JP2003269277A - Fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device that dissipates an electrified charge without using expensive resin and with the reduced number of part items. <P>SOLUTION: A housing body 80 of nonconductive resin for housing a filter element 61 circumferentially surrounds an outer periphery of a fuel pump 20. A distance between a case 30 of the fuel pump 20 and an inner cylinder 81 of the housing body 80 is set at 1 mm or less. The inner cylinder 81 circumferentially surrounds an outer periphery of the case 30 by 50% or more. Despite the formation of the filter body 80 from nonconductive resin, an electrified charge on a filter unit 60 moves by corona discharge to the case 30 of the fuel pump 20 via the housing body 80. An expensive conductive resin and a grounding member are thus unnecessary. <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 supply device in which a cylindrical filter housing surrounds a fuel pump.

[0002]

2. Description of the Related Art For example, as disclosed in WO96 / 23967 or Japanese Patent Publication No. 8-512117,
A fuel supply device is known in which a cylindrical fuel filter is installed so as to surround the fuel pump on the outer periphery of the fuel pump and removes foreign matters in the fuel discharged by the fuel pump. The fuel filter has a filter element and a filter housing that houses the filter element between an inner cylinder and an outer cylinder. When fuel passes through the filter element housed inside the filter housing, the fuel filter is charged due to friction between the non-conductive filter element and the fuel. Therefore, it is necessary to release static electricity from the charged fuel filter.

[0003]

However, since the filter housing is generally made of resin, it is difficult for electric charges to move through the filter housing. The static electricity charged on the fuel filter may reach a high voltage of several tens of kV. Therefore, for example, when a voltage exceeding the dielectric breakdown strength of the material forming the filter housing or the like is applied for a long time, the filter housing or the like formed of resin may be damaged. There is also a problem of inductively charging an object existing in the vicinity. Therefore, it is conceivable to form the filter housing or the filter element with a conductive material. conventionally,
In order to increase the conductivity of the filter housing, a resin whose conductivity is increased by adding carbon, for example, is used. Similarly, a filter paper whose conductivity is increased by adding carbon is used as a filter element. However, the resin and filter paper to which carbon is added are expensive, and there is a problem that the cost is increased. Further, a predetermined distance is secured between the fuel pump and the filter housing in order to reduce vibration and noise during operation of the fuel pump. Therefore, even if the conductivity of the filter housing or the filter element is increased, it is necessary to secure the ground from the filter housing to another conductive portion such as the fuel pump. As a result, it is necessary to add a component for grounding, which causes a problem of increasing the number of components.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel supply device which reduces the number of parts and dissipates a charged electric charge without using an expensive resin. Another object of the present invention is to provide a fuel supply device that promotes transfer of electric charges.

[0005]

According to the fuel supply device of the first aspect of the present invention, the filter housing is made of non-conductive resin and is 50% or more in the circumferential direction on the outer peripheral side of the case of the fuel pump. It is surrounded and installed. The filter housing is formed in a tubular shape having an inner cylinder and an outer cylinder,
The distance between the inner cylinder and the case is less than or equal to a predetermined distance. Keep the distance between the inner cylinder and the case below a certain distance, and make the case 50% in the circumferential direction.
By installing the filter housing surrounding the above, the charged electric charge is dissipated to the metal case via the filter housing. Although the filter housing is made of non-conductive resin, it does not mean that the charge does not move at all. Therefore, the electric charge can be grounded to the case of the fuel pump by setting the positional relationship between the case and the filter housing. Therefore, the charged electric charge can be dissipated without requiring an expensive resin having high conductivity and a component for grounding.

According to the fuel supply device of the second aspect of the present invention, the filter housing surrounds the entire circumference of the fuel pump. The movement of charges becomes easier as the area where the filter housing and the fuel pump face each other increases. Therefore, since the filter housing encloses the case of the fuel pump over the entire circumference, transfer of electric charges is promoted,
The charge can be reduced.

According to the fuel supply device of the third or fourth aspect of the present invention, the distance between the inner cylinder and the case is 1 mm or less. The movement of charges becomes easier as the distance between the inner cylinder of the filter housing and the case of the fuel pump decreases. Therefore, by setting the distance between the inner cylinder and the case to be 1 mm or less, the movement of charges is promoted and the charging can be reduced.

According to the fuel supply apparatus of the fifth aspect of the present invention, the resin forming the filter housing has a volume resistivity value in the range of 10 ¹² Ωcm to 10 ¹⁵ Ωcm. Therefore, an inexpensive resin having high versatility such as a polyacetal resin can be used. According to the fuel supply device of the sixth aspect of the present invention, the wall thickness of the inner cylinder of the filter housing is smaller than that of the outer cylinder. The fuel discharged from the fuel pump passes through the filter element housed between the inner cylinder and the outer cylinder. Therefore, the filter housing is deformed by the pressure of the fuel. By making the inner cylinder thinner than the outer cylinder, the deformation of the inner cylinder becomes larger than that of the outer cylinder. As a result, the inner cylinder is deformed toward the case of the fuel pump, and the distance between the inner cylinder and the case is reduced. Therefore, the movement of charges can be promoted.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A fuel supply system according to an embodiment of the present invention will be described below with reference to the drawings. A fuel supply device according to an embodiment of the present invention is shown in FIG. The mounting member 10 of the fuel supply device 1 is formed in a disc shape, and is attached by being locked to an upper wall of a fuel tank (not shown) that is integrally molded of resin, and other parts of the fuel supply device 1 are the fuel tank. It is housed inside.

A fuel discharge pipe 11 and an electric connector 12 are integrally resin-molded on the mounting member 10. In addition,
The fuel discharge pipe 11 and the electric connector 12 may be attached to the mounting member 10 as separate parts. The fuel discharge pipe 11 is
It is a pipe for discharging the fuel discharged from the fuel pump 20 housed inside the sub tank 2 to the outside of the fuel tank. The electric connector 12 is electrically connected to the terminal portion 21 of the fuel pump 20 by the lead wire 13 and a power supply connector (not shown), and supplies electric power to the fuel pump 20.

The sub tank 2 is not hermetically sealed and is open at the top. Inside the sub tank 2, the suction filter 3, the pressure regulator 40, the fuel pump 2
0, the filter unit 60, etc. are accommodated.
The suction filter 3 collects relatively large foreign matters contained in the fuel sucked from the sub tank 2 by the fuel pump 20. In this embodiment, the suction filter 3 is made of thick non-woven fabric. Conventionally, a mesh cloth or a thin non-woven fabric is used as the suction filter 3. By forming the suction filter 3 with a thick non-woven fabric as in the present embodiment, the amount of foreign matter collected by the suction filter 3 can be significantly increased. The pressure regulator 40 regulates the pressure of the fuel discharged from the fuel pump 20 to a predetermined pressure.

The fuel pump 20 has a motor 22 inside, and a fuel suction force is generated by the rotation of the motor 22. The upper portion of the fuel pump 20 is covered with a resin cover 23.
The motor 22 is a metal case 3 installed on the outer peripheral side.
It is housed at 0. The resin cover 23 is caulked and fixed by the case 30. The fuel pump 20 sucks the fuel that has passed through the suction filter 3 through the suction port 24 formed on the suction filter 3 side, and the impeller 2
After being pressurized by 5, the liquid is discharged from the discharge port 26.

A part of the fuel pressurized by the fuel pump 20 is injected from a nozzle portion (not shown) provided outside the bottom side of the sub tank 2. Nozzle part is sub tank 2
Fuel is injected toward a fuel inlet (not shown) formed in the. The suction pressure generated at this time sucks up the fuel in the fuel tank into the sub tank 2. The nozzle part that injects a part of the fuel pressurized by the fuel pump 20 constitutes a so-called jet pump. A valve member (not shown) is provided to prevent the fuel pumped up by the jet pump from flowing out of the sub tank. Therefore, even if the fuel amount in the fuel tank decreases, the sub tank 2 is filled with the fuel.

The filter unit 60 has a filter housing 70 and a filter element 61.
The filter element 61 is housed in the filter housing 70. The filter housing 70 has a housing body 80 and a lid 71, and is formed in a cylindrical shape as shown in FIG. The housing main body 80 has an inner cylinder 81 that surrounds the outer circumference of the case 30 of the fuel pump 20, and an outer cylinder 82 that surrounds the outer circumference of the inner cylinder 81. The distance between the inner peripheral wall 83 of the inner cylinder 81 and the outer wall 31 of the case 30 is a predetermined distance or less. Further, the filter unit 60 surrounds the outer circumference of the case 30 of the fuel pump 20 by 50% or more in the circumferential direction. The filter element 61 housed in the filter housing 70 is, for example, a filter paper formed in a honeycomb shape or a chrysanthemum shape. The inner cylinder 81 and the outer cylinder 82 of the housing body 80 are different in radial length, that is, wall thickness. Inner cylinder 81 of housing body 80
Is thinner than the outer cylinder 82. Therefore, due to the pressure of the fuel in the housing body 80, the thin inner cylinder 81 is deformed more than the outer cylinder 82. As a result, the inner cylinder 81 is deformed radially inward, that is, toward the case 30 side of the fuel pump 20.

The upper part of the housing body 80 in FIG.
1 is sealed by connecting the inner cylinder 81 and the outer cylinder 82. The inflow port 84 of the housing body 80 is fitted to the discharge port 26 of the fuel pump 20. The fuel from which foreign substances have been removed through the filter element 61 has its fuel pressure adjusted to a predetermined pressure by the pressure regulator 40 and flows out from the outlet 72 of the filter housing 70. The fuel flowing out from the outlet 72 passes through the bellows pipe 73 and is discharged from the fuel discharge pipe 11.

Next, the filter housing 70 of the filter unit 60 of this embodiment will be described in detail. The housing body 80 and the lid 71, which form the filter housing 70, are made of polyacetal resin such as polyoxymethylene (POM). POM resin is
Non-conductive resin with volume resistivity of 10 ¹⁴ Ωcm
It is a degree. This is much larger than, for example, the volume specific resistance value of 10 ² Ωcm of a conductive resin in which carbon is dispersed in the resin. The volume resistivity value is
It is an index indicating the difficulty of movement of charges in the resin, and the movement of the charges in the resin becomes more difficult as the volume resistivity value increases.

As described above, the inner cylinder 8 of the housing body 80
1 inner peripheral wall 83 and the outer wall 3 of the case 30 of the fuel pump 20
The distance to 1 is a predetermined distance or less, and the distance is 1 mm or less. In this embodiment, the inner peripheral wall 83 and the outer wall 31 are in contact with each other, and the distance between the inner peripheral wall 83 and the outer wall 31 is almost zero. Further, in the case of the present embodiment, as shown in FIG. 2, the inner cylinder 81 of the filter unit 60 surrounds the outer circumference of the case 30 of the fuel pump 20 in the circumferential direction, that is, 100%. The reason why the distance between the inner peripheral wall 83 and the outer wall 31 is 1 mm or less, and the inner cylinder 81 is the fuel pump 20.
The reason why the outer circumference of the case 30 is surrounded by 50% or more in the circumferential direction is as follows.

When the fuel passes through the filter element 61 housed in the filter housing 70, friction is generated between the filter element 61 and the fuel, and static electricity is generated. Since the generated static electricity may damage the resin product, it is preferable to discharge it immediately from the viewpoint of safety. Therefore, in this embodiment, the distance between the inner peripheral wall 83 and the case 30 is set to 1 mm or less so that the charged voltage of the filter housing 70 is 2 kV or less, and the inner cylinder 81 surrounds the case 30 in the circumferential direction. The percentage to do
It is set to 0% or more.

Although the POM resin has a large volume resistivity value of 10 ¹⁴ Ωcm as described above, it does not mean that the charge charged in the POM resin does not move at all. That is, POM
Inner cylinder 8 of housing body 80 made of resin
By reducing the distance between the inner peripheral wall 83 of No. 1 and the outer wall 31 of the metal case 30, the housing main body 80
The electric charge charged to the case moves to the case 30. Inner cylinder 81
The smaller the distance between the inner peripheral wall 83 and the outer wall 31 of the case 30, the easier the electric charges move, and the larger the facing area between the inner peripheral wall 83 of the inner cylinder 81 and the outer wall 31 of the case 30, the easier the electric charge moves. Become. Therefore, the inner cylinder 81
The distance between the inner peripheral wall 83 of the case and the outer wall 31 of the case 30 is 1
When the inner cylinder 81 of the housing body 80 surrounds the outer circumference of the case 30 in the circumferential direction at 50% or more, the charged voltage of the housing body 80 can be set to 2 kV or less.

The electric charge charged in the filter unit 60 is
Filter housing 7 made of POM resin
It moves to the case 30 of the fuel pump 20 via the housing body 80 of 0. At this time, since the POM resin has a large volume resistivity value, the housing main body 80 to the case 3 are
The moving speed of the charges moving to 0 becomes slow, and the charges move due to the corona discharge. When a conductive resin is used for the filter housing 70, the moving speed of the charges moving from the housing body 80 to the case 30 is high, and there is a risk that the charges move due to spark discharge. The charges that have moved to the case 30 of the fuel pump 20 move to the electrical connector 12 via the conductor inside the fuel pump 20, and finally to the battery (not shown).

According to the embodiment of the present invention described above,
By defining the positional relationship between the fuel pump 20 and the filter unit 60 installed on the outer peripheral side of the fuel pump 20, the charged voltage of the filter housing 70 can be set to 2 kV or less. Therefore, it is possible to prevent damage to the resin member such as the filter housing 70 due to the discharge of static electricity. Therefore, it is not necessary to use an expensive conductive resin as the filter housing 70. Further, since a member for securing the ground from the filter housing 70 is not required, the number of parts can be reduced.

In one embodiment of the present invention, the inner cylinder 81 of the housing body 80 is formed thinner than the outer cylinder 82. Therefore, the filter element 61 housed between the fuel pump 20 and the inner cylinder 81 and the outer cylinder 82.
When the fuel is supplied to the inner cylinder 81, the inner cylinder 81 is deformed more than the outer cylinder 82 due to the pressure of the fuel. The inner cylinder 81 is deformed radially inward, that is, toward the case 30 side of the fuel pump 20, and the inner cylinder 8
1 inner peripheral wall 83 and the outer wall 3 of the case 30 of the fuel pump 20
The distance to 1 is reduced. Therefore, the transfer of electric charges from the filter housing 70 to the case 30 of the fuel pump 20 can be promoted.

Further, in one embodiment of the present invention, a thick non-woven fabric is used as the suction filter 3. Therefore, the suction filter 3 can collect the foreign matter that has been conventionally collected by the filter element 61. Since the periphery of the fuel pump 20 of the fuel supply device 1 is a dead space, even if the suction filter 3 becomes thicker and the size of the suction filter 3 becomes larger, the fuel supply device 1 does not become larger. By increasing the ability of the suction filter 3 to collect foreign matter, the burden of collecting foreign matter required by the filter element 61 can be reduced. As a result, it is possible to improve the comprehensive performance of collecting foreign matters and to extend the service life of the filter element 61 without increasing the size of the filter element 61.

In the above embodiment, the example in which the fuel pump is installed in the fuel tank has been described. However, according to the present invention, the installation location of the fuel pump is not limited to the inside of the fuel tank. Further, although the case where the filter housing is made of the POM resin has been described in the above embodiment, the present invention is not limited to the POM resin as long as it is a non-conductive resin having a volume resistivity value in the range of 10 ¹² to 10 ¹⁵ Ωcm. can do.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a fuel supply device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a fuel pump and a filter unit taken along line II-II in FIG.

[Explanation of symbols]

1 Fuel supply device 3 Suction filter 20 fuel pump 30 cases 31 outer wall 61 Filter element 70 filter housing 80 housing body 81 inner cylinder 82 outer cylinder 83 Inner wall

Claims (6)

[Claims] 1. An electrically driven fuel pump having a metal case; and a fuel pump which is installed on the outer peripheral side of the case so as to surround at least 50% or more in the circumferential direction, and which is made of non-conductive resin on the inner side of the fuel pump. A filter housing, which is formed in a tubular shape having a barrel and an outer barrel that surrounds the outer circumference of the inner barrel, and has a predetermined distance or less between the inner barrel and the case, and is housed between the inner barrel and the outer barrel. And a filter element for removing foreign matter contained in the fuel discharged by the fuel pump, and a fuel supply device. 2. The fuel supply device according to claim 1, wherein the filter housing surrounds the entire circumference of the fuel pump. 3. The distance between the inner cylinder and the case is
It is 1 mm or less, The fuel supply apparatus of Claim 1 or 2 characterized by the above-mentioned. 4. The fuel supply device according to claim 3, wherein the inner cylinder and the case are in contact with each other. 5. The fuel supply device according to claim 1, wherein the resin forming the filter housing has a volume resistivity value in the range of 10 ¹² Ωcm to 10 ¹⁵ Ωcm. . 6. The wall thickness of the inner cylinder is smaller than the wall thickness of the outer cylinder.
The fuel supply device according to claim 1.