JPH05321865A - Electric fuel pump - Google Patents

Abstract

PURPOSE:To provide an electric fuel pump accumulated with no deposit at a coupling section between an impeller and the rotary shaft of the pump and causing no defective rotation of the impeller even if an alcohol fuel is used or an inferior fuel is used over a long period. CONSTITUTION:The inner periphery of an impeller 73 having multiple vanes on the outer periphery is coupled with a rotary shaft 81, and the impeller 73 is rotated to force-feed the fuel in an electric fuel pump 10. A fuel passage 12 is provided from the motor 80 side toward the coupling section between the rotary shaft 81 and the impeller 73 on the inside of an upper body 71a as a fuel force feed means forcefully feeding the fuel to the coupling section of the impeller 73 in the pump 10, and the retention of the fuel at the coupling section is prevented. No deposit of impurities eluted from an alcohol fuel is formed at the coupling section, and the defective rotation of the pump 10 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric fuel pump, and more particularly to an electric fuel pump in which fuel deposits are less likely to be accumulated in a portion connecting a rotary shaft of the pump and an impeller.

[0002]

2. Description of the Related Art Conventionally, in a fuel system of an internal combustion engine for an automobile, particularly in a fuel system of an electronic fuel injection type internal combustion engine, an electric brushless fuel pump for supplying fuel to an injector by pumping fuel by rotation of an impeller is known. Used (for example, JP-A-1-313668 and JP-A-2-2
(See Japanese Patent No. 15995).

FIG. 6 shows a typical conventional electric fuel pump 6
It is sectional drawing which shows the structure of 0. Inside the casing 61 of the fuel pump 60, there is a controller 90 connected to a power source (not shown) via a motor portion 80 and a power supply terminal 62, and a pump portion 70 is below the casing 61. In the motor section 80, the magnet 83 is attached to the rotary shaft 81 of the motor section 80 via the attachment member 82, and the casing 61
When the controller 90 energizes the coil 84 provided on the inner peripheral portion of the rotary shaft 81, the rotary shaft 81 is rotated.

The lower end of the rotary shaft 81 is rotatably supported by a bearing 72 attached to the pump body 71 of the pump unit 70, and the free end of the rotary shaft 81 is inserted into the pump unit 70. The pump body 71 of the pump unit 70 includes an upper body 71a and a lower body 71b, and between the upper body 71a and the lower body 71b, there are two impellers 73 fitted to the rotating shaft 81. An annular spacer 74 is attached to the outer side of each impeller 73, and a center plate 75 is provided between the two impellers 73. The upper body 71a is attached to the lower end of the casing 61, and the spacer 74, the center plate 75, and the lower body 71b are attached to the upper body 71a by screws 76.

Therefore, the impeller 73 attached to the tip of the rotary shaft 81 includes an upper body 71a, a spacer 74,
An upper body 71a and a center plate 75, and a center plate 75 and a lower body 7 are provided in a space defined by the center plate 75, the spacer 74, and the lower body 71b.
Positioning in the axial direction is carried out by being sandwiched between 1b. Since the thickness of the spacer 74 is formed slightly thicker than the thickness of the impeller 73, there is a slight gap between the upper and lower surfaces of the impeller 73 and the upper body 71a, the spacer 74, or the lower body 71b. The gap allows the impeller 73 to rotate. Further, an appropriate gap is set in the fitting portion between the rotary shaft 81 and the impeller 73, and the impeller 73 is configured to be movable in the direction of the rotary shaft 81.

A suction port 77 for sucking fuel is provided at a predetermined position of the lower body 71b, and the fuel sucked up from the suction port 77 by the rotation of the impeller 73 is
It is configured to be pressure-fed to a motor portion 80 side from a discharge port 78 provided in the upper body 71a through a fuel passage described later. Then, the fuel that has reached the motor unit 80 side is then passed through the side of the controller 90 and is sent to an injector (not shown) from a pressure feed port 64 that is provided so as to project on a cover 63 that is provided on the upper portion of the casing 61. 65 is a pressure feed port 64
It is a check valve provided in.

FIG. 7 is a bottom view taken along the lines AA, BB, and CC in FIG. 6, showing the shape of the impeller 73.
Grooves 74m, 7 provided in the lower surface of the spacer 74, the center plate 75, and the upper body 71a and serving as fuel flow paths.
The shapes of 5 m and 71 m are shown. The fuel that has entered the pump portion 70 through the suction port 77 passes through the flow path indicated by the thick two-dot chain line by the rotation of the impeller 73, and the motor portion 8
It is pumped to the 0 side.

FIG. 8 shows the appearance of the impeller 73. On the outer peripheral portion of the impeller 73, there are a plurality of fins 73a formed by cutting off the wall thickness of the outer peripheral portion with a taper at a predetermined pitch. A boss 73b is provided on the inner peripheral portion of the impeller 73 so as to project therefrom.
A D hole 73c for fitting with the rotating shaft 81 is formed in b.

[0009]

However, in the electric fuel pump having the conventional structure, when the pump is used for pumping alcohol fuel or when poor fuel is used for a long period of time, the fuel pump operates. There was a risk of defects. This will be described with reference to FIG. In an internal combustion engine that uses alcohol fuel, metal parts of the fuel system, such as delivery pipes, may corrode due to the metal corrosive action of alcohol, and the metal components and resin components that are the corrosion products may be mixed in the fuel. is there. Further, the poor fuel may contain polymer components and the like. On the other hand, in the vicinity of the fitting portion K between the rotary shaft 81 and the impeller 73 shown in FIG. 9, the rotational speed of the impeller 73 in the circumferential direction is low, and therefore the movement of fuel is small. For this reason, the metal component, the resin component, the polymer component, and the like described above are easily deposited and deposited on the fitting portion K. In this way, when the deposit is accumulated on the fitting portion K, the impeller 73 and the rotating shaft 81 are fixed to each other, or the angle formed by the impeller 73 and the rotating shaft 83 is inclined from the normal state. As a result, the movement of the impeller 73 in the direction of the rotation axis is restricted, the contact between the upper and lower parts of the impeller 73 and the bump body and the sliding resistance increase, and the improper rotation of the impeller 73 occurs.

Therefore, the present invention solves the above-mentioned problems in the conventional electric fuel pump and allows the impeller and the rotary shaft of the pump to be fitted even if the alcohol fuel is used or the poor fuel is used for a long period of time. It is an object of the present invention to provide an electric fuel pump in which no deposit is accumulated at the joint portion and rotation failure of an impeller does not occur.

[0011]

According to the present invention to achieve the above object, an electric fuel is provided in which the inner peripheral portion of an impeller having a plurality of blades on the outer peripheral portion is fitted to a rotating shaft to rotate and the fuel is pressure-fed. In the pump, a forced fuel feeding means for forcibly supplying the fuel to the fitting portion of the impeller is provided in the pump to prevent the fuel from staying in the fitting portion.

[0012]

According to the electric fuel pump of the present invention, in the electric fuel pump for feeding the fuel under pressure, the inner peripheral portion of the impeller having the plurality of blades on the outer peripheral portion is fitted to the rotating shaft to rotate, and
When the rotating shaft or the impeller rotates, the fuel forced oil feeding means forcibly supplies the fuel to the fitting portion of the impeller, and prevents the fuel from staying in the fitting portion. As a result, deposits are prevented from accumulating in the fitting portion.

[0013]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The same components as those of the conventional electric fuel pump shown in FIG. 6 are designated by the same reference numerals.
FIG. 1 is a sectional view showing the configuration of an electric fuel pump 10 according to the first embodiment of the present invention. Inside the casing 61 of the fuel pump 10, there is a controller 90 connected to a power source (not shown) via a motor section 80 and a power source terminal 62, and a pump section 70 is below the casing 61. In the motor unit 80, the magnet 83 is attached to the rotating shaft 81 via the attachment member 82, and the casing 6
The coil 90 provided on the inner peripheral portion of the controller 90
The rotating shaft 81 is rotated by energizing the rotating shaft 81.

The lower end of the rotary shaft 81 is rotatably supported by a bearing 72 attached to the pump body 71 of the pump unit 70, and the free end of the rotary shaft 81 is inserted into the pump unit 70. The pump body 71 of the pump unit 70 includes an upper body 71a and a lower body 71b, and between the upper body 71a and the lower body 71b, there are two impellers 73 fitted to the rotating shaft 81. An annular spacer 74 is attached to the outer side of each impeller 73, and a center plate 75 is provided between the two impellers 73. The upper body 71a is attached to the lower end of the casing 61, and the spacer 74, the center plate 75, and the lower body 71b are attached to the upper body 71a by screws 76.

Therefore, the impeller 73 attached to the tip of the rotary shaft 81 includes an upper body 71a, a spacer 74,
An upper body 71a and a center plate 75, and a center plate 75 and a lower body 7 are provided in a space defined by the center plate 75, the spacer 74, and the lower body 71b.
Positioning in the axial direction is carried out by being sandwiched between 1b. Since the thickness of the spacer 74 is formed slightly thicker than the thickness of the impeller 73, there is a slight gap between the upper and lower surfaces of the impeller 73 and the upper body 71a, the spacer 74, or the lower body 71b. The gap allows the impeller 73 to rotate. Further, an appropriate gap is set in the fitting portion between the rotary shaft 81 and the impeller 73, and the impeller 73 is configured to be movable in the direction of the rotary shaft 81.

A suction port 77 for sucking fuel is provided at a predetermined position of the lower body 71b, and the fuel sucked up from the suction port 77 by the rotation of the impeller 73 is
The discharge port 78 provided in the upper body 71a is pressure-fed to the motor unit 80 side. Then, the fuel that has reached the motor unit 80 side then passes by the side of the controller 90 and the cover 63 provided on the upper portion of the casing 61.
It is sent to an injector (not shown) from a pressure feed port 64 that is provided so as to project. Reference numeral 65 is a check valve provided in the discharge port 78.

In this first embodiment, the upper body 71a
The check valve 11 is also provided in the discharge port 78 provided in the. Then, inside the upper body 71a, the motor unit 80
The fuel passage 12 is provided from the side toward the fitting portion of the rotary shaft 81 and the impeller 73. Therefore, in the first embodiment, the fuel pressurized by the impeller 73 is supplied to the inside of the pump 10 through the check valve 11 when the pump 10 is operated. The pressure of the fuel on the side of the motor unit 80 is higher than the pressure of the fuel on the side of the impeller 73 due to the function of the check valve 65 provided in the fuel pressure feed port 64. Therefore, the fuel on the motor portion 80 side flows through the fuel passage 12 to the fitting portion between the rotating shaft 81 and the impeller 73. This fuel passes through the gap between the impeller 73 and the pump body 71 or the gap between the impeller 73 and the center plate 75, is pressurized again by the fins of the impeller 73, and flows back to the motor section 80 side.

As described above, when the pump 10 is operated, the fuel is forced to flow into the fitting portion of the rotary shaft 81 and the impeller 73, which flow is small in the prior art, so that impurities in the fuel adhere to the fitting portion. It is difficult for the pump 10 to malfunction. Furthermore, the electric fuel pump 1 according to the first embodiment
At 0, after the pump 10 is stopped, instead of shutting off the fuel inside the pressurized pump by the check valve 11,
It flows through the fuel passage 12 to the fitting portion of the rotary shaft 81 and the impeller 73, and returns from the fuel intake port 77 to the fuel tank side (not shown) through the gap between the impeller 73 and the pump body 71 or the impeller 73 and the center plate 75. Be done. Then, this flow prevents impurities in the fuel from adhering to the fitting portion of the rotary shaft 81 and the impeller 73, and prevents malfunction of the pump due to the adhering substances.

FIG. 2 shows the structure of the electric fuel pump 20 according to the second embodiment of the present invention, (a) shows only the pump portion 70 of the electric fuel pump 20, (b) ) Indicates a bottom surface taken along line XX in (a). The rotary shaft 81 is the pump body 7 of the pump unit 70.
The lower end of the bearing 72 is attached to the bearing 72, and the free end of the rotary shaft 81 is inserted into the pump unit 70. The pump body 71 of the pump unit 70 includes an upper body 71a and a lower body 71b, and between the upper body 71a and the lower body 71b, there are two impellers 73 fitted to the rotating shaft 81. And
An annular spacer 74 is attached to the outside of each impeller 73, and the center plate 7 is provided between the two impellers 73.
5 are provided.

The upper body 71a is attached to the lower end of the casing 61. The upper body 71a has a spacer 74, a center plate 75, and a lower body 71a.
b is attached by screws 76. Similar to the above-described embodiment, the upper and lower surfaces of the impeller 73 and the upper body 71a,
There is a slight gap between the spacer 74 and the lower body 71b, and this gap allows the impeller 73 to rotate. Further, the rotary shaft 81 and the impeller 7
An appropriate gap is set also in the fitting portion of No. 3, and the impeller 73 is configured to be movable in the direction of the rotating shaft 81.

A suction port 77 for sucking fuel is provided at a predetermined position of the lower body 71b, and the fuel sucked up from the suction port 77 by the rotation of the impeller 73 is
The discharge port 78 provided in the upper body 71a is pressure-fed to the motor unit 80 side. In the second embodiment, a concave portion is provided at the tip of the rotary shaft 81, and a projection 21 that is inserted into the concave portion and axially supports the concave portion is provided at the center of the lower body 71b. A fuel passage 22 is provided which reaches the tip of the protrusion 21 from the fuel reservoir inside the pump, through the inside of the upper body 71a, the spacer 74, the center plate 75, and the lower body 71b. In addition, a vertical hole 23 connecting to the fuel passage 22 and a horizontal hole 24 reaching the fitting portion of the two impellers 73 from the vertical hole 23 are provided inside the tip end side of the rotary shaft 81.

In this embodiment, since there are two parallel surfaces in the fitting portion between the rotary shaft 81 and the impeller 73, the lateral hole 24 is open on this parallel surface, but as shown in (c). In addition, when the rotation shaft 81 and the impeller 73 are fitted through the D hole, the lateral hole 24 may be opened on the flat surface and the curved surface, respectively. Therefore, in the second embodiment, the fuel pressurized by the impeller 73 during the operation of the pump 20 is supplied into the pump 20 through the discharge port 78. The pressure of the fuel inside the pump 20, that is, the pressure of the fuel on the side of the motor section 80 is higher than the pressure of the fuel on the side of the impeller 73 due to the function of the check valve 65 provided in the fuel pressure feed port 64. The fuel on the portion 80 side passes through the fuel passage 22, the vertical hole 23, and the horizontal hole 24, and
1 and the impeller 73 flow into the fitting portion. This fuel passes through the gap between the impeller 73 and the pump body 71 or the gap between the impeller 73 and the center plate 75, is pressurized again by the fins of the impeller 73, and flows back to the motor section 80 side.

As described above, when the pump 20 is operated, the fuel is forced to flow into the fitting portion between the rotary shaft 81 and the impeller 73, which flow is small in the prior art, so that impurities in the fuel adhere to the fitting portion. It is difficult for the pump 10 to malfunction. Note that, as in the first embodiment, the upper body 71
If a check valve is also provided in the discharge port 78 provided in a, the fuel inside the pump, which is pressurized even after the pump 20 is stopped, passes through the fuel passage 12 and fits the rotating shaft 81 and the impeller 73. Flow into the rotating shaft, and this flow causes impurities in the fuel to rotate on the rotating shaft 8.
1 and the impeller 73 are prevented from adhering to the fitting portion, and malfunction of the pump due to adhering substances is prevented.

FIG. 3 partially shows the structure of an electric fuel pump 30 according to a third embodiment of the present invention, and the basic structure is the conventional electric fuel pump 10 shown in FIG.
Is the same as. Therefore, in the figure, 70 is the pump part, 7
1 is a pump body having an upper body 71a and a lower body 71b, 72 is a bearing, 73 is two impellers fitted to a rotary shaft 81, 74 is a spacer, 75 is a center plate, 76 is a screw, and 77 is This is the fuel inlet.

Similar to the above-described embodiment, there is a slight gap between the upper and lower surfaces of the impeller 73 and the upper body 71a, the spacer 74, or the lower body 71b, and this gap allows the impeller 73 to rotate. ing. Also,
An appropriate gap is set also in the fitting portion between the rotating shaft 81 and the impeller 73, and the impeller 73 is configured to be movable in the rotating shaft 81 direction. Then, the fuel sucked up from the suction port 77 by the rotation of the impeller 73 is pressure-fed to the motor section 80 side from the discharge port 78 provided in the upper body 71a.

In the third embodiment, a vertical hole 31 is provided inside the tip portion of the rotary shaft 81, and the horizontal hole 3 reaches from this vertical hole 31 to the fitting portion for the two impellers 73.
Two are provided. A spiral groove 33 is provided on the inner peripheral portion of the vertical hole 31 in a direction in which the fuel in the fuel reservoir 34 is sucked up by the rotation of the rotary shaft 81. As a result, the rotation of the rotary shaft 81 causes the fuel in the fuel pool 34 to rise in the vertical hole 31 and is discharged from the horizontal hole 32 to the fitting portion between the rotary shaft 81 and the impeller 73. Due to this fuel flow, the fuel is supplied to the fitting portion and flows out, so that the formation and accumulation of deposits at this portion are prevented, and the gaps between the respective portions of the impeller 73 are properly maintained.

The location of the opening of the lateral hole 32 to the fitting portion is not particularly limited. FIG. 4 partially shows the structure of an electric fuel pump 40 according to a fourth embodiment of the present invention, and the basic structure is the same as that of the conventional electric fuel pump 10 shown in FIG. Therefore, in FIG. 4 (a), 70 is a pump portion, 71 is a pump body having an upper body 71a and a lower body 71b, 72 is a bearing, and 7 is a bearing.
3 is two impellers fitted to the rotary shaft 81, 74 is a spacer, 75 is a center plate, 76 is a screw, and 77 is a fuel inlet.

Similar to the above-mentioned embodiment, there is a slight gap between the upper and lower surfaces of the impeller 73 and the upper body 71a, the spacer 74, or the lower body 71b, and this gap allows the impeller 73 to rotate. ing. Also,
An appropriate gap is set also in the fitting portion between the rotating shaft 81 and the impeller 73, and the impeller 73 is configured to be movable in the rotating shaft 81 direction. Then, the fuel sucked up from the suction port 77 by the rotation of the impeller 73 is pressure-fed to the motor section 80 side from the discharge port 78 provided in the upper body 71a.

In the fourth embodiment, similarly to the first embodiment, the fuel passage 4 is provided inside the upper body 71a from the motor portion 80 side toward the fitting portion of the rotary shaft 81 and the impeller 73.
1 is provided, and the impeller 73 of the rotary shaft 81 is provided.
Collar 4 made of a material that swells with alcohol fuel such as nylon
2 is attached so as to be flush with the outer peripheral surface of the rotary shaft 81. A plurality of vertical grooves 44, which are continuous from the upper end to the lower end, are formed as fuel passages on the outer peripheral surface of the collar 42.

In this collar 42, for example, as shown in FIG. 4 (b), the distal end of the rotary shaft 81 is cut into a D shape in cross section, and a D hole 43 is provided on the collar 42 side to fix it without a gap. Just do it. The inner diameter of the impeller 73 fitted to the collar 42 is made slightly larger than the outer diameter of the collar 42 to improve the assemblability during manufacture. In the fourth embodiment, the fuel pressurized by the impeller 73 during the operation of the pump 10 is supplied into the pump 10 through the discharge port 78. The pressure of the fuel inside the pump 10, that is, the pressure of the fuel on the side of the motor section 80 is higher than the pressure of the fuel on the side of the impeller 73 due to the function of the check valve 65 provided in the fuel pressure feed port 64. Side fuel is fuel passage 4
1 and flows to the fitting portion of the rotary shaft 81 and the impeller 73. This fuel passes through the gap between the impeller 73 and the pump body 71 or the gap between the impeller 73 and the center plate 75, is pressurized again by the fins of the impeller 73, and flows back to the motor section 80 side.

When the alcohol fuel is used, the alcohol fuel flows through the fitting portion between the collar 42 and the impeller 73 as described above, so that the collar 42 swells promptly and the gap existing at the time of assembly disappears. As a result, the components eluted by the alcohol fuel are prevented from being deposited on the fitting portion. FIG. 5 shows the shape of another embodiment of the collar 42 used in the fourth embodiment. In this embodiment, the outer peripheral surface of the collar 42 made of a material that swells with an alcohol fuel such as nylon is scraped off from four sides, and a concave portion 45 having a circular arc shape in cross section is provided on the outer peripheral surface. The collar 42 may also be provided with a D hole 43, and the tip end portion of the rotary shaft 81 may be cut into a D-shape in cross section so as to fix the both without a gap. Further, due to the concave portion 45, the assembling property of the collar 42 and the rotary shaft 81 at the time of manufacturing is also improved.

Also in this embodiment, when the alcohol fuel is used, the alcohol fuel flows through the fitting portion between the collar 42 and the impeller 73, so that the collar 42 swells quickly and the gap existing at the time of assembly disappears. As a result, the components eluted by the alcohol fuel are prevented from being deposited on the fitting portion. In the fourth embodiment, even if the sliding resistance between the impeller 73 and the center plate 75 or the pump body 71 increases, the tip of the rotary shaft 81 is made of a resin that is deformed by swelling. For this reason, the sliding resistance decreases during the use process due to familiarity.

[0033]

As described above, according to the present invention,
Since the fuel is forcibly supplied to the fitting portion of the impeller to prevent the fuel from staying in the fitting portion, accumulation of deposits at the fitting portion is prevented, and rotation failure of the pump is less likely to occur. ..

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a first embodiment of an electric fuel pump of the present invention.

FIG. 2 (a) is a partial cross-sectional view showing the configuration of the second embodiment of the electric fuel pump of the present invention, and FIG. 2 (b) is XX of (a).
FIG. 6 is a view in the direction of an arrow, and (c) is a partial cross-sectional view showing another embodiment of the lateral hole provided in the rotating shaft.

FIG. 3 is a partial cross-sectional view showing the configuration of a third embodiment of the electric fuel pump of the present invention.

4A is a partial cross-sectional view showing the configuration of a fourth embodiment of the electric fuel pump of the present invention, and FIG. 4B is an assembled perspective view showing the configuration of the impeller fitting portion of FIG. 4A. Is.

5 is an assembled perspective view showing the configuration of another embodiment of the collar of FIG. 4. FIG.

FIG. 6 is a cross-sectional view showing a configuration of a conventional electric fuel pump.

FIG. 7 is an explanatory diagram showing a fuel flow path by using arrow views of an AA portion, a BB portion, and a CC portion in FIG.

8 is a perspective view showing the appearance of an impeller used in the electric fuel pump of FIG.

9 is a diagram illustrating a problem in the electric fuel pump of FIG.

[Explanation of symbols]

 10 ... Electric fuel pump of the first embodiment 11 ... Check valve 12, 22, 41 ... Fuel passage 20 ... Electric fuel pump of the second embodiment 21 ... Protrusions 23, 31 ... Vertical holes 24, 32 ... Horizontal holes 30 ... Electric fuel pump of the third embodiment 33 ... Helical groove 34 ... Fuel sump 40 ... Electric fuel pump of the third embodiment 42 ... Collar 43 ... D hole 44 ... Vertical groove 61 ... Casing 62 ... Power supply terminal 70 ... Pump part 71 ... Pump body 72 ... Bearing 73 ... Impeller 74 ... Spacer 75 ... Center plate 76 ... Screw 77 ... Suction port 78 ... Discharge port 80 ... Motor part 81 ... Rotating shaft 82 ... Mounting member 83 ... Magnet 84 ... Coil 90 ... Controller

Claims (1)

[Claims] 1. An electric fuel pump for pumping fuel by rotating an inner peripheral portion of an impeller having a plurality of blades on an outer peripheral portion thereof by fitting the inner peripheral portion of the impeller on a rotating shaft to rotate the inner peripheral portion of the impeller. An electric fuel pump, characterized in that a fuel forced oil supply means for forcibly supplying fuel is provided to prevent fuel from staying in the fitting portion.