JP2004251236A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel pump reduced in pressure loss of the fuel even in the case of providing a discharge opening in a central part of a cover member in the radial direction thereof. <P>SOLUTION: A case member 50 housing a rectifier 60 is fitted to an end of an armature 30 on a cover member 20 side thereof. The case member 50 has a tapered part 55. The case member 50 is formed with the tapered part 55 to form an obtuse angle between the tapered part 5 and the end of the case member 50 in an end of the tapered part 55 on a side thereof opposite to a pump side. The fuel flowing in a fuel passage 51 therefor gradually changes flowing direction thereof. With this structure, the generation of turbulence in the fuel flowing in the fuel passage 51 is restricted, and a flow thereof is stabilized. Pressure loss of the fuel in the fuel passage 51 can be thereby reduced, and the fuel passage 51 can be scaled down with reduction of the pressure-loss. Diameter of the cover member 20 and a housing 11 can be reduced, and the fuel pump 10 can be miniaturized. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel pump that supplies fuel in a fuel tank to an internal combustion engine (hereinafter, the internal combustion engine is referred to as an “engine”).
[0002]
[Prior art]
In a conventional fuel pump, a motor part having an armature is formed in a cylindrical shape having substantially the same outer diameter (see Patent Document 1). Since the outside of the motor part is molded, for example, with resin or the like, the motor part is formed in a cylindrical shape to ensure the chucking property and the sealing property with the molding die during molding. A cover member is installed at one end of the fuel pump, and a discharge port is provided in the cover member. Thereby, the fuel pressurized by the pump part flows along the outer periphery of the motor part, and is then discharged from the discharge port.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-65619
[Problems to be solved by the invention]
By the way, the applicant of the present application is considering providing the discharge port of the fuel pump in the central portion in the radial direction of the cover member. After that, the flow is changed at a right angle toward the axial direction and introduced into the discharge port.
[0005]
As described above, when the fuel flow changes at a right angle many times, the fuel flow in the fuel passage tends to be disturbed, and the fuel flow becomes unstable. As a result, there is a problem that the pressure loss of the fuel increases.
[0006]
Therefore, an object of the present invention is to provide a fuel pump in which the pressure loss of fuel is reduced even if the discharge port is provided in the central portion in the radial direction of the cover member.
[0007]
[Means for Solving the Problems]
According to the fuel pump of the first aspect of the present invention, the case member has the guide portion. The guide portion guides fuel in the fuel passage toward the discharge port. Therefore, the fuel is guided along the guide portion toward the discharge port formed in the central portion in the radial direction of the cover member. As a result, the direction of flow of the fuel flowing through the fuel passage changes gradually. Thereby, the fuel flow is hardly disturbed, and the fuel flow is stabilized. Therefore, the pressure loss of the fuel can be reduced.
[0008]
According to the fuel pump of the second aspect of the present invention, the case member houses the commutator connected to the armature of the motor unit. Therefore, the fuel passage is formed by the outer wall of the case member by attaching the case member containing the commutator to the motor unit. As a result, the connection part between the motor part and the commutator has a simple shape. Therefore, the fuel flow can be guided by the case member, and the pressure loss of the fuel can be reduced.
[0009]
According to the fuel pump of the third aspect of the present invention, the case member has the tapered portion as the guide portion. The outer diameter of the taper portion decreases as it goes to the anti-pump portion. Therefore, the fuel flows along the taper portion from the fuel passage formed outside the motor portion to the discharge port formed in the center portion of the cover portion. Therefore, the flow of fuel changes gently, and the pressure loss of fuel can be reduced.
[0010]
According to the fuel pump of the fourth aspect of the present invention, the tapered portion is connected to the tapered portion of the armature. For this reason, the overall length of the tapered portion in the axial direction of the motor portion is increased. Therefore, the flow of fuel changes gently, and the pressure loss of fuel can be reduced.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A fuel pump according to a first embodiment of the present invention is shown in FIG. The fuel pump 10 is an in-tank type pump installed in a fuel tank such as a vehicle. The housing 11 caulks and fixes the suction side cover 12 and the cover member 20. The cover member 20 has a discharge port 21 through which fuel discharged from the fuel pump 10 flows in a central portion in the radial direction.
[0012]
The pump casing 13 is sandwiched between the suction side cover 12 and the housing 11. The suction side cover 12 and the pump casing 13 forming the substantially C-shaped pump flow path 14 accommodate the impeller 15 in a rotatable manner. The suction-side cover 12, the pump casing 13, and the impeller 15 constitute a pump part in the claims. The pump casing 13 supports the bearing member 16 on the inner peripheral side.
[0013]
Many blade grooves are formed in the outer peripheral edge of the impeller 15 formed in a disk shape. When the impeller 15 rotates together with the shaft 31 by the rotation of the armature 30, a pressure difference is generated by the fluid friction force before and after the blade groove of the impeller 15, and this is repeated by a large number of blade grooves to add fuel to the pump flow path 14. Pressed. The fuel in the fuel tank sucked into the pump flow path 14 from the fuel suction port 17 formed in the suction side cover 12 by the rotation of the impeller 15 is opposite to the cover member 20 of the armature 30 from the communication path 18 of the pump casing 13. Is discharged to the axial end of the side. Further, the fuel flows through the outer periphery of the armature 30 to the discharge port 21 of the cover member 20 via the fuel passage 51 formed between the case member 50 and the cover member 20. The fuel that has flowed into the discharge port 21 passes through a fuel discharge portion (not shown) and is discharged from the fuel pump 10 to the engine side.
[0014]
A plurality of arc-shaped permanent magnets 19 are arranged on the inner peripheral wall of the housing 11 with a predetermined gap. The permanent magnets 19 are arranged so that magnetic poles having different poles are alternately formed in the circumferential direction. The cover 32 covers the axial end of the armature 30 opposite to the case member 50, where the case member 50 is assembled on the other axial end of the armature 30. The shaft 31 of the armature 30 is supported by the bearing member 16 and the bearing member 22 that are accommodated and supported in the pump casing 13 and the cover member 20, respectively.
[0015]
The armature 30 has a central core 33 at the center of rotation. The shaft 31 is press-fitted into the central core 33. The central core 33 is formed in a cylindrical shape having a hexagonal cross section. Six magnetic pole coil portions 34 are installed on the outer periphery of the central core 33 in the rotation direction. The magnetic pole coil section 34 has a coil core 35, a bobbin 36, and a coil 37 formed by winding a wire around the bobbin 36. The coil core 35 is a separate member from the central core 33. The bobbin 36 covers the coil core 35 except for a part. The bobbin 36 magnetically insulates the coil cores 35 adjacent in the rotation direction. The permanent magnet 19, the armature 30, the shaft 31, and the like constitute a motor unit that drives the pump unit.
[0016]
The end of the coil 37 on the side of the commutator 60 is electrically connected to the terminal 41 and is electrically connected to the commutator 60. The end portion on the impeller 15 side opposite to the commutator 60 of the coil 37 is electrically connected to the terminal 42. Six terminals 42 that are adjacent to each other in the rotation direction are electrically connected by terminals 43.
[0017]
As shown in FIGS. 1 and 2, the commutator 60 is accommodated in the case member 50. The case member 50 accommodates a commutator 60 divided into six segments. The commutator 60 is formed of a conductor such as carbon. The case member 50 is formed of a resin that insulates adjacent commutators 60. Thereby, adjacent commutators are electrically insulated by the gap 52 and the case member 50. Each commutator 60 is electrically connected to a terminal 61. When the case member 50 in which the commutator 60 is accommodated rotates together with the armature 30, the commutator 60 sequentially comes into sliding contact with the brush 23 shown in FIG. 1. The brush 23 is insert-molded on the cover member 20. Electric power is supplied to the coil 37 of the armature 30 through the terminal 24, the brush 23, the commutator 60, the terminal 61, and the terminal 41 that are insert-molded in the cover member 20.
[0018]
As shown in FIG. 2, the shaft 31 press-fitted into the armature 30 is inserted into the hole 53 of the case member 50 in which the commutator 60 is accommodated. Then, after the case member 50 is assembled to the armature 30, the C ring 70 is press-fitted into the shaft 31 from the counter armature side of the commutator 60. Thereby, the C ring 70 is installed on the side of the commutator 60 opposite to the armature. Therefore, the C ring 70 prevents the case member 50 containing the commutator 60 from being removed from the shaft 31.
[0019]
As shown in FIG. 3, the case member 50 has a cylindrical portion 54 and a tapered portion 55 as a guide portion. The cylindrical portion 54 is formed in a cylindrical shape centered on the central axis of the housing 11, that is, the central axis of the shaft 31. Thereby, as shown in FIG. 4, the fuel passage 51 is formed in a substantially cylindrical shape between the cylindrical portion 54 and the inner wall of the cover member 20. Further, the tapered portion 55 is connected to the side opposite to the pump portion of the cylindrical portion 54. The outer diameter of the taper portion 55 is reduced as it goes from the cylindrical portion 54 to the side opposite to the pump portion. Therefore, the taper part 55 has an outer wall inclined toward the central axis side of the shaft 31 as it goes to the counter pump part side. Thus, the fuel passage 51 is formed in a substantially truncated cone shape between the tapered portion 55 and the inner wall of the cover member 20.
[0020]
By forming the taper portion 55 in the case member 50, the angle formed by the taper portion 55 and the end portion 50a on the anti-pump portion side of the case member 50 is 90 ° at the end portion of the taper portion 55 on the anti-pump portion side. It is largely less than 180 °. When the discharge port 21 is disposed in the central portion in the radial direction of the cover member 20, the fuel flowing through the fuel passage 51 formed between the case member 50 and the cover member 20 flows from the radially outer side of the case member 50 to the central portion. It flows toward. Therefore, when the angle θ formed by the tapered portion 55 and the end portion 50a of the case member 50 is 90 ° or less, the fuel flowing from the radially outer side of the case member 50 to the central portion is likely to be disturbed. On the other hand, by forming the tapered portion 55 on the case member 50 as in the first embodiment, the fuel flowing on the outer periphery of the armature 30 is guided to the cylindrical portion 54 and the tapered portion 55 of the case member 50 and gently flows. Change direction. Therefore, the direction of flow of the fuel does not change many times at a substantially right angle, and the fuel flowing through the fuel passage 51 formed between the case member 50 and the cover member 20 is less likely to be disturbed. Moreover, the rotation of the armature 30 is not hindered by setting the angle formed between the tapered portion 55 and the end portion 50a on the side opposite to the pump portion of the case member 50.
[0021]
Further, the fuel that has flowed into the fuel passage 51 from the outer periphery of the armature 30 flows at two places, that is, the connecting portion between the cylindrical portion 54 and the tapered portion 55 of the case member 50 and the end portion of the tapered portion 55 on the side opposite to the pump portion. The direction of changes. The fuel flowing through the fuel passage 51 changes the flow direction to an obtuse angle at the connection portion between the cylindrical portion 54 and the tapered portion 55 of the case member 50 and the end portion of the tapered portion 55 on the side opposite to the pump portion. Therefore, the direction of flow of the fuel that has flowed into the fuel passage 51 from the outer periphery of the armature 30 changes gradually, and the flow is less likely to be disturbed.
[0022]
As described above, in the first embodiment described above, by forming the tapered portion 55 in the case member 50, the fuel that has passed through the outer periphery of the armature 30 is gently formed in the central portion in the radial direction of the cover member 20. 21 will guide you. Therefore, the fuel in the fuel passage 51 formed between the case member 50 and the cover member 20 is less likely to be disturbed in the flow, and the flow is stabilized. Therefore, the pressure loss of the fuel pressurized by the pump unit can be reduced.
[0023]
In the first embodiment, the fuel flowing through the fuel passage 51 formed between the case member 50 and the cover member 20 is stable without being disturbed. Therefore, even if the case member 50 and the cover member 20 are brought close to each other, a decrease in fuel pressure loss is suppressed. Thereby, each member of the fuel pump 10 such as the cover member 20 and the housing 11 that houses the cover member 20 can be downsized. Therefore, it is possible to achieve both reduction in size and reduction in fuel pressure loss.
[0024]
In the first embodiment, the commutator 60 is accommodated in the case member 50. Therefore, a mold for integrating the commutator 60 and the armature 30 becomes unnecessary. As a result, the fuel passage 51 is formed by the cylindrical portion 54 and the tapered portion 55 of the case member 50. As a result, the connection portion between the motor unit and the case member 60 that houses the commutator 60 has a simple shape. Since the connecting portion between the motor unit and the case member 60 has a simple shape, the fuel flow is hardly disturbed and the flow is stabilized. Therefore, the pressure loss of the fuel can be reduced. In addition, by housing the commutator 60 in the case member 50, the commutator 60 and the armature 30 can be easily assembled.
[0025]
(Second Embodiment)
A fuel pump according to a second embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the component substantially the same as 1st Embodiment, and description is abbreviate | omitted.
In the second embodiment, as shown in FIG. 5, a taper portion 36 a is formed on the bobbin 36 of the armature 30. The bobbin 36 has a tapered portion 36 a at a part of a cylindrical outer peripheral portion 36 b parallel to the central axis of the shaft 31. The taper portion 36a of the bobbin 36 has an outer diameter that decreases toward the counter pump portion side. Therefore, the outer wall of the tapered portion 36a of the bobbin 36 is inclined toward the central axis. The tapered portion 36 a of the bobbin 36 is connected to the tapered portion 55 of the case member 50. The tapered portion 36a of the bobbin 36 and the tapered portion 55 of the case member 50 have substantially the same inclination angle of the outer wall with respect to the central axis. Thereby, the taper part 36a of the bobbin 36 and the taper part 55 of the case member 50 form one taper part.
[0026]
In the second embodiment, since one taper portion is formed from the taper portion 36 a and the taper portion 55, the total length of the formed taper portion in the direction along the central axis of the shaft 31 is enlarged. Therefore, the angle formed by the tapered portion 36a of the bobbin 36 and the cylindrical outer peripheral portion 36b of the bobbin 36 increases. As a result, the direction of the fuel flowing along the tapered portion 36a and the tapered portion 55 changes gradually. Therefore, the pressure loss of the fuel can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a fuel pump according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view showing an armature, a case member, and a C-ring of the fuel pump according to the first embodiment of the present invention.
FIG. 3 is a perspective view showing a case member of the fuel pump according to the first embodiment of the present invention.
4 is an enlarged view of a portion IV in FIG. 1. FIG.
FIG. 5 is a view showing a fuel pump according to a second embodiment of the present invention and corresponding to FIG. 4;
[Explanation of symbols]
10 Fuel pump 11 Housing 12 Suction side cover (pump part)
13 Pump casing (pump part)
15 Impeller (pump part)
19 Permanent magnet (motor part)
20 Cover member 21 Discharge port 23 Brush 30 Armature (motor part)
31 Shaft (motor part)
50 Case member 51 Fuel passage 55 Tapered portion (guide portion)
60 commutator

Claims (4)

In a fuel pump for supplying fuel in a fuel tank to an internal combustion engine,
A housing containing a motor part and a pump part inside;
A cover member installed at one end of the housing and having a discharge port through which the fuel pressurized by the pump unit is discharged at a central portion in the radial direction;
A case member that is attached to an end portion of the motor portion on the cover member side, and that forms a fuel flow path through which the fuel pressurized by the pump portion flows between the cover member,
The fuel pump according to claim 1, wherein the case member has a guide portion that guides the fuel in the fuel passage toward the discharge port. 2. The case member is connected to an armature of the motor unit and rotates together with the armature, and houses a commutator capable of sliding contact with a brush installed on the cover member. The fuel pump described. 3. The fuel pump according to claim 1, wherein the case member has a tapered portion whose outer diameter decreases as going to the opposite pump portion side as the guide portion. 34. The fuel pump according to claim 33, wherein the tapered portion is connected to a tapered portion of the armature.

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