Rotary kinetic fluid motors or pumps – With means for re-entry of working fluid to blade set – Turbine regenerative pump
Reexamination Certificate
2001-03-29
2002-09-24
Verdier, Christopher (Department: 3745)
Rotary kinetic fluid motors or pumps
With means for re-entry of working fluid to blade set
Turbine regenerative pump
C415S200000, C416S228000, C416S237000, C416S238000
Reexamination Certificate
active
06454522
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an impeller for a circumferential current pump, so-called wesco-pump, utilized as a fuel pump capable of being arranged in a tank (intank-type fuel pump, called hereinlater) of, for example, an automobile.
In the known art, there has been utilized an intank-type circumferential current pump capable of being easily mounted to a vehicle such as an automobile and being operative with low noise and at small pressure variation.
FIG. 19
is an illustrated front view, partially in section, showing a circumferential current pump of a conventional structure and
FIG. 20
is a sectional view of
FIG. 1
in an enlarged scale.
With reference to these
FIGS. 19 and 20
, a circumferential current pump
51
is one disposed in a fuel tank, not shown, and when an impeller
52
of the pump
51
is rotated by means of a motor
53
, energy is applied to the fuel by vanes
54
formed to an outer periphery of the impeller
52
and a pressure of the fuel flowing into a pump passage
56
from a fuel inlet
55
is then increased. The thus pressure-increased fuel is drained on the side of an engine through a fuel drain port
57
.
In such circumferential current pump
51
, the shape of the vane constituting the inpeller
52
largely affects a pumping performance of the pump
51
. Taking the above matter into consideration, the prior art further provides a conventional example (1) such as disclosed in Japanese Patent Laid-open Publication No. SHO 57-206795, which, as shown in FIG.
21
and
FIGS. 22A and 22B
, discloses an inpeller
52
having an arrangement in which an upstream side surface
60
in a rotational (rotating) direction of one vane
54
and a downstream side surface
61
in the rotational direction of another one vane
54
adjacent to the first (above) mentioned vane
54
are parallel to each other (in other words, opposing surfaces
60
and
61
of a vane groove
58
are parallel to each other).
The prior art still further provides conventional examples such as disclosed in Japanese Patent Laid-open Publication No. HEI 8-100780, which includes an example (2) such as shown in
FIG. 23A
showing an impeller
52
in which vanes
54
, each having a constant thickness, is entirely bent and includes an example (3) such as shown in
FIG. 23B
showing an impeller
52
in which a front side end of a vane
54
having a constant thickness inclines forward in the rotational direction thereof. In these prior art examples (2), and (3), the length of the vane surface
60
(length of the vane
52
contacting the fuel) by which a centrifugal force is applied to the fuel and the pump drain pressure is increased.
The prior art still further provides conventional examples such as disclosed in Japanese Patent Laid-open Publication No. HEI 6-229388, which includes an example (4) such as shown in
FIG. 24
showing an impeller
52
, in which an upstream side surface
60
in the rotational direction of a vane
54
is formed entirely in a circular shape and a downstream side surface
61
in the rotational direction thereof extends linearly outward from a radially inner side of the vane
54
to thereby impart a kinetic energy directing to the rotational direction with respect to the fuel in the vane groove by the upstream side surface
60
and hence improve a pumping efficiency.
Further, since the impellers
52
of the respective conventional examples mentioned above always contact the fuels in the tanks, these impellers were formed of resin materials such as phenol resin or PPS resin having excellent resistance to solvent through an injection molding process, and after the injection molding, the side and outer circumferential surfaces were ground and finished so that dimensional performance and/or surface performance are within desired performance ranges, respectively.
The above mentioned prior art examples, however, have still provided the following defects or problems.
In the first example (1), the vane
54
of the impeller
52
is formed so as to provide a thickened portion towards the radially outside portion, so that, as shown in
FIG. 22B
, a mold is clamped by the vanes
54
which are contracted and deformed after the injection molding (deformation from the solid line position to the dotted line position). Hence, a (mold) releasing resistance at the time of releasing the impeller
53
from the mold is made large, and thus, there is a fear of being hard to remove the impeller
52
from the mold or causing an undesired deformation of the impeller
52
by the releasing resistance.
In the second and third examples (2) and (3), the shape or design of the vane
54
of the impeller
52
is changed to increase the pump drain pressure. However, in such examples, the pump drain pressure cannot be sufficiently increased, and accordingly, further improved technology has been required.
In the fourth example (4), the pumping efficiency is improved by changing the shape or design of the vane
54
of the impeller
52
. However, in this example, the pumping efficiency cannot be sufficiently increased, and accordingly, further improved technology has been required.
SUMMARY OF THE INVENTION
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide an impeller for a circumferential current pump.
This and other objects can be achieved according to the present invention by providing, in one aspect, an impeller for a circumferential current pump including a motor unit section having a motor and a pump unit section operatively connected to the motor unit section through a driving shaft of the motor, the pump unit section including a pump casing, a pump cover and an impeller disposed in a space defined between the pump casing and the cover, the impeller comprising:
a disc-shape member having two surfaces and operatively connected to the motor to be rotatable;
a plurality of vane grooves formed to outer peripheral end portions of both the surfaces in a circumferential direction thereof; and
a plurality of vanes arranged between the respective adjacent vane grooves along a radial direction of the disc-shape member,
wherein each of the vanes has an upstream side surface and a downstream side surface in a rotating direction thereof and a center line between both these surfaces extends along a radial direction of the disc-shape member, the upstream side surface has a radially inside portion and a radially outside portion which are formed to be continuous so that the radially inside portion is in parallel to the center line and the radially outside portion is inclined forward in the rotating direction of the disc-shape member, and the downstream side surface is formed entirely to be parallel to the center line.
In this aspect, only the radially outside portion of the vane is formed to be inclined forward in the rotating direction of the disc-shape member, so that the mold releasing resistance after the injection molding of the impeller can be reduced and, hence, the defective deformation of the impeller due to such releasing resistance can be effectively prevented in comparison with a conventional structure of the impeller in which the upstream side surface of the vane in the rotating direction thereof is entirely inclined forward and the downstream side surface of the vane is entirely inclined in a direction reverse to the rotating direction thereof.
In another aspect of the present invention, there is also provided an impeller for a circumferential current pump including a motor unit section having a motor and a pump unit section operatively connected to the motor unit section through a driving shaft of the motor, the pump unit section including a pump casing, a pump cover and an impeller disposed in a space defined between the pump casing and the cover, the impeller comprising:
a disc-shape member having two surfaces and operatively connected to the motor to be rotatable;
a plurality of vane grooves formed to outer peripheral end portions of both the surfaces in a circumferential direction
Sakamoto Yasuyuki
Tatsuzawa Naotaka
Enplas Corporation
Staas & Halsey , LLP
Verdier Christopher
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