JPS5833408B2 - Kosoku Kaitentai - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating body made of fiber-reinforced composite material that can rotate at high speed.

Specific examples of high-speed rotating bodies include flywheels and gas centrifuge rotors.

A flywheel generally consists of a ring or disk-shaped rotating body, and stores energy in the form of rotational energy.Theoretically, the storable energy is equal to the ratio of the flywheel's inertia rate and angular velocity. Materials with high specific strength can store more energy.

Conventional flywheels have been considered difficult to be widely applied until recently because they cannot store enough energy to meet the required conditions in terms of cost per energy and material strength. It's here.

However, by using materials with high specific strength and specific modulus, such as carbon fiber reinforced composite materials, high-speed rotation becomes possible, and it becomes possible to store much more energy than conventional flywheels made of metal materials. be.

Furthermore, centrifugal separators, especially ultrahigh-speed centrifuges used for uranium enrichment, consist of a rotating shell, an end plate, and a rotating shaft, and their separation capacity is theoretically said to be proportional to the fourth power of the circumferential speed of the rotating barrel. Various rotating cylinders and end plates that can withstand high-speed rotation have been studied.

Maraging steel, high-tensile steel, high-tensile aluminum alloy, etc. with high specific strength are used as metal materials for these flywheels or rotating body end plates, but it is difficult to rotate discs made of these materials. If the circumferential speed is 400~5
At 00 m/s, the circumferential stress exceeds the yield point of the material, making it unusable.

Therefore, disks made of fiber-reinforced plastics or the like in addition to the metal materials mentioned above are being considered.

This disk is made by circumferentially winding mainly long fibers using a thermosetting resin as a matrix using a filament winding method. It is extremely low in strength compared to the circumferential strength, and breaks at a relatively low speed due to thermal residual stress during molding or radial stress generated during rotation, making it impossible to fully utilize the characteristics of the material.

Thermal residual stress in a circumferentially wound disk occurs when there is a difference in thermal expansion coefficients in the radial and circumferential directions, a temperature difference between the curing temperature and room temperature, and a constraint on displacement, and its magnitude varies between the inside and outside of the disk. Depending on the diameter ratio (outer diameter/inner diameter ratio), this radial thermal residual stress limits the inner/outer diameter ratio of the disc that can be formed.

In the case of a circumferentially unwound fiber-reinforced plastic disk, assuming a radial strength of 3 kg/m4, the moldable disk has an inner/outer diameter ratio of about 25.

In reality, stress due to rotation is added to this, so it is further restricted.

In order to increase the rotation speed of such a disc, it is necessary to strengthen the radial strength or to create a rotating body with a shape that reduces the radial stress generated during rotation, but for the former, there is no improvement method. As a method, there are two methods: sandwiching a hardened plate or aluminum alloy plate made of non-oriented matte fibers or multi-directional prepreg sheet laminates, or arranging fibers in the radial direction, or using internal methods to avoid generating thermal residual stress. Possible methods include dividing the ring into several stages from the circumference and winding them little by little, or forming several concentric rings with different diameters in advance and combining them into one body by press-fitting or using elastomer. However, it is not necessarily sufficient in terms of performance, and it also requires a large number of manufacturing processes, which is disadvantageous in terms of cost.

Therefore, the present inventors have studied a rotating body that generates less thermal residual stress, has virtually no restrictions on the ratio of inner and outer diameters, and has less radial stress generated during rotation, and has arrived at the present invention.

That is, the present invention provides a high-speed rotating body that is a truncated cone-shaped rotating body made of a fiber-reinforced composite material, and the composite material includes long fibers of reinforcing fibers extending in the circumferential direction of the rotating body. It is characterized by:

The present invention will be explained in detail below.

As the matrix of the material forming the rotating body, thermosetting resins such as polyester resin, epoxy resin, phenol resin, and polyimide resin, or light alloys such as aluminum and titanium are suitable, and reinforcing fibers to strengthen such a matrix are suitable. As the material, carbon fibers, boron fibers, glass fibers, high elastic organic fibers, etc. can be used, and it is also possible to use various combinations of these depending on the required performance and cost.

In addition, the blending ratio of fiber and matrix can range up to about 80% in terms of fiber volume content depending on the required performance, but if it is too low, there is no point in making it a composite material, and if it is too high, the physical properties will deteriorate. Generally, a composite material with a content of 40% to 75% is preferable because it exhibits excellent physical properties.

As for the forming method, the radial stress generated in this rotating body during rotation is sufficiently small, and the circumferential stress becomes a problem, so a forming method that strengthens this direction is generally used. Wet or dry filament winding is used in the same way as printing plates.

Circumferential winding, diagonal winding, or a combination thereof can be used, and of course, various molding methods such as mated die molding, centrifugal molding, and rotational molding can also be used.

Furthermore, the shape of a truncated cone is not limited to a truncated cone in the strict sense, but also includes a pseudo-truncated cone shape, such as truncated cone A, horn shape B, dome shape C, etc., as shown in Fig. 1. are effective, and a combination of these may be used depending on the purpose.

Among the various shapes, the truncated conical shape is easier to mold and has less space loss (easy-to-use shape It is.

The angle that this truncated cone-shaped rotating body makes with the central axis (θ in Figure 1)
is any angle greater than 0° and less than 900, e.g. 5° to 8
5° can be taken, but if the angle is small, the space occupation rate per mass of the rotating body will be large and the space loss will be large (
Become.

If the angle is wide, the shape will be similar to a disk, and the radial stress during rotation and thermal residual stress during molding will be large (this makes high-speed rotation difficult, so in reality it is in the range of 15° to 75°). It is desirable to take an angle in the range of 30° to 600° from the viewpoint of manufacturing and physical properties.

This rotary body has the disadvantage that the space loss is slightly larger than that of a disk, but this can be improved by using a large number of truncated cones stacked on top of each other, as shown in FIG. 2, for example.

Further, although this rotating body can withstand high-speed rotation with just circumferential winding, which is the easiest to form, diagonal winding may be used in combination for forming or attachment to the rotating shaft.

Regarding the shape, as long as it is basically a truncated cone shape, there is no problem in providing a boss or a rib for coupling with the shaft.

Examples will be specifically described below.

Example 1 According to the invention, a truncated cone with an inner diameter of 100 mm, an outer diameter of 200 mm, a radial wall thickness of 10 mm, an inclination angle of 15°, 30°, 45° and 90° (disc) and a carbon fiber volume content of 60% The shape rotating body was formed by circumferential winding using the filament winding method.

In addition, the thermal residual stress distribution of the rotating body when the inclination angle is varied (temperature difference of 130°C), and during rotation (rotational speed of 48,000
Figures 4 and 3 show the results of an analysis of the stress distribution generated at rpm), respectively.

In the case of a disc, the maximum radial thermal residual stress is 25 kg/ma at a temperature difference of 130°C, and the radial stress generated at a rotation speed of 48,000 rpm is approximately 2.3 to 9/r/la.
However, by providing an angle, the radial thermal residual stress can be kept low, and the radial stress generated during rotation is also sufficiently low, and the circumferential stress is close to the fracture strength of the material and the properties of the composite material are maintained. It can be seen that it is used effectively.

The following materials were used.

Carbon fiber: Trading card made by Toshi ■ T300A, tensile strength 2
Continuous fiber with a weight of 80 kg/vast, a Young's modulus of 24.5 t/mA, a specific gravity of 1.77, and a number of filaments of 3000.

The following formulation was used as the matrix.

That is, "Epicote" 828 (epoxy resin manufactured by Shell Chemical Co., Ltd.) (100 parts by weight)/hydrophthalic anhydride (80 parts by weight)
parts by weight)/benzyldimethylamine (1 part by weight).

These molded products were mounted on a spin tester and subjected to a rotation test, and the results are shown in Table 1.

The circumferentially wound disk broke at a circumferential speed of 530 m/s, and the truncated conical rotating body according to the present invention broke at a circumferential speed of about 820 m/s.

This circumferential speed is not achievable using existing metal materials.

Example 2 According to the invention, the inner diameter is 100'IItrIL, the outer diameter is 200
A pseudo-truncated cone-shaped rotating body (horn type, radius of curvature of generatrix 75 mm) with a radial wall thickness of 10 mm, an inclination angle of 45°, and a fiber volume content of 60% was molded using the same material and the same molding method as in Example 1. .

Thermal residual stress in the radial direction of the rotating body when the inclination angle is varied (temperature difference 130°C), during rotation (rotational speed 48000
Figures 6 and 5 show the analysis results of the radial stress generated at rpm).

When this rotating body was attached to a spin tester and a rotation test was performed, it broke at 750 m/s.

Failure occurs due to radial stress, which is a less dangerous failure mode than failure due to circumferential stress.

Example 3 As reinforcing materials, Nitto Boseki's glass fiber and DuPont's high modulus aromatic polyamide fiber "Kevlar" 49 were used.
A truncated cone-shaped rotating body and a disk with an inclination angle of 30° were molded using the following.

The shape, matrix, and molding method are the same as in Example 1.

Moreover, the fiber volume content is about 60% in all cases.

The physical properties of each fiber are shown below.

Glass fiber: tensile strength 250 kg/ma, Young's modulus 7.
3t/mt? t, specific gravity 2.54゜” Kevlar
49: Tensile strength 280 kg/7n1j, Young's modulus 12.6-14 t/mL Specific gravity 1.45° These rotating bodies were attached to a spin tester and a rotation test was conducted.The results are shown in Table 2. It can be seen that the performance of the truncated conical rotating body is excellent.

Example 4 Using long-fiber carbon fiber as a reinforcing material and aluminum as a matrix, the fibers were arranged in a circumferential manner, and a truncated cone-shaped rotating body and disk with an inclination angle of 45° were formed by matt die molding (hot press method under vacuum). was molded.

The shape and dimensions are the same as in Example 1, but in the case of a disc with an inner diameter/outer diameter of 100 mm and 1200 yn, cracks occur due to thermal residual stress and forming is difficult, so 150 m
m/200mm.

Table 3 shows the results of a rotation test carried out by attaching the conical rotating body to a spin tester, and it can be seen that the performance of the truncated conical rotating body is excellent.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a truncated cone-shaped (A, cone type, B, horn type, C, dome type) rotating body of the present invention. FIG. 2 is a schematic sectional view of a rotating body constructed by stacking a plurality of the truncated conical rotating bodies shown in FIG. 1A. FIG. 3 is a graph showing an example of analysis of radial stress during rotation of the truncated cone-shaped rotating body of the present invention. FIG. 4 is a graph showing an example of analysis of radial thermal residual stress of the truncated cone-shaped rotating body of the present invention. FIG. 5 is a graph showing an example of analysis of radial stress during rotation of the horn-shaped rotating body of the present invention. FIG. 6 is a graph showing an example of analysis of radial thermal residual stress of the horn-shaped rotating body of the present invention.

Claims (1)

[Claims] 1. A high-speed rotating body that is a truncated cone-shaped rotating body made of a fiber-reinforced composite material, and the composite material includes long fibers of reinforcing fibers extending in the circumferential direction of the rotating body. .