Rotary kinetic fluid motors or pumps – With means for re-entry of working fluid to blade set – Turbine regenerative pump
Reexamination Certificate
2000-08-04
2001-11-27
Ryznic, John E. (Department: 3745)
Rotary kinetic fluid motors or pumps
With means for re-entry of working fluid to blade set
Turbine regenerative pump
Reexamination Certificate
active
06322319
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electric fuel pump which is mounted in a fuel tank of an automobile or the like, and which forcedly delivers fuel to an engine, and particularly to an electric fuel pump in which the noise level can be lowered and the efficiency can be improved.
2. Description of the Related Art
FIGS. 6 and 7
are an enlarged partial perspective view of an impeller of an electric fuel pump of the conventional art which is disclosed in, for example, JP-B-63-63756, and an enlarged perspective view of the periphery of a radial seal portion of a pump base of the pump.
In the figures,
10
denotes the impeller which has many vane pieces
21
in an outer peripheral edge portion of a disk-like shape. The vane pieces
21
are divided into front and rear groups by a partition wall
22
, and a vane groove
23
is formed between the vane pieces
21
. The reference numeral
9
denotes the pump base which constitutes a pump casing (not shown), and which has an arcuate strip-like pump passage
13
, a suction port
14
, a discharge port
15
, the radial seal portion
9
a
for preventing a reverse flow of fuel from occurring, and an end face
9
b
which changes the flow direction of the fuel.
When the impeller
10
is rotated in the pump casing (not shown), the fuel sucked from the suction port
14
flows into the vane grooves
23
, is provided with a kinetic energy by the vane pieces
21
, and then forcedly sent through the pump passage
13
toward the discharge port
15
. The fuel which is forcedly sent to the discharge port
15
as described above collides against the end face
9
b
of the radial seal portion
9
a
which is formed in the final end of the pump passage, and is then discharged from the discharge port
15
while the direction is changed.
In this configuration, therefore, the fuel portions respectively entering the right and left vane grooves
23
which are divided into front and rear groups by the partition wall
22
simultaneously collide against the end faces
9
b
of the radial seal portions
9
a.
Consequently, the configuration has a problem in that the level of noises due to the fuel collision is high.
As a countermeasure against this problem, for example, known is the configuration which is disclosed in JP-A-60-173390 and shown in FIG.
8
. In an impeller
10
of the configuration, vane pieces
21
on both the sides of a partition wall
22
are shifted from each other by ½ pitch, so that timings when the fuel portions respectively entering vane grooves
23
on both the sides of the partition wall
22
collide against end faces
9
b
of radial seal portions
9
a
are shifted from each other. As a result, the impact force due to the fuel collision is reduced, thereby lowering the noise level. The periphery of the radial seal portion is configured in the same manner as above-described FIG.
7
.
In the configuration which is disclosed in JP-A-61-59283 and shown in
FIGS. 9 and 10
, a step
9
c
is disposed in an end face
9
b
of each radial seal portion
9
a
of a pump base
9
which constitutes a pump casing (not shown), whereby timings of fluid collision are shifted from each other to lower the noise level. Furthermore, the outer peripheral face of each vane piece
21
is protruded from that of a partition wall
22
in an outer peripheral direction, so that a reverse-flow region (a region where the pumping function is impeded) is prevented from being produced immediately above the partition wall
22
, whereby the pump efficiency is improved.
Recently, needs for lowering the operating sound level and reducing fuel consumption are increasing. In order to satisfy the needs, in an electric fuel pump of the conventional art, a countermeasure in which the shape of an impeller is changed so as to lower the operating sound level as described above, or that in which the shape of an impeller is changed and the shape of a pump base is changed so as to lower the operating sound level and improve the pump efficiency is taken. From the viewpoints of dimensional accuracy and mechanical strength, however, a pump base is usually produced by aluminum die casting. Consequently, there is a problem in that modification or production of production dies is very expensive.
SUMMARY OF THE INVENTION
The invention has been conducted in order to solve the above-discussed problems. It is an object of the invention to provide an electric fuel pump in which the noise level during operation is lowered and the pump efficiency is high, without changing the shape of a pump base.
To achieve the above object, according to the invention, there is provided an electric fuel pump comprising: an impeller which has many vane pieces in an outer peripheral edge portion of a disk-like shape; a motor section which rotates the impeller; and a pump casing which houses the impeller, which forms an arcuate strip-like pump passage that elongates along the outer peripheral edge portion of the impeller, and which has a suction port in one end portion of the pump passage, and a discharge port in another end portion, wherein, in the impeller, the vane pieces which are divided into front and rear groups by a partition wall are arranged in a staggered pattern, and outer peripheral faces of the vane pieces are protruded toward an outer peripheral side with respect to an outer peripheral face of the partition wall.
Also, according to the invention, an inclined face wall of the partition wall is formed so that, as the inclined face wall approaches nearer to a side face wall of each of the vane pieces, a distance between the inclined face wall of the partition wall and an end face of the impeller on a side of the vane piece is further reduced.
Further, according to the invention, the inclined face wall of the partition wall is formed into a spherical shape.
Furthermore, as seeing each of the vane pieces in a circumferential direction, the vane piece stands with overlapping another adjacent vane piece.
Further, according to the invention, inner face walls of the vane pieces are formed to obliquely intersect with the outer peripheral face of the partition wall.
REFERENCES:
patent: 3915589 (1975-10-01), Vander Linden
patent: 4141674 (1979-02-01), Schonwald
patent: 5011367 (1991-04-01), Yoshida et al.
patent: 5123809 (1992-06-01), Ito
patent: 5174713 (1992-12-01), Iwai et al.
patent: 5209630 (1993-05-01), Roth
patent: 5221178 (1993-06-01), Yoshioka et al.
patent: 5265997 (1993-11-01), Tuckey
patent: 5372475 (1994-12-01), Kato et al.
patent: 5375970 (1994-12-01), Iwai et al.
patent: 4-350394 (1992-12-01), None
patent: 6-2690 (1994-01-01), None
patent: 6-159283 (1994-06-01), None
Mitsubishi Denki & Kabushiki Kaisha
Ryznic John E.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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