JPH0765320B2 - Vibration control foundation for precision facilities - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is intended for mounting a foundation or precision equipment of a vibration-damping building, such as a semiconductor factory, an optical equipment factory, or a laboratory, which dislikes not only vibration but also electric noise. Regarding the new damping foundation in the independent foundation.

(Conventional technology and its problems) In semiconductor factories and optical equipment factories that use a lot of precision equipment, and in laboratories that carry out precise measurements and experiments with precision equipment, use it in a general building to reduce the vibration in the facility. A structure with considerably higher rigidity is adopted. Furthermore, the support ground, footing, and piles are designed to reduce vibration.

However, these do not take into consideration the twist mode and the locking mode at present, and have not shown effective results. That is, when vibrations in the twisting direction and the rocking direction occur, vibrations at a point away from the twisting center and the rocking center of the building appear to be considerably large, and the effective area as a damping building is limited to a very small area. There was a problem to say.

In addition, in precision factories and laboratories that make full use of such precision equipment and precision equipment, it is strictly required to suppress various electrical noise components. A net is needed. An earth with a resistance of 10Ω or less is called a first-class earth, but it is a complicated and precise measurement system,
In such facilities where a large number of control systems are used, the highest grade ground wiring having a resistance of 3Ω or less, preferably 1Ω or less is indispensable. When this ground is grounded from one grounding point to the entire factory, the wiring length becomes too long, and even if it is called grounding, a potential is generated, and there is a problem that the above requirements cannot be endured. In addition, such a ground is extremely insufficient for AC components and high frequency components, and is not suitable for the ground of the target precision facility.

(Object of the present invention) The present invention has been made in view of the above-mentioned conventional example, and the object of the present invention is not only extremely strong against vibration in the torsional direction, but also epoch-making which is suitable for severe ground conditions. To provide a vibration control basis for various precision facilities.

(Means for Solving Problems) In the first aspect of the present invention, in order to achieve the above-mentioned object; In the independent foundation (A) for mounting, on the outer peripheral surface of the foundation (A) and the following relational expression: ex = Σiky · ilx / ky = 0 ey = Σikx · ily / kx = 0 where ex = x Eccentric distance in the direction ey = Eccentric distance in the direction kx = Spring constant in the x direction ky = Spring constant in the y direction lx = Distance in the x direction from the center of gravity to the point of action of the vertical fin ly = Point of action of the vertical fin from the center of gravity A vertical fin (la) for underground embedding is provided at a position effective for a twist mode that substantially satisfies the distance in the y direction between the two.

In the second item, the horizontal fins (lb) for underground embedding are arranged at a position effective for the rocking mode of the foundation of the vibration-free building or the independent foundation. .

In the third or fourth clause, the vertical fins (la) or the horizontal fins (l) for underground burial are adopted.
Provide a metal plate such as copper on the surface of b).

The technical means called; is adopted.

(Operation) When external translational vibration is transmitted to a building with uneven distribution of mass or rigidity, torsional vibration that accompanies the entire floor rotation and rocking that causes rocking of the building occur. Further, similar torsional vibrations and rocking also occur due to torque excitation received from, for example, environmental equipment arranged on the outer peripheral portion of the building.

In this case, in the vicinity of the center of gravity (G), the rabbit is also a corner, and as the distance from the center of gravity (G) increases, the torsional vibration rocking becomes very large, and the space that can be practically used is limited. Vertical and / or horizontal underground burying fins (l) protruding from the outer peripheral surface of the foundation (A) of
a) (lb) resistance effectively blocks this torsional vibration and locking.

As a result, the entire building can be used as a vibration-free space, and the layout of research equipment including precision control equipment can be freely set to achieve the intended purpose.

Furthermore, by installing a metal plate (4) such as copper on the underground embedding fins (1) projectingly provided on the outer peripheral surface of the foundation (A) or the independent foundation (A) of the unsuccessful building, The earth is taken from the ground from multiple points, and it becomes an independent earth for each area in the facility, which is essential for this kind of facility.
Ω or less, preferably ground wiring having a resistance of 1 Ω or less.

(Examples) Hereinafter, the present invention will be described in detail with reference to illustrated examples. As mentioned above, semiconductor factories, optical instrument factories, etc.
In a laboratory that has precision equipment and performs precise measurements and experiments,
In order to reduce the vibration in the facility, a structure with much higher rigidity than that of general buildings is adopted, and the design of the supporting ground, footing, piles, etc. has been made in consideration of vibration reduction. However, at present, the torsion mode and the rocking mode are not fully taken into consideration and the effective results have not been shown, but as a result of the research, it is possible to control such vibration in the torsion direction and the rocking direction. In order to achieve this, it was found that increasing the torsional rigidity and rocking rigidity of the building and adjusting the center of gravity and the rigid center of the building so that they coincide with each other by fins are the most effective. That is, in this case, a spring effect is provided at a position as far as possible from the center of gravity (G) of the building, and the torsional rigidity and rocking rigidity of the foundation (A) are increased to increase the amplitude response in the low range from the resonance point. Inversely reduces torsional vibration and rocking vibration and shifts the resonance point to a high frequency to make the building or foundation structure that is hard to shake due to torsional vibration and rocking vibration. The center of gravity and the center of rigidity are made coincident with each other by being provided at the position to prevent occurrence of moment excitation due to external translational vibration input. This makes it possible to effectively eliminate vibrations in the twisting direction and the rocking direction.

Therefore, a fin for undergrounding (1) is projected on the outer peripheral surface of the foundation (A) of a building such as a semiconductor factory, an optical equipment factory, or a laboratory where vibration is disliked or an independent foundation (A) for mounting precision equipment. Then, firmly fix it in the ground. Figure 1 is a schematic plan view when vertical fins (la) are used. Vertical fins (l) are attached to the center of the outer periphery of the building foundation (A) or independent foundation (A).
This is an example of projecting a). FIG. 2 is a schematic sectional view thereof. In the illustrated embodiment, the vertical fins (la) have a trapezoidal shape with a wide base portion, but the vertical fins (la) are not limited to this and may have a rectangular shape or other shapes. Further, as shown in FIG. 2, a triangular reinforcing rib (2) may be provided at the base of the vertical fin (la), or as shown in FIG. 7, the vertical fin (la) may be perpendicular to the corner of the building. You may project.

Hereinafter, measures against the torsional vibration will be described. Now, even in such a building (A), environmental equipment (3) such as an air conditioner is always necessary, and it is arranged in the peripheral portion inside the building, which easily becomes a vibration source of torque excitation. Is. In addition to this, translational external vibrations in the XY directions are also transmitted from the outside of the building, and if such external vibrations are transmitted to a building with uneven distribution of mass or rigidity, only one side or both sides will rotate the entire floor. The accompanying torsional vibration is generated. However, this torsional vibration is greatly reduced by the action of the vertical fins (la).

That is, a building undergoes a large torsional vibration due to moment excitation due to vibration of an air conditioner or external vibration from outside the building, but the equation of motion at this time when damping is ignored is: It is represented by.

Here, kx = spring constant in X direction ky = spring constant in Y direction Kθ = spring constant in θ direction = acceleration in X direction = acceleration in Y direction = angular acceleration M = mass I = moment of inertia x = amplitude in X direction y = amplitude in Y direction θ = angular amplitude At this time, It is represented by.

lx = distance in the X direction from the center of gravity to the point of action of the fins ly = distance in the Y direction from the center of gravity to the point of action of the fins where kx and ky are determined by the ground contact area (A)
Alternatively, it is possible to effectively increase (Kθ) by attaching the fin (1) having a required area to the outside of the independent foundation (A).

Now, the torsional compliance (θ
Considering / F), the effect of increasing the torsional rigidity reduces the amplitude response in the low range from the resonance point in inverse proportion to the increment and moves the resonance point to a high frequency, making it difficult for the building or foundation (A) to shake. It has a structure.

Also, to make the center of gravity of a building coincide with the center of gravity is kx, k
Adjust y, lx, ly, To obtain the position of the fin (1) and the spring constant. At this time, the system eliminates the rotational coupling term and can reduce the torsional vibration generated by the input of ground vibration (external translational vibration).

This equation of motion is; , And the inputs are not coupled.

Next, a countermeasure against rocking vibration will be described.
Figures 8 and 9 show effective positions for the rocking mode on the foundation of an unsettled building or independent foundation (for example, the imbalance due to uneven distribution of mass in the building is balanced by mounting horizontal fins (lb)). Etc.), the horizontal fin (1b) is arranged on the vertical fin (1a). Of course, the horizontal fin (1b) may be provided independently. This allows
The vertical spring constant can be increased, the natural frequency of the rocking mode of the foundation (A) can be increased, and the compliance can be effectively reduced. The motion of the foundation (A) at this time can be considered in the same manner as in the case of horizontal vibration. For simplicity, a rocking mode around the Y-axis is taken out and an equation in which attenuation is neglected is constructed as follows.

Here, Iy = moment of inertia about the Y axis Ry = rotation angle about the Y axis.

The eccentric distance is as follows.

Here, when the horizontal fin (1b) is provided on the foundation (A), Z
Since the eccentric distance (Ez) in the direction and the spring constant (Kz) change, if this is (Ez ′) (Kz ′), , Becomes. Also, the locking rigidity is To get In the case of such a fin structure, a large lFx can be taken, and the horizontal fin (1b) can also be expected to have upper and lower ground, so that a large spring constant can be taken.

The vertical fins (1a) and the horizontal fins (1b) can be used individually to exert their respective predetermined effects, or by combining them, both effects can be simultaneously exerted. Is also possible.

Further, in such a precision facility, it is strictly required to suppress various electrical and electrical noise components in order to make full use of precision equipment and devices as mentioned above. By installing a metal plate (4) such as copper on the surface of the underground burying fin that is provided so as to project on the outer peripheral surface of the independent foundation, it is possible to easily obtain the highest grade resistance of 3 Ω or less, further 1 Ω or less. It can be grounded. The metal plate (4) is attached to one side or both sides of the fin (1), and the attaching method is not particularly specified. In this case, at least four grounds can be independently grounded in the embodiment shown in FIGS. 1 and 6, and eight grounds can be independently grounded in the embodiment shown in FIG.

This enables the construction of factories and research laboratories that can suppress not only small vibration but also electric noise.

(Example 1) In a clean room factory with a size of (30 m x 50 m), the projecting fin (1) in the example of Fig. 7 (projecting length of fin (1) = 5 m,
When the embedded depth of the fin (1) = 5 m and the height (width) of the fin (1) = 20 cm), the vibration amplitude in the horizontal direction was 1 μm, but it decreased to 0.1 μm or less. .

The positioning accuracy of a stepper, which is a kind of semiconductor manufacturing equipment and is an ultra-precision equipment, has been fluctuated by 0.1 .mu.m to 0.2 .mu.m in the conventional 3 .sigma.

(Effect) As described above, the present invention is an underground foundation on the outer peripheral surface of a foundation for a foundation of a vibration-insensitive building such as a semiconductor factory, an optical equipment factory, or a laboratory, or an independent foundation for mounting precision equipment. Since the embedding fins are projected, firstly, according to the vertical fins, the working distance (l) of the spring effect and the ground contact area (k
x), (ky) can be increased, and as a result, the torsional rigidity (Kθ) can be increased. As a result of the increased torsional rigidity, the amplitude response in the low range from the resonance point is inversely proportional to the increment. There is an advantage that the torsional vibration can be reduced, the resonance point can be moved to a high frequency, and the building or the foundation can be made to have a structure that is hard to shake due to the torsional vibration. Second, adjust the position of the fins, Is satisfied so that the center of gravity of the building coincides with the center of gravity of the building, and the generation of moment excitation due to external translational vibration input is prevented. This has the advantage that vibration in the torsional direction due to two causes can be effectively eliminated, and the entire building can be made into a substantially uniform microvibration state.

As for horizontal fins, (lfx) can be increased, so rocking rigidity including the term (lfx ² ) is also increased, and upper and lower ground can be expected, so a large spring constant is used. It is possible to suppress the locking effectively.

In terms of grounding, metal plates such as copper are provided on the surface of the underground burying fins protruding from the outer peripheral surface of the foundation of the vibration-free building or the independent foundation. Since this means that the ground is taken to the ground, it becomes an independent ground for each area in the facility, and it is the highest grade ground wiring with a resistance of 3Ω or less, preferably 1Ω or less, which is indispensable for this type of facility. Can be

[Brief description of drawings]

FIG. 1 ... Schematic plan view of one embodiment of the present invention FIG. 2 ... Schematic cross-sectional view of one embodiment of the present invention FIG. 3 ... Schematic plan view showing the influence of torsional vibration FIG. Schematic plan view showing the state of vibration generation Fig. 5 Graph showing the effect of fins Fig. 6 Schematic plan view of the second embodiment of the present invention Fig. 7 Schematic of the third embodiment of the present invention Plan view FIG. 8 ... Front view of the underground buried portion when horizontal fins are installed on the vertical fins of the present invention, FIG. 9 ... Side view of FIG. 5, FIG. 10 ... Case of FIG. The front view equivalently represented by a spring. (A) …… Building or foundation, (G) …… Center of gravity (1) …… Fin, (1a) …… Vertical fin (1b) …… Horizontal fin, (2) …… Rib (3) …… Environmental equipment , (4) …… Metal plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Showa 59-116442 (JP, U) Showa 62-140152 (JP, U) Japanese public Sho 56-20414 (JP, B1) Japan Acoustic Materials “Handbook for Noise and Vibration Countermeasures” edited by the association (1982-1-30) Gihodo Publishing Co., Ltd. 436-446

Claims (4)

[Claims] 1. In an independent foundation for mounting a base of a vibration-insensitive building such as a semiconductor factory, an optical equipment factory, or a research laboratory or a precision equipment, on the outer peripheral surface of the foundation and the following relational expression: ex = Σiky Ilx / ky = 0 ey = Σikx ily / kx = 0 where ec = eccentric distance in x direction ey = eccentric distance in y direction kx = spring constant in x direction ky = spring constant in y direction lx = from center of gravity The distance in the x direction between the points of action of the vertical fins ly = The vertical fin for undergrounding is projected at an effective position for the twist mode that substantially satisfies the distance in the y direction from the center of gravity to the points of action of the vertical fins. Damping foundation for precision facilities characterized by being installed. 2. A horizontal fin for underground embedding is arranged at a position effective for a rocking mode such as a foundation of an unsuccessful building or an independent foundation, according to claim 1. Vibration control basis for the listed precision facilities. 3. The vibration damping foundation for precision facilities according to claim 1, wherein a metal plate such as copper is provided on the surface of the vertical fins. 4. A vibration damping foundation for a precision facility according to claim 2, wherein a metal plate such as copper is provided on the surface of the vertical fins or the horizontal fins.