JPH07109964A - Filter - Google Patents

Abstract

PURPOSE:To provide a filter which prevents clogging and properly catches the foreign materials, simultaneously. CONSTITUTION:The large diameter part 8 of a filter body 3 is pressfitted and fixed at the inlet part of an inner wall 25 forming a through hole 5 on a nozzle holder 2. As for the first, second, and the third small diameter parts 8, 10, and 11 which are connected with the large diameter part 8, the outer wall on the outlet side is formed gradually larger in comparison with on the inlet side. Accordingly, each filter gap L, M, S which becomes smaller gradually towards the downsream side is formed between each of the first small diameter parts 9, 10, and 11 and the inside wall 25. The fuel on the inlet side of the filter body 3 is introduced into the filer gap L between the inside wall 25 and the outer wall of the first small diameter part 9, passing through the passage between the inside wall 25 and the first foreign material catching groove 12. The foreign material in the fuel is caught at a proper place having each dimension of the filter gap L, M, S according to the dimension of the foreign material, and the fluid from which the foreign material is removed flows to the outlet side of the filter body 3, passing through the filter gap L, M, S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter, and more particularly to a bar filter for preventing foreign matter in fuel from entering a fuel injection valve for a diesel engine.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Utility Model Laid-Open No. 3-6052, there is known a fuel injection nozzle provided with a filter for removing foreign matters in the fuel at the fuel nozzle inlet of a diesel engine. The filter attached to the inlet of this fuel injection nozzle has a spiral bar-shaped groove formed on the outer peripheral surface of a cylindrical bar filter, and the fuel filtration gap formed by this groove is uniformly reduced to remove foreign matter. ing.

[0003]

However, according to such a conventional filter as described above, the groove of the filter is apt to be clogged, which obstructs the passage of fuel or blocks the fuel passage. Is likely to occur. Generally, as the injection pressure of fuel is further advanced to cope with the stricter exhaust gas regulations of diesel engines, and the diameter of the injection hole of the fuel injection nozzle is being reduced, the fuel inlet of the fuel injection nozzle is There is a strong demand for accurate removal of foreign substances that enter from the outside, even small foreign substances.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a filter which prevents clogging and at the same time accurately collects foreign matter.

[0005]

A filter according to claim 1 according to the present invention for solving the above-mentioned problems is fixed to a nozzle holder having a through hole for flowing a liquid and an inlet portion of an inner wall forming the through hole. A large-diameter portion, a small-diameter portion that is connected to the large-diameter portion, forms a filtration gap between the inner wall that forms the through hole and becomes smaller as it goes downstream, and an inlet side of the large-diameter portion. A filter body having a foreign matter collecting groove formed on the outer wall of the large diameter portion so as to communicate with the filtration gap.

A filter according to a second aspect of the present invention for solving the above-mentioned problems is a nozzle holder having an inner wall forming a through hole, a large diameter portion fixed to the inlet side of the inner wall, and an outlet of the inner wall. And a filter body having a small diameter part for filtering liquid on the side, the large diameter part has a foreign substance collecting groove for communicating the inlet side and the outlet side on the outer wall thereof, and the small diameter part has an outer wall thereof. The outer wall is formed to have a larger diameter on the outlet side than on the inlet side so that a filtration gap having a different diameter is formed between the inner wall and the inner wall.

[0007]

According to the filter of the present invention, the fluid on the inlet side of the through hole passes through the passage between the inner wall of the through hole and the foreign substance collecting groove, and is filtered between the inner wall of the through hole and the outer wall of the small diameter portion. Enter the gap. Since this filtration gap gradually becomes smaller toward the downstream side, the foreign substance is stopped at an appropriate location of the size of the filtration gap according to the size of the foreign substance, and the fluid from which the foreign substance has been removed passes through the filtration gap. It flows to the outlet side of the filter body.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a filter according to a first embodiment of the present invention.
Shown in. The filter 1 is constructed by inserting and fixing a filter body 3 inside a nozzle holder 2.

The nozzle holder 2 has a large-diameter through hole 5 having a circular cross section and extending in the axial direction at the inlet portion, and a small-diameter through hole 6 communicates with the lower end thereof. The filter body 3 is inserted and fixed in the through hole 5. The material of the filter body 3 is, for example, S45C
It is F and withstands high pressure, and its axial length is, for example, 20-30 m.
m. The filter body 3 has a cylindrical large diameter portion 8 fixed to the inlet side of the through hole 5 by press fitting, a cylindrical first small diameter portion 9 connected to the lower end of the large diameter portion 8, and the first small diameter portion 9. The second small diameter portion 10 has a diameter slightly larger than the small diameter portion 9, and the third small diameter portion 11 connected to the lower end of the second small diameter portion 10 has a diameter slightly larger than the second small diameter portion 10.

The first foreign matter collecting groove 1 is formed on the outer peripheral side wall of the large diameter portion 8.
2 and 13 are formed in a concave shape on the outer wall portion facing each other by 180 °. The entrance sides of the first foreign matter collecting grooves 12 and 13 communicate with the upper end of the large diameter portion 8 and the lower end thereof extends to a middle portion of the outer wall of the first small diameter portion 9. The first foreign matter collecting grooves 12 and 13 have a role of circulating the fuel and a role of collecting the foreign matter.

The second foreign matter collecting grooves 14 and 15 are rotated by 90 ° from the first foreign matter collecting grooves 12 and 13, and the first small diameter portion 9 is formed.
Further, the outer wall of the second small diameter portion 10 is formed in a concave shape.
Further, the third foreign matter collecting grooves 16 and 17 are located on the downstream side of the fuel in the axial extension of the first foreign matter collecting grooves 12 and 13, and the second small diameter portion 1 is provided.
0 and the third small diameter portion 11 are formed. Further, in this embodiment, in order to increase the passage cross-sectional area, the third small diameter portion 11
Although the flow grooves 18 and 19 are formed so as to communicate from the middle part of the outer wall to the lower end, the flow grooves may be eliminated in the present invention.

Inner wall 2 of nozzle holder 2 forming through hole 5
5 and the filtration gap L between the outer wall of the first small diameter portion 9 and the inner wall 2
5 and the filtration gap M between the outer wall of the second small diameter portion 10 and the filtration gap S formed between the inner wall 25 and the outer wall of the third small diameter portion 11 have a relationship of S <M <L. . This is because among the foreign matters that have entered the first foreign matter collection groove 12 from the inlet side of the filter body 3, those larger than the filtration gap L are collected in the first foreign matter collection grooves 12 and 13 and Foreign matter that is smaller and larger than the filtration gap M is collected by the second foreign matter collection grooves 14, 14, and foreign matter that is smaller than the filtration gap M and larger than the filtration gap S is the third foreign matter collection groove 1.
This is to collect at 6 and 17. As a result, the first collecting grooves 12, 13, the second collecting groove 14,
15, the foreign matter is collected in the third collecting grooves 16 and 17, and the fuel from which the foreign matter is removed is filtered through the clearances L, M, S and the circulation groove 1.
It passes through 8 and 19 and flows out to the through hole 6 on the downstream side of the filter body 3.

For example, the filtration gaps L, M and S are each 6
0, 40, 20 μm, the first foreign matter collecting grooves 12, 1
In 3, the foreign matter having an outer diameter of 60 μm or more is collected, and in the second foreign matter collecting grooves 14 and 15, the foreign matter having a diameter of 60 to 40 μm or more is collected,
In the third foreign matter collecting grooves 16 and 17, foreign matter of 40 to 20 μm can be removed. According to the present embodiment, the foreign matter collecting groove is formed in three stages, and the fuel filtration gaps L, M, and S are made variable. Since different parts are filtered, large foreign matters are collected in a relatively large gap and do not reach a small downstream gap, so that clogging due to large foreign matters can be prevented.

Further, according to this embodiment, among the foreign matters in the fuel flowing in one direction through the through hole 5 extending in the axial direction, the relatively large foreign matters are collected on the upstream side and the relatively small foreign matters are collected on the downstream side. Because of the "layer filtration", the clogging is effectively prevented. Further, the filter body 3 can be easily formed by processing a cylindrical member and is easy to manufacture, and since the outer shape is a shape with high pressure resistance, the filter function due to the shape retention effect under high pressure fuel can be properly applied even under high pressure. Demonstrate. The filter body 3 is attached by a simple operation of press-fitting the filter body 3 into the through hole 5, and at the same time as the press-fitting, the foreign matter collecting groove and the filtration gap are formed.

Next, the foreign matter removing action will be described.
When the fuel is pumped from a fuel injection pump (not shown) and reaches the inlet side of the filter 1, the fuel enters the first foreign matter collecting grooves 12 and 13, and further the second foreign matter collecting grooves 14 and 15, and then the third foreign matter. It flows into the collection grooves 16 and 17. When the fuel passes through the foreign matter collecting grooves 12, 13, 14, 15, 16 and 17, foreign matter having different sizes can be removed by the filtration gaps L, M and S. That is, by providing a plurality of foreign matter collecting grooves and gradually reducing the filtration gap in a stepwise manner, it is possible to remove smaller foreign matter and prevent clogging of foreign matter.

Next, a second embodiment is shown in FIGS. The second embodiment is an example in which the stepped small-diameter portion shown in the first embodiment is replaced by a tapered small-diameter portion. In the second embodiment, the outer diameter of the first small-diameter portion 30 connected to the lower end of the large-diameter portion 8 of the filter body 3 is formed in a truncated cone shape so that the diameter becomes gradually larger as it goes downward, and the lower end thereof is The two small diameter portions 31 are formed. The filtration gap K between the outer wall of the first small diameter portion 30 and the inner wall 25 forming the through hole 5 is gradually narrowed from the upper side to the lower side, and the minimum filtration gap is the filtration gap S.
Is consistent with.

According to the present embodiment, the fuel that has entered the first foreign matter collection groove 12 flows through the filtration gap K around the first small diameter portion 30 and further through the filtration gap S that follows to the through hole 6.
Foreign matter in the fuel that is larger than the inner filtration gap K is collected by the first foreign matter collection groove 12, and foreign matter smaller than this foreign matter and larger than the filtration gap S is removed in the middle of the filtration gap K.
Therefore, foreign matter larger than the filtration gap K does not flow into the filtration gaps K and S, so that clogging due to large foreign matter is prevented.

According to this embodiment, as in the first embodiment, a filter body whose outer diameter changes in the axial direction is manufactured, and this filter body can be easily inserted into a small-diameter through hole by an operation. Can make filters.

[0019]

As described above, according to the filter of the present invention, the foreign matter in the fuel can be removed without causing clogging due to the foreign matter. Further, according to the present invention, by providing the function of performing the layer filtration of the foreign matter in the fuel, it is possible to suppress the occurrence of clogging due to the large foreign matter of the fuel.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention and is shown in FIG.
It is a -I line sectional view.

2 shows the first embodiment of the present invention and is shown in FIG.
FIG.

FIG. 3 is a sectional view taken along line III-III shown in FIG.

4 shows a second embodiment of the present invention and is shown in FIG.
FIG. 4 is a sectional view taken along line IV-IV.

5 shows a second embodiment of the present invention, and is a view in the direction of the arrow V shown in FIG.

6 is a sectional view taken along line VI-VI shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 filter 2 nozzle holder 3 filter body 5 through hole 8 large diameter part 9 first small diameter part 10 second small diameter part 11 third small diameter part 12, 13 first foreign matter collecting groove 14, 15 second foreign matter collecting groove 16, 17 Third Foreign Object Collection Groove 18, 19 Circulation Groove 25 Inner Wall L Filtration Gap M Filtration Gap S Filtration Gap K Filtration Gap

Claims (2)

[Claims] 1. A nozzle holder having a through hole for flowing a liquid, and a large diameter portion fixed to an inlet portion of an inner wall forming the through hole,
A small diameter portion that is connected to this large diameter portion and forms a filtration gap that becomes smaller as it goes downstream with the inner wall that forms the through hole, and connects the inlet side of the large diameter portion and the filtration gap. And a filter body having a foreign matter collecting groove formed on the outer wall of the large diameter portion. 2. A nozzle holder having an inner wall forming a through hole, a filter body having a large diameter portion fixed to the inlet side of the inner wall and a small diameter portion filtering the liquid at the outlet side of the inner wall. The large-diameter portion has a foreign matter collecting groove on its outer wall that communicates the inlet side and the outlet side, and the small-diameter portion has a filtration gap of a different diameter between the outer wall and the inner wall. A filter having an outer wall having a larger diameter on the outlet side than on the inlet side.