JP2002331209A - Filter member and fuel injection device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter member that is easily formed and capable of removing fine foreign matters contained in fuel. SOLUTION: The filter member 50 is press-fitted and fixed to the fuel inlet 40 of an injector. The filter member 50 has a filtration bores group 60 on which a plurality of bores are formed. The filtration bores group 60 is disposed on a helical line around an axis at an equal interval. Inner diameters of respective bores constituting the filtration bores group 60 are formed to a smaller size than the foreign matter to be removed. Therefore, the foreign matters contained in the fuel are certainly removed. The fuel flowing-in from an inlet 43 is passed through the respective bores of the filtration bores group 60 from an inner periphery side of a cylinder part 51 to an outer periphery part side. Therefore, the foreign matters are captured at the inner periphery side of the cylinder part 51 and are collected at the inner periphery side of a bottom part 52. The bores can be continuously and easily formed by disposing the respective bores constituting the filtration bores group 60 on the helical line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter member for removing foreign substances in a fluid and a fuel injection device using the same.

[0002]

2. Description of the Related Art Conventionally, a fuel injection device for an internal combustion engine is provided with a filter member for removing foreign substances contained in fuel. In recent years, for example, in the case of diesel engines,
In order to reduce NOx or particulate matter contained in exhaust gas, atomization of fuel is required. Therefore, it is necessary to increase the fuel injection pressure and to reduce the diameter of the injection hole from which the fuel is injected. Therefore, the filter needs to have the ability to remove finer foreign matter without increasing the pressure loss of the fuel.

As a filter member for removing foreign matter contained in fuel, for example, a filter for a fuel injection nozzle disclosed in Japanese Utility Model Laid-Open No. 3-6052 is known. Heikai 3-
According to the edge filter disclosed in No. 6052,
The foreign matter collecting groove is formed in a spiral shape. By forming the foreign-matter collecting groove in a spiral shape, the foreign-matter collecting groove is extended, and the cross-sectional area of the passage through which the fuel flows increases. Further, by forming the foreign matter collecting groove in a spiral shape, the gap for filtering the fuel is uniformly reduced, and it is possible to remove finer foreign matter.

[0004]

However, in the case of a conventional filter as well as the filter of the fuel injection nozzle disclosed in Japanese Utility Model Application Laid-Open No. 3-6052, a filter is formed between the filter and a portion where the filter is mounted. Foreign matter is collected in the gap. Therefore, there is a risk that the foil-like foreign matter may pass through the gap.

On the other hand, in order to enhance the ability to collect minute foreign matters such as foil-like substances, it is necessary to reduce the gap formed between the filter and the portion where the filter is mounted.
However, when the gap is small, there is a problem that the area of the flow path through which the fuel flows cannot be sufficiently secured, and the pressure loss of the fuel increases.

Accordingly, an object of the present invention is to provide a filter member from which minute foreign substances contained in fuel are removed and which can be easily formed. Another object of the present invention is to provide a filter member which is small in size, has high strength, and has low pressure loss, by removing minute foreign matter contained in fuel. Another object of the present invention is to provide a fuel injection device that promotes atomization of fuel.

[0007]

According to the filter member of the present invention, a hole is formed in the cylindrical main body so as to communicate between the outer peripheral side and the inner peripheral side. The holes are arranged on a helical line around the axis of the body. For example, by setting the inner diameter of the hole formed in the main body smaller than the foreign matter to be removed, the foreign matter contained in the fuel can be reliably removed. In addition, by arranging the holes on the helical line, the holes can be formed while processing the filter member from the first formed hole to the last formed hole continuously. Therefore, the positioning means at the time of molding the filter member can be simplified, and the holes in the filter member can be easily and rapidly processed.

According to the filter member of the third or fourth aspect of the present invention, the cylindrical main body is formed with a hole communicating between the outer peripheral side and the inner peripheral side. The holes are arranged such that the distance from the center of any specific hole of the plurality of holes to the center of another hole adjacent to the specific hole is substantially the same. By making the distance between the centers of adjacent holes the same, for example, the center of each hole can be arranged at the vertex of an equilateral triangle.
Therefore, a large number of holes can be efficiently arranged while appropriately maintaining the distance between adjacent holes. As a result, the size of the filter member can be reduced while maintaining the strength, and more holes can be formed while maintaining the size and the strength. Therefore, it is possible to sufficiently secure the flow path area of the fuel and reduce the pressure loss.

According to a fifth aspect of the present invention, there is provided a fuel injection device, wherein the filter member according to any one of the first to fourth aspects is provided in the fuel passage. Therefore, minute foreign substances contained in the fuel can be removed. As a result, the diameter of the injection hole of the fuel injection device can be reduced, and the atomization of fuel can be promoted.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) An injector as a fuel injection device according to a first embodiment of the present invention is shown in FIG. The injector 1 is mounted by being inserted into a cylinder head of an internal combustion engine (not shown), and is configured to directly inject fuel into each cylinder of the internal combustion engine.

The injector 1 according to the first embodiment is applied to a common rail type fuel injection system. The injector 1 mainly includes a housing 10, a nozzle unit 20, an electromagnetic drive unit 30, and a fuel inlet 40. The nozzle unit 20 is provided on the side of the housing 10 opposite to the electromagnetic drive unit. The nozzle portion 20 has a nozzle body 21, and a nozzle hole 2 is provided near the tip of the nozzle body 21.
2 are formed. A valve needle 23 is housed on the inner peripheral side of the nozzle body 21 so as to be able to reciprocate in the axial direction. A contact portion 231 is formed on the valve needle 23 and can contact a valve seat portion 211 formed on the inner peripheral side of the nozzle body 21. When the contact portion 231 is seated on the valve seat portion 211 or the contact portion 231 is separated from the valve seat portion 211, the fuel injection from the injection hole 22 is interrupted.

A control piston (not shown) that is in contact with the valve needle 23 is housed on the inner peripheral side of the housing 10. A pressure control chamber (not shown) is formed on the inner peripheral side of the housing 10 on the side opposite to the valve needle of the control piston. The high-pressure fuel supplied from the fuel inlet 40 is stored in the pressure control chamber. The high-pressure fuel stored in the pressure control chamber urges the control piston downward in FIG. When the control piston is urged by the fuel in the pressure control chamber, the valve needle 23 in contact with the control piston is urged in the injection hole closing direction. That is, the contact portion 231 of the valve needle 23 is urged in a direction to be seated on the valve seat portion 211 of the nozzle body 21.

The electromagnetic drive unit 30 is installed on the side of the housing 10 opposite to the nozzle unit. The electromagnetic drive unit 30 has an electromagnetic valve (not shown) for intermittently discharging the fuel stored in the pressure control chamber. When the solenoid valve is opened and the fuel in the pressure control chamber is discharged, the pressure inside the pressure control chamber decreases, and the force for urging the valve needle 23 in the injection hole closing direction decreases. Then, the valve needle 23 is more urged by the pressure of the fuel in the vicinity of the valve seat portion 211 than by the force of urging the valve needle 23 in the injection hole closing direction by the pressure of the fuel in the pressure control chamber.
When the force for urging the nozzle 3 in the nozzle opening direction increases, the valve needle 23 lifts upward in FIG. When the valve needle 23 is lifted, the contact portion 231 is moved to the valve seat portion 211.
And the fuel is injected from the injection hole 22.

On the other hand, when the solenoid valve is closed and the discharge of fuel from the pressure control chamber is stopped, the pressure inside the pressure control chamber increases, and the force for urging the valve needle 23 in the nozzle hole closing direction increases. I do. Therefore, when the valve needle 23 moves downward in FIG. 2 and the contact portion 231 is seated on the valve seat portion 211, the injection of fuel from the injection hole 22 is stopped.

The fuel inlet 40 is formed integrally with the housing 10. The fuel inlet 40 is supplied with high-pressure fuel stored in a common rail (not shown) in a pressure-accumulated state. A part of the high-pressure fuel supplied from the common rail is supplied to the pressure control chamber via the fuel passage 41, and another part is supplied to the nozzle unit 20. The fuel inlet 40 is provided with a filter member 50 for removing foreign substances contained in the fuel.

Next, the filter member 50 will be described in detail. As shown in FIG. 1, the filter member 50 is a bottomed cylindrical member. The filter member 50 has a main body including a substantially cylindrical tubular portion 51 and a bottom portion 52 provided at one end of the tubular portion 51. An enlarged diameter portion 53 is formed at an end on the side opposite to the bottom of the cylindrical portion 51. Enlarged part 5
3 is substantially the same as the inner diameter of the mounting portion 42 formed in the fuel inlet 40. Therefore, the filter member 50 can be fixed to the fuel inlet 40 by, for example, press-fitting the filter member 50 into the mounting portion 42.

The filter member 50 is formed of, for example, a metal material such as stainless steel. Filter member 50
Has a thickness that can withstand the pressure of the high-pressure fuel supplied from the common rail. A filter hole group 60 including a plurality of holes communicating between the inner peripheral side and the outer peripheral side is formed in the cylindrical portion 51. Each of the holes constituting the group of filtration holes 60 is formed so as to have an inner diameter smaller than that of the foreign substance desired to be removed.

In the case of the first embodiment, a plurality of holes constituting the filter hole group 60 are formed in the circumferential direction and the axial direction of the cylindrical portion 51 as shown in FIG. The holes constituting the filtration hole group 60 are formed such that the center of each hole is located on a spiral line around the axis of the cylindrical portion 51. For example, when the centers of the holes that constitute the filtration hole group 60 are connected by a line on the outer peripheral side of the cylindrical portion 51, the cylindrical portion 51 is rotated around the outer peripheral side of the cylindrical portion 51 in the circumferential direction.
Is a helical line displaced in the axial direction at a constant rate.

The holes constituting the filter hole group 60 are formed such that the centers of the holes are equally spaced on a spiral line. By forming the centers of the holes constituting the filter hole group 60 at equal intervals on a spiral line, the filter hole group 60 can be easily formed. For example, as shown in FIG.
It is possible to use a processing apparatus including a filter member holding portion 71 that moves the shaft 0 at a constant speed while rotating at a predetermined speed, and a hole forming portion 72 that forms a hole.
When such a processing apparatus is used, for example, the filter member 5
From the hole at the top of 0 to the hole at the bottom can be processed continuously and at high speed.

Next, the movement of fuel and foreign matter flowing through the filter member 50 will be described. The fuel supplied from the common rail flows in from the inlet 43 of the fuel inlet 40 as shown in FIG. The fuel that has flowed into the fuel inlet 40 flows from the enlarged-diameter portion 53 side of the filter member 50 to the inner peripheral side of the cylindrical portion 51, and flows into one of the filtration hole groups 60. The fuel that has passed through any of the holes of the filtration hole group 60 flows out to the outer peripheral side of the cylindrical portion 51 and flows to the fuel passage 41. Foreign matter contained in the fuel cannot pass through each of the holes constituting the group of filtration holes 60, and is thus trapped on the inner peripheral side of the cylindrical portion 51. The trapped foreign matter is collected on the inner peripheral side of the bottom part 52 by the flow of the fuel.

As described above, according to the filter member 50 of the injector 1 according to the first embodiment, the filter holes 6
The inside diameter of each hole constituting 0 is formed smaller than the foreign matter to be removed. Therefore, minute foreign matter contained in the fuel can be reliably removed. Further, since a plurality of holes constituting the filter hole group 60 are formed, a sufficient fuel circulation area can be secured. Therefore, the pressure loss of the fuel can be reduced.

In the first embodiment, the centers of the holes constituting the filter hole group 60 are formed at equal intervals on a helical line around the axis of the cylindrical portion 51. Therefore, a plurality of holes can be formed in the filter member 50 while positioning them continuously and at high speed. Therefore, the processing of the filter member 50 is easy, and the number of processing steps and processing cost can be reduced.

According to the injector 1 of the first embodiment, the filter member 50 can reliably remove even minute foreign matter. Therefore, it is possible to prevent the injection hole 22 from being blocked by foreign matter. Therefore, since the inner diameter of the injection hole 22 can be further reduced, the atomization of the fuel can be further promoted.

(Second Embodiment) FIG. 5 shows a fuel inlet of an injector 1 according to a second embodiment of the present invention. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the second embodiment, the mounting state of the filter member 50 mounted on the fuel inlet 40 is different from the first embodiment. In the second embodiment, the filter member 50 is mounted on the fuel inlet 40 in a state where it is inverted in the axial direction from the first embodiment, that is, in a state where the bottom portion 52 is located on the inlet 43 side of the fuel inlet 40.

In the case of the second embodiment, the fuel supplied from the common rail flows in from the inlet 43 of the fuel inlet 40. The fuel that has flowed into the fuel inlet 40 passes between the filter member 50 and the inner peripheral wall of the mounting portion 42 and passes through the cylindrical portion 51.
Flows into one of the holes of the filter hole group 60 from the outer peripheral side. The fuel that has passed through any of the holes of the filtration hole group 60 flows out to the inner peripheral side of the cylindrical portion 51 and flows to the fuel passage 41. Foreign matter contained in the fuel cannot pass through each of the holes constituting the filter hole group 60, and is thus trapped on the outer peripheral side of the cylindrical portion 51. The captured foreign matter is collected by the flow of the fuel in the space 56 formed by the outer peripheral portion of the cylindrical portion 51, the enlarged diameter portion 53, and the mounting portion. In the second embodiment, the filter member 5
Even when the fuel cell 40 is mounted on the mounting part 42 of the fuel inlet 40 in a state where 0 is reversed in the axial direction with respect to the first embodiment, foreign substances contained in the fuel can be reliably removed.

(Third Embodiment) A filter member applied to an injector according to a third embodiment of the present invention will be described. Components substantially the same as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The third embodiment differs from the first embodiment in the arrangement of the holes constituting the filter hole group 90 formed in the filter member 50. In the case of the third embodiment, as shown in FIG. 6, the holes constituting the group of filtration holes 90 are arranged such that the center of the holes is located substantially at the apex of an equilateral triangle. That is, the distances between the center of a specific hole 91 and the centers of other holes 92, 93, 94, 95, 96, 97 adjacent to the specific hole are all substantially the same.

By forming each of the holes constituting the filtration hole group 90 such that the center of each hole is located at the vertex of an equilateral triangle, the number of holes that can be formed per unit area can be maximized. That is, a plurality of holes constituting the filtration hole group 90 can be efficiently arranged in the limited cylindrical portion 51. Therefore, when securing a predetermined area as the opening area of the holes constituting the filtration hole group 90, that is, the fuel circulation area, the size of the filter member 50 can be reduced,
In addition, a decrease in strength can be prevented.

Further, in the third embodiment, the filter member 5
When the physique of 0 is constant, the number of holes constituting the filter hole group 90 that can be formed in the filter member 50 increases. Therefore, the flow area of the fuel is increased, and the pressure loss of the fuel by the filter member 50 can be reduced. The filter member 50 according to the third embodiment is different from the first embodiment in that
It can be mounted in any state described in the embodiment or the second embodiment.

As described above, in the plural embodiments of the present invention, an example has been described in which the filter member of the present invention is applied to a common rail type injector to remove foreign matter in fuel. However, the filter member of the present invention can be applied not only to the common rail type injector and the foreign matter in the fuel but also to a filter for removing foreign matter in the fluid including other injectors.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a filter member mounted on a fuel inlet of an injector according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view illustrating an injector according to a first embodiment of the present invention.

FIG. 3 is a schematic perspective view showing a filter member of the injector according to the first embodiment of the present invention.

FIG. 4 is a schematic view showing a processing apparatus for processing a filter member according to a first embodiment of the present invention.

FIG. 5 is a schematic sectional view showing a filter member mounted on a fuel inlet of an injector according to a second embodiment of the present invention.

FIG. 6 is a schematic view showing an arrangement of holes constituting a group of filtration holes formed in a filter member mounted on a fuel inlet of an injector according to a third embodiment of the present invention.

[Description of Signs] 1 Injector (fuel injection device) 40 Fuel inlet 41 Fuel passage 42 Mounting part 50 Filter member 51 Tubular part (main body) 52 Bottom part (main body) 60, 90 Filtration hole group (hole)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Ryo Katsura 1-1-1 Showa-cho, Kariya-shi, Aichi F-Term in Denso Corporation (reference) 3G066 AA07 AB02 AC09 AD07 BA03 BA32 BA46 BA55 BA67 CC06U CC14 CD11 CE22 CE34 4D064 AA23 BM03 BM37

Claims (5)

[Claims] 1. A filter member installed in a fluid passage through which a fluid passes, comprising: a cylindrical main body having a plurality of holes communicating between an outer peripheral side and an inner peripheral side; A filter member, which is arranged on a spiral line around an axis of a main body. 2. The filter member according to claim 1, wherein the holes are arranged at equal intervals on the helical line. 3. A filter member installed in a fluid passage through which a fluid passes, comprising: a cylindrical main body having a plurality of holes communicating between an outer peripheral side and an inner peripheral side; The filter member is arranged so that the distances to other holes are substantially the same. 4. The filter member according to claim 3, wherein the center of the hole is arranged at a vertex of a substantially equilateral triangle. 5. A fuel injection device comprising the filter member according to claim 1 in a fuel inlet into which fuel flows.