JPH0777741B2 - Fiber reinforced resin rotating body - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced resin rotating body having a central hole in a central shaft portion such as a rotor of a water pump.

[0002]

2. Description of the Related Art Conventionally, a fiber-reinforced resin rotating body having a central hole in a central shaft portion such as a rotor of a water pump is arranged in a shaft portion having a central hole extending in the axial direction and in the central hole of the shaft portion. It is made of a fiber-reinforced resin and is insert-molded. A shaft serving as a rotating shaft is press-fitted into the insert metal fitting of the resin molded body having the insert metal fitting. Due to the expansion pressure applied to the shaft when the shaft of the rotary shaft is press-fitted into the insert fitting, hair cracks may occur in the shaft, resulting in a defective product. It is presumed that hair cracks were generated along the interface between the reinforcing fiber and the resin due to the expansion pressure.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and is a fiber that does not cause a hair crack in a resin around a center hole when a shaft of a rotary shaft is press-fitted into an insert fitting. It is intended to be a reinforced resin rotating body.

[0004]

A fiber-reinforced resin rotating body according to the present invention comprises a shaft portion having a central hole extending in the axial direction, a cylindrical insert metal fitting arranged in the central hole, and a shaft portion of the shaft portion. A rotating body integrally formed by insert molding from a fiber reinforced resin, which comprises a rotating portion projecting from one end side in a radial direction, wherein the shaft portion is formed by injecting a molding material from the one end side. The orientation of the reinforcing fibers is random around the holes.

The fiber-reinforced resin rotating body of the present invention is integrally formed of fiber-reinforced resin by insert molding, and is composed of a shaft portion, insert metal fittings, and a rotating portion. Pressed in. The shaft portion is located at the center of the rotating body, has a center hole for insert, and insert metal fittings are arranged by insert molding. The shaft of the rotary shaft is usually press-fitted into the insert fitting after the molded body is solidified.

The insert metal fitting is formed by insert molding in the center hole of the shaft portion when the rotary body is molded, and the shaft of the rotary shaft is press-fitted. The rotating portion constitutes a blade portion of this rotating body, and usually a plurality of blades radially projects from the shaft portion. Depending on the case, a plurality of radial blades may be formed on a disc protruding from the shaft.

When the shaft is press-fitted, the expansion pressure is transmitted to the resin layer through the insert fitting. At this time, if the resin layer has anisotropy of strength, it cannot withstand the expansion pressure and cracks occur. In particular, in a resin reinforced with reinforcing fibers, strength anisotropy is likely to occur depending on the orientation state of the reinforcing fibers. When most of the orientation direction of the reinforcing fibers is oriented in the direction parallel to the shaft portion, it is presumed that a force in the expansion direction cannot be countered and a hair crack occurs at the interface between the reinforcing fibers and the resin.

In the injection-molded body of the fiber-reinforced resin, the orientation state of the reinforcing fibers depends on the flow direction of the injected resin. For example, the resin injected from the gate into the mold flows from the gate toward the end face to fill the mold. If the shape is such that the flow is branched or flows backward along the way, it will be filled as a turbulent flow. Therefore, the orientation of the reinforcing fibers is likely to be random like the resin.

Therefore, the molding die of this molded body is used as a dead end surface on the one end surface side of the shaft portion, and a resin flow is first filled in the shaft portion and then in a rotating portion extending in the radial direction from the shaft portion. When the gate position of the mold is set so that the orientation of the reinforcing fibers can be made random. For example, the resin flow can be formed by providing a gate on one end side of the shaft portion near the portion where the rotating portion projects.

The shape of the gate is not particularly limited, and an ordinary film gate, pin gate, or the like can be used, and it is preferable to dispose the gate at the center of the shaft. By arranging such a gate and adjusting the pressure during molding, the orientation of the reinforcing fibers can be made random. In particular, in the ratio of the orientation of the reinforcing fibers in the direction parallel to the axis and the other direction, if the parallel direction is 40% or less, cracks do not occur and a molded product that is strong against forced fracture can be formed.

As a result, it is possible to obtain a fiber-reinforced resin rotating body in which hair cracks do not occur even when the shaft of the rotating shaft is press-fitted into the insert fitting. This fiber-reinforced resin rotating body is made of an ordinary thermoplastic resin such as nylon or PB.
Polyester resin such as T and polycarbonate, PP
Examples of the molded article include resins obtained by adding reinforcing fibers such as glass fibers to engineering plastics such as ether resins such as O and PPS. Particularly, it is more effective when the addition amount of the reinforcing fiber is large (20% or more).

[0012]

In the fiber-reinforced resin rotating body of the present invention, the reinforcing fibers are randomly oriented in the resin layer in the shaft portion having the insert fitting into which the shaft of the rotating shaft is press fitted. Therefore, the resin layer has no anisotropy and has uniform strength in each direction. Therefore, when the shaft is press-fitted into the solidified insert member of the rotating body, even if an expansion pressure is applied to the resin layer of the shaft portion, since the resin has the original strength, the occurrence of hair cracks can be prevented. If the orientation of the reinforcing fibers is not random but oriented in a direction parallel to the axis, the strength of the resin will be anisotropic and the strength in the expansion direction will decrease and hair cracks will easily occur, but in the present invention it is random. Therefore, the generation of cracks can be suppressed.

The random dispersion state of the reinforcing fibers can be easily achieved by providing the position of the gate in the molding die at the end portion near the rotating portion protruding from the shaft portion and making the resin flow turbulent. .

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples. FIG. 1 shows a cross-sectional view of a rotor which is a fiber-reinforced resin rotating body of the embodiment. This rotor includes a shaft portion 1 having a central hole extending in the axial direction, and a cylindrical insert metal fitting 2 arranged in the shaft portion 1.
And a plurality of blade-shaped rotating portions 3 protruding in the radial direction from one end side of the shaft portion 1, which are integrally formed from a fiber reinforced resin by insert molding.

In this rotating body, a hexagonal insert metal fitting 2 having an outer diameter of the rotating portion 3 of about 78φ, a height of the shaft portion 1 of about 20 mm and a diameter of 15 mm is formed by insert molding. The molding is performed by one end side 1 of the shaft portion 1 closer to the protruding rotating portion 3.
It is a mold with a film gate in the center of 0 (arrow part), and is made of glass fiber reinforced PPS resin (Sustain GT-
Insert injection molding was performed using a cylindrical insert metal fitting 2 using 50 glass fiber 40% and manufactured by Toso Corporation.

The molding conditions are a mold temperature of 150 ° C. and a cylinder temperature of 310, 300, 29 on an injection molding machine of 100 tons.
0, 280 ° C., holding pressure (gauge pressure) 40 kg / cm ² , injection time 15 seconds. In the embodiment, as shown in FIG. 1, a gate 4 (in the direction of an arrow) is provided with a shaft portion 1 on which a rotating portion 3 is formed.
Was provided on the center side of one end side 10 of the. The resin injected from the gate 4 into the mold first advances straightly in the axial direction of the shaft portion 2 in the wide space and then reverses when it hits the end face to fill the rotating portion 3 in the narrow space protruding from the lower side surface of the shaft portion 1. Flow like you do. Therefore, since the shaft portion 2 has a dead end surface in the inflow direction of the resin flow, the resin flow is not fixed in a fixed direction but forms a turbulent flow and is solidified in a state where the entire mold is filled. For this reason, the glass fibers kneaded in the resin are also oriented in a state corresponding to the flow of the resin, so that the glass fibers of the shaft portion 2 become random. Therefore, there is no anisotropy in the reinforcing direction of the glass fiber, and the original strength of the reinforcing resin can be maintained. Therefore, even if the shaft of the rotary shaft is press-fitted into the insert metal fitting 2 of the molded rotating body and expansion pressure is applied to the resin layer, hair cracks do not occur.

When the shaft portion 1 of this molded rotating body was cut and the resin of the cross section was dissolved with a solvent and the orientation state of the glass fiber was visually observed, the orientation of the glass fibers was about 10 in total.
% Or less, indicating a nearly random state. Again 1
The strength was such that it could not be broken by the forced breaking force by applying a pressure of 300 kgf. 8 for 10 molding rotors
The shaft was press-fitted by applying a pressure of 00 kgf, but no crack was found.

For comparison, the position of the gate 4 (arrow) is shown in FIG.
As shown in FIG. 3, the molding was provided on the side opposite to the example and on the side opposite to the one end side 10 from which the rotating portion 3 projects. When molded in this mold, even if the resin flow hits the end face of the shaft portion 1 as shown in the schematic view of FIG. Most of the glass fibers in 1 are solidified in the state of being oriented in the resin flow direction, that is, in the direction parallel to the shaft 1. Therefore, the reinforcing direction of the glass fiber becomes unidirectional, and the reinforcing of the resin is anisotropic. Therefore, the strength in the direction against the force of expansion when the shaft is press-fitted into the insert fitting 2 is not sufficient, and hair cracks are likely to occur. When this molded rotating body was broken in the same manner as in the example to observe the orientation state of the reinforcing fibers on the fracture surface, it was found that about 5 fibers were oriented parallel to the shaft 1.
0% was not random. When a press-fitting test was performed on the shaft, cracks occurred in all 10 of them.

[0019]

In the fiber-reinforced resin rotating body of the present invention, the orientation state of the reinforcing fibers in the resin layer of the shaft portion is mainly random. Therefore, a resin phase is formed which is reinforced against the expansion pressure when the shaft of the rotary shaft is press-fitted into the insert fitting. Therefore, even if the shaft is press-fitted into the insert fitting, the generation of cracks in the resin phase is suppressed.

In order to form such a fiber-reinforced resin rotating body, the position of the gate is set so that the resin flow at the time of molding hits the dead end surface and then becomes a turbulent flow to the rotating portion protruding in the radial direction. As a result, the orientation state of the reinforcing fibers can be easily made random.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molded body of an example.

FIG. 2 is a schematic view showing an orientation state of glass fibers in a shaft portion of an example.

FIG. 3 is a cross-sectional view of a molded body of a comparative example.

FIG. 4 is a schematic view showing an orientation state of glass fibers in a shaft portion of a comparative example.

[Explanation of symbols]

1 shaft part, 2 insert metal fittings, 3 rotating part, 4
Gate,

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area B29K 105: 22 B29L 31:08

Claims (1)

[Claims] 1. A fiber comprising a shaft portion having a central hole extending in the axial direction, a cylindrical insert metal fitting arranged in the central hole, and a rotating portion protruding radially from one end side of the shaft portion. A rotating body integrally formed from a reinforced resin by insert molding, wherein the shaft portion is formed by injecting a molding material from the one end side, and the orientation of the reinforcing fibers is random around the center hole. Fiber-reinforced resin rotating body characterized by.