JPH0374565A - Automotive fuel pump device - Google Patents

Abstract

PURPOSE:To discharge vapor positively by disposing a suction port and a discharge opening opposedly interposing an impeller accommodating part in a pump part in between and providing an air vent hole for piercing a pump casing at a part between the suction port and the discharge opening. CONSTITUTION:A fuel pump device is formed of a pump part 3, a motor part 4 and a terminal holder part 5 disposed in a cylindrical housing 2. Fuel sucked from a suction port 10 by the rotation of an impeller 8, accommodated in a shallow circular recessed part 7 formed at the axial end face of the outer casing 6b of a pump casing 6, by the motor part 4 is discharged by the pump part 3 from a discharge opening 11 into the housing 2 and delivered outside through a fuel outlet pipe 21 with a built-in check valve 20. In this case, an air vent hole 32 piercing the outer casing 6b is provided at a part between the suction port 10 and the discharge opening 11. Vapor is therefore caught before reaching the suction port 10 and can be discharged outside a fuel pump 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a fuel pump device for an automobile, and particularly to an improvement of a Wesco fuel pump.

<Prior art> Fuel pump devices for automobiles, especially fuel pump devices for fuel injection engines, are required to be compact and stable at low flow rates and high pressures, so a non-displacement regenerative pump called a Wesco pump is used. Pumps have been increasingly used in recent years.

On the other hand, this type of fuel pump rotates an impeller, which has many blade grooves on its outer periphery, at high speed in a volatile liquid such as gasoline, which tends to cause cavitation, which causes the vapor to flow into the fuel liquid. At the same time, the vapor is sucked into the pump channel, causing a so-called vapor lock, which causes a problem of deterioration of pump efficiency.

In order to deal with such problems, a structure for discharging vapor from the inside of the pump flow path is proposed, for example, in Japanese Patent Laid-Open No. 60-7
Japanese Patent No. 9193 discloses a pump device in which an enlarged flow path portion of an appropriate length is provided on the fuel inlet side of the pump flow path, and a vapor discharge port communicating with the outside of the pump is provided at the end thereof. According to this, the vapor contained in the fuel is separated while flowing through the enlarged flow path portion and is discharged from the discharge port to the outside of the pump.

<Problems to be Solved by the Invention> Now, the above-mentioned Wesco type pump prevents the high-pressure fuel from being completely discharged from the blade grooves of the impeller, and the amount remaining in the blade grooves from circulating back to the suction port. I can't. Furthermore, in order to make the pump flow path as long as possible, it is common for the suction port and the discharge port to be arranged adjacent to each other.
In order to accommodate the impeller rotatably within the casing,
A predetermined clearance must be maintained between the impeller housing and the impeller. Therefore, it is unavoidable that some discharge pressure leaks to the suction side where the pressure tends to be negative. It was discovered that the leaked high-pressure fuel boiled due to a sudden pressure drop, which was one of the causes of vapor generation. In other words, the conventional exhaust hole structure focused only on the generation of vapor due to the agitation of the impeller.
The inventor of the present application realized that not only is it necessary to substantially reduce the length of the pump flow path, but also that it is insufficient to exhaust vapor in a rapid manner.

The present invention was devised to solve these problems, and its main purpose is to more reliably discharge the vapor in the fuel to the outside of the pump without reducing pump efficiency. An object of the present invention is to provide a fuel pump device for an automobile that can be used in a fuel pump.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, this object is achieved by forming an impeller with a large number of radial blade grooves formed on the outer periphery and configured to receive a disc-shaped impeller. a fuel intake port and a fuel discharge port provided at positions facing the blade groove portion of the impeller and adjacent to each other in the circumferential direction; and surrounding the blade groove along the outer periphery of the impeller. A fuel pump device for an automobile having a pump casing comprising an arcuate pump flow path communicating between the fuel intake port and the fuel discharge port, This is achieved by providing a fuel pump device for an automobile, characterized in that a communicating air bleed hole is provided in a portion of the impeller accommodating portion sandwiched between the fuel intake port and the fuel discharge port.

<Operation> With this configuration, vapor generated when high-pressure fuel leaks from the discharge port to the suction port is discharged to the outside of the pump via the air vent hole before reaching the suction port.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show the entire motor-built-in fuel pump device to which the present invention is applied, cut away along its axial direction. This fuel pump 1 is used while being submerged in the fuel tank of a vehicle, and includes a pump part 3 provided at one end of a cylindrical housing 2, and a pump part 3 provided in the center. It consists of a motor section 4 and a terminal holder section 5 provided at the other end.

The pump section 3 has a pump casing 6 formed by joining an inner casing 6a and an outer casing 6b to each other. A shallow circular recess 7 is formed in the axial end face of the outer casing 6b facing the inner casing 6a, and an impeller 8 is rotatably received in the circular recess 7. And this pump casing 6 is
It is integrally fixed to the housing 2 by fitting its outer periphery to the inner periphery of one opening of the housing 2 and caulking one opening end 2a of the housing 2 inward. Note that the rotation of the pump casing 6 in the circumferential direction can be prevented by caulking and protruding the thin wall portion on the open end 2a side of the housing 2 into the axial groove 9a recessed in a part of the outer peripheral surface of the pump casing 6. is being done.

A fuel inlet 10 is provided in the outer casing 6b facing outward in the axial direction. And inner casing 6
A fuel discharge port 11 communicating with the inside of the housing 2 is opened at a. These suction ports 10 and discharge ports 11 are
They are provided adjacent to each other in the circumferential direction on the outer periphery of the impeller 8.

In the surface of the inner casing 6a facing the outer casing 6b and in the circular recess 7 of the outer casing 6b,
Arc grooves 12a and 12b each having a starting end at the suction port 10 and a terminal end at the discharge port 11 are recessed along the outer peripheral contour of the impeller 8. Both of these arcuate grooves 12a, 12
b defines an arcuate pump flow path 13 along the outer periphery of the impeller 8.

A large number of blade grooves 14 are formed at equal intervals in the same direction on the outer periphery of both end surfaces of the impeller 8 in the axial direction. By rotating the impeller 8, fuel sucked from outside the fuel pump 1 through the suction port 10 is pressurized as it flows through the pump flow path 13, and flows into the housing 2 from the discharge port 11. It is now being sent.

Note that the inner casing 6a and the outer casing 6b have recesses 15a and 1 at the center of their opposing surfaces, respectively.
5b is formed, and this recess 1 in the impeller 8
The pressure between both the recesses 15a and 15b is balanced through a through hole 16 provided in a portion facing 5a◆15b.

The terminal holder portion 5 is caulked and fixed to the other open end 2b of the housing 2 in the same manner as the pump portion 3 described above.

Further, this terminal holder portion 5 is also prevented from rotating in the circumferential direction by deforming the outer circumferential portion on the other open end 2b side of the housing 2 and inserting it into the axial groove 9b recessed in the outer circumferential surface. is being done.

A pair of terminal members 17 are integrally fixed to the terminal holder portion 5, and a power supply line (not shown) is connected to the threaded portion 17a of the terminal member 17 protruding outside the terminal holder portion 5, and the housing By electrically connecting a pair of brushes 18 made of, for example, metal graphite to the end 17b of the terminal member 17 facing the inside of the terminal member 2 through one choke coil, power is supplied to the motor section 4, which will be described later. ing.

A fuel outlet pipe 21 having a built-in check valve 20 is provided in the center of the terminal holder portion 5 to protrude outward in the axial direction. A bearing member 22 is fixed to the inside of this fuel outlet pipe 21. The bearing member 22 also includes a fuel outlet pipe 2.
A through hole 23 is provided for allowing fuel to pass toward the fuel cell 1.

A fixed shaft 24 extends through the center of the housing 2 along its axial direction. One end of the fixed shaft 24 is press-fitted into the center of the outer casing 6b, and the other end is connected to the center hole 22 of the bearing member 22.
It is inserted in a.

A hollow rotating shaft 26 is rotatably supported on the fixed shaft 24 through bushings 25a and 25b fitted to each end thereof. In addition, the fixed shaft 24 has
A thrust washer 27 that can come into contact with each end of the rotating shaft 26
is fitted so that it acts as a thrust bearing when the rotating shaft 26 is displaced in the axial direction.

The end of the rotary shaft 26 on the side of the pump section 3 is engaged with the center hole 8a of the impeller 8 so as to be immovable in the circumferential direction and to be relatively movable to some extent in the axial direction. Thereby, the impeller 8 is connected to the rotary shaft 26 so as to be able to rotate integrally therewith.

A rotor 30 of the motor is integrated into the central part of the rotating shaft 26 in the axial direction, and includes a known armature 28 in which a conductive wire is wound around a core made of laminated steel plates, and two commutators electrically connected to the conductive wire. It is set up as follows. A pair of permanent magnets 31 are fixed to the inner circumferential surface of the housing 2, which faces the outer circumferential surface of the armature 28.

Now, when the motor unit 4 is energized to drive the impeller 8,
From the suction port 10 on the outer casing 6b side to the pump flow path 1
The fuel entering the pump 3 is pressurized in the vane groove 14, which moves at high speed in the pump channel 13 as the impeller 8 rotates. The fuel is then discharged into the housing 2 from the discharge port 11 on the inner casing 6a side, passes through the outer circumference of the rotor 30 of the motor section 4, and is supplied from the fuel discharge pipe 21 to a fuel injection valve of the engine (not shown).

Incidentally, the fuel is pressurized due to fluid friction between the fuel and the blade groove 14, and all of the pressurized fuel flows through the discharge port 1.
The air is not discharged from the blade groove 14, but slightly from the blade groove 14.
The amount remaining in the interior may flow back to the suction port, or the pressure difference between the discharge port 11 and the suction port 10 may cause the discharge port 11 to
It is unavoidable that leakage occurs from the air to the suction port 10.

When the high-pressure fuel leaks to the low-pressure suction port 10 side in this way, the fuel boils due to the sudden pressure drop, and the vapor generated thereby returns to the pump channel 10.
There is a risk that the vapor may flow into the inside of the tank and cause a so-called vapor lock. Therefore, in the present invention, the suction port 10 and the discharge port 1
An air vent hole 32 is provided that penetrates the outer casing 5t) at a portion between the fuel pump 1 and the fuel pump 1 (see FIG. It is assumed that

As shown in FIGS. 3 and 4, a recess 34 along the axial direction is provided in the land portion 33 facing the outer circumferential surface of the impeller 8 in a portion between the suction port 10 and the discharge port 11. If the blade grooves 14 on both sides of the impeller 8 are made to communicate with the dirt floor, the pressure balance on both sides of the impeller 8 can be adjusted and the air bleeding effect can be further improved.

Furthermore, as shown in FIGS. 5 to 7, if another air vent hole 35 communicating with the outside of the outer casing 6b is additionally provided in the middle part of the pump flow path 13, the agitation of the impeller 8 This makes it possible to bleed out air including vapor caused by cavitation.

<Effects of the Invention> As described above, according to the present invention, it is possible to suitably discharge vapor generated by a sudden pressure drop when high-pressure fuel leaks from the discharge side to the suction side to the outside of the pump. Therefore, it is possible to fundamentally eliminate one of the causes of vapor contamination in the pump flow path, which is highly effective in suppressing the decline in pump efficiency and maintaining stable fuel pressure. can.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a fuel pump device to which the present invention is applied, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. It is an enlarged view of the main part shown,
4 is a partial cross-sectional view taken along the line TV-IV in FIG. 3. FIG. 5 to 7 are diagrams showing a modified embodiment of the present invention when only the outer casing is seen from the line ■-■ in FIG. 1. 1...Fuel pump 2...Housing 2a/2
b... Opening end 3... Pump part 4... Motor part
5... Terminal holder portion 6... Pump casing 6a... Inner casing 6b... Outer casing 7... Circular recess 8... Impeller 9... Pump casings 9a, 9b... Axial direction Groove 10...
Suction port 11...Discharge port 12a, 12b...
Arc groove 13... Pump channel 14... Vane groove 15a.1
5b... Recessed portion 16... Through hole 17... Terminal member 17a... Threaded portion 17b... End portion 18
...Brush 19...Choke coil 20...Check valve 21...Fuel outlet pipe 22...Bearing member 22a
... Center hole 23 ... Through hole 24 ... Fixed shaft
25a, 25b... Bushing 26... Rotating shaft 27... Thrust washer 28... Armature 2... Commutator 30... Rotor
31...Permanent magnet 3? ...Air vent hole 33
...Land portion 34...Concave portion 35...When air is vented Applicant: Honda Motor Co., Ltd.
Attorney Patent Attorney Yo Oshima Figure 2 Figure 3

Claims (1)

[Claims] (1) an impeller accommodating portion having a large number of radial blade grooves formed on the outer periphery and defined to receive a disc-shaped impeller; and an impeller housing portion that faces the blade groove portion of the impeller and is adjacent to each other in the circumferential direction. an arc-shaped pump that communicates between a fuel intake port and a fuel discharge port provided at a position such that the fuel intake port and the fuel discharge port surround the blade groove along the outer periphery of the impeller; A fuel pump device for an automobile having a pump casing comprising a flow path, wherein an air vent hole communicating between the inside and outside of the pump casing is interposed between the fuel intake port and the fuel discharge port in the impeller accommodating portion. 1. A fuel pump device for an automobile, characterized in that the device is provided in a portion where the fuel pump device is installed.