JPH0449426Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a vibration isolation structure that prevents vibration from being transmitted from a vibration source such as a pump to precision equipment connected via piping.

(Prior technology) Precision equipment such as semiconductor manufacturing equipment, laser equipment, and NC control equipment is generally installed on vibration-proof frames because vibrations from inside and outside will adversely affect their performance. It is. Furthermore, recently, support stands for precision instruments that have a vibration-isolating structure have become popular in preparation for earthquakes and the like.

On the other hand, since the precision equipment mentioned above uses cooling water or cleaning water during operation, it is often connected to a pump, etc. through piping, and the vibrations generated by the pump, etc. are transmitted to the precision equipment through the piping and the floor. There are some drawbacks.

For this reason, conventionally, a vibration isolating joint is inserted in the middle of the piping to absorb the vibration, and the pump and precision instruments are placed on a vibration insulating foundation to insulate the vibration from the floor.

(Problem that the invention aims to solve) However, conventional vibration isolation structures have the drawback of not being able to completely block vibrations transmitted through piping, which has become a bottleneck in improving the precision of precision instruments.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a vibration isolation structure that can reliably isolate vibrations transmitted from a vibration source such as a pump to precision instruments via piping.

(Means for solving the problem) In order to achieve the above object, in the present invention, in the vibration isolation structure of precision instruments connected from the vibration source through piping, a plurality of vibration isolation joints are connected in series in the middle of the piping. At the same time, the piping between the vibration-isolating joints is connected to a heavy object, and the heavy object is installed on the foundation via a vibration-absorbing layer.

(Function) In the vibration isolation structure according to the present invention, a heavy object is connected to the piping part between the vibration isolating joints interposed in the middle of the piping, and the heavy object is installed on the foundation via a vibration absorption layer. It is possible to reduce the vibration transmission rate of the anti-vibration joint and improve its anti-vibration effect, and furthermore, the remaining vibration can be absorbed by the anti-vibration joint used for precision equipment.

(Example) FIG. 1 shows a vibration isolation structure according to the present invention.

The precision instrument 10 is placed on a concrete block 12 via a vibration isolator 11 and a vibration isolator (not shown). This concrete block 12 is buried in a recess of a foundation 13 with a layer of foaming agent 14 interposed therebetween, thereby forming an insulating foundation against vibrations.

Further, one end of a pipe 15 is connected to the side surface of the precision instrument 10, and the other end of the pipe 15 is connected to a pump 1.
6. The pump 16 is for sending a predetermined fluid to the precision instrument 10 through the piping 15, and is placed on the foundation 13 by a support stand 17.

Bellows-type anti-vibration joints 18 and 19 are interposed at two locations in the middle of the piping 15, and the piping portion between both anti-vibration joints 18 and 19 is connected to a concrete block 21 via a rod 20. connected. This concrete block 21 is buried in a separate recess of the foundation 13 via a layer of foaming agent 14, thereby forming an insulating foundation against vibrations.

In general, the vibration transmissibility τ (outlet side force/inlet side force) of an anti-vibration joint is calculated as follows, where f is the excitation frequency and fn is the natural frequency of the anti-vibration joint. f/fn) ² | ...(1)

Also, let fn be the natural frequency, k be the spring constant of the anti-vibration joint, g be the gravitational acceleration, and W be the weight of the transmission side. It is expressed as

Therefore, if W is increased in equation (2), fn becomes smaller, and since f is a constant frequency, f/fn becomes larger. Therefore, as can be seen from the graph in Figure 3, in the frequency ratio f/fn > 1, as fn becomes smaller, that is, as f/fn becomes larger, the vibration transmissibility τ in the radial and axial directions also becomes smaller. This reduces the vibrations transmitted.

Here, W is the weight of the downstream side of the anti-vibration joint 18, that is, the sum of the weight of the pipe 15 and the weight of the fixed point, so it is necessary to connect the heavy concrete block 21 to the pipe 15 as shown in Fig. 1. For example, the natural frequency fn
and the vibration transmissibility τ decreases and approaches zero.

Furthermore, when the vibration-proof joint 19 is connected to the downstream side of the piping, the vibration transmission coefficient of the vibration-proof joint 18 is τ1, and the vibration-proof joint 1 is
9 If the vibration transmissibility is τ2, then the overall vibration transmissibility τ
is expressed as τ=τ1+τ2.

τ1 is extremely small due to the provision of fixed points as described above, and this small vibration is further reduced by vibration-proof joint 1.
9, the vibration is hardly transmitted to the precision instrument 10.

On the other hand, part of the vibration of the pump 16 is caused by
The signal is transmitted to the foundation 13 through the cable, and then to the precision equipment 10 side. However, this vibration is almost completely absorbed by the layer of foaming agent 14 and the vibration isolating rubber 11 located in the middle of the transmission path.

Figure 2 shows a vibration isolation structure that also has earthquake resistance. In this embodiment, the same reference numerals are used for parts having the same configuration as the embodiment shown in FIG.

In this anti-vibration structure, a precision instrument 10 is placed on a floor 22, a vertical anti-vibration rubber 11 is interposed between the floor 22 and a concrete block 12, and an anchor 23 is inserted through the anti-vibration rubber 11. The floor 22 and concrete block 12 are connected to each other. In this case, a vibration isolation device may be inserted between the concrete block 12 and the floor 22.

Furthermore, a long flexible joint 19A is connected to the downstream side of the piping 15 instead of the vibration-proof joint 19, so that the structure can follow the vibration displacement of the precision instrument 10.

On the other hand, a vertically long anti-vibration rubber 24 is also attached to the lower surface of the support stand 17 of the pump 16, and the entire body is attached with bolts 25.
A stopper 26 having an L-shaped cross section is installed on the outside of the support base 17. This stopper 26 is arranged at a predetermined distance from the upper and side surfaces of the support base 17, and its lower part is fixed to the foundation 13 by an anchor 27.

Incidentally, for the earthquake-resistant structure of the floor 22 and the support base 17, known means are sufficient.

In the vibration isolation structure described above, the pipe 15 from the pump 16
The vibration transmitted to the building can be insulated by the anti-vibration joint 18 and the concrete block 21 at the fixed point, and the long flexible joint 19A can be used to prevent earthquakes.
The anti-vibration rubbers 11 and 24 can sufficiently cope with this problem. Further, the stopper 26 can restrict displacement of the support base 17 of the pump 16 in the vertical and horizontal directions. Furthermore, since the flexible joint 19A is also bellows-shaped, it can not only absorb displacement but also exhibit a certain degree of vibration damping effect to suppress vibration transmission.

(Effects of the invention) As detailed above, according to the invention, it is possible to reduce the vibration transmission rate of the anti-vibration joint and improve its anti-vibration effect, and moreover, it is possible to reduce the remaining vibrations to those of precision equipment. Since vibration can be absorbed by the anti-vibration joint, it is possible to almost completely block the vibration transmitted from the vibration source to the precision equipment via the piping.

[Brief explanation of the drawing]

Figure 1 is a simplified side view showing the vibration isolation structure, Figure 2 is a simplified side view showing the vibration isolation structure that also has earthquake resistance, and Figure 3 is a graph showing the relationship between excitation frequency and vibration transmissibility. be. In the diagram, 10... Precision equipment, 13... Fundamentals, 14
...Blowing agent, 15 ... Piping, 16 ... Pump, 1
8, 19... Anti-vibration joint, 19A... Flexible joint, 20... Rod, 21... Concrete block.

Claims (1)

[Scope of Claim for Utility Model Registration] In a vibration isolation structure for precision equipment connected from a vibration source through piping, a plurality of vibration isolation joints are interposed in series in the middle of the piping, and the vibration isolation between the vibration isolation joints is A vibration isolation structure characterized in that a piping part is connected to a heavy object, and the heavy object is installed on a foundation via a vibration absorption layer.