JP2004092403A - Suction filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prolong life without unnecessarily increasing thickness of a filter member while ensuring a gap formed to the filter member, and prevent falling off of a fiber. <P>SOLUTION: This suction filter 30 for removing a comparatively large foreign matter sucked to a fuel pump 1 is loaded to a fuel intake port 27 of the fuel pump 1. The suction filter 30 comprises the filter member 40 made of nonwoven fabric. The filter member 40 is provided with a dense layer part arranged to an inside thereof and a coarse layer part arranged to an outside thereof. A second fiber forming the coarse layer part has a larger outer diameter than a first fiber forming the dense layer part. Therefore, even when the coarse layer part and the dense layer part are pressurized and joined, the gap formed in the coarse layer part is not reduced and is not broken. Accordingly, the life of the filter member 40 is prolonged without unnecessarily increasing thickness of the coarse layer part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a suction filter for removing foreign substances contained in fuel sucked into a fuel pump of an internal combustion engine (hereinafter, the internal combustion engine is referred to as an “engine”).
[0002]
[Prior art]
Conventionally, a fuel pump that discharges fuel in a fuel tank to the outside has been known. The fuel pump sucks fuel in the fuel tank and supplies it to the engine. A suction filter is provided on the fuel suction side of such a fuel pump. The suction filter collects foreign substances contained in the fuel and prevents the foreign substances from entering the inside of the fuel pump.
[0003]
As a conventionally used suction filter, for example, a filter obtained by laminating a plurality of nonwoven fabrics having different densities is used. When nonwoven fabrics having different densities are laminated, relatively large foreign matter is collected in the coarse layer portion and relatively small foreign matter is collected in the dense layer portion, so that the life of the filter member constituting the suction filter can be extended. it can.
[0004]
[Problems to be solved by the invention]
When forming a filter member having a coarse layer portion and a dense layer portion, the amount of fibers for forming the coarse layer portion is generally smaller than the amount of fibers for forming the dense layer portion. Thereby, the gap formed in the rough layer portion becomes larger than in the dense layer portion. However, when the filter member is composed of the nonwoven fabric forming the coarse layer portion and the nonwoven fabric forming the dense layer portion, the respective nonwoven fabrics are joined under pressure. Therefore, the voids formed in the nonwoven fabric in the coarse layer portion during pressurization are reduced. As a result, there is a problem in that the ability of the filter member to collect foreign matter is reduced and the life of the filter member is shortened.
[0005]
On the other hand, in order to extend the life of the filter member, it is conceivable to increase the thickness of the filter member. The suction filter is mounted on the fuel pump by mounting means. When the mounting means sandwiches the filter member, the space between the mounting means and the filter member is sealed. This prevents fuel from being drawn into the fuel pump through the space between the mounting means and the filter member without passing through the filter member. Therefore, the filter member needs a certain thickness in order to enhance the sealing property between the filter member and the mounting means. However, if the thickness of the filter member is increased more than necessary, the size of the suction filter increases.
[0006]
Further, the fibers forming the filter member made of the nonwoven fabric are merely intertwined with each other. Therefore, some of the fibers forming the nonwoven fabric may fall off due to the flow of the fuel, and may be sucked into the fuel pump. Therefore, a filter member conventionally formed of a non-woven fabric is covered with, for example, a cloth-like sheet to prevent the fibers that have fallen out from being sucked into the fuel pump. However, there is a problem that a sheet for covering the filter member is required, and the number of components is increased.
[0007]
Therefore, an object of the present invention is to provide a suction filter in which the life is prolonged without increasing the thickness of the filter member more than necessary and the fiber is prevented from falling off, while ensuring a gap formed in the filter member. It is in.
[0008]
[Means for Solving the Problems]
According to the suction filter of the first or second aspect of the present invention, the second fibers forming the coarse layer portion of the filter member have a larger outer diameter than the first fibers forming the dense layer portion. Therefore, the voids formed in the coarse layer portion become large, and the voids formed in the coarse layer portion are not easily reduced at the time of bonding with the dense layer portion. Further, since the gap in the rough layer portion is not easily reduced, it is not necessary to increase the thickness of the filter member more than necessary in order to enhance the ability to collect foreign substances. Therefore, the service life can be extended without increasing the thickness of the filter member more than necessary while securing the void formed in the rough layer portion. The dense layer portion and the coarse layer portion contain binder fibers. At least the outer peripheral portion of the binder fiber is melted by heating, and the first and second fibers in the vicinity are welded to each other, and the dense layer portion and the coarse layer portion are joined. Therefore, it is possible to prevent the fibers from falling off the filter member. Note that the binder fibers in the dense layer portion and the binder fibers in the coarse layer portion do not necessarily need to have the same material or outer diameter, for example.
[0009]
According to the suction filter of the second aspect of the present invention, the outer diameter of the second fiber is at least 1.5 times the outer diameter of the first fiber. When the outer diameter of the second fiber is smaller than 1.5 times the outer diameter of the first fiber, the gap formed in the coarse layer portion at the time of joining the dense layer portion and the coarse layer portion may be reduced. Therefore, the outer diameter of the second fiber is set to be 1.5 times or more the outer diameter of the first fiber.
[0010]
According to the suction filter of the third aspect of the present invention, the compression ratio is ≤95. The compression ratio is calculated as t2 / t1 × 100, where t1 is the thickness of the filter member before being sandwiched between the mounting members, and t2 is the thickness of the filter member that is compressed and reduced when being sandwiched between the mounting members. You. If the compression ratio is larger than 95, the first fibers or the second fibers forming the dense layer portion and the coarse layer portion may be cut by compression. Therefore, the compression ratio is set to 95 or less. Further, as the compression ratio increases, the gaps formed in the dense layer portion and the rough layer portion of the filter member sandwiched between the mounting members are reduced. Therefore, the pressure loss of the filter member at the portion where the mounting member is sandwiched increases, and the sealing performance is improved. Therefore, the compression ratio is desirably 95 or less and larger.
[0011]
According to the suction filter described in claim 4 of the present invention, the filter member is formed in a bag shape with the dense layer portion being inside the coarse layer portion. Therefore, the area through which fuel passes can be increased without increasing the size of the filter member.
According to the suction filter described in claim 5 of the present invention, a skeletal member that supports the filter member from the inside is installed on the inner peripheral side of the filter member. Therefore, the bag-shaped filter member is not crushed by the pressure of the fuel. Therefore, the area through which fuel passes can be increased without increasing the size of the filter member.
[0012]
According to the suction filter of the sixth aspect of the present invention, the binder fiber is formed of an oil-resistant resin. Therefore, it is possible to prevent the binder fibers from deteriorating due to the passage of the fuel. The softening point of the oil-resistant resin forming the binder fiber is lower than the softening points of the first fiber and the second fiber. Therefore, even when the first fiber and the second fiber are welded by heating, the first fiber and the second fiber are not softened and the strength is not reduced.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example showing an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 shows a fuel pump to which a suction filter according to one embodiment of the present invention is applied. The fuel pump 1 is installed inside a fuel tank (not shown), and sucks up fuel inside the fuel tank and discharges the fuel to the outside of the fuel tank.
[0014]
The housing 2 of the fuel pump is made of resin and has a flange member 10, a case member 11 and a support member 12. The disk portion 13 of the flange member 10 is attached to a fuel tank (not shown). The flange member 10 has an external connector 14, an internal connector 15, and a discharge pipe mounting part 16, and a discharge pipe 17 is mounted on the discharge pipe mounting part 16. The external connector 14 and the internal connector 15 supply electric power to the pump body 20 and output a signal indicating the liquid level detected by the liquid level gauge 21 to an external ECU.
[0015]
The case member 11 has a case 18 and a cap 19, and the case 18 and the cap 19 are joined. The case 18 has a filter case 181 and a pump case 182. The filter element 22 is housed in a filter case 181, and the pump body 20 is housed in a pump case 182. The support member 12 prevents the pump body 20 and a pressure regulator (not shown) from falling off.
[0016]
The liquid level gauge 21 has a float 23, an arm part 24, and a sensor part 25, and the sensor part 25 is detachably attached to a liquid level gauge mounting part 26. The sensor unit 25 detects a change in the rotation angle of the arm 24 due to a change in the fuel amount, so that the amount of fuel in the fuel tank is measured. The pressure regulator (not shown) is connected to a fuel passage (not shown) that supplies fuel from the filter element 22 to the discharge pipe 17 and adjusts the pressure of the fuel discharged from the discharge pipe 17 to the outside of the fuel tank.
[0017]
The suction filter 30 is connected to a fuel inlet 27 on the fuel suction side of the fuel pump 1. The suction filter 30 removes relatively large foreign matters contained in the fuel drawn into the pump body 20 from the fuel inlet 27. The fuel stored in the fuel tank is drawn into the fuel pump 1 from the fuel inlet 27 after relatively large foreign matters are removed by the suction filter 30. The fuel sucked into the fuel pump 1 is pressurized by the pump body 20 and flows into the filter element 22. In the filter element 22, minute foreign matters contained in the fuel are removed. After the pressure of the fuel that has passed through the filter element 22 is adjusted by a pressure regulator (not shown), the fuel is discharged from the discharge pipe 17 to the outside of the fuel pump 1.
[0018]
Next, the suction filter 30 will be described in detail.
As shown in FIG. 1, the suction filter 30 has a filter member 40 formed of a nonwoven fabric, and a skeleton member 50 and a mounting member 60 as mounting means. As shown in FIG. 3, the filter member 40 has a dense layer portion 41 having a small gap formed by entangled fibers and a coarse layer portion 42 having a large gap. As shown in FIG. 1, the filter member 40 formed in a bag shape has a dense layer portion 41 on the inside and a coarse layer portion 42 on the outside. Therefore, the fuel passing through the filter member 40 flows from the outer coarse layer portion 42 to the inner dense layer portion 41 as shown by the arrow in FIG.
[0019]
By forming the filter member 40 of the suction filter 30 into a bag shape, fuel flows from the outside to the inside of the filter member 40. By forming the filter member 40 in a bag shape, the area required for installing the filter member 40 having the same filtration area is reduced as compared with a case where the filter member 40 is not a bag shape. Therefore, the filtration area of the filter member 40 can be increased without increasing the size of the suction filter 30. The skeleton member 50 supports the filter member 40 from the inside. Therefore, even when the suction filter 30 is installed inside the fuel stored in the fuel tank (not shown), the filter member 40 of the suction filter 30 maintains a bag-like shape, and a filtration area is secured.
[0020]
In the case of the present embodiment, the dense layer portion 41 is formed of a nonwoven fabric formed of a first fiber having an outer diameter of about 11 μm, and the coarse layer portion 42 is formed of a nonwoven fabric formed of a second fiber having an outer diameter of about 25 μm. By making the outer diameter of the second fiber of the rough layer portion 42 larger than the outer diameter of the first fiber of the dense layer portion 41, the nonwoven fabric forming the rough layer portion 42 has improved strength against compression. In addition, as the outer diameter of the second fiber increases, the density of the second fiber forming the coarse layer portion 42 decreases, and the ratio of voids formed in the coarse layer portion 42 increases. That is, the coarse layer portion 42 of the filter member 40 is coarser than the dense layer portion 41. Therefore, even when the filter member 40 is formed by pressing and bonding the nonwoven fabric to be the dense layer portion 41 and the nonwoven fabric to be the coarse layer portion 42, the voids of the rough layer portion 42 having improved strength are reduced, Does not collapse.
[0021]
As shown in FIG. 4A, the dense layer portion 41 and the coarse layer portion 42 contain a binder fiber 90 in addition to the first fiber or the second fiber composed of the ordinary fiber 80. A binder layer 91 is formed on the outer periphery of the binder fiber 90. In the case of the present embodiment, the first fiber and the second fiber made of the ordinary fiber 80 are formed of PET (polyethylene terephthalate) resin having high oil resistance. In the binder fiber 90, the base 92 is formed of a PET resin, and the binder layer 91 is formed of a polyamide-based resin having high oil resistance. The binder fibers 90 are contained in the dense layer portion 41 and the coarse layer portion 42 at predetermined ratios. The base 92 of the binder fiber 90 has the same outer diameter as the first fiber in the dense layer portion 41 and has the same outer diameter as the second fiber in the coarse layer portion 42. In addition, the base 92 of the binder fiber 90 may be the same as the outer diameter of the first fiber or the second fiber in any of the dense layer portion 41 and the rough layer portion 42, and may be the same as the first fiber or the second fiber. Different outer diameters may be used.
[0022]
The binder layer 91 is melted by heating, and is welded to the nearby ordinary fibers 80 as shown in FIG. The softening point of the PET resin forming the base 92 of the first fiber and the second fiber made of the normal fiber 80 and the binder fiber 90 is about 220 ° C., whereas the softening point of the polyamide resin forming the binder layer 91 is The softening point is about 250 ° C. Therefore, after forming the nonwoven fabric from the first fiber and the second fiber consisting of the normal fiber 80 and the binder fiber 90, even if the formed nonwoven fabric is heated to melt the binder layer 91, the first fiber and the second fiber and The base 92 does not soften or decrease in strength. After the nonwoven fabric is formed from the first fiber or the second fiber and the binder fiber 90, each nonwoven fabric is pressed and heated. Thus, the binder fibers 90 contained in the dense layer portion 41 and the coarse layer portion 42 are melted and welded to the nearby fibers, and the dense layer portion 41 and the coarse layer portion 42 are joined.
[0023]
The filter member 40 is sandwiched between the skeletal member 50 and the mounting member 60 as shown in FIGS. The skeleton member 50 has a tubular portion 51, a flange portion 52, and a main body 53, and the tubular portion 51, the flange portion 52, and the main body 53 are integrally formed of an oil-resistant resin. As shown in FIG. 6, a concave portion 54 is formed on the outer peripheral side of the cylindrical portion 51 of the flange portion 52. The cylindrical portion 51 is formed with a projection 55 projecting radially outward.
[0024]
The mounting member 60 is formed of resin, and is attached to the fuel inlet 27 of the fuel pump 1 as shown in FIGS. As shown in FIG. 5, the mounting member 60 has a mounting port 61 into which the fuel inlet 27 is inserted and through which the fuel passing through the filter member 40 flows. The mounting member 60 has an insertion portion 62 into which the tubular portion 51 is inserted on the skeleton member 50 side of the mounting opening 61. As shown in FIG. 6, a groove 63 is formed on the inner peripheral side of the insertion portion 62. By inserting the tube portion 51 into the insertion portion 62, the protrusion 55 of the tube portion 51 is fitted into the groove 63 of the insertion portion 62, and the skeletal member 50 and the mounting member 60 are connected by snap fitting. The mounting member 60 has a flange portion 64 protruding radially outward of the insertion portion 62 and a protruding portion 65 protruding toward the skeleton member 50. The protrusion 65 is inserted into the recess 54 of the skeletal member 50.
[0025]
The filter member 40 is formed in a rectangular shape having an opening 43 in the center as shown in FIG. By inserting the tubular portion 51 of the skeletal member 50 from the dense layer portion 41 side of the opening 43 and attaching the mounting member 60 to the skeletal member 50, the filter member 40 is connected to the skeletal member 50 as shown in FIGS. It is sandwiched between the mounting member 60. As shown in FIG. 6, the filter member 40 is sandwiched between the flange portion 52 of the skeletal member 50 and the flange portion 64 of the mounting member 60, and the inner wall 54 a of the concave portion 54 of the skeletal member 50 and the projecting portion of the mounting member 60. 65 is sandwiched between the outer peripheral side and the outer peripheral side. By sandwiching the filter member 40 between the inner wall 54a of the recess 54 and the protruding portion 65, the filter member 40 is compressed in a direction in which the thickness decreases.
[0026]
After the skeletal member 50 and the mounting member 60 are attached to the opening 43, the filter member 40 is bent so that the ends in the longitudinal direction overlap each other with the dense layer portion 41 inside. Then, the outer edge of the folded filter member 40 is welded by heating, so that the filter member 40 is formed in a bag shape in which the frame member 50 is accommodated inside as shown in FIGS.
[0027]
By compressing the filter member 40 between the inner wall 54a of the concave portion 54 and the protruding portion 65, the gap formed in the dense layer portion 41 and the coarse layer portion 42 of the filter member 40 is reduced. Therefore, the pressure loss of the fuel flowing through the compressed portion of the filter member 40 increases. Further, since a tightening force is generated between the skeletal member 50 and the mounting member 60 with the filter member 40 interposed therebetween, fuel does not easily flow at the boundary between the filter member 40 and the skeletal member 50 and the mounting member 60. As a result, the frame member 50 and the mounting member 60 are sealed with the filter member 40 interposed therebetween, and the fuel passes through the uncompressed portion of the filter member 40 having a smaller pressure loss. As a result, the fuel passing through the filter member 40 is prevented from entering the inside of the filter member 40 via the boundary between the filter member 40, the skeleton member 50, and the mounting member 60.
[0028]
At this time, in the present embodiment, the compression ratio of the filter member 40 is set as follows. As shown in FIG. 8, when the thickness of the filter member 40 before being compressed is represented by t1, and the thickness reduced by compression is represented by t2, the compression ratio P of the filter member 40 is defined as P = t2 / t1 × 100. Then, P ≦ 95 is set. In order to reduce the space inside the filter member 40 in the compressed portion and increase the pressure loss, it is preferable that P is larger. However, if P> 95, the first fiber and the second fiber of the nonwoven fabric constituting the filter member 40 may be cut, and the pressure loss of the filter member 40 in the compressed portion may be reduced. Therefore, the upper limit of the compression ratio P is set to 95.
[0029]
In the embodiment of the present invention described above, the outer diameter of the second fiber forming the coarse layer portion 42 is larger than that of the first fiber, and the strength of the coarse layer portion 42 is increased. Therefore, when the filter member 40 is sandwiched between the skeletal member 50 and the mounting member 60 and compressed, the gap formed in the rough layer portion 42 is not reduced or crushed. As a result, relatively large foreign matter contained in the fuel is collected by the coarse layer portion 42, and clogging of the dense layer portion 41 is reduced. Therefore, the life of the filter member 40 can be extended. Further, since the clogging of the dense layer portion 41 is reduced, the thickness of the filter member 40 does not need to be increased more than necessary. Therefore, it is possible to avoid an increase in the size of the suction filter 30. Furthermore, by sandwiching the filter member 40 between the skeletal member 50 and the mounting member 60, the sealing property between the skeletal member 50 and the mounting member 60 and the filter member 40 can be ensured.
[0030]
Further, in the present embodiment, the first fibers or the second fibers constituting the dense layer portion 41 and the coarse layer portion 42 contain the binder fiber 90. When the dense layer portion 41 and the coarse layer portion 42 are heated, the binder layer 91 formed on the outer peripheral portion of the binder fiber 90 is melted, and the fibers near the binder fiber 90 are welded to each other. Therefore, the first fibers and the second fibers do not fall off from the filter member 40. Therefore, a cover or the like for collecting the dropped fibers becomes unnecessary, and the number of parts can be reduced. The binder layer 91 is formed of a polyamide resin having high oil resistance. Therefore, deterioration of the binder layer 91 due to fuel can be prevented.
[0031]
As described above, in the embodiment of the present invention, an example in which the suction filter is applied to the fuel pump has been described. However, the suction filter of the present invention is not limited to the fuel pump described above, and is limited to the above embodiment, such as a fuel supply device having a sub-tank and a suction filter disposed at the bottom of the fuel pump. is not. Further, in the above-described embodiment, the example in which the binder fiber having the binder layer on the outer peripheral side of the base is applied is described. For example, the entire binder fiber is formed of the same material as the binder layer, and the entire binder fiber is heated. May be melted. Further, in the above embodiment, the case where the filter member is formed in a rectangular bag shape has been described. However, the filter member is not limited to a rectangular shape, and may have a desired shape such as a circular shape or a polygonal shape. Not limited to this, it can be made into a sheet.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a suction filter according to one embodiment of the present invention.
FIG. 2 is a partial sectional view showing a fuel pump to which a suction filter according to one embodiment of the present invention is applied.
FIG. 3 is a view showing a filter member of the suction filter according to one embodiment of the present invention, and is a schematic view showing a state of fibers constituting a dense layer portion and a coarse layer portion.
4A and 4B are diagrams illustrating a filter member of a suction filter according to an embodiment of the present invention, wherein FIG. 4A is a schematic diagram illustrating a positional relationship in which binder fibers are located in ordinary fibers, and FIG. FIG. 3 is a schematic view showing a state in which ordinary fibers in the vicinity are welded by binder fibers.
FIG. 5 is a partial cross-sectional view illustrating a suction filter according to an embodiment of the present invention.
FIG. 6 is an enlarged sectional view of a main part of FIG. 5;
FIG. 7 is a developed schematic view of a filter member of a suction filter according to an embodiment of the present invention.
FIG. 8 is a schematic diagram for explaining compression of a filter member of a suction filter according to one embodiment of the present invention.
[Explanation of symbols]
1 fuel pump 27 fuel inlet (fuel intake side)
Reference Signs List 30 suction filter 40 filter member 41 dense layer portion 42 coarse layer portion 50 skeletal member (attachment means)
60 Mounting member (mounting means)
90 Binder fiber 91 Binder layer

Claims (6)

A filter member provided on the fuel suction side of the fuel pump and formed of non-woven fabric; and mounting means for sandwiching the filter member to support the filter member and attaching the filter member to the fuel suction side of the fuel pump. A suction filter for removing foreign substances contained in the fuel sucked into the fuel pump,
The filter member,
The first fiber, and a dense layer portion formed of a binder fiber at least the outer peripheral portion of which is melted by heating,
A second fiber having an outer diameter larger than the first fiber, and a coarse layer portion formed from the binder fiber and bonded to the dense layer portion,
A suction filter comprising: The suction filter according to claim 1, wherein the outer diameter of the second fiber is 1.5 times or more the outer diameter of the first fiber. The filter member has a thickness t1 before being sandwiched by the mounting means, a thickness t2 which is compressed and reduced when the filter member is sandwiched, and a compression ratio ≦ 95 when a compression ratio = t2 / t1 × 100. The suction filter according to claim 1, wherein: The suction filter according to claim 1, 2 or 3, wherein the filter member is formed in a bag shape with the dense layer part being inside the coarse layer part. The mounting means includes a skeletal member that supports the filter member formed in a bag shape from the inside, and the filter member is fitted between the skeletal member and the filter member by sandwiching the filter member between the skeletal member and the skeletal member. 5. The suction filter according to claim 4, further comprising a mounting member that can be mounted on a fuel suction side of the fuel pump. The said binder fiber is formed of oil resistant resin, The softening point of the said oil resistant resin is lower than the softening point of the said 1st fiber and the 2nd fiber, The Claim 1 characterized by the above-mentioned. The described suction filter.

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