JPH06246189A - Centrifuge rotor - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] The present invention relates to a rotor for a centrifuge and a method for manufacturing the same. The rotor is made of a composite material of short fibers and a thermosetting resin. Since it was integrally molded, the weight was reduced and the material yield was greatly improved. [Structure] In FIG. 1, a sample container search hole 2 formed equidistant from a rotary shaft 4 of a rotor 1 is provided, and mounting to a drive shaft 4 is performed by a coupling 3 and a fixing bolt 5. Short fiber reinforced composite material 1 of short fibers having a length of 3 to 50 mm and a thermosetting resin which is a matrix
A rotor for a centrifuge, which is made of 0, and in which the composite material and the sample container bucket 6 are integrally molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifuge rotor and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, a centrifuge rotor 1 is provided with a sample container search hole 2 arranged equidistantly from a rotation axis as shown in FIG.
The bucket 6 for a metal sample container containing thereinto is inserted, and the boss portion of the aluminum alloy coupling 3 into which the drive shaft 4 is fitted has a shaft hole. The rotor 1 and the boss portion are fixed by a fixing bolt 5. The sample is rotated at a predetermined number of revolutions and centrifugal force is used to separate the sample in the sample container by the difference in specific gravity. Conventionally, the total capacity of the sample is 1000 to 3000 cc class and the rotation speed is 20,0.
As a large rotor material for centrifuges at 00 rpm or less,
Aluminum alloy has been used. However, a conventional large rotor made of aluminum alloy has a diameter of 250 to 350 mm and a height of 100 mm.
Since the weight is about 20 to 30 mm and the weight is about 20 to 30 kg, it has a drawback that the handleability such as attachment / detachment of the rotor to / from the centrifuge body is poor and that it takes a long time to accelerate. Also, recently in one centrifugation operation, 3
There is a demand to separate a large volume sample of 000 cc or more.

Therefore, as a more lightweight rotor material, for example, a reinforcing fiber type composite material such as a sheet-like woven prepreg as disclosed in JP-A-64-11659 is laminated in the direction of the rotation axis by the rotor height, It has been proposed that the resin in the prepreg is heated and pressure-bonded to be hardened to form a disk, and then the sample container search hole is machined to be used as a rotor material. This laminated-type fiber-reinforced plastic is made up of circular prepregs one by one at a fixed angle (for example, 15
The layers are laminated while being rotated by 90 °, 30 °, 45 °) each so that the direction perpendicular to the rotation axis is pseudo-isotropic.

[0004]

In the conventional rotor, since the above pseudo isotropic laminated plate is manufactured and used, it is necessary to stack 300 to 1000 circular prepregs by shifting them by a constant angle. Therefore, a lot of time is spent on cutting and laminating the circular prepreg from the prepreg sheet, resulting in poor productivity and high cost. Further, in the pseudo isotropic laminated plate, circular prepregs are laminated in the rotational axis direction of the rotor, and the reinforcing fibers are oriented in the direction perpendicular to this direction, so that high strength can be obtained. However, in the direction of the rotation axis, there is only the strength between layers of circular prepregs, that is, the adhesive strength of the resin, and the strength is very small compared to the direction perpendicular to the rotation axis, so the direction of the sample container search hole relative to the rotation axis naturally becomes. Since it has a limit, it is particularly suitable for a vertical type rotor in which the rotation axis and the sample container search hole are arranged in parallel.

Further, in order to insert the metal bucket containing the plastic sample container, the sample container insertion hole is accurately machined at an equal distance from the rotation axis after forming the pseudo-isotropic laminated plate. However, the work was troublesome, the productivity was poor, and the rotor was expensive. The total volume of the sample container insertion hole removed by machining is about 40 to 50% of the molded rotor material. Therefore, the yield of the used material is very poor, and a lot of time is spent on machining to maintain high dimensional accuracy of the insertion hole.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide short fiber and heat in a centrifuge rotor provided with a sample container search hole formed equidistant from the rotating shaft. It is made of a composite material with a curable resin, and the composite material and a bucket for a sample container are integrally molded, and the short fiber is one or more of carbon fiber, aramid fiber, Kevlar fiber, and glass fiber. The combination thereof has a fiber length of 3 to 50 mm, a fiber content of 30 to 70% by weight, and the thermosetting resin is any one of epoxy resin, unsaturated polyester resin, phenol resin, and polyimide resin. In addition, it is characterized in that a bucket for a sample container is mounted on the surface of a bucket mounting pin of a molding die, a composite material is filled in the mold, and pressure heating is performed to perform integral molding. There is provided a large rotor centrifuge.

In order to further reduce the weight of the large rotor material for the centrifuge, the short fiber and the thermosetting resin are combined so that the strength can be improved even in the direction of the sample container search hole inclined with respect to the rotation axis. The present invention has been completed by paying attention to the fact that it is made of a composite material and that the composite material and the bucket for the sample container can be integrally molded to eliminate the perforation of the sample container insertion hole due to the post-processing.

A rotor formed by laminating sheet-like prepregs, which has been conventionally used, has a very high strength in the direction perpendicular to the rotating shaft. In particular, an angle type rotor has a sample container search hole with respect to the rotating shaft. Since the centrifugal force generated on the hole wall of the search hole is decomposed in the direction parallel to the direction perpendicular to the hole wall surface, the laminated plate acts in the direction of peeling the sheet. In order to prevent this, the strength in the direction of the sample container search hole was improved by orienting the short fibers randomly in the matrix resin.Therefore, in the angle type rotor, the sample container search hole is inclined with respect to the rotation axis. The angle can be set large. The short fibers reinforce the matrix resin, and carbon fibers, which have the highest specific strength, are particularly preferable, and aramid fibers, Kevlar fibers, and glass fibers are also preferable. Further, two or more kinds of short fibers may be combined in order to further increase the strength. The fiber length is preferably 3 to 50 mm, and particularly preferably 7 to 30 mm in consideration of strength and orientation. If it is 3 mm or less, the reinforcing effect is small, and if it is 50 mm or more, the short fibers are entangled with each other or broken during molding, which is not preferable.
The short fibers impregnated with this resin are made into a bundle of 1000 to 12,000 long fibers using a thermosetting resin, and while impregnating the resin, it is subjected to pultrusion molding, which is one of the continuous molding methods, and chopped to a predetermined length. Cut into pieces. The short fiber content of the chop material is preferably 30 to 70% by weight from the viewpoint of pultrudability and strength, but in consideration of moldability and higher strength, it is particularly 4
0 to 60% by weight is preferable. When the amount is 30% by weight or less, the strength is not improved as expected, and when the amount is 70% by weight or more, the moldability is extremely poor because the amount of the matrix resin is small. Judging from the fact that higher strength is obtained and moldability is easy, when a thermosetting resin is used, the short fiber length is 15 mm and the short fiber content is 45% by volume.

Epoxy resin, unsaturated polyester, phenol resin, and polyimide resin are suitable as the thermosetting resin. Among them, the epoxy resin is particularly high in strength, and the moldability is good, so that cost reduction can be realized. When an epoxy resin is used as an example, its composition is bisphenol A.
It is a mixed epoxy resin obtained by adding 50 to 80% by weight of a phenol / novolak type epoxy resin to the type epoxy resin and further adding a small amount of a curing agent and a curing accelerator.

Next, the molding method will be described in detail. Figure 2
FIG. 6B is a cross-sectional view of the molding die in the step of mounting the sample container bucket on the bucket mounting pin. Short fiber reinforced composite material 1
0 and the sample container bucket 6 are integrally molded by mounting the bucket on the pin fixing mold 9 so that the required number of sample container insertion holes for the rotor for the centrifuge can be formed equidistant from the rotation axis of the rotor. The pin 7 is press-fitted or fixed with a screw or the like, and the cup-shaped sample container bucket 6 is mounted with an accuracy such that no gap is created therein. Next, a chopped material having a short fiber length of 3 to 50 mm is combined with one or two or more kinds of fiber lengths so that a required amount of the composite material is formed into a molding die having an inner diameter of 350 mm and a height of 150 mm so that the short fiber directions are random. And heat the entire molding die using a heating source such as a heater to 120 to 1
Heat to 80 ° C. Thereafter, as shown in FIG. 3, a pressing die system is adopted so that the composite material 10 in the mold can be pressed from above and below by using a molding upper mold 11 and a molding lower mold 12, and a pressing force of 100 to 300 kgf / cm. compression molded at ² to 1 to 2 hours curing molding. After molding, the molded product is taken out of the molding die and used as it is as a rotor without machining, or is machined into a predetermined shape.

As a result of cutting the molded product and examining the orientation and the state of voids of the short fibers, the short fibers inside were randomly oriented, and there were many escape directions of the air remaining inside, so almost all voids were also seen. It has a uniform structure,
No particular anisotropy of strength was observed. Further, regarding the integral molding of the chop material and the bucket for the sample container, the bucket was firmly adhered by the thermosetting resin, and no looseness or displacement was observed. The sample container bucket can be used if it has a high specific strength, and aluminum alloy and titanium alloy are particularly suitable. In addition to the compression molding described above, extrusion molding is also possible according to the equipment capacity. Further, in addition to the vertical type large rotor using the short fiber reinforced composite material, the angle type can be sufficiently applied by devising the shape of the molding die and changing the mounting angle of the bucket mounting pin.

[0012]

In the present invention, the large rotor for a centrifuge having the sample container search hole formed equidistant from the rotation axis is made of a composite material of short fibers and a thermosetting resin. Since the sample container and the bucket for the sample container are integrally molded, not only can it be made lighter than the aluminum rotor, but also the sample container insertion hole is not machined and shaved in post processing, so only the required amount of material is used. The material yield can be greatly improved. In addition, by randomly orienting the short fibers in the matrix resin, the strength is isotropic, and the strength in the direction of the sample container search hole inclined with respect to the rotation axis can be improved.

[0013]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 has a sample container search hole 2 in which six sample containers having a total capacity of 3000 cc can be searched at a rotation speed of 10,000 rpm, and a sample container bucket 6 is formed at the same time as molding.
FIG. 3 is a cross-sectional view of a vertical-type large-sized rotor 1 in which is mounted. This large-sized rotor 1 uses a chop material having a carbon fiber length of 15 mm, and the mold is applied at 135 ° C. for 2 hours under a pressure of 1
Maximum diameter of 35 after compression molding at 50 Kgf / cm ² and hardening
A short fiber reinforced composite material having a height of 0 mm and a height of 120 mm was molded, and only the outer peripheral surface was machined into a rotor shape. The content of short fibers was 50% by weight, and a mixed epoxy resin was used as a matrix resin. The rotor 1 and the drive shaft 4 of the motor are fixed by fastening an aluminum alloy coupling 3 to the bottom surface of the rotor with a fixing bolt 5, so that the drive shaft 4 is mounted in the coupling search hole. Rotation speed 10,000 rp
The start-stop test was repeated for 5 minutes at m. As a result, the target number of repetitions was achieved, there was no problem in the strength in the direction of the sample container search hole, and the sample container bucket was not loosened or misaligned, and was practical.

[0015]

According to the present invention, a rotor for a centrifuge having a sample container search hole formed equidistant from a rotation axis is composed of short fibers having a reinforcing fiber length of 3 to 50 mm and a matrix. It consists of a short fiber reinforced composite material with a thermosetting resin, and since this composite material and the sample container bucket are integrally molded, conventional machining for drilling holes for sample containers is possible. Material yield is 90 because it is unnecessary
%, Which is significantly improved. Further, by randomly orienting the short fibers in the matrix resin, the strength is isotropic, and even when the short fibers are inclined with respect to the rotation axis, the strength in the sample container search hole direction can be improved. Since the molding is less troublesome like cutting and laminating circular prepregs from conventional sheets, it is only a work of filling the mold with chop material and compression molding, so a large reduction in man-hours is achieved, In addition, productivity is improved, and there is an effect that a lightweight and inexpensive rotor can be manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view of a rotor showing an embodiment of the present invention.

FIG. 2 is a sectional view of a molding die for mounting the sample container bucket on the bucket mounting pin.

FIG. 3 is a cross-sectional view of a molding die in which a composite material and a bucket for a sample container are integrally molded.

FIG. 4 is a cross-sectional view of a rotor in which a sample container insertion hole is provided by post-machining machining in a conventional example.

[Explanation of symbols]

1 is a rotor, 2 is a sample container search hole, 3 is a coupling,
4 is a drive shaft, 5 is a fixing bolt, 6 is a sample container bucket, 7 is a bucket mounting pin, 8 is a cylindrical mold, 9 is a pin fixing mold, 10 is a composite material, 11 is a molding upper mold, and 12 is a mold. A lower molding die, 13 is a sample container.

Claims (4)

[Claims] 1. A centrifuge rotor provided with a sample container insertion hole formed equidistant from a rotation axis, comprising a composite material of short fibers and a thermosetting resin, the composite material and a sample container bucket. A rotor for a centrifugal separator, characterized in that and are integrally molded. 2. The short fibers are made of any one kind or a combination of two or more kinds of carbon fibers, aramid fibers, Kevlar fibers, and glass fibers, and have a fiber length of 3 to 50 mm and a fiber content of 30 to 70 weight. %, The centrifuge rotor according to claim 1. 3. The rotor for a centrifuge according to claim 1, wherein the thermosetting resin is made of any one of epoxy resin, unsaturated polyester resin, phenol resin and polyimide resin. 4. A bucket for a sample container is mounted on the surface of a bucket mounting pin of a molding die, a predetermined amount of the composite material is filled in the mold, and pressure molding is performed to mold the composite material. Rotor for the centrifuge.