration in the vertical direction is IG, the attenuation rate ζ≧0
．． It may be set to 25.

By providing the damper 9 that satisfies these conditions, horizontal vibrations and vertical vibrations from the loading platform 2 are isolated.

In addition, in this embodiment, the hanging member 6 has flanges 41° and 51°.
However, instead of this, the rod 42゜52
It may be installed on.

〔Effect of the invention〕

As explained above, in the present invention, in particular, horizontal movement is performed between the loading platform and the base, and the weight of the equipment is W, the effective length of the hanging member is Q, and the gravitational acceleration is g, so the vertical vibration of the loading platform is It is possible to provide a vibration isolating device capable of insulating horizontal vibration caused by the horizontal vibration of the loading platform and horizontal vibration of the loading platform.

[Brief explanation of drawings]

FIG. 1 is a front view showing the transportation state of a device using a vibration isolating device according to an embodiment of the present invention, FIG. 2 is a plan layout of the vibration isolating device shown in FIG. 1, and FIG. 4 is a cross-sectional view of the main body of the vibration isolator shown in the figure, FIG. 4 is a diagram showing the suspended state of the hanging member shown in FIG. 3, FIG. FIG. 6 is a partial cross-sectional perspective view of a main body of a vibration isolating device showing another embodiment of the present invention, and FIG. 7 is a schematic configuration diagram showing a conventional vibration isolating device. 1... Base, 2... Loading platform. 3... Vibration isolator main body, 4... Outer case, 41
...Flange, 42...Rod, 5...Inner case, 51...Flange, 52...Rod,
6...Hanging member. 61...Connection fittings, 7...Bolts, 8.
...Precision equipment, 9...Dumper. Agent Patent Attorney Yudo Ken Chika Ken Daishimaru Figure 1 Figure 2 ↑l-8e Ces tit Figure 5 Figure 6

Claims (1)

[Claims] A vibration isolating device main body and a damper are provided between the loading platform and the base of the equipment, and the vibration isolating device main body includes an inner case fixed to either the loading platform or the base, an outer case fixed to the other side, and the inner case and the damper. and a series of hanging members with low bending rigidity that connect the outer cases, and the damper is operated in a horizontal direction to reduce the weight of the equipment by W.
, a vibration isolating device characterized in that the damping constant C satisfies the relationship C≧W/[2√(lg)], where the effective length of the hanging member is l and the gravitational acceleration is g. .