JPH0835498A - Fuel pump - Google Patents

Abstract

PURPOSE:To prevent any leakage of fuel at the isolation part of Wesco type fuel pump and improve the pump efficiency. CONSTITUTION:A fuel pump is provided with a pump housing having at least one pump room provided with a nearly C letter shaped fuel passage 15 between a fuel intake port and a fuel discharge port mutually isolated by an isolation part 18 and at least one impeller 30 having on its outer peripheral part, blades 31 extending in a radial direction, while the blades 31 are provided rotatably in the fuel passage 15. Labyrinth seal opposed to the outer peripheral edge and both side surfaces of the blades 31 of the impeller 30 is provided in the isolation part 18 of the fuel passage 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump used in automobiles and the like, and more particularly to a Wesco type fuel pump.

[0002]

2. Description of the Related Art Conventionally, in this type of Wesco type fuel pump, at least one fuel passage having a substantially C-shaped fuel passage is provided between a fuel intake port and a fuel discharge port separated by a separating portion. A pump housing with a pump chamber,
There is known a fuel pump including at least one impeller having blades extending in a radial direction on an outer peripheral portion and the blades being rotatably provided in a fuel passage. The rotation of the impeller causes the fuel in the blade groove of the impeller to flow out into the fuel passage, while the fuel in the fuel passage flows into the blade groove from the side surface of the blade. The pressure is increased in the passage and the fuel is discharged from the fuel discharge port.

[0003]

However, in the fuel pump having such a conventional structure, there is a leak through the clearance between the impeller and the pump housing, which lowers the pump efficiency. Therefore, there has been proposed a fuel pump in which a labyrinth seal is provided on a pump housing facing the outer edge of the impeller to reduce leakage from the clearance. (See, for example, JP-A-57-171092). However, the amount of leakage from the fuel discharge port to the fuel discharge port through the separated portion due to the rotation of the impeller blades is large, and the above-described labyrinth seal structure cannot sufficiently prevent leakage.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel pump capable of preventing leakage at a separated portion of a Wesco type fuel pump and improving pump efficiency. To do.

[0005]

The present invention has been made to achieve the above object, and a fuel pump according to the present invention has a fuel inlet and a fuel outlet substantially separated by a separating portion. A pump housing provided with at least one pump chamber having a C-shaped fuel passage, and at least an outer peripheral blade having a radially extending vane rotatably provided in the fuel passage. A fuel pump including one impeller, wherein a labyrinth seal facing the outer edge portion and both side surfaces of the impeller blades is provided in a separated portion of the fuel passage. Is.

Further, the labyrinth seal includes one side groove facing one side surface of the impeller blade, an outer peripheral groove facing the outer edge portion of the blade and being bent and continuous to the one side groove, and the other side of the blade. Another side surface groove that is opposed to a side surface and is bent and continuous to the outer peripheral groove, and is provided so as to surround the impeller blade in a U shape.

Further, the labyrinth seal is characterized in that the side surface groove is formed to have a length substantially the same as the length of the impeller blade.

[0008]

The present invention is configured as described above, and the labyrinth seal improves the clearance sealability on the outer edge side of the impeller in the separated portion of the fuel passage, and
On both sides of the impeller blades, the leakage flow that is dragged by the rotation of the blades toward the fuel intake port is weakened to prevent leakage of fuel passing through the separation portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fuel pump of the present invention will be described below with reference to the drawings.

This fuel pump comprises a pump portion 5 incorporated in the lower portion of a cylindrical metal housing 1 and a motor portion 40 incorporated in the upper portion thereof.
Is a pump housing 10 having pump chambers 14, 24 having spacings 18, 28 and fuel passages 15, 25.
And two impellers 30 and 30, and the separating portion 18,
The labyrinth seals 19 and 29 are provided on the outer peripheral edge of the blades 31 of the impellers 30 and 30 and on both side surfaces thereof, respectively.

A pump housing 1 constituting the pump section 5
In the embodiment, 0 is composed of a synthetic resin pump body 12, a partition wall 20 and a pump cover 22, a low pressure side pump chamber 14 is formed between the pump body 12 and the partition wall 20, and the partition wall 20 and the pump cover 22 are formed. A pump chamber 24 on the high pressure side is formed between and.

A substantially C-shaped fuel passage 15 is formed in the outer peripheral portion of the pump chamber 14, a fuel intake port 16 is provided at the start end of the fuel passage 15, and a start end is provided at the end thereof. A communication hole 21 that serves as a fuel discharge port is provided with the separation portion 18 interposed therebetween.

Further, a substantially C-shaped fuel passage 25 is formed in the outer peripheral portion of the pump chamber 24.
5, one end of the communication hole 21 is opened as a fuel intake port of the high-pressure side pump chamber 24, and a fuel discharge port 27 is provided at the terminal end of the communication hole 21 with a separation section 28 interposed therebetween. ing. Therefore, the fuel inlet 16 to the fuel outlet 27 are connected so as to form a spiral shape.

The pump chambers 14 and 24 and the fuel passage 1
A pump body 12, a partition wall 20,
The shape of the pump cover 22 will be described in detail with reference to FIGS.

The fuel passage 15 is composed of a passage groove 15a provided on the upper surface of the pump body 12 and a passage groove 15b provided on the lower surface of the partition wall 20. Pump body 1
A pump chamber 14 having a depth substantially equal to the wall thickness of the impeller 30 is provided on the upper surface of 2, and the pump chamber 14 has a C-shape on the outer periphery of the pump chamber 14, the diameter being larger than the diameter of the impeller 30 and deeper than the pump chamber 14. Is provided with a passage groove 15a. Further, an annular rising wall 13 is formed outside the passage groove 15a, and the impeller 3 is provided between the start end and the end of the passage groove 15a.
A wide portion 13a is formed close to the outer edge portion of 0 with a clearance (see FIG. 3). A fuel inlet 16 is provided at the beginning of the passage groove 15a.

On the other hand, on the lower surface of the partition wall 20, the fuel passage 15
Is provided with a passage groove 15b forming substantially the upper half of the above. The passage groove 15b is formed substantially symmetrically with the passage groove 15a, and a communication hole 21 is provided at the end thereof (see FIG. 4).

A labyrinth seal 19 is provided at a space 18 between the beginning and the end of the fuel passage 15. The labyrinth seal 19 is formed on the side of the pump body 12 and has a radially extending side surface groove 19a, and an outer peripheral groove 19b that is continuous with the side surface groove 19a and is provided at the inner end of the wide portion 13a in parallel with the rotation axis of the impeller 30. And is formed on the side of the partition wall 20 and faces the side surface groove 19a, and the outer peripheral groove 1
9b and a side surface groove 19c continuous with each other, and is formed by a group of four U-shaped grooves at predetermined intervals (FIGS. 8 to 1).
0). The length of the side surface grooves 19a and 19c is preferably set to be the same as or slightly longer than the length L of the blades 31 of the impeller 30 described later.

The fuel passage 25 is composed of a passage groove 25a provided on the upper surface of the partition wall 20 and a passage groove 25b provided on the lower surface of the pump cover 22. The upper surface of the partition wall 20 is provided with a passage groove 25a which forms a substantially lower half portion of the fuel passage 25 and is substantially symmetrical to the passage groove 25b, and the downstream end of the communication hole 21 is opened at the start end thereof. (See FIG. 5).

On the other hand, the lower surface of the pump cover 22 is provided with a pump chamber 24 having a thickness substantially equal to that of the impeller 30.
A C-shaped passage groove 25b, which is larger in diameter than the impeller 30 and deeper than the pump chamber 24, is provided on the outer periphery of the pump chamber 24. An annular rising wall 23 is formed outside the passage groove 25b, and a wide portion 23a close to the outer periphery of the impeller 30 is provided between the start end and the end of the passage groove 25b.
Are formed. A fuel discharge port 27 communicating with the inside of the motor chamber 45 is provided at the end of the passage groove 25b (see FIG. 6).

A labyrinth seal 29 is provided at a space 28 between the beginning and the end of the fuel passage 25. The labyrinth seal 29 is formed on the partition wall 20 side,
The side surface groove 29a extending in the radial direction is formed on the pump cover 22 while being continuous with the side surface groove 29a.
An outer peripheral groove 29b provided parallel to the rotation axis of the impeller 30 at the inner end of a, and a side surface groove 29a continuous with the outer peripheral groove 29b.
And a side groove 29c facing each other, and is formed by a group of four U-shaped grooves having a predetermined interval (see FIG. 9).
The lengths of the side surface grooves 29a and 29c are preferably set to be equal to or slightly longer than the length L of the blades 31 of the impeller 30.

The impeller 30 has a disk shape, and the blade grooves 3 are provided on both side surfaces (both upper and lower side surfaces in FIGS. 1 and 2) of the outer peripheral portion.
A large number of blades 31 are formed by 2 to have a predetermined length L and extend in the radial direction (see FIGS. 7 to 9). The impellers 30, 30 include a shaft 43 of the motor unit 40.
It is attached to the lower end and arranged so as to rotate in the pump chambers 14 and 24, respectively.

The motor section 40 is fixed to the inner peripheral surface of the housing 1 by a magnet 41 serving as a stator and a rotor 42.
The upper and lower ends of the shaft 43 of the rotor 42 are rotatably supported by the motor cover 50 and the pump cover 22 attached to the upper end of the housing 1 via bearings 44, 44, respectively. And housing 1
A motor chamber 45 is formed between the inner motor cover 50 and the pump cover 22.

A brush 47, which is elastically slidably contacted with the commutator 46 of the rotor 42, is incorporated in the motor cover 50. The brush 47 is electrically connected to an external connection terminal (not shown) via a choke coil 48. ing. Further, the motor cover 50 is provided with a fuel outlet 52 for connecting a fuel supply pipe, which communicates with, for example, a fuel injection valve of an automobile engine, and the fuel outlet 52 has a check valve 51 for preventing backflow of fuel. Is incorporated.

Next, the operation of the fuel pump thus constructed will be described.

In the fuel pump of the present invention, the impellers 30, 30 of the pump unit 5 rotate as the motor unit 40 is driven by using a battery (not shown) of an automobile or the like as a power source.
As a result, the fuel in the fuel tank is pumped into the pump chamber 14 from the fuel inlet 16. The pumped fuel is pressurized by the rotation of the impeller 30, passes through the fuel passage 15, and is discharged from the communication hole 21 to the pump chamber 24. Then, the pressure is further increased in the pump chamber 24, is discharged from the fuel discharge port 27 through the fuel passage 25 and enters the motor chamber 45, and thereafter, the fuel delivery port 5 of the motor cover 50.
It is discharged from 2.

At this time, the fuel in the pump chamber 14 is boosted in pressure as it progresses from the fuel suction port 16 of the fuel passage 15 to the communication hole 21, and the pressure in the communication hole 21, which is the fuel discharge port, becomes maximum.

In the spacing portion 18 of the fuel passage 15, there is a clearance between the outer edge portion of the impeller 30 and the inner end portion of the wide portion 13a, and both side surfaces of the vane 31 and the pump body 12,
There is a clearance between the partition wall 20 and the pressurized communication hole 21.
As for the fuel in the part, a leakage flow is generated in the clearance of the outer edge of the impeller 30 toward the fuel intake port 16. In addition, a leakage flow that is dragged by the rotation of the blade 31 toward the fuel intake port 16 is generated in the clearance between both side surfaces of the blade 31.

These leak flows are weakened by the labyrinth seal 19 formed of the side surface groove 19a, the outer peripheral groove 19b and the side surface groove 19c provided in the separating portion 18, and the leakage to the fuel intake port 16 is prevented.

Further, the fuel in the pump chamber 24 is increased in pressure as it goes from the communication hole 21 which is the fuel intake port of the fuel passage 25 to the fuel discharge port 27, and the pressure at the fuel discharge port 27 portion becomes the maximum. .

At the spacing 28 of the fuel passage 25, there is a clearance between the outer edge of the impeller 30 and the inner end of the wide portion 23a, and between both side surfaces of the vane 31 and the partition wall 20 and the pump cover 22. The fuel at the fuel discharge port 27 portion having a clearance and increased in pressure causes a leakage flow toward the communication hole 21 through the clearance at the outer edge of the impeller 30. Further, in the clearances on both side surfaces of the blade 31, a leakage flow that is dragged by the rotation of the blade 31 toward the communication hole 21 is generated.

These leakage flows are generated by the side surface groove 29a, the outer peripheral groove 29b, and the side surface groove 29 provided in the separating portion 28.
c, that is, the flow is weakened by the labyrinth seal 29,
Leakage to the communication port 21 is prevented.

FIG. 11 shows the effect of this embodiment when the discharge pressure is constant (for example, 284 kpa).
It is a characteristic curve figure showing the relation between the number of rotations N of 0, and discharge flow rate Q. In FIG. 11, the solid line shows the labyrinth seal 1.
The characteristics of the conventional fuel pump without 9 and 29 are shown, and the alternate long and short dash line shows the characteristics of the fuel pump of this embodiment. As shown in the figure, by providing the labyrinth seals 19 and 29, the average flow rate increased by 3 L / h and the invalid flow rate rotation speed decreased by 150 rpm.

The present invention is not limited to the above description and the illustrated examples, and its embodiment can be modified without departing from the technical idea of the present invention. For example, it goes without saying that only one pump chamber is required.

[0034]

As described above, according to the fuel pump of the present invention, since the labyrinth seals facing the outer edge portion and both side surfaces of the impeller blades are provided in the separated portion of the fuel passage, the fuel suction in the separated portion is performed. It is possible to improve the sealing property between the port and the fuel discharge port and prevent the fuel from being leaked by the rotation of the impeller from the fuel discharge port to the fuel suction port through the separation portion.

Therefore, the discharge flow rate at the same rotation speed can be increased, and the invalid flow speed rotation speed of the fuel pump can be lowered, so that the pump efficiency can be greatly improved.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a fuel pump according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the pump unit in FIG.

FIG. 3 is a plan view of a pump body of the pump housing.

FIG. 4 is a bottom view of the partition wall of the pump housing.

FIG. 5 is a plan view of a partition wall of the pump housing.

FIG. 6 is a bottom view of the pump cover of the pump housing.

FIG. 7 is a plan view of the impeller.

FIG. 8 is a plan view of a pump body equipped with an impeller.

9 is a cross-sectional view taken along the line AA of FIG.

FIG. 10 is a sectional view taken along line BB of FIG. 9;

FIG. 11 is a characteristic curve diagram showing the relationship between the impeller rotation speed of the fuel pump and the discharge flow rate.

[Explanation of symbols]

 5 Pump Part 10 Pump Housing 14,24 Pump Chamber 15,25 Fuel Passage 16 Fuel Inlet 18,18 Separation 19,29 Labyrinth Seal 19a, 29a Side Groove 19b, 29b Peripheral Groove 19c, 29c Side Groove 21 Communication Hole 30 Impeller 31 blade 40 motor part

Claims (3)

[Claims] 1. A pump housing having at least one pump chamber having a fuel passage formed in a substantially C shape between a fuel intake port and a fuel discharge port separated by a separation part, and a pump housing on an outer peripheral portion. A fuel pump, comprising: a blade extending in a radial direction, the blade being provided with at least one impeller rotatably provided in the fuel passage, wherein the impeller blade is provided at a separation portion of the fuel passage. A fuel pump characterized in that labyrinth seals facing each other are provided on an outer edge portion and both side surfaces of the fuel pump. 2. The fuel pump according to claim 1, wherein the labyrinth seal is one side surface groove facing one side surface of the impeller blade, and the one side surface groove is bent toward the outer edge portion of the impeller. A continuous outer peripheral groove, and another side surface groove that faces the other side surface of the blade and is continuous with the outer peripheral groove by bending, and is provided so as to surround the impeller blade in a U shape. Characteristic fuel pump. 3. The fuel pump according to claim 1, wherein a side groove of the labyrinth seal is formed to have a length substantially equal to a length of a blade of the impeller. pump.