JPS6241070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotor for an ultracentrifuge and a method for manufacturing the same. Current rotors for ultracentrifuges are made of aluminum alloy or titanium alloy and have a maximum centrifugal acceleration of 60
The limit is around 10,000G. It is advantageous for the rotor material to have high strength and low specific gravity. In other words, a material with high specific strength is preferable. In contrast, titanium alloys have traditionally been used as the best material, but titanium alloys are expensive and difficult to machine. Therefore, in the present invention, by providing a circumferentially reinforced fiber-reinforced plastic ring on the outer periphery of a quasi-isotropic laminate having a sample hole, it is possible to achieve a maximum centrifugal acceleration equal to or higher than that of aluminum alloy or titanium alloy. Moreover, it is possible to provide an inexpensive rotor.

Filament winding cylinders and pseudo-isotropic disks have conventionally been used as fiber-reinforced plastics that rotate at high speeds. The filament winding cylinder was excellent as a high-speed rotating body because it maximized the strength of the fibers. However, in the case of a rotor for a centrifuge, it is necessary to provide a hole for the sample.
When a hole is made in a filament winding cylinder, the fibers are cut there, the strength is reduced, and the characteristics of filament winding are not utilized, and the centrifugal force of the sample placed in the sample hole and residual stress during molding caused delamination. . On the other hand, pseudo-isotropic disks made by laminating woven fabrics or unidirectional sheets impregnated with resin by rotating them at a constant angle have lower strength than filament winding cylinders, and although their maximum rotational speed is inferior, they are isotropic. Even when holes are drilled and rotated, there is no sudden decrease in strength or delamination.

Therefore, the present inventor created a rotor for a centrifuge that can withstand high-speed rotation and is free from delamination by providing a sample hole in a quasi-isotropic laminate and a fiber-reinforced plastic ring reinforced in the circumferential direction on the outer periphery. We have discovered that this can be done, and have come up with the present invention.

The pseudo-isotropic laminate of the present invention is a laminate in which a large number of woven fabrics or sheets with fibers arranged in one direction are laminated and bonded with resin, and the elastic modulus and strength are equal in the direction parallel to the rotating surface. It is directional. In order to obtain this, a woven fabric serving as a reinforcing fiber or a sheet in which fibers are arranged in one direction may be rotated and shifted by a certain angle and laminated. At least, the purpose can be achieved by rotating the fibers in three or more directions.

The woven fabric or sheet is made of carbon fiber, aromatic polyamide fiber, glass fiber, etc., and one or more of these fibers may be used. For example, the weft of the woven fabric may be carbon fiber and the warp yarn may be glass fiber, or a woven fabric made of carbon fiber and a woven fabric made of glass fiber may be overlapped. As the bonding resin, thermosetting resins are preferred, and epoxy resins, polyester resins, polyimide resins, and the like are particularly preferred.

It goes without saying that the pseudo-isotropic laminate is molded or machined into a shape such that the elastic modulus and strength are isotropic in the direction parallel to the plane of rotation. Therefore, it only needs to be axially symmetrical with respect to the rotation axis, and it does not need to be a cylinder with a constant diameter along the rotation axis direction, but may be a two-stage cylinder. In addition to the sample hole, the pseudo-isotropic body may have a hole for inserting a rotor driving cone, or a hole for attaching a metal shaft.

The sample hole in the rotor provided in the quasi-isotropic laminate can withstand and support the test tube containing the sample (thin plastic or metal tube), and also allows the test tube to withstand internal pressure. There is no particular limitation as long as it can maintain its shape.

Therefore, the sample hole may or may not penetrate the pseudo-isotropic laminate. Further, a test tube containing a sample may be placed directly into a hole that is not penetrated or a hole that is penetrated, or a bucket made of metal or fiber-reinforced plastic to hold the test tube may be attached. The sample hole may be provided parallel to the rotation axis of the pseudo-isotropic laminate or may be provided at an angle. Further, there is no particular limitation on the cross-sectional shape of the sample hole. Further, the number of sample holes may be one, but preferably two or more holes are arranged axially symmetrically with respect to the rotation axis of the pseudo-isotropic laminate.

The circumferentially reinforced fiber-reinforced plastic ring may be made by winding woven fabric or fiber sheets and bonding them with resin, but it is preferably molded by a filament winding method. Carbon fibers, aromatic polyamide fibers, glass fibers, etc. are used as the fibers, and thermosetting resins are preferably used as the bonding resin, with epoxy resins, polyester resins, and polyimide resins being particularly used. The fiber-reinforced plastic ring may be provided over the entire outer periphery of the pseudo-isotropic laminate, or may be provided partially. Further, it is preferable that the specific longitudinal elastic modulus (the longitudinal elastic modulus divided by the specific gravity) in the circumferential direction of the fiber-reinforced plastic ring is larger than the specific longitudinal elastic modulus in the rotating surface direction of the pseudo-isotropic body. That is, as the rotor rotational speed increases, the bond between the two becomes stronger. If the specific longitudinal elastic modulus of the fiber-reinforced plastic ring in the circumferential direction is smaller than the specific longitudinal elastic modulus of the pseudo-isotropic body in the direction of the rotating surface, the amount of deformation of the fiber-reinforced plastic ring increases as the rotor rotation speed increases. This is because the amount of deformation of the pseudo-isotropic body becomes larger than the amount of deformation of the pseudo-isotropic body, and a force is applied in the direction of separating the two bonds. Therefore, it has low strength and may break. Therefore, when the difference in specific longitudinal elasticity between the pseudo-isotropic laminate and the fiber-reinforced plastic ring is small, or when the specific longitudinal elasticity of the pseudo-isotropic laminate is large, the fiber-reinforced plastic ring is expanded by heat or external force. Alternatively, the maximum rotational speed can be increased by shrinking the pseudo-isotropic laminate using heat or external force, or by expanding the fiber-reinforced plastic ring and simultaneously contracting and bonding the pseudo-isotropic laminate. can.

By changing the direction of the reinforcing fibers, the fiber-reinforced plastic ring suppresses the deformation of the quasi-isotropic laminate, and in addition to the effect of absorbing centrifugal force applied to the sample hole, it also suppresses the deformation of the quasi-isotropic laminate by changing the direction of the reinforcing fibers. Strength can be reinforced. That is, it is sufficient to include a ring made of fiber-reinforced plastic whose fiber direction is inclined with respect to the rotation direction. Furthermore, when a ring made of fiber-reinforced plastic with a uniform specific longitudinal elastic modulus in the circumferential direction is rotated, tensile force is generated in the thickness direction within the ring, which causes delamination and reduces the maximum rotational speed. Therefore, by constructing a fiber-reinforced plastic ring with an inner layer and an outer layer, and making the circumferential specific longitudinal elastic modulus of the inner layer (the layer in contact with the quasi-isotropic laminate) lower than the circumferential specific longitudinal elastic modulus of the outer layer, it is possible to The tensile force is reduced and a compressive force can be generated between the inner layer and the outer layer.

A method for making the circumferential specific modulus of elasticity of the inner layer lower than that of the outer circumference can be obtained by changing the material composition such that glass fiber is used for the inner layer and carbon fiber is used for the outer layer. It can also be realized by tilting the fibers in the inner layer more toward the axis of rotation than the fibers in the outer layer. For example, when making a fiber-reinforced plastic ring using the filament winding method, the inner layer may have a winding angle (angle with respect to the axis) of 0° to 75°, and the outer layer may have a winding angle of 76° to 90°.

Choosing the winding angle of the inner layer from 0° to 75° also generates strength in the axial direction, increasing the axial strength of the fiber-reinforced plastic ring, which is useful for reinforcing quasi-isotropic laminates that have low axial strength. It's very desirable.

Further, in order to reduce the tensile force in the delamination direction during rotation of the fiber-reinforced plastic ring and to prevent residual stress during molding, it is more preferable to manufacture the fiber-reinforced plastic ring with a plurality of layers.
When providing multiple layers, an inner layer and an outer layer form one layer, and multiple layers are provided in close contact with each other, and the circumferential specific modulus of longitudinal elasticity of each layer is increased in turn toward the outside. Just do it like this.

When a plurality of layers are provided, there is no restriction as to which layer must have a larger circumferential specific longitudinal elastic modulus, but it is preferable that the outer layer has a higher circumferential specific longitudinal elastic modulus than the inner layer. There are various ways to increase the circumferential specific modulus of longitudinal elasticity of the inner and outer layers in order toward the outside, but the basic methods include changing the material, changing the orientation angle of the fibers, and There is no limitation as long as there is a way to change the thickness ratio and the purpose is achieved.

One way to change the materials is to provide an inner layer and an outer layer made of aromatic polyamide fiber on the outside of an inner layer and an outer layer made of glass fiber, and then provide an inner layer and an outer layer made of carbon fiber on the outside. (Specific longitudinal elastic modulus carbon fiber > aromatic polyamide fiber > glass fiber).

In addition, as a method of changing the fiber orientation angle, filament winding is used to create a layer in which the inner layer has a winding angle of 10° and the outer layer has a winding angle of 90°. This method involves providing a layer with a winding angle of 75 degrees, and then providing a layer with an inner layer having a winding angle of 75 degrees and an outer layer having a winding angle of 90 degrees. (The circumferential modulus of longitudinal elasticity increases as the winding angle increases from 0° to 90°.) Also, as a method of changing the ratio of the thickness of the inner layer and the outer layer, for example, filament winding is used to reduce the inner layer.
A layer with a thickness of 3 mm at a winding angle of 45°, an outer layer with a thickness of 1 mm at a winding angle of 90°, an inner layer with a thickness of 2 mm at a winding angle of 45°, and an outer layer with a thickness of 2 mm at a winding angle of 90°. There is a method of providing a layer with a thickness of 2 mm, and further providing an inner layer with a winding angle of 45° and a thickness of 1 mm, and an outer layer with a winding angle of 90° and a thickness of 3 mm. In other words, by increasing the thickness ratio of the outer layer, which has a high circumferential longitudinal elastic modulus, toward the outside of the ring, the circumferential specific longitudinal elastic modulus of the layer consisting of the inner layer and the outer layer can be increased outward. You can gradually increase the size as you go.

In addition, as a manufacturing method for forming a fiber-reinforced plastic ring around the outer periphery of a pseudo-isotropic laminate, the outer periphery is shaved after the pseudo-isotropic laminate is molded and cured, and a fiber-reinforced plastic ring is created using the filament winding method, woven cloth, or sheet winding. However, when considering residual stress etc., it is preferable to mold and harden the pseudo-isotropic laminate and the fiber-reinforced plastic ring separately and then bond them together.

As a combination bonding method, press-fitting a quasi-isotropic laminate with a tapered outer periphery to a fiber-reinforced plastic ring reinforced in the circumferential direction with a tapered inner periphery is a strong bonding method because it can be bonded by applying pressure. A rotor that can be bonded without gaps and can withstand high-speed rotation can be obtained. In order to provide a taper on the outer periphery of the pseudo-isotropic laminate, it is preferable to perform machining after molding and curing. To provide a taper on the inside of a fiber-reinforced plastic ring, the fiber-reinforced plastic may be molded using a mandrel with a tapered outer periphery, or the inner periphery may be machined after molding and curing.

The degree of taper is preferably within 4/10. Adhesives include epoxy resin, nylon-epoxy resin,
Phenol-epoxy resin, polyester resin,
A polyurethane resin or the like may be used, but there is no particular limitation. Also, silica powder or other fillers may be mixed with the adhesive.

Next, an example will be described.

FIG. 1 constitutes a pseudo-isotropic laminate. It is an exploded perspective view showing parallel cloth (woven fabric). The 0° rotation cloth 1 is a plain weave carbon fiber cloth impregnated with epoxy resin. On top of that, a 60° rotated cloth 2, in which the weft and warp threads of a similar cloth were rotated by 60°, was layered, and then a 120° rotated cloth 3, in which the weft and warp threads of the same cloth were rotated by 120°, was layered. By stacking three layers, it basically becomes pseudo-isotropic, but since the three layers are thin, 500 layers are stacked one after another, shifted by 60 degrees, and placed in a mold and heated and pressed in a press. A block of quasi-isotropic laminate was made. In the embodiment, the layers were laminated by rotating them by 60 degrees, but if the number of cloth sheets is large, they may be shifted by 1/n of 60 degrees (n=1, 2, 3, 4, . . . ).

FIG. 2 is a perspective view showing an embodiment of the present invention.
The motor 4 can rotate from 0 to 100,000 rpm. The rotor driving cone 5 is inserted into the insertion hole of the rotor and rotates the rotor by frictional force. The rotor is usually rotated in a vacuum.
Eight bucket attachment holes 9 are provided in the pseudo-isotropic laminate 8. The pseudo-isotropic laminate 8 is made of carbon fiber, but may be made of glass fiber or the like depending on the purpose. There is a fiber-reinforced plastic ring 10 on the outer periphery of the part of the quasi-isotropic laminate with a large outer diameter and a bucket attachment hole.The fiber-reinforced plastic ring 10 is made by a carbon fiber filament winding method and has axial reinforcement. Inner layer consisting of layer 11 and axial reinforcing layer 12 and 90° circumferential layer 1
The outer layer consists of 3 layers. Bucket mounting hole 9
A metal bucket 15 is inserted and fixed with bucket fixing screws. A test tube 16 containing a sample is placed in a bucket 15 with a test tube lid 17, and then a bucket screw lid 18 is attached. For balance reasons, buckets are inserted into all eight bucket mounting holes 9.

FIG. 3 shows a sectional view of the rotor shown in FIG. 2. The quasi-isotropic laminate is rotor driving cone 5
The outer diameter of the insertion hole portion 6, which has the insertion hole 7 into which it is inserted, is smaller. This is because if there is a hole, the stress in the vicinity of the hole becomes large, so the outer diameter of the insertion hole portion 6 is made small to reduce the stress caused by centrifugal force.

FIG. 4 shows a cross-sectional view of an embodiment in which the bearing portion of the rotor is made of metal. The holed pseudo-isotropic laminate 19 has bucket attachment holes 20 and a fiber-reinforced plastic ring 21 around its outer periphery. A hole is made in the center of the holed pseudo-isotropic laminate 19, and a metal shaft 22 is inserted. One end of the shaft 22 is a screw, and is fixed with a shaft fixing screw 23. The other end of the shaft 22 has an insertion hole 24 into which the rotor driving cone 5 is inserted. Also, the shaft 22 and the holed pseudo-isotropic laminate 1
A rotation stopper 25 is provided between the shaft 22 and the holed pseudo-isotropic laminate 19 to prevent the shaft 22 from slipping.

FIG. 5 shows a half sectional view of a fiber-reinforced plastic ring consisting basically of an inner layer and an outer layer. The inner layer 26 is made of carbon fiber and has a winding angle of 45 degrees and a thickness of 5 mm, and the outer layer 27 has a winding angle of 90 degrees and a thickness of 10 mm. FIG. 6 shows a half sectional view of a ring made of fiber-reinforced plastic made of multiple layers.

This ring is made by a filament winding method using carbon fiber, and the inner layer 28 has a winding angle of 45 degrees and a thickness of 3 mm, and the outer layer 31 has a winding angle of 90 degrees and a thickness of 1 mm. The inner layer 29 has a winding angle of 45 degrees and a thickness of 2 mm, and the outer layer 32 has a winding angle of 90 degrees and a thickness of 2 mm. The inner layer 30 has a winding angle of 45 degrees and a thickness of 1 mm, and the outer layer 33 has a winding angle of 90 degrees and a thickness of 6 mm. inner layer 2
The specific longitudinal elastic modulus in the circumferential direction of the layer consisting of 8 and the outer layer 31 is
3950Kg/mm ² , the circumferential specific longitudinal elasticity modulus of the layer consisting of the inner layer 29 and outer layer 32 is 5650Kg/mm ² , and the circumferential specific longitudinal elasticity modulus of the layer consisting of the inner layer 30 and outer layer 33 is 8070Kg/mm 2
mm ² and gradually increase in height toward the outside. FIG. 7 shows an exploded sectional view of a rotor consisting of a pseudo-isotropic laminate with a tapered outer circumference and a fiber-reinforced plastic ring with a tapered inner circumference.

The pseudo-isotropic laminate 34 has a bucket attachment hole 36 and an insertion hole 37 for inserting a rotor driving cone. The insertion hole portion 35 has a small outer diameter and is not covered by the fiber-reinforced plastic ring. The outer periphery of the pseudo-isotropic laminate 34 has a taper of 5/100. The inner circumference of the fiber-reinforced plastic ring 38 also has a taper of 5/100. An adhesive made by kneading uncured epoxy resin and fine silica powder was applied to both tapered surfaces, and a load was applied from the top and bottom directions as shown in FIG. 7 to bond them together.

Rotating rotor shown in Figure 2
No fracture occurred even at 65,000 rpm, but the rotor made of the quasi-isotropic laminate was fractured at 40,000 rpm. As described above, the rotor for a centrifugal separator of the present invention is useful because it can withstand high-speed rotation and can be supplied at a lower cost than rotors made of titanium alloy or the like.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing parallel crosses constituting a pseudo-isotropic laminate, Fig. 2 is a perspective view showing an embodiment of the present invention, and Fig. 3 is a sectional view of the rotor shown in Fig. 2. , Fig. 4 is a cross-sectional view of an embodiment in which the rotor bearing portion is made of metal, Fig. 5 is a half-sectional view of a ring made of fiber reinforced plastic consisting of the basic structure of an inner layer and an outer layer, and Fig. 6 is a cross-sectional view of a ring made of fiber reinforced plastic consisting of multiple layers. FIG. 7 is an exploded sectional view of a rotor consisting of a quasi-isotropic laminate having a tapered outer periphery and a fiber-reinforced plastic ring having a tapered inner periphery. Explanation of symbols, 1...0° rotating cross, 2...60° rotating cross, 3...120° rotating cross, 4...motor, 5...cone for rotor drive, 6...part with insertion hole, 7...insert Hole, 8...Pseudo-isotropic laminate, 9...Bucket mounting hole, 10...Fiber-reinforced plastic ring, 11...Axial reinforcement layer (+45
゜), 12... Axial reinforcement layer (-45°), 13... Surrounding layer, 14... Bucket fixing screw, 15... Bucket, 16... Test tube, 17... Test tube lid, 18... Bucket screw cap, 19... Hole Pseudo-isotropic laminate, 2
0... Bucket mounting hole, 21... Fiber reinforced plastic ring, 22... Shaft, 23... Shaft fixing screw, 24... Insertion hole, 25... Stopper, 26... Inner layer (±45°), 27... Outer layer (90゜),
28...Inner layer (±45°), 29...Inner layer (±45°), 3
0...Inner layer (±45°), 31...Outer layer (90°), 32...
Outer layer (90°), 33... Outer layer (90°), 34... Pseudo-isotropic laminate, 35... Portion with insertion hole, 36... Bucket mounting hole, 37... Insertion hole, 38... Fiber reinforced plastic ring, 39...inner periphery taper, 40...outer periphery taper.

Claims (1)

[Scope of Claims] 1. A rotor for a centrifuge, characterized in that a ring made of fiber-reinforced plastic reinforced in the circumferential direction is provided on the outer periphery of a pseudo-isotropic laminate having a sample hole. 2. The rotor for a centrifuge according to claim 1, wherein the fiber-reinforced plastic ring is a ring manufactured by a filament winding method. 3. Claims 1 or 2, wherein the fiber-reinforced plastic ring is composed of an inner layer and an outer layer, and the inner layer has a circumferential specific longitudinal elastic modulus lower than the outer layer's circumferential specific longitudinal elastic modulus. A rotor for a centrifuge as described in Section 1. 4. The fiber-reinforced plastic ring is composed of multiple layers in which the inner layer and the outer layer are in close contact with each other, and the specific modulus of longitudinal elasticity of each layer in the circumferential direction increases in turn toward the outside. A rotor for a centrifuge according to claim 1 or 2, which is a ring. 5 A quasi-isotropic laminate with a taper on the outer periphery,
A method for manufacturing a rotor for a centrifugal separator, characterized in that the rotor is press-fitted and bonded to a circumferentially reinforced fiber-reinforced plastic ring having a taper corresponding to the taper on the inner periphery.