JPH05149208A - Manufacture of filter for fuel injection valve - Google Patents

Abstract

PURPOSE:To prevent foreign matter from entering the inside of an injection valve resulting from generating a gap in an installation part at the time of installing a fuel filter on the fuel injection valve. CONSTITUTION:A mesh 100a is attached and fixed on the outer periphery of the body 1a of a fuel injection valve 1, and an outer pattern 110 for resin molding is fitted on the outer periphery of the body 1a. Moreover, the body 1a is used as an inner pattern, and a mesh supporting frame 100b is resin-formed directly around the body 1a to form a fuel filter 100. It is thus possible to make the filter supporting frame 100b and the body 1a come into close contact with each other without generating any gap regardless of the machining tolerance of the body 1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a fuel filter for a so-called side-feed type fuel injection valve having a fuel inlet on a side surface of a cylindrical body.

[0002]

2. Description of the Related Art FIG. 5 is a side view of a side-feed type fuel injection valve 1 having a fuel filter 10 manufactured by a conventional method, and FIG. 6 is a sectional view taken along line VI-VI of FIG. Figure 6
As shown in FIG. 1, the fuel injection valve 1 has a cylindrical main body (case) 1
a, a valve body 2 that reciprocates in the case 1a along an axis, and an injection port 3 that is opened and closed by the valve body 2.

Reference numeral 4 in FIG. 6 is a solenoid for driving the valve element 2, and reference numeral 5 is a spring for pressing the valve element 2 downward in the drawing. Further, reference numeral 6 in FIG. 6 denotes a plurality of fuel supply ports provided in the case 1a in the radial direction.
When the fuel injection valve 1 is attached to the mounting seat 7 of the intake manifold of the internal combustion engine, the outer peripheral portion of the case 1a and the mounting seat 7 are
An annular fuel supply passage 8 is formed between and. Fuel is
From the supply passage 8 to the fuel supply port 6 of the fuel injection valve body 1a
And flows into the fuel passage 2a provided at the center of the valve body 2. When the solenoid 4 is energized, the valve body 2 is spring 5
Moves upward against the urging force of. Therefore, the injection port 3 is opened, and the fuel in the fuel passage 2a is injected from the injection port 3 into the intake manifold. When the energization of the solenoid 4 is stopped, the valve body 2 is pushed by the spring 5 and the injection port 3 is closed, so that the fuel injection is stopped. Therefore, the amount of fuel injected can be controlled by adjusting the energization time of the solenoid 4.

A fuel filter 10 for covering the fuel supply port 6 is provided on the outer peripheral portion of the injection valve case 1a in order to prevent malfunction of the valve body 2 and clogging of the minute gap portion due to dust or foreign matter in the fuel. ing. As shown in FIGS. 5 and 6, the fuel filter 10 includes a metal mesh 10a for removing foreign matters in the fuel, and the injection valve case 1 that holds the mesh 10a.
The support frame 10b is made of resin for fixing to a. The support frame 10 has a substantially cylindrical shape having an opening 10c at a position corresponding to the fuel supply port 6 of the injection valve 1, and the mesh 1
It is resin-molded integrally with 0a. The conventional filter 10 is manufactured separately from the fuel injection valve housing 1a, and is fitted to the outer peripheral portion of the injection valve case 1a after the fuel injection valve 1 is assembled.

That is, when the assembly of the fuel injection valve 1 is completed, the filter 10 is press-fitted onto the outer circumference of the injection valve case 1a from the injection port 3 side along the axial direction and fixed at a predetermined position. Next, in order to prevent the filter 10 from falling off, a metal ring upper 12 is similarly press-fitted along the axial direction, and is fixed at a position on the outer peripheral portion of the case 1a in contact with the support frame 10b of the filter 10. Furthermore, in order to hold the O-ring seal 13, a ring lower 14 also made of metal is used.
Is fitted to the outer peripheral portion of the case 1a, and an O-ring seal holding groove is formed between the case 1a and the ring upper 12.

[0006]

When the fuel filter 10 is separately manufactured and fitted in the injection valve case 1a as in the conventional case, the following problems occur. That is, due to the processing tolerance of the injection valve case 1a and the dimensional tolerance of the filter 10 during resin molding, a gap may be generated between the case 1a and the case 1a in the radial direction and the axial direction when the filter 10 is fitted. Therefore, there is a risk that foreign matter in the fuel may enter the inside of the injection valve through this gap, causing malfunction of the valve body 2 and the like. By setting the dimensional tolerance so that the inner diameter of the filter 10 becomes small, it is possible to prevent the generation of the radial gap at the time of fitting, but in order to prevent the filter 10 from cracking during press fitting, this inner diameter is It is difficult to completely eliminate the radial clearance because it needs to be large to some extent.

Further, in the conventional method, a step of fitting the ring upper 12 and the ring lower 14 into the case 1a after the filter 10 is fitted is required, which requires a lot of man-hours and may cause a problem of poor ring press-fitting. was there. Especially, in the extreme case where the ring press-fitting failure occurs, the ring 1
Since there is a risk that the valves 2, 14 and the filter 10 will fall out of the injection valve case 1a, the precision of the ring press-fitting must be maintained high, which has been a factor of cost increase for maintaining the processing precision and assembly precision of the parts.

In order to solve the problem associated with the press-fitting of the ring, the filter support frame is divided into two along the axial direction, and the ring is integrally assembled with the main body in advance by assembling it from the radial direction to the outer peripheral portion of the injection valve case 1a. A filter structure that can be processed has also been proposed (Actual Kaihei 1-831).
No. 67), it is impossible to prevent the possibility that a gap may occur between the filter support frame and the case 1a.

In view of the above problems, it is an object of the present invention to provide a method of manufacturing a fuel filter, which can prevent the generation of a gap between the injection valve case and the support frame and can omit the ring press-fitting step. There is.

[0010]

According to the present invention, there is provided a filter manufacturing method for forming a mesh filter at a fuel inlet provided on a side surface of a fuel injection valve having a cylindrical main body,
A step of arranging a mesh so as to cover the fuel inlet on the outer periphery of the fuel injection valve main body, and fixing the mesh to the main body by a fixing means; and then a resin molding outer periphery on the outer periphery of the mesh mounting portion of the fuel injection valve main body. A step of mounting a mold, a molten resin is injected into a mold space formed between the outer mold and the fuel injection valve main body, and the mesh support frame is directly resin-molded on the fuel injection valve main body. A method of manufacturing a filter for a fuel injection valve, the method including the steps of:

[0011]

[Function] After the fuel injection valve is assembled, the outer mold for resin molding is mounted on the outer periphery of the main body, and the filter support frame is resin-molded by using the injection valve main body as the inner mold, regardless of the processing tolerance of the injection valve main body. The support frame is formed in close contact with the main body, and no radial or axial gap is created. Further, since it is not necessary to press fit the filter in the axial direction, the ring upper and the ring lower can be processed and formed integrally with the injection valve body, and the above-mentioned problems associated with the press fitting of the ring can be completely eliminated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fuel filter manufacturing method of the present invention will be described below with reference to the accompanying drawings. 1 is a front view of a fuel injection valve equipped with a filter manufactured by the method of the present invention, FIG. 2 is a longitudinal sectional view taken along line II-II of FIG. 1, and FIG. 3 is taken along line III-III of FIG. FIG. Note that FIG.
3 to 3, the same reference numerals as those in FIGS. 5 and 6 denote the same elements.

In FIG. 1, the filter 100 is directly formed on the outer periphery of the main body (case) 1a of the injection valve 1 by a method described later. In this embodiment, the filter 100 is the injection valve case 1a.
It is composed of a metal mesh 100a wound around the outer periphery and a cylindrical resin support frame 100b formed on the outer side thereof,
The support frame 100b is provided with openings 100c at positions corresponding to the four fuel supply ports 6 on the outer periphery of the injection valve case 1a,
The foreign matter in the fuel flowing in through this part is meshed with the mesh 10.
It is designed to be removed at 0a. On the outer peripheral portion of the injection valve case 1a, a concave portion 6 having a substantially rectangular shape is provided around the fuel supply port 6.
a (see FIGS. 2 and 3) is formed, and the support frame opening 100c of the filter 100 is formed in a position and shape that match the recess 6a.

In FIG. 2, above and below the recess 6a of the injection valve housing 1a, a bridge portion (entire peripheral portion) of the support frame 100b (FIG. 1, 101a,
Cylindrical processing surfaces 9a and 9b which serve as an inner mold for forming 101b) are provided over the entire circumference. Similarly, between the recesses 6a, a processed surface (FIGS. 3 and 9c) which functions as an inner mold for forming rib portions (FIG. 1, columnar portions 101c connecting the bridge portions 101a and 101b) of the support frame 100b. ) Is provided.

In this embodiment, the ring upper 12 and the ring lower 14 shown in FIG. 6 are integrally formed in advance on the injection valve case 1a by machining (FIGS. 2, 112, 11).
4). Next, a method of manufacturing the fuel filter 100 will be described with reference to FIG. FIG. 4A shows a cross section of the injection valve case 1a before forming the filter 100, taken along line III-III of FIG.

In this embodiment, as the first step of forming the filter 100, the metal mesh 10 is formed on the outer periphery of the housing 1a.
Install 0a. The mesh 100a has a strip shape having a width larger than the axial width of the recess 6a of the housing 1a, and is wound around the outer periphery of the housing 1a so as to cover the recess 6a and the processing surfaces 9a, 9b, 9c. The length of the mesh is longer than the outer peripheral length of the machined surfaces 9a and 9b, and the mesh ends overlap each other when wound around the housing 1a (FIG. 4 (b)). (The part indicated by "A" in Fig. 4 (b))
Is positioned on one of the processed surfaces 9c of the housing 1a, and the mesh overlapping portion is fixed to the processed surface 9c by a fixing means such as spot welding or pinning. As a result, the mesh 100a is fixed to the outer periphery of the housing 1a while covering the processed surfaces 9a, 9b, 9c.

After fixing the mesh 100a, as a second step, the outer mold 1 for resin molding is formed on the outer periphery of the housing 1a.
10 is attached (FIG. 4 (c)). The outer mold 110 is divided into two along the axis, and the mold is clamped by sandwiching the housing 1a from both sides. On the inner periphery of the outer mold 110, an annular groove (not shown) is provided at a position facing the above-described entire circumferential working surfaces 9a and 9b of the housing 1a, and an axial direction connecting these annular grooves at a position facing the working surface 9c. Grooves 110b are formed (FIG. 4C). Therefore, in the mold clamped state, the machined surface 9a,
The bridge portion 101a, 1 of the support frame 100b is provided at the portion 9b.
01b, and the rib portion 10 of the support frame 100b connecting the annular spaces in the processed surface 9c portion.
An axial space corresponding to 1c is formed.

Then, in this state, a heat-traceable resin such as nylon is injected into the space between the housing 1a and the outer mold 110. The resin injected into the mold space fills the annular space forming the bridge portions 101a and 101b through the space forming the rib portion 101c, and the mesh 100a and the processing surfaces 9a, 9b and 9c through the mesh portion of the mesh 100a.
Since it also fills the gap between the filter support frame 100 and
There is no gap between b and the housing 1a. When the outer mold 110 is removed after the resin is cooled, the filter 100 shown in FIGS. 1 to 3 is formed on the housing 1a.

Thus, the main body (housing) of the injection valve 1
Support frame 101b directly on the main body using 1a as the inner mold
By resin molding, the support frame 101b and the main body are always in close contact with each other regardless of the processing tolerance of the main body 1a, so that there is no gap, and the problem caused by the mixture of foreign matter is completely solved. You can Further, since there is no step of fitting the filter in the axial direction, the ring upper and the ring lower can be integrally formed on the main body in advance, and the ring press fitting step can be omitted. Therefore, the problems associated with the ring press-fitting described above are solved, the number of parts can be reduced, and the manufacturing cost can be reduced as a whole.

[0020]

As described above, according to the present invention, the fuel injection valve main body is used as an inner mold for resin molding as described above, and the filter is directly formed on the main body. This has the effects of completely solving problems such as defects, and improving product quality and reducing manufacturing costs by reducing the number of parts and man-hours.

[Brief description of drawings]

FIG. 1 is a front view of a fuel injection valve provided with a filter manufactured by the method of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

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

FIG. 4 is a diagram illustrating a fuel filter manufacturing process of the present invention.

FIG. 5 is a front view of a fuel injection valve equipped with a conventional filter.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel injection valve 1a ... Injection valve main body (case) 6 ... Fuel supply port 6a ... Recesses 9a, 9b, 9c ... Processing surface 10 ... Fuel filter (conventional example) 12 ... Ring upper 14 ... Ring lower 100 ... Fuel filter (main) Invention 100a ... Mesh 100b ... Support frame 100c ... Openings 101a, 101b ... Bridge section 101c ... Rib section 110 ... Outer mold

Claims (1)

[Claims] 1. A filter manufacturing method for forming a mesh filter at a fuel inlet provided on a side surface of a fuel injection valve having a cylindrical main body, wherein a mesh is provided so as to cover the fuel inlet at the outer periphery of the fuel injection valve main body. Arranging and fixing the mesh to the main body with fixing means, then mounting an outer mold for resin molding on the outer periphery of the mesh mounting portion of the fuel injection valve main body, the outer mold, and the fuel injection valve A method of manufacturing a filter for a fuel injection valve, comprising the steps of injecting a molten resin into a mold space formed between the main body and the main body, and molding the support frame of the mesh directly on the fuel injection valve main body.