JPH03260413A - Drive shaft made of fiber reinforced plastic - Google Patents

Abstract

PURPOSE:To obtain a drive shaft made of fiber reinforced plastic having sufficient torsional strength and high modulus of elasticity in axial direction by winding and molding two or more kinds of reinforced fibers simultaneously as hybrid layer at a specific angle in the axial direction of a pipe. CONSTITUTION:Two or more kinds of reinforced fibers as a hybrid layer 4 are wound and molded simultaneously at an angle from + or -10 to + or -45 deg. in the axial direction of a pipe. By this, it becomes possible to obtain a drive shaft made of fiber reinforced plastic having sufficient torsional strength and high modulus of elasticity in axial direction. Furthermore, it is desirable to provide glass fiber layers 3 and 5 on the outermost layer to improve impact resistance and on the innermost layer to prevent deterioration of drive shaft due to electrolytic corrosion.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive shaft made of fiber reinforced plastic (hereinafter abbreviated as "FRPJ") used, for example, as a propeller shaft for automobiles.

(Conventional technology) In recent years, FRP has been used as a material for propeller shafts in the automobile industry not only to reduce weight but also to reduce vibration and noise.
is starting to be used.

FRP is characterized by high specific strength and specific modulus of elasticity compared to general metal materials, and therefore has various advantages over conventional steel propeller shafts.

For example, the primary bending natural frequency f that governs the critical rotational speed is generally expressed by the following equation.

Here, E: Axial elastic modulus ■: Moment of inertia of area g: Gravitational acceleration A: Cross-sectional area γ: Specific weight 2: Axial length Therefore, weight can be reduced by using CFRP etc. with a high specific elastic modulus. At the same time, higher speed rotation is possible,
It can be longer than a steel propeller shaft.

Furthermore, since FRP has excellent vibration damping properties, it is also effective in reducing noise and vibration.

From this point of view, many proposals regarding FRP propeller shafts have already been made. In many of these proposals, as typified by Japanese Patent Publication No. 61-487, the fibers are wound at an angle of ±30° to ±60° with respect to the axial direction as the conditions for winding the shaft.
, typically oriented at ±45° and torsionally reinforced; a second layer 2 oriented axially between 0° and ±20° and reinforced against bending; and impact resistance. It was usually formed from a third layer 3 provided as the outermost layer in order to impart the following properties (see Fig. 6).

In addition, for the first layer 1 reinforced against twisting of ±30° to 60″, glass fiber is used from the viewpoint of cost, and O
For the second layer 2 reinforced against bending of ''~±20'', carbon fiber was usually used since a high elastic modulus was required.

(Problem to be Solved by the Invention) However, in the conventional method, when different fibers are laminated at different angles, there is a problem that peeling tends to occur at the boundary layer due to the difference in thermal expansion coefficient during heating and cooling. was there.

This problem varies depending on the diameter of the shaft and the thickness of each layer, but the smaller the diameter or the larger the layer thickness, the more likely this problem will occur. In addition, the first layer (±3
If a layer (0° to 60°) is placed on the inside, the torsion strength will be lower than if it is placed on the outside, and it is unsuitable for applications that require particularly high torsion strength. there were.

In addition, FRP shafts are usually shaped using the filament winding method, but since the first and second layers are wound with different reinforcing fibers, setup changes such as replacing rovings are required midway through, which reduces manufacturing efficiency. There was also a problem.

The present invention aims to solve the problems of the prior art described above, prevent the occurrence of peeling in each boundary layer, increase production efficiency, and provide an FRP drive shaft that has high torsional strength. .

(Means for Solving the Problem) As a result of various studies conducted by the present inventors in order to solve the above-mentioned problems, it has become clear that an FRP drive shaft having good characteristics can be obtained by the following method.

Conventional FRP drive shafts use constituent materials separately for each layer, such as a CFRP layer for the first layer, a CFRP layer for the second layer, and a CFRP layer for the 3N (outermost layer). There was only one type of fiber.

However, there is a method of mixing two or more types of reinforcing fibers at the same time to form the bottom shape without separating them into layers. In this case, the orientation angle is a problem, but it has been found that by selecting an appropriate orientation angle, it is possible to manufacture a drive shaft with strength equal to or greater than that of the conventional structure.

The present invention has been developed based on this knowledge, and is a hollow cylindrical shaft in which two or more types of fibers are simultaneously wound at an angle of ±10° to ±45° with respect to the tube axis direction. This is a fiber-reinforced plastic drive shaft having a molded layer.

(Function) In the present invention, the orientation angle is set within the range of ±10° to ±45° because within this range, sufficient torsional strength and high axial elastic modulus can be obtained. It is.

In other words, when the orientation angle is ±10° without grooves, the axial elastic modulus is sufficiently high, but as shown in Figure 4, the torsional strength is small, so it is necessary to increase the wall thickness of the drive shaft. This is because the weight reduction effect will be impaired.

On the other hand, as the orientation angle increases, the resiliency increases up to ±45°, but as shown in FIG. 5, the axial elastic modulus and bending strength decrease. The axial elastic modulus affects the natural frequency of the shaft, as shown in equation (2) above, and is an important factor in determining the critical rotational speed. Therefore, in order to increase the critical rotational speed, the smaller the orientation angle, the better. As shown in Figure 4, the torsion strength is determined by the orientation angle of ±45
It reaches a peak when the orientation angle is .degree., and even if the orientation angle is increased further, the shear strength becomes weaker. In other words, setting the orientation angle to more than ±45° is negative from the standpoint of shear strength, critical rotational speed, and bending strength.

Therefore, it is desirable that the orientation angle of the layer responsible for torsional strength and bending strength in the structure of the drive shaft be ±45° or less.

In the present invention, two or more types of fibers are wound at the same time, and the advantages of having a so-called intralayer hybrid structure in which two or more types of fibers are wound at the same time are as follows.

First, in the conventional method of laminating each layer separately, a stress step is created at the interface between the CF layers, and complex secondary stress is generated, which may cause a decrease in strength or peeling between the eyebrows.

On the other hand, this can be prevented by using an intralayer hybrid.

Another advantage is that the number of times the molding process must be replaced is reduced. Molding traditional laminate configurations required changing rovings when changing fibers, but intralayer hybrids eliminate this task.

The materials used here include epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol resin, etc. as the matrix resin, and glass fiber (E glass, S glass), carbon fiber, Continuous fibers such as aramid fibers can be used.

The manufacturing method is normal filament winding (
In addition to the FW) method, a method of laminating prepreg sheets, a tape winding method of winding with prepreg tape, etc. are applied.

The diameter of the shaft to be molded depends on the application and characteristics, but the diameter is φ50
rm~φ120mm, wall thickness 511O1~15m
It is about 1 liter.

In addition, it is desirable to provide a glass fiber layer on the outermost layer to improve impact resistance, and the angle thereof is ±80° to ±90°.
is appropriate. Further, by providing a glass fiber layer also in the innermost layer, deterioration of the drive shaft due to electrolytic corrosion can be prevented. Furthermore, a carbon fiber layer may be provided within the FRP layer to improve bending strength and axial elastic modulus.

(Example) The present invention will be described below based on the example shown in FIGS. 1 to 3. Note that in FIGS. 1 to 3, the same numbers as in FIG. 6 indicate the same or corresponding parts, and detailed explanations will be omitted.

In Figures 1 to 3, numeral 4 indicates a hybrid layer formed by simultaneously winding and forming two or more types of fibers, and the winding angle is in the range of ±10° to ±45° with respect to the tube axis direction. ing. In all of these embodiments, the third layer 3 for improving impact resistance is formed around the outside of the hybrid layer 4.

By the way, the embodiment shown in FIG. 1 has a two-layer structure consisting of the hybrid layer 4 and the third layer 3, but the embodiment shown in FIG. 2 further includes a glass fiber layer 5 inside the hybrid layer 4.
However, in the embodiment shown in FIG. 3, a carbon fiber layer 6 is provided between the high print layer 4 and the third layer 3.

Next, the results of implementation conducted to confirm the effects of the present invention will be explained.

Part 1) A shaft was formed on a steel mandrel with an outer diameter of φ80m+++ by the filament winding method. The matrix resin is an epoxy resin (trade name "Epicote 828" manufactured by Yuka Shell Epoxy Co., Ltd.) and an acid anhydride curing agent (trade name "R").
HN-2200J (manufactured by Hitachi Chemical Co., Ltd.) was mixed at a weight ratio of 100:80.

Glass fiber (product name "Glasron R-1150J" manufactured by Asahi Fiberglass Co., Ltd.) is used as a type of high-print layer in the layer, and carbon fiber (product name "Trading Card T-300J" manufactured by Toshiba Co., Ltd.) is used as another type of fiber. Co., Ltd.)
It was used.

The hybrid configuration is 70% by volume of glass fiber and 30% by volume of carbon fiber, and out of the 10 rovings that can be used for wrapping, 7 are glass fibers and 3 are carbon fibers, which are impregnated in the same resin tank. Performed filament winding. The orientation angle at this time was ±206. Moreover, the layer thickness was 3B.

Further, in order to improve impact resistance, glass fiber was wound around the third outermost layer to a thickness of 0.2 ymr with an orientation angle of ±85°.

The shaft obtained above was examined for the presence or absence of glabellar detachment using ultrasonic measurements. Furthermore, the torsional fracture torque and axial elastic modulus were determined. The results are shown in Table 1.

The comparative example in Table 1 is an example of a shaft with a conventional layer structure, in which two GFRP layers with an angle of ±45° are used as the first layer.
．． 1 m, 0.9 ±10° CFRP layer as second layer
M, the outermost layer is a ±85° GFRP layer wound to a thickness of 0.2 m.

As is clear from Table 1 above, the shaft of the present invention is free from peeling in each boundary layer and has good torsional fracture torque and axial elastic modulus.

Part 2) Using the same material with the same diameter mandrel as Part 1),
First, after wrapping 0.2mm of ±45゛ glass fiber layer,
2.8 rt glass fiber and carbon fiber hybrid layer
I wrapped it m times. The orientation angle of this layer is also ±20'', and the high-purin F' ratio is 65% by volume of glass fiber and 35% by volume of carbon fiber.Also, as in part 1), the outermost layer is provided with impact resistance by ±85°. A glass fiber layer with an orientation angle of 0.2
It was wound with a thickness of am. Figure 2 shows its configuration.

By adopting such a configuration, when applied to an automobile that mainly drives in a humid area, deterioration of the drive shaft due to electrolytic corrosion can be prevented and durability can be improved.

Part 3) Using the same material with a mandrel of the same diameter as Part 1),
First, the orientation angle is ±2o°, and the hybrid ratio is glass fiber 80.
Hybrid 1 containing 20% by volume of carbon fiber was wound two times, and a carbon fiber layer was wound thereon to a thickness of Jun at an orientation angle of ±10'. Furthermore, a glass fiber layer of 0.2 m was wound around the outermost layer at an angle of ±85°. This configuration is shown in FIG.

This configuration prevents delamination between the carbon fiber layer and the glass fiber layer, which was a problem with conventional methods, and at the same time provides a drive with high bending strength and high axial elastic modulus. You can create an axis.

(Effects of the Invention) As explained above, the present invention has made it possible to provide an FRP drive shaft that is free from delamination, has high production efficiency, and has high torsional strength.

[Brief explanation of drawings]

1 to 3 are partial sectional views showing one embodiment of the present invention,
FIG. 4 is a diagram showing the relationship between the torsional strength and the orientation angle of an FRP cylinder, FIG. 5 is a diagram showing the relationship between the elastic modulus and the orientation angle, and FIG. 6 is a partial sectional view showing the structure of a conventional shaft. 4 is a hybrid layer. Figure 1 is also 'f ladle (0)

Claims (1)

[Claims] (1) A fiber-reinforced hollow cylindrical shaft characterized by having a layer formed by simultaneously wrapping two or more types of fibers at an angle of ±10° to ±45° with respect to the tube axis direction. Plastic drive shaft.