Circumferential flow pump

Abstract

A circumferential flow pump in which the quantity of swelling by alcohol or toluene contained in fuel, is curbed and an impeller thereof is prevented from locking is provided.A circumferential flow pump for feeding into an internal combustion engine, fuel from the fuel tank thereof includes an impeller, made of fiber-reinforced PPS, having a base portion fitted to a motor rotor, a vane portion provided outer-circumferentially on the base portion, and an outer ring portion provided outer-circumferentially on the vane portion; the vane portion is composed of a plurality of vanes arranged radially protruding straightly from the base portion and each vane includes a bend thereon; and furthermore, given that a projected area of the entire vane portion is S1, that of the ring portion, S2, that of the base portion, S3, when the impeller, is projected from a direction along a motor shaft of the motor rotor, the ratio of S3 to S1 is made to fall between 9:1 to 15:1, and the ratio of S2 to S1 is made to fall between 0.10:1 to 0.13:1.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to circumferential flow pumps that are housed in the fuel tank of, for example, an automobile, and supply fuel to the internal combustion engine thereof at a predetermined pressure.[0003]2. Description of the Related Art[0004]An impeller mounted on a circumferential flow pump is provided with a base portion that is fitted to a motor rotor, a vane portion that is formed outer-circumferentially on the base portion, and an outer ring portion that is formed outer-circumferentially on the vane portion. In conventional circumferential flow pumps, impellers have being developed for the purpose of raising efficiency or lowering noise. As an impeller of this king, it is known that the vane portion is made thinner, and that fiber-reinforced polyphenylene sulfide(PPS), being excellent in moldability and dimensional stability, is used. It is also known that a bend is formed on each vane (e.g., Japanese...

AI Technical Summary

Benefits of technology

[0005]In conventional circumferential flow pumps, resin's flow during injection molding tends to be blocked due to bends on the vane portion. When fiber-reinforced PPS is used as the molding resin, the orientation of the fiber, being reinforcing material, tends to be uniform at the bends of the vane portion. During the injection molding, the molding resin is injected through the vane portion into the outer ring portion, in which fiber's orientation tends to be uniform also in the ring under the effect of the vane portion. It is effective to enhance randomness of the fiber-orientation or enhance crystallinity of the fiber-reinforced PPS, in order to curb its swelling by alcohol and toluene that are contained in fuel. In the base portion, dwelling operation during the injection molding can enhance the crystallinity of the PPS, but in the vane portion and the ring portion, the dwelling pressure cannot be transferred thereto to such an extent that the crystallinity thereof can be enhanced. Consequently, due to the low randomness of fiber-orientation in the vane portion and the ring portion, the quantity of swelling thereof by alcohol and toluene becomes large compared with that in the base portion. When the impeller swells so much as to contact with a pump-housing, there arises a problem in that the impeller locks.

[0007]The present invention is made in order to solve above-described problems and provide a circumferential flow pump, in which the impeller mounted on the circumferential flow pump is made of fiber-reinforced PPS, so as to curb the quantity of swelling by alcohol and toluene contained in the fuel, so that the impeller is prevented from locking.

[0013]According to the present invention, because a circumferential flow pump having an impeller made of fiber-reinforced PPS is provided, the quantity of swelling by alcohol and toluene contained in the fuel can be curbed, so that a circumferential flow pump can be provided in which the impeller is prevented from locking.

Problems solved by technology

In conventional circumferential flow pumps, resin's flow during injection molding tends to be blocked due to bends on the vane portion.

Consequently, due to the low randomness of fiber-orientation in the vane portion and the ring portion, the quantity of swelling thereof by alcohol and toluene becomes large compared with that in the base portion.

When the impeller swells so much as to contact with a pump-housing, there arises a problem in that the impeller locks.

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