JP2003193992A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve pump efficiency of a fuel pump. <P>SOLUTION: An impeller rotating in a pump casing is approximately disk- shaped. In an area extending along the outer peripheries of two sides, groups of recess parts are formed repeatedly and mutually spaced at certain intervals in the circumferential direction. A partition wall is secured between adjoining recess parts. The inner end part and the outer end part of the partition wall in the radial direction are on the same radius. The intermediate part of the partition wall in the radial direction is bent backward in the rotational direction of the impeller. The fuel pump is capable of obtaining high pump efficiency by suppressing the rate of occurrence of break away or vortex in a flow of fuel. Preferably, maximum bend is 0.1-1.0 mm, the shape of a bend of the front side of the rotational direction on two sides of the partition wall is a circular arc with a radius of 2.3-4.3 mm, and/or the shape of a bend on the back side of the rotational direction is a circular arc with a radius of 3.0-5.0 mm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump that sucks a fuel such as gasoline, pressurizes it, and discharges the boosted fuel.

[0002]

2. Description of the Related Art A fuel pump that sucks and discharges fuel by rotating an impeller inside a pump casing is known. An example of this is the special table 9-511812
It is described in Japanese Patent Publication No. The impeller rotating in the pump casing is substantially disc-shaped, and in the regions extending along the outer peripheries of the front and back surfaces, a group of recesses that repeat in the circumferential direction at intervals are formed, and between the adjacent recesses. A partition is secured and is rotated at high speed around the axis of rotational symmetry by the motor.

The life of a fuel pump is often determined by the progressive wear between the commutator and the brush of the motor. The current value of the motor closely affects the speed at which the wear progresses, and the wear is small if the current is small. Therefore, there is a demand that the life of the fuel pump is extended by increasing the pump efficiency, decreasing the motor current, and decreasing the progress speed of wear.

In the technique disclosed in Japanese Patent Publication No. 9-511812, the pump efficiency is improved by inclining the partition walls forming a group of recesses that repeat in the circumferential direction on both the front and back surfaces of the impeller. That is, it teaches a technique for increasing pump efficiency by displacing the radially outer end portion of the partition wall more than the radially inner end portion thereof in the rotation direction.

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention An object of the present invention is to further improve pump efficiency.

[0006]

[Means and Actions for Solving the Problems] In the fuel pump created by the present invention, the impellers rotating in the pump casing are substantially disc-shaped, and are spaced apart from each other in the regions extending along the outer peripheries of the front and back surfaces. A group of recesses that are repeated in the circumferential direction is formed, and a partition wall is secured between adjacent recesses, and the radially inner end and the outer end of the partition wall are located on the same radius. It is characterized in that the radial middle portion of the partition wall is curved rearward in the rotational direction of the impeller.
In the case of this fuel pump, the rate of occurrence of separation phenomenon or vortex in the fuel flow is suppressed, and high pump efficiency is obtained.

When the diameter of the impeller is 30 to 36 mm, the radial length of the partition wall is 2.9 to 4.5 mm,
The circumferential distance between the partition walls is 1.5 to 2.5 mm, the partition wall thickness is 0.2 to 1.5 mm, the impeller thickness is 3.0 to 4.5 mm, and the maximum amount of bending is 0.1-
It is preferably 1.0 mm. Alternatively, the curved shapes on the front and rear sides of the partition wall on the front side in the rotation direction have a radius of 2.3 to
It is an arc of 4.3 mm and / or the curved shape on the front and back surfaces of the partition wall on the rear side in the rotation direction has a radius of 3.0 to.
It is preferably an arc of 5.0 mm. The inner and outer ends of the partition wall in the radial direction are located on the same radius,
In addition to the feature of bending the radial middle part of the partition wall to the rear side in the rotational direction of the impeller, it is preferable that the following features are further provided. -The partition wall is inclined rearward in the rotational direction as it goes inward in the thickness direction from both front and back surfaces. .. The partition wall is inclined by 40 to 60.degree. From the intermediate surface in the thickness direction. ..The partition wall is continuous in a gentle arcuate surface on the front side in the rotation direction of the intermediate surface in the thickness direction. -The thickness of the partition wall becomes thicker from both the front and back sides toward the inside in the thickness direction. .. The thickness of the partition wall on the intermediate surface in the thickness direction is 0.1 to 0.4 mm thicker than the thickness on both front and back surfaces. -The radially inner end surface of the recess located between the partition walls has two arcuate surfaces that are in contact with each other at the intermediate surface in the thickness direction-The radius of the arcuate surface is 0.7 to 2.2 mm. -The radially outer end faces of the recesses located between the partition walls are expanded from the middle face in the thickness direction toward both the front and back surfaces. ..The opening angle from the intermediate surface in the thickness direction is 20 ° or less. .. The outer end surface has two arc surfaces that are in contact with each other at the intermediate surface in the thickness direction. ... The radius of the arc surface is 0.2 to 1.0 mm. If one or more of these characteristics are provided in combination, the pump efficiency is increased, the pump drive current is suppressed small, and the pump life is extended.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION First, among the characteristics found in the embodiments of the present invention, the characteristics useful for improving pump efficiency will be listed. A. The radially inner end and the outer end of the partition wall are located on the same radius, and the radially middle portion of the partition wall is curved rearward in the rotational direction of the impeller. This feature is important,
The present invention utilizes this feature. In this case, it is preferable that the following features are further provided. In particular, "the outer diameter of the impeller is 30 to 36 mm, the radial distance of the partition wall is 2.9.
~ 4.5 mm, circumferential distance between partitions is 1.5-2.5 m
m, the thickness of the partition wall is 0.2 to 1.5 mm, and the thickness of the impeller is 3.0 to 4.5 mm, high efficiency can be obtained if the numerical conditions described below are satisfied. A1: The large bending amount is 0.1 to 1.0 mm, or A2: the front-side curving radius is 2.3 to 4.3 mm, or A3: the rear-side curving radius. Is preferably 3.0 to 5.0 mm. B. The partition wall inclines rearward in the rotational direction as it goes inward in the thickness direction from both front and back surfaces. In this case, B1: the inclination angle to the intermediate plane in the thickness direction is 40 to 60 °
B2: It is preferable that the inclined partition wall is continuous with a gentle arcuate surface on the front side in the rotation direction of the intermediate surface in the thickness direction. C. The thickness of the partition wall increases from both the front and back sides toward the inside in the thickness direction. C1: The thickness of the partition wall on the intermediate surface in the thickness direction is preferably 0.1 to 0.4 mm thicker than the thickness on both the front and back surfaces. D. The inner end surface in the radial direction of the fuel storage space (recess) formed between the partition walls has two arc surfaces that are in contact with each other at the intermediate surface in the thickness direction. In this case, it is preferable that D1: the radius of the arc is 0.7 to 2.2 mm. E. The radially outer end surface of the fuel storage space (recess) formed between the partition walls expands from the middle surface in the thickness direction toward both the front and back surfaces. E1: The spread angle is preferably 20 ° or less. Instead of this or in addition to this, it is preferable that E2 has two arc surfaces that are in contact with each other at an intermediate surface in the thickness direction. E3: High efficiency is obtained when the radius of the arc is 0.2 to 1.0 mm.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A fuel pump according to an embodiment of the present invention will be described with reference to the drawings. The fuel pump of this embodiment is a fuel pump for an automobile, is used in a fuel tank, and is used for supplying fuel to an engine of the automobile.

In FIG. 1, which is a sectional view of the fuel pump, the fuel pump is composed of a pump portion 1 and a motor portion 2 for driving the pump portion 1. Motor part 2
Is a brushed DC motor, in which a magnet 5 is arranged in a substantially cylindrical pump housing 4, and a rotor 6 is arranged concentrically with the magnet 5.

The lower portion of the shaft 7 of the rotor 6 is rotatably supported by a pump cover 9 attached to the lower end of the pump housing 4 via a bearing 10. The upper end of the shaft 7 is attached to the motor cover 12 attached to the upper end of the pump housing 4 by a bearing 13.
It is rotatably supported via.

The motor section 2 rotates the rotor 6 by energizing a coil (not shown) of the rotor 6 via a terminal (not shown) provided on the motor cover 12. Since the structure of the motor unit 2 is well known, detailed description thereof will be omitted. Further, as the motor unit 2, other types than the illustrated one can be used.

The structure of the pump unit 1 driven by the motor unit 2 will be described. The pump unit 1 includes a pump cover 9, a pump body 15 and an impeller 16. The pump cover 9 and the pump body 15 are formed by, for example, die casting of aluminum, and by combining the two, a pump casing 17 that houses the impeller 16 therein is configured.

The impeller 16 is formed by resin molding,
As shown in FIG. 2, it is substantially disc-shaped, and in a region extending along the outer peripheries of the front and back surfaces, a group of recesses 16 a that are repeated in the circumferential direction at intervals are formed, and at the center of the impeller 16, A substantially D-shaped engagement hole 16n is formed.
The engagement shaft portion 7a having a D-shaped cross section at the lower end portion of the shaft 7 is engaged with the engagement hole 16n. As a result, the impeller 16
Is connected to the shaft 7 so as to be capable of following rotation and slightly movable in the axial direction. Side 16p of impeller 16
Is a circumferential surface.

An enlarged view of the impeller is shown in FIG. 3, and a partition wall 16b is secured between the adjacent recesses 16a. The impeller 16 has the following features. -The outer diameter D of the impeller is 30 to 36 mm, the radial distance W of the partition walls is 2.9 to 4.5 mm, the circumferential distance L between the partition walls is 1.5 to 2.5 mm, and the partition wall thickness t is 0.2. ~ 1.5m
m, and the thickness T of the impeller is set to 3.0 to 4.5 mm. -Radial inner end 16b1 and outer end 1 of the partition wall 16b
6b2 are located on the same radius 16q, and the radial intermediate portion 16r of the partition wall is curved to the rear side R in the rotational direction of the impeller. -The maximum bending amount A is 0.1 to 1.0 mm-The bending radius R3 on the front side in the rotation direction is 2.3 to 4.3 mm, -The bending radius R4 on the rear side in the rotation direction is 3.0 to 5 It is 0.0 mm. -As shown in FIG. 4, the partition wall 16b inclines toward the rear R side in the rotation direction from both the front and back surfaces toward the inner side in the thickness direction. -The inclination angle with respect to the thickness direction intermediate surface 16s is 40 to 60 °.
Is. The inclined partition wall 16b is continuous with a gentle arcuate surface 16f on the front side F in the rotation direction of the intermediate surface 16s in the thickness direction. -The thickness of the partition 16b becomes thicker from both the front and back sides toward the inner side in the thickness direction. In the figure, 16e is a partition wall 16b
Of the front surface 16c of FIG.
Indicates the thickness of the partition wall 16b at the thickness direction intermediate surface 16s. In the figure, t2 indicates the thickness of the partition wall 16b on the front and back surfaces. t1 is thicker than t2, and t1-t2 is 0.1 to
It is 0.4 mm. As shown in FIG. 5, the radially inner end surface of the fuel storage space 16a (recess) formed between the partition walls 16b has two arcuate surfaces 16g, 16 that are in contact with each other at the intermediate surface 16s in the thickness direction.
have h -Radius R1 of arcs 16g and 16h is 0.7 to 2.2 mm
Is. The end faces 16i, 16j on the outer side in the radial direction of the fuel storage space 16a (recess) formed between the partition walls 16b are expanded from the middle face 16s in the thickness direction to both the front and back surfaces, as shown in FIG. -The divergence angle is 20 ° or less. Alternatively, as shown in FIG. 6 showing the second embodiment, two arc surfaces 16 contacting with each other at an intermediate surface 16s in the thickness direction.
I have a k and 16m.・ The radius of the arcs 16k and 16m is 0.2 to 1.0 mm
Is.

As shown in FIG. 1, the pump cover 9 includes:
A circumferentially extending concave portion 21 that forms a circumferentially extending flow channel between the concave portion 16a of the impeller 16 and the concave portion 2
It has a discharge port 24 communicating with the downstream end of No. 1 and a peripheral wall 9b. As shown in FIG. 1, the discharge port 24 penetrates the pump cover 9 and communicates with the internal space 2 a of the motor unit 2. The inner peripheral surface 9c of the peripheral wall 9b faces the outer peripheral surface 16p of the impeller 16 with a clearance.

The pump body 15 is fixed to the lower end portion of the pump housing 4 by caulking or the like in a state of being superposed on the pump cover 9. A thrust bearing 18 is fixed to the center of the pump body 15. The thrust bearing 18 receives the thrust load of the shaft 7. The pump cover 9 and the pump body 15 form a pump casing 17. The impeller 16 is housed inside the pump casing 17 so as to be rotatable and slightly movable in the axial direction. On the inner surface of the pump body 15, there are formed a circumferentially extending concave portion 20 that forms a circumferential flow passage groove between the concave portion 16a of the impeller 16 and a suction port 22 that communicates with the upstream end of the concave portion 20. Has been done.

A recess 21 extending in the circumferential direction of the pump cover 9.
And the recess 20 extending in the circumferential direction of the pump body 15 extends from the position corresponding to the suction port 22 on the pump body 15 side to the position corresponding to the discharge port 24 on the pump cover 9 side along the rotational direction of the impeller 16. A channel groove is formed which extends and extends in the circumferential direction from the suction port 22 to reach the discharge port 24.
When the impeller rotates in the direction, the fuel is sucked into the flow channel from the suction port 22, and the fuel is sucked from the suction port 22 to the discharge port 24 in the flow channel.
The fuel flows to the side, is pressurized during that time, and the pressurized fuel is sent out from the discharge port 24 to the motor unit 2. The recesses 21 and 20 are not formed from the position corresponding to the discharge port 24 on the pump cover 9 side to the suction port 22 on the pump body 15 side along the rotation direction of the impeller 16, and the boosted fuel is The return to the suction port 22 side is prevented as much as possible. The high-pressure fuel sent to the motor unit 2 is discharged from the discharge port 28.
Pumped out of the pump. The fuel pump of this embodiment has a high pump efficiency because it has both the qualitative characteristics and the quantitative characteristics described above. It has the same pumping capacity as the conventional pumping current of 2.2 amps.
It could be achieved with a motor current of 5 amps.

[0019]

EFFECTS OF THE INVENTION In the fuel pump of the present invention, partition walls are secured between adjacent recesses that are repeatedly formed in the circumferential direction at intervals in the regions extending along the outer peripheries of the front and back surfaces of the impeller. The inner and outer ends in the radial direction of the partition wall are located on the same radius, and the radial middle portion of the partition wall is curved rearward in the rotational direction of the impeller, so that the pump efficiency is high. As a result, the pump drive current is suppressed to a small value and the pump life is extended.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a fuel pump according to an embodiment.

FIG. 2 is a plan view of an impeller.

FIG. 3 is an enlarged plan view of a part of the impeller.

FIG. 4 is a IV-IV view of FIG.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a view corresponding to FIG. 5 of the second embodiment.

[Explanation of symbols]

16 impeller 17 Pump casing 16a recess 16b partition 20 channel grooves 21 channel groove 22 Suction port 24 outlets

Claims (15)

[Claims] 1. An impeller rotating in a pump casing, the impeller having a substantially disc shape, and forming a group of recesses which are spaced apart from each other and which are repeated in the circumferential direction in regions extending along the outer peripheries of both front and back surfaces. The partition wall is secured between the adjacent recesses, the inner and outer ends in the radial direction of the partition are located on the same radius, and the radial middle part of the partition is the rotation of the impeller. A fuel pump characterized by being curved rearward in the direction. 2. The impeller has a diameter of 30 to 36 mm, and the partition wall has a radial length of 2.9 to 4.5 mm.
The circumferential distance between the partition walls is 1.5 to 2.5 mm, the partition wall thickness is 0.2 to 1.5 mm, the impeller thickness is 3.0 to 4.5 mm, and the maximum amount of the bending is Is 0.1
The fuel pump according to claim 1, wherein the fuel pump has a diameter of about 1.0 mm. 3. The impeller has a diameter of 30 to 36 mm, and the partition wall has a radial length of 2.9 to 4.5 mm.
The circumferential distance between the partition walls is 1.5 to 2.5 mm, the partition wall thickness is 0.2 to 1.5 mm, the impeller thickness is 3.0 to 4.5 mm, and the front and back surfaces of the partition wall are The fuel pump according to claim 1, wherein the curved shape on the front side in the rotation direction is an arc having a radius of 2.3 to 4.3 mm. 4. The impeller has a diameter of 30 to 36 mm, and the partition wall has a radial length of 2.9 to 4.5 mm.
The circumferential distance between the partition walls is 1.5 to 2.5 mm, the partition wall thickness is 0.2 to 1.5 mm, the impeller thickness is 3.0 to 4.5 mm, and the front and back surfaces of the partition wall are The fuel pump according to claim 1 or 3, wherein the curved shape on the rear side in the rotation direction is an arc having a radius of 3.0 to 5.0 mm. 5. The fuel pump according to claim 1, wherein the partition wall is inclined rearward in the rotational direction as it goes inward in the thickness direction from both front and back surfaces. 6. The partition wall is 40 from an intermediate surface in the thickness direction.
The fuel pump according to claim 5, wherein the fuel pump is inclined at an angle of -60 °. 7. The fuel pump according to claim 5, wherein the partition wall is continuous with a gentle arcuate surface on the front side in the rotation direction of the intermediate surface in the thickness direction. 8. The fuel pump according to claim 1, wherein the partition wall has a thickness that increases from both the front and back sides inward in the thickness direction. 9. The fuel pump according to claim 8, wherein the thickness of the partition wall on the intermediate surface in the thickness direction is 0.1 to 0.4 mm thicker than the thickness on both front and back surfaces. 10. The fuel pump according to claim 1, wherein a radially inner end surface of the recess has two arcuate surfaces that are in contact with each other at an intermediate surface in the thickness direction. 11. The fuel pump according to claim 10, wherein the radius of the circular arc surface is 0.7 to 2.2 mm. 12. The fuel pump according to claim 1, wherein a radially outer end surface of the recess extends from an intermediate surface in the thickness direction toward both front and back surfaces. 13. The opening angle from the intermediate surface in the thickness direction is 2
The fuel pump according to claim 12, wherein the fuel pump is 0 ° or less. 14. The fuel pump according to claim 12, wherein the outer end surface in the radial direction of the recess has two arc surfaces that are in contact with each other at an intermediate surface in the thickness direction. 15. The fuel pump according to claim 14, wherein the radius of the arc surface is 0.2 to 1.0 mm.