Rotary kinetic fluid motors or pumps – With means for re-entry of working fluid to blade set – Turbine regenerative pump
Reexamination Certificate
2000-10-27
2003-03-18
Verdier, Christopher (Department: 3745)
Rotary kinetic fluid motors or pumps
With means for re-entry of working fluid to blade set
Turbine regenerative pump
C415S106000, C415S200000, C416S24100B
Reexamination Certificate
active
06533537
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an impeller of a circumferential current pump used as an in-tank type fuel pump of an automobile.
2. Description of the Prior Art
An in-tank type circumferential current pump having an improved property for being mounted to a vehicle and having a low noise and a small pressure change has been conventionally used in a fuel pump for an electronically controlled type fuel injection apparatus of an automobile.
FIGS. 17
to
19
show a circumferential current pump
51
for an automobile. The circumferential current pump
51
shown in these drawings is placed within a fuel tank (not shown), and is structured such as to apply an energy to a fuel by a vane
54
formed on an outer periphery of an impeller
52
when the impeller
52
is rotated by a motor
53
so as to increase a pressure of the fuel flowing into a pump flow passage
56
from a fuel inlet port
55
and discharge the fuel having the increased pressure to an engine side from a fuel discharge port
57
.
In the circumferential current pump
51
mentioned above, in order to maintain a pump efficiency and a discharge pressure in a desired state, it is necessary to set gaps w
1
and w
2
in a side of side surfaces
58
a
and
58
b
of the impeller
52
within a predetermined size so as to reduce a leaked flow amount.
Further, in the circumferential current pump
51
mentioned above, in order to prevent one side surface
58
a
of the.impeller
52
from being pressed to a pump casing
60
and prevent another side surface
58
b
of the impeller
52
from being pressed to a pump cover
61
by maintaining the gaps w
1
and w
2
in the side of the side surfaces
58
a
and
58
b
of the impeller
52
in a suitable size, a pressure adjusting hole
62
open to both side surfaces
58
a
and
58
b
of the impeller
52
and communicating the gaps w
1
and w
2
in the side of both side surfaces
58
a
and
58
b
of the impeller
52
is formed. In the circumferential current pump
51
structured in this manner, a pressure balance in the side of both side surfaces
58
a
and
58
b
of the impeller
52
is achieved by the pressure adjusting hole
62
, the impeller
52
smoothly rotates in a state of being a little apart from the pump casing
60
and the pump cover
61
, and an abrasion of the side surfaces
58
a
and
58
b
of the impeller
52
is prevented, so that a size change caused by the abrasion of the side surfaces
58
a
and
58
b
of the impeller
52
is prevented and an improved pump function can be achieved for a long time.
Since the impeller
52
of the conventional circumferential current pump
51
mentioned above is always in contact with the fuel within the fuel tank, a phenol resin or a PPS resin excellent in a solvent resistance is used, whereby the impeller
52
is formed in a desired shape in accordance with an injection molding. Then, the pressure adjusting hole
62
of the impeller
52
mentioned above is formed by a pin
64
stood within a cavity
63
(refer to FIG.
20
).
However, as shown in
FIG. 20
, when the pin
64
for the pressure adjusting hole
62
is at the position apart from an axial hole forming portion
65
, a part of a molten resin flow
67
injected into the cavity
63
from an injecting gate
66
is brought into contact with the pin and branched and thereafter the molten resin flow
67
is combined in a downstream side of the pin
64
, so that there is generated a disadvantage (a weld phenomenon) that a surface accuracy of the combined portion is deteriorated. Further, in the conventional structure mentioned above, since it is necessary to arrange a plurality of narrow pins
64
within the cavity and a structure of an injection molding metal mold
68
is complicated, the injection molding metal mold
68
becomes expensive, thereby preventing a producing cost of the impeller
52
from being reduced.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an impeller for a circumferential current pump which can make a structure of an injection molding metal mold compact without generating a weld phenomenon.
In accordance with a first aspect of the present invention, there is provided an impeller for a circumferential current pump which is provided with a plurality of vane grooves in an outer peripheral side of a synthetic resin disc-like member rotated by a motor and is rotatably received within a substantially disc-like space formed between a pump casing and a pump cover. In this structure, an axial hole engaging with a drive shaft of the motor is formed in a center portion of the disc-like member and a pressure adjusting groove open to both side surfaces of the disc-like member is formed in the axial hole.
In accordance with the present invention having the structure mentioned above, the pressure adjusting groove formed in the axial hole functions so as to keep a balance of a pressure applied to both side surface side of the impeller. As a result, the impeller smoothly rotates in a state of keeping a little gap between the pump casing and the pump cover.
In accordance with a second aspect of the present invention, there is provided an impeller for a circumferential current pump as recited in the first aspect mentioned above, wherein an annular recess portion for arranging a ring gate for an injection molding is formed at a position a predetermined size apart from an outer peripheral side of the axial hole.
Since it is possible to receive a burr within the annular recess portion even when the burr is generated at a time of separating the ring gate for the injection molding, the surface accuracy of the impeller side surface is not deteriorated by the burr.
REFERENCES:
patent: 3551070 (1970-12-01), Glucksman
patent: 4451213 (1984-05-01), Takei et al.
patent: 4477228 (1984-10-01), Duffy et al.
patent: 4767277 (1988-08-01), Buse
patent: 5409357 (1995-04-01), Yu et al.
patent: 5952747 (1999-09-01), Nakase
patent: 7-151091 (1995-06-01), None
Bachman & LaPointe P.C.
Enplas Corporation
Verdier Christopher
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