Rotary kinetic fluid motors or pumps – With means for re-entry of working fluid to blade set – Turbine regenerative pump
Reexamination Certificate
1999-04-06
2001-05-01
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
C416S19700C
Reexamination Certificate
active
06224323
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an impeller for an electro-drive type fuel pump.
BACKGROUND ART
FIG. 1
shows an electro-drive type fuel pump of an in-tank system, which is installed in a fuel tank. The electro-drive type fuel pump illustrated in
FIG. 1
is composed of a motor portion
1
and a pump portion
2
, which are incorporated in a cylindrically formed housing
3
. A motor cover
4
and a pump cover
5
are attached to the upper and lower end portions of the ahousing
3
.
By supporting the upper and lower end portions of a shaft
8
at the motor cover
4
and the pump cover
5
via bearings
9
and
10
, respectively, an armature
7
is disposed in a motor chamber
6
so as to rotate therein. A plurality of commutator segments
12
, which are connected to a coil and which are composed of copper and silver as their principal components, are disposed on the armature
7
and are insulated from each other. A magnet
11
is disposed on the inner wall surface of the housing
3
. A brush
13
, which can slidingly contact the commutator segments
12
of the armature
7
, and a spring
14
that biases the brush
13
are incorporated in the motor cover
4
. The brush
13
is connected to an external connection terminal via a choke coil
15
.
A check valve
17
is incorporated in a discharge port
16
secured to the motor cover
4
, and a fuel feeding pipe is connected to the discharge port
16
. A pump body
18
is attached to the lower end portion of the housing
3
by caulking it to the lower side of the pump cover
5
. A fuel inlet opening
19
is provided in the pump body
18
and a fuel outlet opening
20
is provided in the pump cover
5
. The inlet opening
19
and the outlet opening
20
are provided at positions separated from each other in the circumferential direction of the pump chamber formed by the pump body
18
and pump cover
5
. A disk-shaped impeller
21
having a plurality of blade grooves
22
formed on the upper and lower sides in the circumferential direction is disposed in the pump chamber formed by the pump body
18
and the pump cover
5
. The impeller
21
is formed of resin, etc., and is fitted onto the shaft
8
of the armature
7
.
In an electro-drive type fuel pump constructed as described above, when the motor portion
1
is energized to rotate the armature shaft
8
, the impeller
21
is driven for rotation. As the result, fuel in the fuel tank is drawn up through the inlet opening
19
and enters the motor chamber
6
through the outlet opening
20
, and the fuel is discharged to a fuel feeding pipe through the discharge portion
16
.
A known impeller is described in Japanese Laid-open Patent Publication No. 7-54726.
FIGS. 2 through 5
show the known impeller.
FIG. 2
is a perspective view of the impeller,
FIG. 3
is an enlarged view of section III identified in
FIG. 2
,
FIG. 4
is a sectional view (sectional view taken in the radial direction) taken along the line IV—IV in FIG.
3
and
FIG. 5
is a sectional view (sectional view taken in the circumferential direction) taken along the line V—V in FIG.
3
. Blades
23
are provided along the circumferential direction on the outer circumferential portion of both sides of the impeller
21
and a blade groove
22
is formed between the blades
23
. A flow line groove
35
is formed at portions of the pump cover
5
and the pump body
18
that correspond to the blade grooves
22
of the impeller
21
. Thus, the flow line groove
35
forms a flow line
36
from the inlet opening
19
to the outlet opening
20
. In the radial direction sectional view, the blade grooves
22
are formed in a curved shape as shown in FIG.
4
.
Furthermore, in the circumferential direction view, the blade grooves
22
are formed in a rectilinear shape that is parallel to the plane of the impeller as shown in FIG.
5
. The connection portion
26
between the end face
24
of the blade
23
at the front side of the rotational direction and the end face
25
of the blade
23
at the rear side of the rotational direction has a right angle, that is, a rectangular shape. An opening portion of the blade groove
22
is formed so that the opening edge portion
28
in the radial direction at the rear side of the rotational direction has a rectilinear shape as shown in
FIG. 3
, and at the same time, connection portions
31
and
32
between the opening edge portion
28
and the opening edge portion
29
or
30
in the circumferential direction has a right angle.
In such a known impeller
21
, when fuel flows from the inlet opening
19
to the outlet opening
20
, a circulating vortex flow is generated wherein fuel flows outward of the radial direction along the blade grooves
22
of the impeller
21
as shown by the arrows in FIG.
4
and collides with the wall surface in the radial direction of the flow line
36
. The fuel flows inwardly in the radial direction along the flow line groove
35
and again flows outward of the radial direction along the blade grooves
22
. Because the speed of the circulating vortex flow in the circumferential direction is slower than the peripheral speed of the impeller
21
, the fuel that flows inwardly in the radial direction along the flow line groove
36
is caused to flow in the blade grooves
22
at the rear side of the rotational direction. At this time, because the connection portions between the blade grooves
22
and the end faces
24
or
25
of the blade
23
are formed to a right angle when viewed in the circumferential direction, the speed of the circulating vortex flow in the circumferential direction is decelerated by fluid resistance at the right angled connection portion
26
, and thus, pump efficiency was not satisfactory.
Furthermore, an impeller in which blades are inclined in the rotational direction as described in Japanese Laid-open Patent Publication No. 6-299983, and an impeller in which the blades are chamfered as described in Japanese Laid-open Patent Publication No. 7-189973, etc., has been described.
However, with respect to impellers in which blades are inclined in the rotational direction and blades or chamfered, the number of resin materials can form the impeller are limited, because the impeller shape is complicated. In particular, it becomes difficult to mold the impellers with thermosetting resin. Because the strength, anti-swelling properties when contacting with gasoline, etc., of thermosetting resins are higher than those of thermoplastic resins, etc., reliability may be a problem if the impellers are made of a resin such as thermoplastic resin, etc., other than the thermosetting resin, etc.
Further, because the opening edge portion
28
in the radial direction at the rear side of the rotational direction of the opening portion of the blade grooves
22
shown in
FIG. 3
has a rectilinear shape, and the connection portions
31
and
32
between the opening edge portion
28
and the opening edge portion
29
in the circumferential direction outward of the radial direction or the opening edge portion
30
in the circumferential direction inwardly in the eradial direction have a right angle, the speed of a circulating vortex flow flowing out from the blade grooves
22
in the circumferential direction is decelerated, and inflow of fuel into the blade grooves
22
is not smooth. Therefore, pump efficiency is not satisfactory.
In addition, although vapor exhaust port
37
that exhausts vapor (air bubbles) in the blade grooves
22
is disposed in one flow line groove
35
of the pump cover
5
or the pump body
18
, vapor in the blade grooves
22
that is disposed in the side opposite of the vapor exhaust port
37
cannot be immediately exhausted through the vapor exhaust port
37
. Therefore, pump efficiency is not satisfactory. Further, because the outlet opening
20
is provided at one side (the upper side in the case of
FIG. 1
) of both upper and lower sides of the impeller
21
, fuel in the blade grooves
22
opposite to the side where the outlet opening
20
is disposed scarcely flows into the outlet opening
20
side. Therefore, pump ef
Fujii Shinichi
Ikeda Satoru
Murase Seiji
Usui Takayuki
Aisan Kogyo Kabushiki Kaisha
Dennison, Scheiner Schultz & Wakeman
Ryznic John E.
LandOfFree
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