JPH11139104A - Vibration-controlled carriage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a flaw and breakage or the like generated by vibration by absorbing and moderating instantaneously as much as possible vibration of a carriage generated by a floor applied mainly with a grating treatment. SOLUTION: In this vibration-controlled carriage, an isolator 20 in which a rope body bundled and threaded with several hard steel wires is wound spirally, in which a spring is formed by arranging a fixing frame plate parallel to its wound direction, and which absorbs vibration with frictional heat generated by spring action is arranged in one part of the carriage 10 for conveying a precision product, parts and the like. A ratio of a natural frequency (fn ) of the isolator 20 to an estimated frequency (ft ) generated by the carriage traveling on a floor surface applied with a grating treatment or the like is set to satisfy ft /fn >√2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trolley for transporting high-precision parts such as semiconductor manufacturing wafers and liquid crystals in factories, offices and the like, and more particularly, to a trolley used in a clean room or the like. The present invention relates to a bogie suitable for traveling on a floor provided with grating.

[0002]

2. Description of the Related Art In a clean room such as a semiconductor manufacturing plant, a suction port for absorbing air blown from a ceiling is provided on a floor side, and a large number of holes are formed in the floor surface so that air can flow. A so-called grating process is performed in which a board is laid.

However, when components such as wafers for manufacturing semiconductors and liquid crystal are placed on a cart and conveyed on the floor subjected to the grating process, vibrations are generated between the wheels of the traveling cart and many holes. The vibrations may affect the products on the trolley, causing friction or collision, which may cause damage or damage. Since the product is required to have high accuracy, a slight damage becomes a serious defect of the product, and has a drawback that the yield is deteriorated.

As a countermeasure, for example, a method of alleviating vibration with rubber, a single-wire spring, air, or the like is conceivable. And constantly changes to the left and right, and changes in the pressing force and speed of the person, and the presence or absence of unevenness on the slope and floor, etc., and the vibration is not static but dynamic, so it is complicated. Vibration is caused.

Therefore, according to the above method, although the vibration is gradually attenuated, the backward movement is unavoidable during that time, and is effective only in one direction with respect to the vibration. It is unsuitable, and as a result, the friction between the above products and parts is repeated many times, resulting in scratches, breakage, and the like.

[0006]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above problems, and absorbs and alleviates the vibration of a bogie mainly caused by grating as quickly as possible, so that a scratch or breakage caused by the vibration is obtained. And so on to improve product yield.

[0007]

According to the present invention, there is provided an anti-vibration trolley comprising a helical rope body formed by bundling a plurality of hard steel wires and hanging on a part of a trolley for transporting precision products and parts. The spring is formed by arranging a fixed frame plate in a direction parallel to the rotation to form a spring, and an isolator for absorbing vibration by frictional heat generated by the action of the spring is provided. The natural frequency (f and _n), the ratio of the grating processed frequency that is assumed to floor choice resulting from carriage to travel (f _f) is configured to set such that _f f / f _n> √2 You.

When the truck travels on the floor subjected to the grating processing, vibration occurs. When energy of the vibration is applied to the isolator, the natural frequency (f _n ) of the isolator and the floor surface subjected to the grating processing are generated. occur damped oscillation by the ratio between the frequency (f _f) which is assumed to result from carriage that travels choice was _f f / f _n> √2,
In addition, since the bundled wires are in contact with each other, they tend to generate frictional heat, which is converted into energy for damping, and the vibration is absorbed to such an extent that there is almost no backward movement. At that time, since several strands are used as a bundle of strands, even if the vibration generation direction is up and down, left and right, and back and forth, the three-dimensionally generated friction is uniform, Regardless of the direction in which the vibration occurs, the vibration is evenly absorbed, and it corresponds to a complex vibration.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cart 10 to which the present invention is applied is used for transporting precision products such as semiconductor manufacturing wafers and liquid crystal panels in factories, offices, and laboratories. Although the shape does not matter, as described above, since the vehicle travels on the floor or the like on which the grating processing has been performed, as shown in FIG.
At least a caster 12 is arranged below the support leg 11,
It refers to an arrangement on which a base plate 13 for placing a product to be conveyed is placed.

Next, as shown in FIGS. 2 and 3, the isolator 20 is a wire 2 which is obtained by heat-treating a hard steel wire and then drawing it.
For example, a strand 21b is formed by bundling about 15 to 20 strands of 1a to form a strand 21b, and further bundling about 5 to 10 sets of the strands and bundling again to form one rope body 21. This is spirally turned to form a spring, and fixed plates 22a and 22b sandwiched up and down are arranged above and below the rope body 21 to fix the rope, and the vertical direction of the fixed plates 22a and 22b. The spring is configured to exhibit elasticity by a spring.

As shown in FIG. 2, the spiral winding of the rope body 21 is performed by turning one of the right and left sides to the right and then turning back at the center.
A mode in which the left side is turned to the opposite left is desirable because the elasticity is balanced in the left and right directions. However, the present invention is not limited to this mode of turning, and it may be formed only in a single left or right turning direction.

Then, between the base plate 13 and the support leg 11, at a position where the vibration transmitted from the support leg 11 is not transmitted to the product M, for example, as shown in FIG.
The isolator 20 is disposed between the first and the third components. The isolator 20 may be provided as a single unit as shown in FIG. 2 on a part of the truck, or may be replaceable in combination with a replacement member 30. For example, as shown in FIG. 11
On the other hand, U-shaped engaging pieces 32a and 32b fitted on the curved portions of the coupling frames 31a and 31b are provided on the vibration isolator 20 side, The connecting rods 33a and 33b that fit within the U shape are slightly elongated, and fixing screws 34a and 34b are provided at the tip of the connecting rods 33a and 33b.

When the truck 10 runs on the floor subjected to the grating processing, unevenness is generated by a large number of holes formed in the grating, and
Small vibrations occur continuously. Further, the present invention is not limited to grating, but if a wiring cord is laid on the floor surface, a relatively large impact vibration is generated when the caster 12 is placed on the floor.

In response to the above vibration, the isolator 2 of the present invention
0 causes the vibration in response to this, and when it is expressed by the equation of motion, it can be expressed as d ² x / dt ² + 2γdx / dt + ω ² x = 0 γ: damping ratio x: amplitude ω: natural circular frequency , And its damping ratio γ is as follows: γ = c / 2√ (mk) c: damping coefficient m: mass k: spring constant

The relationship between the spring constant of the spring, the load applied to the carrier, and the deflection occurring therefrom is as follows: k = f / d k: spring constant f: load d: deflection.

At this time, the spring has a natural frequency such that f _n = 1 / 2π√ (k / m) where f _n is a natural frequency and m is a mass.

In order to induce damping vibration in the spring of the present invention, the frequency between the frequency ( _ff ) generated in the bogie and the natural frequency of the spring is given by: f _f / f _n > √2 f _f : bogie frequency f _n occurring: set the natural frequency to the natural frequency of the relationship between the spring holds.

[0018] Here, T = Output / Input T: when the vibration transmissibility, the relationship between T and _f f / f _n, damping ratio (gamma)
However, the results obtained when γ = 0.10 and γ = 0.20 are as shown in FIG. γ = 0.10 and γ = 0.20
This is because the damping ratio of the spring of the present invention is approximately γ =
This is because 0.10 to γ = 0.20.

[0019] From FIG. 5, the value of T _f f / f _n is at the least √2 becomes 1 or less, further rapidly the value is reduced.
That is, if the ratio between the transmitted frequency and the natural frequency of the spring is set to an appropriate value in advance, an extremely small value of the vibration transmissibility can be obtained, and a large vibration damping effect can be obtained. Is shown.

Therefore, from the load applied to the carrier, the shape of the grating, the casters and the support legs of the truck, etc., T
Assuming the “input” value of the above, a spring having a natural frequency corresponding to this value is set, and when the load changes, the spring is changed in accordance with this load, that is, as described above, If the exchange members 30 in which the connecting frames 31a and 31b having the portions formed and the attachment pieces 32a and 32b are combined and the isolators can be exchanged freely, the most appropriate vibration damping effect even when the load of the load changes. Can be obtained.

When vibration energy is applied to the isolator 20, friction occurs inside the wire 21a of the spring and between the wires 21a, and this is easily led to energy conversion into damping. Because the essence of the damping force is the force that resists the movement caused by the energy of the vibrations escaping out of the system through the surrounding media or being spent internally as heat, the isolator In the case of 20, the bundled strands 21a are in contact with each other, so that frictional heat is easily generated, that is, the energy of vibration is converted into heat, and a large vibration-proof effect is easily exerted. In addition, since several strands 21a are relied on as a bundle of strands 21b, and the strands 21b are relied on the bundle again, even if the direction of vibration generation is up and down, left and right, and back and forth. The three-dimensionally generated friction is uniform, so that the isolator 20 can exhibit a vibration-damping effect for all three-dimensional vibrations, no matter how complicated.

[0022]

[Test Example] As shown in FIG. 6, a truck provided with casters provided with a vibration-proof property made of urethane resin was prepared, an isolator was provided between the support legs of the truck and the base plate, and placed on the base plate. A cell A for measurement and a cell B were placed on a plate passed between supporting legs, and a value obtained by converting acceleration into a voltage through both cells A and B was drawn on an oscilloscope. The case was set on the floor of the grating for CR and the case where the round cord wire of 10 mm was laid on the floor as an obstacle. On the floor, a) the case of pushing manually at a constant speed (constant speed), and b) the case of pushing out and accelerating by hand (acceleration) are set. The load of the load is 10 kg and 20 kg. And the combinations shown in Table 1.

[Table 1]

FIG. 7 is a graph displayed on an oscilloscope in which the acceleration measured from the test cell is converted into a voltage.
When the value of T and the value of the vibration isolation effect are read from now on, for example, N
In the case of O1, T = output / input = 0.2451 / 7.7054 = 0.0
3 The vibration isolation ratio = (1−0.03) × 100 = 97%. Table 2 shows the results of the same tests performed on NOs 1 to 6 in the same manner.

[Table 2]

As a result, in all cases, the vibration isolation ratio was 95% to 98%.
%, And it has been confirmed that an extremely high vibration-proof effect with almost no return is exhibited.

[0025]

According to the anti-vibration trolley of the present invention having the above-described structure and operation, the characteristics of the isolator, which easily converts the vibration energy into heat, can be used to transfer the grating-treated floor or the like. A high vibration damping effect is obtained in which vibrations occurring in the semiconductor device are absorbed to such an extent that almost no recurrence occurs, damage to high-precision products such as semiconductor manufacturing wafers and liquid crystals can be prevented, and the yield can be greatly improved. In this case, since the vibration energy is absorbed three-dimensionally, it is possible to adapt to any complicated vibrations caused by the conveyance. Furthermore, since the product load and the form of grating can be calculated, it can be set arbitrarily if the isolator suitable for it can be exchanged, and it is extremely advantageous that it can respond even if the amount of transport or the type of product changes. Invention.

[Brief description of the drawings]

FIG. 1 is an overall side view of a truck according to the present invention.

FIG. 2 is a perspective view of the isolator of the present invention.

FIG. 3 is a perspective view when the isolator of the present invention is in a replaceable mode.

FIG. 4 is a sectional view of a wire forming the spring of the present invention.

FIG. 5 is a graph showing the relationship between the vibration transmissibility and the damping ratio of the isolator of the present invention.

FIG. 6 is a side view showing a test device.

FIG. 7 is a graph displayed on an oscilloscope obtained by converting acceleration measured from a test cell into a voltage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Dolly 11 Support leg 12 Caster 13 Base plate 20 Isolator 21 Rope body 21a Element wire 21b Strand 22a, 22b Fixed plate 30 Exchange member 31a, 31b Coupling frame 32a, 32b Engagement piece 33a, 33b Connection rod 34a, 34b Screw

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16F 15/06 F16F 15/06 Z

Claims (2)

[Claims] 1. A rope fixed to a part of a bogie for transporting precision products, parts, etc., in which a plurality of hard steel wires are bundled and tied to form a spiral, and the rope is fixed in a direction parallel to the rotation. A spring is formed by arranging a plate, and an isolator that absorbs vibration by frictional heat generated by the action of the spring is provided. The natural frequency (f _n ) of the isolator, the grating surface, etc. vibration proof truck ratio between the frequency (f _f) which is assumed to result from carriage to travel, characterized in that set so that _f f / f _n> √2 a. 2. A pair of upper and lower connecting frames each having a curved portion are provided on the base plate side and the supporting leg side, and an engaging piece and a fixing screw to be fitted into the curved portions of the pair of connecting frames are provided. 2. The vibration-damping bogie according to claim 1, wherein the bobbin is integrated with the connecting rod, and an isolator is arranged between the engaging pieces so as to be replaceable.