JP3621831B2 - High speed rotating body protection device and centrifuge having rotating body protection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention occurs when a rotating body is broken in a centrifuge or a high-speed rotating tester used in the fields of medicine, chemistry, pharmacy, material engineering, etc. The present invention relates to preventing damage to the entire device, impact, and high-speed movement, reducing the weight of the protective device, and reducing the weight and cost of the entire centrifuge.
[0002]
[Prior art]
Conventional rotating body protection devices are thick and heavy cylinders made of metal such as steel, allowing high-speed flying debris of broken rotors to be plastically deformed and received by a large momentum of metal to damage the outer device Was preventing. This type of rotating body defense device is disclosed in, for example, Japanese Patent Publication No. 53-9865 and Japanese Utility Model Publication No. 53-3499. These conventional examples are shown in FIGS. In the figure, a rotating body 1 is rotated at a high speed by a drive unit 3 composed of an electric motor or the like via a rotating shaft 2. The rotating body 1 of the ultracentrifuge used in the medical research field is usually composed of a relatively hard material such as an aluminum alloy or a titanium alloy having a high specific strength, and the maximum rotational speed is from 100,000. 150,000 revolutions / minute, centrifugal acceleration reaches 800,000 to 900,000 G, and the peripheral speed at this time reaches about 700 m / s. A rotating chamber 4 that rotatably supports the rotating body 1 includes an upper plate 5, a side cylinder 6, and a bottom plate 7. These components may be structured to maintain a vacuum in order to prevent the temperature of the rotating body from rising. The door 8 is a component that opens and closes the rotating body insertion port of the upper plate 5, and is sealed with the upper plate 5 by an O-ring 9. The defense cylinder 10 surrounds the rotating body 1 and extends in the vertical direction, and is composed of an inner cylinder 11 made of a hard metal such as steel or an outer cylinder 12 made of a soft metal such as lead and a hard metal such as steel. Has been. In the case of the ultracentrifuge used in the medical research field, the protective cylinder 10 is made of steel and has a thickness of about 50 mm, and its mass is about 120 kg. In such a configuration, when the rotating body 1 breaks, the fragments collide with the defense cylinder 10 at a high speed by centrifugal force. The deformation is caused by hitting or piercing the debris. The energy of the debris is absorbed by this deforming energy.
[0003]
[Problems to be solved by the invention]
When a rotating body breaks with a high-speed rotating device, the fragments fly at high speed, but if the impact stress due to the collision with the defensive wall exceeds the elastic limit, even if it pierces the defensive wall or reflects it, it is accompanied by plastic deformation Therefore, the defense cylinder receives a large force in one direction in the collision direction. FIG. 4 shows a method of determining the stress and particle velocity due to the collision at this time. Currently used steel has a Yugonio elastic limit (HEL stress) 24 stress of at most 1 GPa and a particle velocity of 40 m / s. For most high-speed rotating bodies with impact velocity of 80 m / s or more, FIG. As shown, the impact stress due to the collision exceeded the Yugonio elastic limit of the steel, and as described above, a large force was applied in the collision direction, resulting in high-speed movement and vibration of the device, and there was a problem in safety. In addition, since the deformation of the plastic area due to high-speed collision is large, the protective wall must be thickened, the centrifuge and the test machine must be heavy to prevent the entire device from being destroyed by a large momentum and to ensure the safety of the user. There wasn't.
[0004]
An object of the present invention is to solve the above-described problems and provide a high-speed rotating body defense device that is lightweight and highly safe.
[0005]
[Means for Solving the Problems]
The above object is achieved by making the defense cylinder a multi-layer structure of ceramics and metal.
[0006]
Furthermore, the schematic of the path | route of the flying fragment | piece explaining the high-speed rotary body defense apparatus of this invention in FIG. 5 is shown. By using a double cylinder structure of ceramic and metal for the defense cylinder, the impact and movement of the device due to collision will be significantly reduced by utilizing the high Yugonio elastic limit of ceramics, and the thickness and weight of the defense wall will be reduced. To work. Well-sintered ceramics such as alumina and silicon nitride have a Yugonio elastic limit of 10 GPa or more and a particle speed of the Yugonio elastic limit of 200 m / s or more. When the collision speed is 400 m / s or more (the collision speed in the direction perpendicular to the wall is less than the radius of the rotating body × angular speed × cos θ), the stress due to the collision is less than the Yugonio elastic limit as shown in FIG. Fits in the elastic zone, and the debris reflects elastically without sticking. Moreover, since the collision of the flying fragments 31 has a vector in the rotational direction, the collision angle θ is expressed by SinＳ ¹ = r1 / r2, and if r1 / r2 is 0.707 or more, θ is 45 degrees or more. Therefore, not only can the impact stress be reduced, but the flying debris repeats the reflection collision with the defense wall many times as shown in FIG. 5 and stops slowly. In this case, the impact force due to the impact is received by the ceramics, and is surrounded by a metal tube closely attached to the outside in order to support the quasistatic stress after the impact and to prevent quasistatic brittle fracture of the ceramics. Therefore, the impact caused by the collision of the fragments is distributed and the impact and movement of the apparatus are minimized, so that safety is remarkably enhanced. In this case, the ceramic does not plastically deform and bounces off the fragments. Therefore, the thickness of the ceramic and metal can be significantly reduced compared to the case of only metal, and the density of most ceramics is less than half that of steel. Since it is small, the mass of the part can be reduced to half or less.
[0007]
As reference data, FIG. 8 shows an impedance matching method (collision speed 400 m / s) between metal and metal and ceramics. In addition, the explanation of determining the impact state using the reflection of the collision surface regarding the impedance matching method is disclosed in “Impact Engineering (October 1988, Chapter 8 (Ultra High Speed Impact))” published by Nikkan Kogyo Shimbun. Has been.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a longitudinal sectional view of a high-speed rotating body defense device according to an embodiment of the present invention. In the figure, a rotating body 1 is rotated at a high speed by a drive unit 3 composed of an electric motor or the like via a rotating shaft 2. A rotating chamber 4 that rotatably supports the rotating body 1 includes an upper plate 5, a side cylinder 6, and a bottom plate 7. These components are structured to maintain a vacuum in order to prevent the temperature of the rotating body from rising. The door 8 is a component that opens and closes the rotating body insertion port of the upper plate 5, and is sealed with the upper plate 5 by an O-ring 9. The defense cylinder 10 surrounds the rotating body 1 and extends in the vertical direction, and includes a ceramic inner cylinder 11 and an outer cylinder 12 made of hard metal such as steel. In such a configuration, when the rotating body 1 is broken, the fragments collide with the inner cylinder 11 of the defense cylinder 10 at a high speed by centrifugal force. Since the inner cylinder 11 is formed of ceramics as described above, when the debris hits, the debris bounces back and gradually loses energy and stops. Specifically, in the case of the ultracentrifuge used in the above-mentioned medical research field, the thickness of the thin ceramic inner cylinder 11 is about 3 to 5 mm, and the protective cylinder 10 is made of steel with a thickness of 20 mm or less. It is estimated that a cylinder is sufficient. In this case, the mass of the entire defense cylinder is about 60 kg, and the weight is reduced to half or less than the mass of the conventional defense cylinder of about 120 kg. The impact force due to the impact is received by the thin ceramic inner cylinder 11 and is surrounded by the outer cylinder 12 closely attached to the outside in order to support the quasi-static stress after the impact and to prevent the quasi-static brittle fracture of the ceramic. . As described above, ceramics are not plastically deformed and repel the debris. Therefore, the impact caused by the collision of the debris is dispersed, and the impact and movement of the apparatus are minimized. Further, the load applied to the components around the protective cylinder is reduced, and these structures also have the effect of simplifying and reducing the weight.
[0009]
FIG. 2 is a top sectional view showing a part of a high-speed rotating body defense device according to another embodiment of the present invention. In the figure, reference numeral 11a denotes a ceramic plate-like block, which is arranged so as to be in close contact with the outer outer cylinder 12. Further, a presser plate 13 is provided on the inner side to fix the ceramic plate-like block 11a. There is no. Even in such a configuration, the protection against the fragments of the rotating body operates as described above. Such a configuration is advantageous in manufacturing, and has a great effect in terms of molding and manufacturing ceramics and assembling a defense device. Note that it is determined that a good result can be obtained by using an adhesive or the like for fixing the ceramic plate-like block 11a to the outer cylinder 12.
[0010]
FIG. 3 is a longitudinal sectional view of a high-speed rotating body defense device according to another embodiment of the present invention. In the figure, reference numeral 11 denotes a ceramic inner cylinder, the length of which is shortened in the vertical direction so as to be the length of only the portion where the fragments collide when the rotating body breaks, and the outer cylinder 12 is moved upwardly from the inner cylinder. A step 14 is provided to prevent the movement. Even in such a configuration, the protection against the fragments of the rotating body operates as described above. Such a configuration can reduce the manufacturing cost of ceramics.
[0011]
【The invention's effect】
According to the present invention, a rotating body defense device is provided in a rotating chamber that supports a high-speed rotating body in a rotatable manner. Therefore, the broken piece of the rotating body repeats a reflection collision many times on the defense wall and stops slowly, and the safety is remarkably improved compared to the metal that stops by plastic deformation or piercing. In this case, since the ceramic does not plastically deform and bounces off the fragments, the thickness of the ceramic and the metal can be much thinner than that of the metal alone, and the density of most ceramics is less than half that of steel. Since it is small, the mass of the entire defense cylinder can be reduced to about half. Further, the structural members around the protective cylinder can be simplified in structure and reduced in weight, so that the cost can be reduced.
[0012]
In addition, the ceramic inner cylinder is divided into a plurality of plate-shaped blocks, and is made to adhere to the outer metal cylinder, so that the ceramic is less likely to break, and the ceramic block can be easily manufactured and assembled. Also improves. Furthermore, the assemblability can be further improved by arranging a pressing plate inside the ceramic block.
[0013]
In addition, the vertical length of the ceramic inner cylinder is shortened so that it is only the length of the part where the fragments collide when the rotating body breaks, and the outer cylinder is prevented from moving upwards of the inner cylinder. Providing the step can reduce the cost of the defense device and can provide an inexpensive defense device.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a high-speed rotating body defense device according to the present invention.
FIG. 2 is a top cross-sectional view showing another high-speed rotating body defense device according to the present invention.
FIG. 3 is a longitudinal sectional view showing another high-speed rotating body defense device according to the present invention.
FIG. 4 is a Yugonio diagram showing stress-particle velocity for determining stress and particle velocity of shock wave due to collision in the present invention.
FIG. 5 is a diagram showing a route of a flying fragment according to the present invention.
FIG. 6 is a longitudinal sectional view showing a conventional high-speed rotating body defense device.
FIG. 7 is a longitudinal sectional view showing a conventional high-speed rotating body defense device.
FIG. 8 is a graph showing an impedance matching method between a metal and a metal and ceramics.
[Explanation of symbols]
1 is a rotating body, 2 is a rotating shaft, 3 is a drive unit, 4 is a rotation chamber, 5 is a top plate, 6 is a side cylinder, 7 is a bottom plate, 8 is a door, 9 is an O-ring, 10 is a protective cylinder, 11 is Ceramic inner cylinder, 11a is a ceramic plate block, 12 is a metal outer cylinder, 13 is a pressing plate, 14 is a step, 21 is a ceramic yugonio, 22 is a ceramic yugonio elastic limit, 23 is a metal yugonio, 24 Is the Yugonio elastic limit of the metal, 25 is the Yugonio of the flying object, 26 is the Yugonio elastic limit of the flying object, 27 is the impact velocity, 28 is the expected flight path of the fragments, 29 is the radius r1 of the rotating body, 30 is the ceramic radius The defense cylinder radii r2 and 31 are the collision angle θ.

Claims (6)

A rotating chamber that supports a high-speed rotating body in a rotatable manner is characterized in that a multilayer structure is formed by ceramics having a Yugonio elastic limit stress of 9 GPa or more extending in the vertical direction so as to surround the rotating body and a metal closely adhered to the outside. High-speed rotating body protection device. 2. The high-speed rotating body defense apparatus according to claim 1, wherein ceramics extending in a vertical direction so as to surround the rotating body are divided into a plurality of blocks and are in close contact with an outer metal cylinder. 3. The high-speed rotating body defense device according to claim 2, wherein a pressing plate is disposed inside the plurality of ceramic blocks. The high speed rotation body in the rotation chamber to be supported on rotatable in high speed rotation body defense system of a multiple structure extending in the vertical direction as to surround the rotating ceramic and metal in close contact with the outside, the vertical length of the ceramic The high-speed rotating body defense device is characterized in that the length of the outer cylinder is set to the length of the part where the fragments collide when the rotating body is broken, and the outer cylinder is provided with a step so as to prevent the upward movement of the inner cylinder. . Rotation characterized by having a multi-structure of ceramics with a Yugonio elastic limit stress of 9 GPa extending in the vertical direction surrounding the rotating body and a metal closely attached to the outside in a rotating chamber that rotatably supports the rotating body Centrifuge with body defense device. 6. The centrifuge having a rotating body protection device according to claim 5, wherein the vertical length of the ceramic is set to the length of a portion where a broken piece collides when the rotating body is broken.

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