U.S. patent application number 11/905754 was filed with the patent office on 2008-04-10 for fuel pump.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Tadashi Hazama, Kiyonori Moroto.
Application Number | 20080085199 11/905754 |
Document ID | / |
Family ID | 39275067 |
Filed Date | 2008-04-10 |
United States Patent
Application |
20080085199 |
Kind Code |
A1 |
Hazama; Tadashi ; et
al. |
April 10, 2008 |
Fuel pump
Abstract
A fuel pump includes a plurality of magnets that are disposed
circumferentially on an inner surface of a housing of the fuel pump
and alternately form different magnetic poles, an armature
rotatably disposed inside the permanent magnets, a rotating member
disposed on a rotary shaft that is connected with the armature and
rotates with the rotary shaft by rotating the armature, a pump
casing that accommodates and rotatably supports the rotating
member, and a discharge port disposed on the pump casing so as to
discharge fuel pressurized by the rotation of the rotating member.
According to the present invention, an imaginary line extending
straight through the discharge port in a flow direction of fuel
discharging from the discharge port extends into a circumferential
gap between two of said permanent magnets.
Inventors: |
Hazama; Tadashi; (Chita-gun,
JP) ; Moroto; Kiyonori; (Kariya-city, JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
39275067 |
Appl. No.: |
11/905754 |
Filed: |
October 3, 2007 |
Current U.S.
Class: |
417/423.3 |
Current CPC
Class: |
F04D 5/007 20130101;
F05B 2250/503 20130101; F04D 5/002 20130101 |
Class at
Publication: |
417/423.3 |
International
Class: |
F04B 17/00 20060101
F04B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 4, 2006 |
JP |
2006-272933 |
Claims
1. A fuel pump for supplying fuel suctioned from a fuel tank to an
internal combustion engine, comprising: a housing; a plurality of
magnets that are disposed circumferentially on an inner surface of
said housing, and forming different magnetic poles alternately; an
armature disposed rotatably inside the permanent magnets; a
rotating member disposed on a rotary shaft that is connected with
the armature and rotates with the rotary shaft by rotating the
armature; a pump casing that accommodates and rotatably supports
the rotating member; and a discharge port disposed in the pump
casing to discharge fuel pressurized by the rotation of the
rotating member; wherein: an imaginary line extending straight
through the discharge port in a flow direction of fuel discharging
from the discharge port extends into a circumferential gap between
two of said permanent magnets.
2. The fuel pump according to claim 1, wherein: said imaginary line
extends along an inner inclined surface of the discharge port.
3. The fuel pump according to claim 1, wherein: an edge between an
inner inclined surface of the discharge port and an outer surface
of the pump casing is disposed axially below said circumferential
gap.
4. A fuel pump for supplying fuel suctioned from a fuel tank to an
internal combustion engine, comprising: a housing; a plurality of
magnets that are disposed circumferentially on an inner surface of
said housing, and forming different magnetic poles alternately; an
armature disposed rotatably inside the permanent magnets; a
rotating member disposed on a rotary shaft that is connected with
the armature and rotates with the rotary shaft by rotating the
armature; a pump casing that accommodates and rotatably supports
the rotating member; and a discharge port disposed in the pump
casing to discharge fuel pressurized by the rotation of the
rotating member; wherein: an imaginary line extending in a flow
direction of fuel discharging from the discharge port along an
inner inclined surface of the discharge port extends between
upstream ends of adjacent permanent magnets.
5. The fuel pump according to claim 4, wherein: a distance d
between an edge face of the permanent magnets which face the pump
casing and an opening of the discharge port which faces the
permanent magnet is equal to or less than 10 mm.
6. The fuel pump according to claim 4, wherein: there are two
permanent magnets.
7. The fuel pump according to claim 6, wherein: a circumferential
angle .theta. of the permanent magnets is equal to or less than 150
degrees and more than 120 degrees.
8. The fuel pump according to claim 4, wherein: an angle between
the imaginary line and the outer surface of the pump casing is
equal to or less than 60 degrees and more than 10 degrees.
9. A fuel pump for supplying fuel suctioned from a fuel tank to an
internal combustion engine comprising: a housing; a plurality of
magnets that are disposed circumferentially on an inner surface of
said housing, and forming different magnetic poles alternately; an
armature disposed rotatably inside the permanent magnets; a
rotating member disposed on a rotary shaft that is connected with
the armature and rotates with the rotary shaft by rotating the
armature; a pump casing that accommodates and rotatably supports
the rotating member; and a discharge port disposed on the pump
casing to discharge fuel pressurized by the rotation of the
rotating member; wherein: an edge between an inner inclined surface
of the discharge port and an outer surface of the pump casing being
disposed axially below a circumferential gap formed between two of
said permanent magnets.
10. The fuel pump according to claim 9, wherein: a distance d
between an edge face of the permanent magnets which face the pump
casing and an opening of the discharge port which faces the
permanent magnet is equal to or less than 10 mm.
11. The fuel pump according to claim 9, wherein: there are two
permanent magnets.
12. The fuel pump according to claim 11, wherein: a circumferential
angle .theta. of the permanent magnets is equal to or less than 150
degrees and more than 120 degrees.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based upon, claims priority from and
incorporates herein by reference the contents of Japanese Patent
Applications No. 2006-272933 filed on Oct. 4, 2006.
FIELD OF THE INVENTION
[0002] The present invention relates to a fuel pump that supplies
fuel suctioned from a fuel tank to an internal combustion
engine.
BACKGROUND OF THE INVENTION
[0003] Fuel pumps that include a motor section and a pump section
that is driven by the motor section, pumps up and pressurizes fuel
for supplying the fuel from a fuel tank to an internal combustion
engine through the inside of the motor section are well-known, as
disclosed in JP-A-5-187382, JP-A-6-167291 and JP-A-6-229390. The
motor section includes a plurality of permanent magnets that are
positioned about a circumference of its housing so as to form a
plurality of magnetic poles in a circumferential direction, an
armature disposed inside the permanent magnets, etc.
[0004] As shown in FIG. 4, fuel pressurized in the pump section is
discharged toward the permanent magnets 310 from a discharge port
302 formed in a pump casing 300 of the pump section, which
accommodates a rotating member. Fuel discharged from the discharge
port 302 flows through the inside of the motor section.
Specifically, the discharged fuel flows through a gap between an
outer surface of the armature and an inner surface of the permanent
magnets (not shown), and a gap 312 between the adjacent permanent
magnets 310 arranged in the circumferential direction of the inside
of the motor section.
[0005] However, in the fuel pump, fuel discharged from the
discharge port 302 of the pump casing 300 cannot flow smoothly into
a gap 312 between the adjacent permanent magnets 310 because the
fuel collides with an edge surface 314 of the permanent magnets
310, as shown in FIG. 4. This increases the pressure loss of the
fuel flow.
SUMMARY OF THE INVENTION
[0006] In view of the foregoing problems, it is an object of the
present invention to provide a fuel pump, in which the fuel
pressurized in the pump section can flow smoothly into the gap
between the adjacent permanent magnets of the motor section.
[0007] According to the present invention, a fuel pump includes a
plurality of magnets that are disposed circumferentially on an
inner surface of a housing of the fuel pump and alternately form
different magnetic poles, an armature rotatably disposed inside the
permanent magnets, a rotating member disposed on a rotary shaft
that is connected with the armature and rotates with the rotary
shaft by rotating the armature, a pump casing that accommodates and
rotatably supports the rotating member, and a discharge port
disposed on the pump casing so as to discharge fuel pressurized by
the rotation of the rotating member. According to the present
invention, an imaginary line extending straight through the
discharge port in a flow direction of fuel discharging from the
discharge port extends into a circumferential gap between two of
said permanent magnets. In a first embodiment, an imaginary line
extending in a flow direction of fuel discharging from the
discharge port along an inner inclined surface of the discharge
port extends between upstream ends of adjacent permanent magnets.
In a second embodiment, an edge between the inner inclined surface
of the discharge port and an outer surface of the pump casing is
below a gap formed between two permanent magnets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The above and other objects, features and advantages of the
present invention will become more apparent from the following
detailed description with reference to the accompanying drawings.
In the drawings:
[0009] FIG. 1 is a longitudinal cross-sectional view showing a fuel
pump according to the first embodiment of the present
invention;
[0010] FIG. 2A is a plan view showing a pump casing of the fuel
pump shown in FIG. 1;
[0011] FIG. 2B is an enlarged cross-sectional view of a portion
around an discharge port of the pump casing of the fuel pump shown
in FIG. 1;
[0012] FIG. 3A is a plan view showing a pump casing of the fuel
pump according to the second embodiment of the present
invention;
[0013] FIG. 3B is an enlarged cross-sectional view of a portion
around an discharge port of the pump casing of the fuel pump
according to the second embodiment of the present invention;
[0014] FIG. 4A is a plan view showing a pump casing of a
conventional fuel pump; and
[0015] FIG. 4B is an enlarged cross-sectional view of a portion
around an discharge port of the pump casing of the conventional
fuel pump.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0016] A fuel pump 10 according to the first embodiment will be
described with reference to FIGS. 1 and 2.
[0017] The fuel pump 10 is an in-tank type turbine pump that is
usually accommodated in a fuel tank (not shown) of a vehicle, such
as two-wheel vehicle or four-wheel vehicle. The fuel pump 10
pressurizes fuel suctioned from the fuel tank, and supplies the
pressurized fuel to an internal combustion engine.
[0018] The fuel pump 10 includes a pump section 12 and a motor
section 13 that drives the pump section 12. The pump section 12 and
the motor section 13 are housed in a housing 14. A casing cover 20
is caulked at the outer periphery thereof by the edge portion of
the housing 14. With this structure, the pump casing 22 can be held
between the casing cover 20 and a step 15 formed on the inner
surface of the housing 14.
[0019] The pump section 12 is a turbine pump that includes the
casing cover 20, a pump casing 22 and an impeller 30. The pump
section 12 is arranged on the upstream side of the motor section 13
in the axial direction of the rotation axis of an armature 50 of
the motor section 13. The impeller 30 (as a rotating member) is
assembled on a rotary shaft 56 (as a rotation axis). The casing
cover 20 and the pump casing 22 form a casing member, which
accommodates and rotatably supports the impeller 30. The casing
cover 20 has a fuel suction port 200, through which fuel is pumped
up from the fuel tank into pump passages 202a,202b. The fuel
passages 202a,202b are formed as C-shaped grooves along an outer
edge of the impeller 30 in the casing cover 20 and the pump casing
22, respectively. The impeller 30 is disc-shaped, and a plurality
of blades and blade ditches are alternately formed at the outer
edge of the impeller 30. When the impeller 30 rotates with the
rotary shaft 56 by rotating the armature 50 of the motor section
13, fuel flows out of the blade ditches of the impeller 30 toward
the inner surface of the fuel passage 202a,202b. The fuel returns
to the blade ditches from the inner surface of the fuel passage
202a,202b and flows out of the blade ditches of the impeller 30
again. After the fuel repeats the above flowing out and returning,
the fuel is pressurized and forms a circulating flow in the fuel
passage 202a,202b. Thus, fuel can be pumped up through the fuel
suction port 200 and be pressurized in the fuel passage 202a,202b
by the rotating impeller 30. Fuel pressurized in the fuel passage
202a,202b flows together in a discharge port 204 of the pump casing
22, and is discharged into the motor section 13 through the
discharge port 204.
[0020] The motor section 13 includes permanent magnets 40a,40b, the
armature 50, a commutator 60, a brush 80 and a choke coil 82.
Permanent magnets 40a,40b have arc-shaped cross sections,
respectively, and are fixed on the inner surface of the housing 14
with adhesive at equal intervals, so that S-pole and N-pole are
positioned. As shown in FIG.2A, a circumferential angle .theta. of
the permanent magnets 40a,40b is equal to or less than 150 degrees
and more than 120 degrees. Accordingly, gaps 208a,208b are formed
between edge faces of the permanent magnets 40a,40b that are
disposed in the circumferential direction of the housing 14. A
plate spring 42 is disposed in the gap 208b. On the other hand, a
support member 72 of a bearing holder 70, which extends toward the
pump section 12, is disposed in the gap 208a. The plate spring 42
and the support member 72 can prevent permanent magnets 40a,40b
from shifting in the circumferential direction. In this embodiment,
a distance d (shown in FIG. 2B) between an edge face 41 of the
permanent magnets 40a,40b which face the pump casing 22 and an
opening 206 of the discharge port 204 which faces the permanent
magnet 40a is equal to or less than 10 mm.
[0021] The armature 50 is rotatably positioned inside two permanent
magnets 40a,40b so that a clearance space is formed as a fuel
passage 210 between inner surfaces of the permanent magnets 40a,40b
and an outer surface of the armature 50. The armature 50 has a core
52 that is made of the laminated magnetic steel sheets, and coils
wound around the core 52. The core 52 has a plurality of magnetic
pole cores 54 which are arranged in the rotation direction of the
armature 50. The coils are wound around each of the magnetic pole
cores 54. Moreover, the rotary shaft 56 is inserted into a core 52.
A metal bearing 24 rotatably supports one end of the rotary shaft
56, and a metal bearing 26 rotatably supports the other end of the
rotary shaft 56. The bearing 24 is disposed in the pump casing 22,
and the bearing 26 is disposed in the bearing holder 70.
[0022] The commutator 60 is formed as a plane disk-shape, and is
disposed on the opposite side of the impeller 30 with respect to
the armature 50. The commutator 60 has a plurality of segments 62
which are arranged in the rotation direction of the armature 50.
The segments 62 are made of carbon, for example, and electrically
connected to the coils of the armature 50. The adjacent segments 62
are separated by a gap or an insulating resin. This prevents the
adjacent segments 62 from connecting electrically. With this
structure, when the armature rotates, each segment 62 will make
contact with the brush 80 sequentially, and drive current to be
supplied to the coils of the armature 50 will be commutated. A
terminal 64 is inserted in an end cover 74. Drive current is
supplied to the coils of the armature 50 from an external power
source through the terminal 64, the brush 80, and the commutator
60. The end cover 74 is caulked at the outer periphery thereof by
the edge portion of the housing 14, as shown in FIG. 1. With this
structure, the bearing holder 70 can be held between the end cover
74 and a step 16 formed on the inner surface of the housing 14. A
discharge port 212 is disposed on the end cover 74, and
accommodates a check valve 90 for preventing back-flow of fuel
discharged from the discharge port 212. The bearing holder 70 and
the end cover 74 are made of resin.
[0023] With the above-described structure, fuel discharged from the
discharge port 204 of the pump section 12 will be supplied to the
internal combustion engine through the gap 208a,208b, the fuel
passage 210 and the discharge port 212. Thus, fuel pressurized in
the pump section 12 flows in the motor section 13. Accordingly, the
fuel flowing in the motor section 13 cools the motor section 13,
and improves the lubricity of a slide member in the motor section
13.
[0024] Especially, with the structure of the fuel pump described in
the present invention, an imaginary line extending straight through
the discharge port in a flow direction of fuel discharging from the
discharge port extends into a circumferential gap between two of
said permanent magnets. Accordingly, fuel discharging from the
discharge port 204 flows straight into the gap 208b between two
permanent magnets 40a,40b.
[0025] In a first embodiment, as shown in FIG. 2B, an inner
inclined surface 205 is formed in the discharge port 204 on the
front side of the rotation direction of the impeller 30. An
imaginary line 220 extending in a flow direction of fuel
discharging from the discharge port 204 along the inner inclined
surface 205 extends between the upstream ends of the adjacent
permanent magnets 40a,40b. Thus, the imaginary line 220 is inclined
to the outer surface 23 of the pump casing 22, which faces the
motor section 13. In this embodiment, an angle .alpha. between the
imaginary line 220 and the outer surface 23 of the pump casing 22
is equal to or less than 60 degrees and more than 10 degrees. The
discharge port 204 is disposed in the vicinity of the gap 208b in
which the plate spring 42 is disposed. The plate spring 42 is made
of thin plate so as to reduce the pressure loss of the fuel flowing
through the gap 208b.
[0026] In the first embodiment, described above, the imaginary line
220 extends in a flow direction of fuel discharging from the
discharge port 204 along the inner inclined surface 205 that is
formed in the discharge port 204 on the front side of the rotation
direction of the impeller 30. Moreover, the imaginary line 220
extends between the upstream ends of the adjacent permanent magnets
40a,40b. With this structure, pressurized fuel that is discharged
from the discharge port 204 flows smoothly into the gap 208b, which
is closer to the discharge port 204. As a result, pressure loss of
the fuel flowing into the gaps 208a,208b is reduced. At the same
time, a noise generated due to fuel flowing from the pump section
12 into the motor section 13 is reduced.
[0027] In the first embodiment, described above, the angle e of
circumference of the permanent magnets 40a,40b is equal to or less
than 150 degrees and more than 120 degrees. Thus, larger gaps
208a,208b are formed. Accordingly, the pressure loss of the fuel
flowing into the gaps 208a,208b is reduced.
[0028] In the first embodiment, described above, the distance d
between the edge face 41 of the permanent magnets which face the
pump casing 22 and the opening 206 of the discharge port 204 which
faces the permanent magnet 40a is equal to or less than 10 mm.
Accordingly, the pump section 12 can be closer to the motor section
13. Therefore, the fuel pump 10 can be downsized.
[0029] In the first embodiment, described above, the angle .alpha.
between the imaginary line 220 and the outer surface 23 of the pump
casing 22 is equal to or less than 60 degrees and more than 10
degrees. With this structure, the direction of fuel flowing in the
rotation direction of the impeller 30 through the fuel passage
202a,202b is not changed significantly. Therefore, fuel will be
discharged smoothly along the inner inclined surface 205 that is
formed in the discharge port 204 on the front side of the rotation
direction of the impeller 30.
Second Embodiment
[0030] A fuel pump according to the second embodiment will be
described with reference to FIG. 3. The same or similar reference
numerals hereafter indicate the same or substantially the same
part, portion or component as the first embodiment.
[0031] As shown in FIG. 3, an edge 207 between the inner inclined
surface 205 of the opening 206 and the outer surface 23 of the pump
casing 22 is axially below the gap 208b formed between permanent
magnets 40a,40b. With this structure, fuel discharged from the
discharge port 204 flows smoothly into the gap 208b. Therefore,
pressure loss of the fuel flowing into the gap 208a,208b is
reduced. At the same time, noise generated due to fuel flowing from
the pump section 12 into the motor section 13 is reduced.
[0032] The range of the circumferential angle .theta. of the
permanent magnets 40a,40b, the distance d between the edge face 41
and the opening 206, and the angle .alpha. between the imaginary
line 220 and the outer surface 23 in the second embodiment are the
same as described in the first embodiment.
[0033] (Variation)
[0034] In the above embodiments, the circumferential angle .theta.
of the permanent magnets 40a,40b is equal to or less than 150
degrees and more than 120 degrees. However, the angle .theta. may
be defined outside of the above range.
[0035] In the above embodiments, the distance d between the edge
face 41 and the opening 206 is equal to or less than 10 mm.
However, the distance d may be defined outside of the above
range.
[0036] In the above embodiments, the angle .alpha. between the
imaginary line 220 and the outer surface 23 is equal to or less
than 60 degrees and more than 10 degrees. However, the angle
.alpha. may be defined outside of the above range.
[0037] In the above embodiments, two permanent magnets are
provided. However, four permanent magnets, or the even more than
four permanent magnets, may be provided.
[0038] Various other modifications and alternations may be made to
the above embodiments without departing from the spirit of the
present invention. Thus, while the invention has been described in
connection with what is presently considered to be the most
practical and preferred embodiments, it is to be understood that
the invention is not to be limited to the disclosed embodiments,
but on the contrary, is intended to cover various modifications and
equivalent arrangements included within the spirit and scope of the
appended claims.
* * * * *