JPH0688558A - Solenoid type fuel injection valve - Google Patents

Abstract

PURPOSE:To facilitate the assembly of an injection valve by eliminating any overhanging part in the inner part of a housing, and securing a magnetic path by means of fixed ring separated from the housing, while forming a magnetic field generating part and a feeding coupler part into a resin-molded sleeve assembly. CONSTITUTION:A valve part A is composed of a needle valve 10a and a valve seat body 14 housing the former as well as a movable core 9 being displaced by dint of magnetic force. On the other hand, a magnetic field generating part B is composed of a bobbin 3 winding a coil 4 and a sleeve 2 inserted into the center of this bobbin 3. Those of valve part A and magnetic field generating part B are assembled in a housing 1a in a state of holding a magnetic fixed ring 23 between. In brief, this magnetic fixed ring 23 is set up in an intermediate part between the movable core 9 and the coil 4, thereby conducing to the secureness of a magnetic path produced by the coil 4. With the magnetic fixed ring 23 installed like this, such a requirement that an overhanging part for securing this magnetic path is formed on an inner wall of the housing 1a is eliminated. In addition, a coupler part 24 is solidly molded to the magnetic field generating part B, constituting a simple sleeve assembly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection valve for an internal combustion engine, and more particularly to an electromagnetic fuel injection valve having a structure that facilitates assembly.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing an example of a conventional electromagnetic fuel injection valve.

In FIG. 1, a hollow pipe-shaped sleeve 2 made of a magnetic material is fitted inside a housing 1 formed of a soft magnetic material in a cylindrical shape. In the space formed between the housing 1 and the sleeve 2,
A solenoid coil (hereinafter, simply referred to as a coil) 4 wound around a bobbin 3 is arranged so as to surround the sleeve 2.

With the sleeve 2 fitted in the housing 1, the housing 1 is provided with a flange portion 2 of the sleeve 2.
It is crimped to a. As a result, the O-ring 8 is pressed against the inner wall of the housing 1 by the end surface of the bobbin 3 and is clamped in a compressed state. Fuel intake 1 of the housing 1
The lid 5 is fixed to the end on the first side.

A lead wire 6 electrically connected to the coil 4.
Is penetrated through the flange portion 2a of the sleeve 2 by the connecting portion 7 of the bobbin 3, and further penetrated through the lid body 5 to be drawn out to the coupler portion. A movable core 9 is arranged at an end portion of the sleeve 2 on the injection port 15 side at a predetermined small interval with respect to the sleeve 2. The movable core 9 is a needle valve 10
It is crimped to one end of the needle valve 10 so as to be integrated with.

A compression spring 12 is inserted into the hollow hole of the sleeve 2, one end of which abuts on the inner cylinder 13 of the sleeve 2 and the other end of which abuts on the movable core 9. The compression spring 1
By 2, always (when coil 4 is not energized)
Is a movable core 9, that is, a needle valve 10 integrated with the movable core 9.
Is pressed against the valve seat 16 of the valve seat body 14 to prevent fuel from being injected from the injection port 15. FIG. 3 shows a state in which the coil 4 is not energized.

The pintle 17 provided at the tip of the needle valve 10 is provided to atomize the fuel injected from the injection port 15 with an ideal spread. Fuel intake 1
A filter 19 having a filter net 18 is attached to the unit 1.

A plate 20 for clearance adjustment is arranged between the valve seat body 14 and the internal overhanging portion 22 of the housing 1. The pintle 17 is protected by a protective cover 21.

In FIG. 3, the fuel filtered by the filter 19 passes through the hollow portion of the sleeve 2 and is guided to the periphery of the movable core 9 and the space formed by the needle valve 10 and the valve seat body 14.

When current is supplied to the coil 4, a magnetic path passing through the housing 1, the movable core 9 and the sleeve 2 is formed, and the movable core 9 is attracted to the sleeve 2 against the repulsive force of the spring 12. . As a result, the needle valve 10 separates from the valve seat 16, and fuel is injected from the injection port 15.

[0011]

The above-mentioned conventional injection valve has a problem that the assembling process is complicated. In the above-mentioned injection valve, the housing 1 has the inner protruding portion 22.
It is divided in two. Then, the needle valve 10 is provided on one of the partitioned portions, that is, a portion in the direction of the injection port 15.
The valve portion A including the valve seat body 14 is accommodated, and the magnetic field generating portion B including the coil 4 and the sleeve 2 for driving the needle valve 10 is accommodated in the other portion, that is, the portion toward the fuel intake port 11. Has been done.

Therefore, the assembling step is to insert the valve portion A and the magnetic field generating portion B into the housing 1 from two opposite directions, which is one obstacle to improving the efficiency of the assembling work.

The process of assembling the above injection valve is as follows. First, after inserting the needle valve 10 into the adjustment plate 20, the end portion is fitted into the movable core 9 and caulked. This is housed in the hollow portion of the valve seat body 14, and the protective cover 21 is covered to complete the valve portion A.

On the other hand, the magnetic field generator B is assembled as follows. First, the inner cylinder 13 and the filter 19 are arranged inside the sleeve 2. Then, the sleeve 2 is inserted through the center of the bobbin 3 around which the coil 4 is wound.

In the next step, the magnetic field generating portion B is inserted from one side of the housing 1 and one end portion of the housing 1 is caulked with the flange portion 2a to be integrated.

After that, a material such as butylene resin is molded around the housing 1 and the sleeve 2 to form the lid 5 and the coupler portion. Furthermore, a cleaning step is added after the molding.

Finally, the compression spring 12 is interposed between the concave portion of the sleeve 2 and the movable core 9, and the valve portion is fitted and inserted from the other side of the housing 1. Secure the ends by crimping.

As described above, in the conventional injection valve, the valve portion A and the magnetic field generating portion B cannot be assembled to the housing 1 from one direction, and the work of cleaning the resin mold portion is added during the assembly. The process was complicated.

The present invention has been made to solve the above problems.

[0020]

In order to solve the above-mentioned problems, the present invention is arranged in a magnetic field generated by a coil, the outer circumference of which is inscribed in the housing, and the inner circumference of which is a predetermined small distance. And a magnetic fixing ring provided so as to face at least a part of the outer periphery of the movable core, and the magnetic field generating portion including the coil and the valve portion are partitioned by the magnetic fixing ring. The first feature is that it is attached to the.

Further, the present invention comprises a coupler section for accommodating a lead wire for supplying power to the coil, the coupler section being coupled to the magnetic field generating section by resin molding, and the magnetic field generating section. The second characteristic is that a single assembly is formed by the coupler section.

[0022]

In the past, the magnetic path continuous with the movable core was formed by the projecting portion on the inner surface of the housing. However, in the present invention having the above-mentioned first feature, the magnetic path can be secured by the magnetic fixing ring. In this way, it was possible to eliminate the overhanging portion on the inner surface of the housing while maintaining the magnetic path of the magnetic field generating portion that displaces the movable core as usual. Therefore, the valve portion including the needle valve and the magnetic field generation portion are not separated by this overhang portion, and
The valve part and the magnetic field generation part can be inserted and assembled from one direction.

Further, the second feature makes it possible to construct an assembly which is integrally molded with the coupler unit in advance. Therefore, the washing step after molding is not performed in the middle of the step of assembling the valve portion and the magnetic field generating portion into the housing, and the steps can be simplified.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall sectional view of an injection valve showing an embodiment of the present invention, and FIG. 2 is a sectional view of the main part of the injection valve.
In the figure, the same reference numerals as those in FIG. 3 indicate the same or equivalent parts.

In FIG. 1, unlike the housing 1 shown in FIG. 3, the housing 1a is not provided with a projecting portion for partitioning the housing 1a into two parts. Instead,
A magnetic fixing ring (hereinafter, simply referred to as a fixing ring) 23 made of a magnetic material is provided between the bobbin 3 and the adjusting plate 20. The outer diameter of the fixed ring 23 is inscribed in the small-diameter portion of the housing 1a, and the inner circumference is dimensioned so as to maintain a small gap with the movable core 9. It is desirable that this small interval be small as long as the fixed ring 23 does not come into contact with the movable core 9 and hinder the displacement thereof.

The needle valve 10a has a contact portion with the inner wall of the valve seat body 14, that is, a large diameter portion 1 of the needle valve 10a.
In order to improve the wear resistance of 0b and 10c, the outer diameters of the large diameter portions 10b and 10c are circular and the entire circumference is in contact with the inner wall of the valve seat body 14. Therefore, a communication passage 10f is formed in the center of the needle valve 10a so as to connect to the holes 10d and 10e.

The valve seat body 14 has an annular protrusion 14 at its tip.
a is provided so that the pintle 17 is protected.

The compression spring 12a for pressing the needle valve 10a against the valve seat 16 of the valve seat body 14 by exerting its repulsive force on the movable core 9 is arranged so as not to interfere with the inner wall of the sleeve 2 rather than the end thereof. It is shaped like a drum with a small coil diameter in the center.

The magnetic field generator B, which is composed of the coil 4, the bobbin 3, the sleeve 2, etc., is the housing 1a.
Before being inserted into the connector, it is molded with resin and integrated with the coupler portion 24. This integrated product is called a sleeve assembly.

As shown in FIG. 2, this sleeve assembly is first formed by inserting the sleeve 2 into the hole of the bobbin 3 around which the coil 4 is wound to form a primary assembly. Thereafter, the primary assembly is molded with the resin 5a so as to wrap the whole at the same time as the molding of the coupler portion 24 to form a single sleeve assembly.

Next, the process of assembling the injection valve of this embodiment will be described. First, the valve seat body 14 is attached to the small diameter portion of the housing 1a.
Insert. Next, of the assembly including the needle valve 10 a, the adjusting plate 20, and the movable core 9, the needle valve 10 a portion is inserted into the hollow portion of the valve seat body 14. In this way, the valve portion A is formed. Then, the fixing ring 23 is inserted into the housing 1a at a position where it comes into contact with the adjustment plate 20.

Thereafter, with the drum-shaped compression spring 12a interposed between the movable core 9 and the inner cylinder 13, the coils 4,
The sleeve assembly including the bobbin 3 and the sleeve 2 (magnetic field generating portion B) and the coupler portion 24 is fitted into the large diameter portion of the housing 1a. Finally, the base 18a to which the filter net 18 is attached is fitted into the sleeve 2.

The O-ring 25 is arranged to prevent leakage between the injection valve and a connecting pipe (not shown) connected to the injection valve. Similarly, the O-ring 2
6, 27, 8 are arranged.

The fuel injection operation in this embodiment is shown in FIG.
The description is omitted because it is the same as that described above.
However, the fuel that has passed through the sleeve 2 is supplied to the hollow portion of the valve seat body 14 from the holes 10d and 10e, not through the outside of the needle valve 10 but through the communication passage 10f.

In this embodiment, the needle valve 10
The shape of the needle valve 10a is set so that the outer circumferences of the large diameter portions 10b and 10c of a uniformly contact the inner wall of the valve seat body 14. This greatly contributes to the improvement of wear resistance when using a so-called new composition gasoline containing alcohol. However, even if the needle valve 10 having a shape as shown in FIG. It goes without saying that the purpose of can be achieved.

[0037]

As is apparent from the above description, according to the present invention, the following effects can be achieved. (1) The overhanging part inside the housing was eliminated, and the magnetic path was secured by the fixing ring separated from the housing. As a result, the valve part and the magnetic field generation part can be inserted into the housing from one direction, and the assembly process can be greatly simplified. (2) A sleeve assembly in which the magnetic field generator and the power supply coupler are both resin-molded is constructed. As a result, it is possible to avoid the complexity of the assembly in which the magnetic field generating unit is assembled to the housing as in the conventional case, and after the molding work and the cleaning process as the subsequent process, the process is returned to the assembly process of the valve unit. .

[Brief description of drawings]

FIG. 1 is a sectional view of an injection valve showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a sleeve assembly of an injection valve.

FIG. 3 is a sectional view of an injection valve showing a conventional technique.

[Explanation of symbols]

1, 1a ... Housing, 2 ... Sleeve, 3 ... Bobbin, 4 ... Coil, 9 ... Movable core, 10, 10a ...
Needle valve, 14 ... Valve seat body, 15 ... Injection port, 1
6 ... Valve seat, 23 ... Magnetic fixing ring

Claims (2)

[Claims] 1. A coil disposed around the movable core, the needle valve having one end fitted to the movable core and the other end arranged to face a valve seat surrounding the ejection port. In the electromagnetic fuel injection valve in which the movable core is displaced by the generated magnetic force, and thereby the injection port is opened and closed by the needle valve, in the bobbin around which the coil is wound and the sleeve inserted in the center of the bobbin. A magnetic field generating section, a valve section including the needle valve and a valve seat, a housing that accommodates the magnetic field generating section and the valve section, and a magnetic field generated by the coil, the outer periphery of which is inside the housing. A magnetic fixing ring that is in contact with the movable core and that is opposed to at least a part of the outer periphery of the movable core while maintaining a predetermined small interval between An electromagnetic fuel injection valve, wherein the magnetic field generating portion and the valve portion are mounted in the housing in a state of being partitioned by the magnetic fixing ring. 2. A coupler section for accommodating a lead wire for supplying power to the coil is provided, and the coupler section is coupled to the magnetic field generation section by resin molding, and the magnetic field generation section and the coupler section are used. The electromagnetic fuel injection valve according to claim 1, wherein a single assembly is constructed.