JPH03115793A - Rotor for pump - Google Patents

Abstract

PURPOSE:To decrease a dimensional change to be caused by moisture absorption and set a clearance between the peripheral surface of a rotor and the inner surface of a housing as small as possible by blending phenol aralkyl resin and the filler in phenol resin to form a rotor for pump. CONSTITUTION:Phenol aralkyl resin and the filler are blended in phenol resin to form a rotor for pump. Phenol aralkyl resin, which is ordinary used for the purpose to improve the heat resistance, is used for forming a rotor for pump with resin on the basis of the point that this resin is effective in restraining moisture absorption, and a rotor made of resin with a small dimensional change can be realized. As a result, a clearance, which is important for a pump, between the peripheral surface of the rotor and the inner surface of a housing can be set as small as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resin pump rotor suitable for automobile fuel pumps and the like.

BACKGROUND OF THE INVENTION With the trend toward higher performance, smaller size, lighter weight, and lower cost of automobile parts, electric fuel pumps are also required to have rotors made of resin.

As shown in FIG. 1, the pump rotor has irregularities repeatedly formed on its periphery to form an impeller. When this rotor is housed in a housing, it is important to maintain the clearance between the circumferential surface of the rotor and the inner surface of the housing as small as possible in order to ensure the discharge performance of the pump. Therefore, the rotor is required to have high dimensional accuracy on the order of μm.

Conventionally, regarding the use of resin for rotors, molded products made of glass fiber-filled phenolic resin, which have relatively good dimensional accuracy, have been considered.

Problems to be Solved by the Invention However, the rotor made of glass fiber-filled phenolic resin undergoes large dimensional changes due to moisture absorption and swells. Therefore,
If the clearance between the rotor circumferential surface and the housing inner surface is not large enough, the rotor circumferential surface may come into contact with the housing inner surface due to swelling, which may cause the pump to stop.

An object of the present invention is to provide a pump rotor made of resin whose dimensions change little due to moisture absorption. A further object of the present invention is to provide a rotor made of resin with a smooth surface.

Means for Solving the Problems A pump rotor according to the present invention is characterized in that it is molded by blending a phenol resin with a phenol aralkyl resin and a filler. It is preferable to use a combination of glass fiber and spherical filler as the main filler.

Functional phenolic aralkyl resins are usually used for the purpose of improving heat resistance. Based on the new knowledge that the resin is effective in suppressing moisture absorption, the present inventors
By applying this to resin for pump rotors, it has become possible to create resin rotors with small dimensional changes.

By using a combination of glass fiber and spherical filler as the main filler, a rotor with high mechanical strength and a smooth surface can be obtained.

That is, the presence of the spherical filler improves the fluidity of the resin during molding, allowing the rotor surface to be molded smoothly. In addition, the presence of glass fibers makes it possible to maintain sufficient mechanical strength.

EXAMPLE The phenolic resin, phenol-aralkyl resin, used in the practice of this invention is one that is usually reprinted. If necessary, a curing agent such as hexamine 1. Add curing accelerator.

Both organic and inorganic fillers can be used, examples of which are as follows. Glass fiber, glass powder, glass beads (spherical filler), silica powder, silica beads (spherical filler), talc, clay, mica, aluminum hydroxide, aromatic polyamide fiber, billuron fiber. others,
A coloring agent and the like are appropriately added, mixed with a resin, kneaded, and then ground to obtain a molding material.

As the molding means, compression molding, injection molding, and transfer molding can be used as appropriate.

Examples 1 to 4, Comparative Examples 1 to 5 Blends of resins, fillers, and other additives having the compositions shown in Table 1 were mixed in rolls, kneaded, and ground to obtain molding materials. This was molded using a 50 mm injection molding machine to obtain a rotor as shown in the drawing. The molding conditions are mold temperature 180℃
°C, cylinder temperature (front 90°C, rear 50'C).

The characteristics of the rotors of the above examples and comparative examples are also shown in Table 1. Dimensional change due to moisture absorption is 70°C/90%RHX
Evaluation was made based on the change in outer diameter after 1000 hours of treatment. Also,
The mechanical strength of the rotor was determined by applying pressure to the uneven portion in the vertical direction and measuring the breaking strength.

◎: Excellent 0: Good Δ: Good Effects of the Invention As is clear from Table 1, the resin pump rotor according to the present invention has little dimensional change (swelling) due to moisture absorption.

Therefore, for a pump in which it is important to set the clearance between the rotor circumferential surface and the housing inner surface as small as possible, its industrial value is extremely large.

Further, by combining glass fiber and spherical filler as fillers, it is possible to improve the flatness of the rotor while maintaining mechanical strength.

[Brief explanation of drawings]

FIG. 1 shows a pump rotor to which the present invention is applied, (a
) is a side view, and (b) is a plan view.

Claims (1)

[Claims] 1. A pump rotor molded by blending a phenol resin, a phenol aralkyl resin, and a filler. 2. The pump rotor according to claim 1, wherein the main fillers are glass fibers and spherical fillers.