JPH0579424A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To remarkably reduce the manufacturing cost of a fuel injection valve by integrating a coil bobbin to an outer periphery of a sleeve assembly directly through injection molding, and enabling winding of a coil around the coil bobbin under a fixed condition to the sleeve assembly. CONSTITUTION:A sleeve assembly A is formed by airtightly connecting a circular fixed iron core 1, a circular non-magnetic tube body 2, and a circular yoke 3 wherein a valve seat body housing hole 3C is opened and a circular yoke flange part 3D is formed in an outer side direction, to each other coaxially. A coil bobbin 4 made of synthetic resin around which a coil 6 is wound is integrally formed on an outer periphery of the sleeve assembly A. A housing 7 is arranged on an outer periphery of the sleeve assembly A including the coil 6, which housing 7 has one end which is magnetically connected to the yoke 3 and the other end which is magnetically connected to the fixed iron core 1. The housing 7 has a bottomed cup-like shape, in the vicinity of whose opening end part 7B an engagement stepped portion 7E engageable with the yoke flange part 3D is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a housing, a movable iron core which is magnetically attracted to a fixed iron core by a coil arranged in the housing, a valve portion formed at the front end, and a movable iron core at the rear end. The present invention relates to a fuel injection valve having a needle valve integrally fixed and a valve seat body having a valve seat that is continuous with a valve hole in which a valve portion of the needle valve is seated. Used for.

[0002]

2. Description of the Related Art A conventional fuel injection valve is disclosed in, for example, Japanese Patent Laid-Open No. 3-7.
No. 0864. According to this, a pipe made of a non-magnetic material having a cylindrical body fitted to the outer periphery of the fixed iron core and a flange portion whose outer periphery comes into contact with the inner periphery of the housing is provided, and the pipe is provided to the fixed iron core and the yoke, respectively. These are joined together, and the fixed iron core, the pipe, and the yoke form a sleeve assembly.

According to such a sleeve assembly, the fuel flowing down from the fixed iron core to the yoke through the pipe is prevented from leaking to the outside of the sleeve assembly, and an O-ring or the like for preventing fuel leakage. The airtightness holding member is unnecessary.

However, in such a conventional fuel injection valve, a coil bobbin serving as a base for winding a coil arranged in the housing is prepared separately from the sleeve assembly, and the coil bobbin is arranged on the outer periphery of the sleeve assembly. Therefore, the production cost is increased, which is not preferable. That is, the coil bobbin is injection-molded by a molding machine in advance, and then a coil is wound around the outer circumference of the coil bobbin by a winding machine to form a coil assembly, which is then arranged on the outer circumference of the sleeve assembly. The number of assembly processes for placing the assembly on the outer periphery should be increased. The management man-hours for managing each coil assembly according to the coil specifications will increase. A loading process is required to load the completed coil assembly into the assembly process of the sleeve assembly. Furthermore, a storage space is required to store the completed coil assembly. caused by.

Further, when forming the coil bobbin, the diameter of the guide hole formed in the center in the axial direction in order to insert and arrange the sleeve bobbin on the outer periphery of the sleeve assembly must be accurately controlled, and the number of inspection steps increases. Lead to That is,
If the diameter of the guide hole is small, it becomes difficult to insert the guide hole into the sleeve assembly. On the other hand, if the diameter of the guide hole is large, a large gap is generated between the guide hole and the sleeve assembly, and the coil assembly vibrates.

[0006]

SUMMARY OF THE INVENTION A fuel injection valve according to the present invention has been made in view of the above problems, and its main purpose is to provide a fuel injection valve which is inexpensive to manufacture.

[0007]

In order to achieve the above-mentioned object, a fuel injection valve according to the present invention is made of a tubular magnetic material having a first through hole formed in the interior thereof along the axial direction. An iron core, a non-magnetic tubular body made of a tubular non-magnetic material having a second through hole bored along the axial direction, and a third through hole bored in the axial direction toward the end. And a yoke made of a magnetic material having a tubular shape for accommodating a valve seat body are mechanically and airtightly joined together on the same axis to form a sleeve assembly, and a coil is wound around the outer circumference of the sleeve assembly. A coil bobbin made of a resin material is integrally molded, and a housing, one end of which is magnetically coupled to the yoke and the other end of which is magnetically coupled to a fixed core, is arranged on the outer periphery of the sleeve assembly including the coil. To do.

[0008]

The coil bobbin is integrally formed by injection molding directly on the outer circumference of the sleeve assembly, and the coil can be wound around the coil bobbin fixed to the sleeve assembly, so that the manufacturing cost of the fuel injection valve is greatly reduced. Can be achieved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fuel injection valve according to the present invention will be described below with reference to the drawings. 1 is a vertical cross-sectional view showing an embodiment of the fuel injection valve according to the present invention, FIG. 2 is a vertical cross-sectional view of the sleeve assembly in FIG. 1, and FIG. 3 is a coil bobbin integrally molded with the sleeve assembly in FIG. FIG. 4 is a vertical cross-sectional view of the rotated state, and FIG. 4 is a vertical cross-sectional view of the housing in FIG. In the description, upper, lower, left, and right are referred to in the drawings, and the present invention is not limited to these.

Reference numeral A denotes a sleeve assembly which is arranged at the center of the fuel injection valve in the axial direction.
And a non-magnetic tube body 2 and a yoke 3.

The fixed iron core 1 is made of a tubular magnetic material, and has a first through hole 1A penetrating the inside thereof in the axial direction from the upper side to the lower side.
B, and a small diameter portion 1C is concentrically formed at the lower end portion.

The non-magnetic tubular body 2 is made of a tubular non-magnetic material, has a second through hole 2A formed in the axial direction from the upper side to the lower side, and extends outward near the lower end. A large diameter hole 2D continuous with the second through hole 2A is opened at the lower end surface 2C of the non-magnetic tubular collar portion 2B.

The yoke 3 is formed of a tubular magnetic material, has a third through hole 3A formed in the axial direction from the upper side to the lower side, and has a third through hole 3A in the lower end surface 3B.
A valve seat body accommodating hole 3C having a diameter larger than that of the third through hole 3A is opened. Further, the non-magnetic tube body 2 is provided on the upper end surface 3E of the flange portion 3D of the yoke 3 which is located at the upper end of the yoke 3 and extends outward.
A positioning protrusion 3F that is positioned and inserted in the large-diameter hole 2D is formed to protrude, and the lower end surface 3B of the yoke 3 is further formed.
A thin portion for crimping 3G for folding and crimping is formed on the outer periphery in the vicinity of the valve seat body storage hole 3C and the third through hole 3
A step portion 3H is formed at a connection portion with A.

In order to form the sleeve assembly A, the second through hole 2A of the non-magnetic tube body 2 is inserted into the outer periphery of the small diameter portion 1C formed at the lower end of the fixed iron core 1 and then the non-magnetic tube body 2 is inserted. The positioning protrusion 3F of the yoke 3 is inserted into the large diameter hole 2D below. According to this, the fixed iron core 1, the non-magnetic tube body 2, and the yoke 3 are positioned and controlled concentrically (inward and outward). (First through hole 1A, second through hole 2A, third through hole 3
A and the valve seat body housing hole 3C are arranged at the same axis. )

Next, the contact portion B between the fixed iron core 1 and the non-magnetic tube body 2 and the contact portion C between the non-magnetic tube body 2 and the yoke 3 are joined by brazing, for example. The state of this sleeve assembly A is well shown in FIG.

According to this, the contact portions B and C are mechanically joined to each other and the contact portions are kept airtight. That is, the first through hole 1A, the second through hole 2A, the third through hole 3
A, the valve seat body accommodating holes 3C are mechanically joined to each other with their respective axes being the same axis and forming a single passage, and this passage is kept airtight to the outside of the sleeve assembly A. It

Incidentally, the fixed iron core 1, the non-magnetic tube body 2, the yoke 3
The means for restricting the positioning in the inner and outer peripheral directions (left and right direction in FIG. 2), the contact portion, and the joining means are not limited to those in the above embodiment.

The sleeve assembly A is placed in a cavity formed by a movable mold and a fixed mold and injection-molded, so that the coil bobbin 4 made of a synthetic resin material is integrally formed on the outer periphery of the sleeve assembly A. Can be formed as desired. The coil bobbin 4 includes a guide tube 4A surrounding the outer periphery of the sleeve assembly A in the axial direction,
A lower flange portion 4B extending outward from the lower end portion of the guide cylinder 4 and arranged on the flange portion 2B of the non-magnetic tube body 2.
And an upper flange portion 4C extending outward from the upper end of the guide tube 4 and having the terminal 5 planted in the terminal support portion 4D. This state is shown in FIG.

A coil 6 is wound around the outer circumference of the guide cylinder 4A of the coil bobbin 4 integrally attached to the sleeve assembly A as described above by a winding machine. The coil winding work by the winding machine is performed as in the conventional case because there is no interference portion in the sleeve assembly A including the coil bobbin 4 in the outer peripheral direction of the guide cylinder 4A between the upper collar portion 4C and the lower collar portion 4B. Lines are possible. The end of this coil 6 is connected to the terminal 5 as usual. A state in which the coil 6 is wound around the coil bobbin 4 is shown by a chain line in FIG.

Reference numeral 7 is a bottomed cup-shaped housing made of a magnetic material. The housing 7 has a bottom portion 7A formed at one end (upper side) and the other end (lower side).
Open at the open end 7B. A fixed iron core insertion hole 7C that is inserted into the outer periphery of the fixed iron core 1 is formed at approximately the center of the bottom portion 7A,
A terminal support portion insertion hole 7D for inserting the terminal support portion 4D is formed, a locking step portion 7E is formed on the inner periphery near the opening end portion 7B, and a thin portion 7F for caulking is formed on the outer periphery. It is formed. The housing 7 is shown in FIG.

The fuel injection valve is assembled as follows. Opening end 7B of housing 7 from above sleeve assembly A to which coil 6 and coil bobbin 4 are integrally attached
Insert. According to this, the fixed iron core insertion hole 7C formed in the bottom portion 7A of the housing 7 is inserted into the outer periphery of the fixed iron core 1, and the terminal support portion insertion hole 7D is inserted with the terminal support portion 4D of the coil bobbin 4. The locking step portion 7E of the housing 7 is arranged on the upper end surface 3E of the collar portion 3D of the yoke 3. In such a state, the housing 7 and the sleeve assembly A can be fixed to each other by crimping the thin portion 7F of the housing 7 toward the collar portion 3D of the yoke 3, and the inner periphery of the housing 7 and the outer periphery of the sleeve assembly A can be fixed. The coil 6 wound around the coil bobbin 4 can be housed in the space.

Next, the movable iron core 9 integrally fixed to the needle valve 8 having the valve portion 8A formed at the tip from the opening of the lower end surface 3B of the yoke 3 of the sleeve assembly A, the movable iron core 9 and the needle valve 8. The stopper 10 arranged between the collar portion 8B and the stopper 10 is inserted upward, and then the needle valve storage hole 11A for guiding the needle valve 8 movably in the axial direction and the lower end portion of the needle valve storage hole 11A. There, a valve seat 11B controlled to be opened / closed by the valve portion 8A of the needle valve 8 and a valve hole 11C opened further downward than the valve seat 11B.
The valve seat body 11 including the valve seat body 11 is inserted into the valve seat body housing hole 3C through the opening of the lower end surface 3B of the yoke 3.

According to this, the upper end of the movable iron core 9 is arranged to face the lower end of the fixed iron core 1 via the spring 12, and the valve portion 8A of the needle valve 8 is arranged to face the valve seat 11B. The stopper 10 is arranged between the step portion 3H of the yoke 3 and the upper end of the valve seat body 11. In this state, the thin caulking portion 3G of the yoke 3 is caulked inward toward the valve seat body 11. Then, the sleeve assembly A
The valve seat body 11 can be integrally fixed to the yoke 3, and the movable iron core 9 including the needle valve 8 is allowed to reciprocate in the axial direction.

When the coil 6 is not supplied with electric current, the movable iron core 9 is set to a position separated from the fixed iron core 1 by the spring 12, so that the valve portion 8A of the needle valve 8 has a valve seat. 11B is held in a closed state, the pressurized fuel supplied from the connector pipe 1B reaches the valve seat 11B through the through holes in the sleeve assembly A and the needle valve accommodating hole 11A. It is never injected from 11C.

On the other hand, when the coil 6 is supplied with current, the fixed iron core 1 is magnetized and electromagnetic force is generated to move the movable iron core 9 against the spring force of the spring 12.
Suction to the side and move. According to this, the needle valve 8 integrated with the movable iron core 9 moves upward, and the needle valve 8
Valve portion 8A opens the valve seat 11B, and the valve hole 11C
More fuel is injected.

As described above, according to the fuel injection valve of the present invention, the coil bobbin 4 is formed integrally with the sleeve assembly A by injection molding, the coil 6 is wound around the coil bobbin 4, and the coil 6 is wound. Since the sleeve assembly A can be prepared in this state, the step of taking out the relatively small coil bobbin 4 and attaching it to the outer circumference of the sleeve assembly A is unnecessary in the process of assembling the fuel injection valve. It is possible to reduce the man-hours for assembling, and to significantly reduce the inventory of coil bobbins, the management of shipping, etc. and the loading into the production line, the storage space of the coil bobbins, etc. It is a thing.

Further, the coil bobbin 4 is integrally formed on the outer periphery of the sleeve assembly A by out-molding, so that the inner diameter portion of the guide cylinder 4A of the coil bobbin 4 and the outer diameter portion of the sleeve assembly A can be surely brought into close contact with each other. Since the inner diameter inspection of the guide tube 4A of the coil bobbin 4 as in the conventional art is completely unnecessary, the inspection process can be reduced and the workability can be improved, and further, the fuel injection when mounted on the engine can be achieved. Coil bobbin 4 even if the valve receives vibration
Does not generate vibrations on the sleeve assembly A.

Further, when the respective constituents of the sleeve assembly A are joined, there is a possibility that the joining material may project to the outer periphery of the sleeve assembly A. However, when the coil bobbin 4 is out-molded, the synthetic resin material includes this projection. Since the coil bobbin is molded by the above, there is no problem even if the bonding material projects.

Further, since the joint portion of each component of the sleeve assembly A is out-molded with the synthetic resin material, this joint portion is sealed by the thick airtight material, and the airtightness of the sleeve assembly A is maintained. Is also effective.

FIG. 5 shows another embodiment. The structure different from that of the first embodiment will be described, and those having the same structure will be denoted by the same reference numerals and will not be described. Reference numeral 20 denotes a tubular non-magnetic tubular body made of a non-magnetic material, which is disposed in the middle portion of the sleeve assembly A and is made of a straight tubular material. That is, the feature is that it does not have the collar portion in the first embodiment.

According to such a second embodiment, the non-magnetic tube body 2
Since 0 is a straight pipe material and has no flange portion, it is possible to arrange the coil bobbin 4 and the coil 6 downward by the thickness of this flange portion. According to this, Center P- of coil 6 in the axial direction
P is the lower end 1D of the fixed iron core 1 and the upper end 9A of the movable iron core 9.
Since it has become possible to bring it closer to the center RR of the gap between the fuel injection valve and the movable iron core 9, the overall height of the fuel injection valve can be designed smaller by that amount. It was possible to increase the degree of freedom of placement in the car.

[0032]

According to the fuel injection valve of the present invention, the housing, the movable iron core magnetically attracted to the fixed iron core by the coil arranged in the housing, the valve portion at the front end, and the rear end are formed. In a fuel injection valve having a needle valve integrally fixed to a movable iron core and a valve seat body having a valve seat connected to a valve hole in which the valve portion of the needle valve is seated A fixed core made of a tubular magnetic material having a first through hole formed therein, and a non-magnetic tubular body made of a tubular non-magnetic material having a second through hole formed therein along the axial direction, A yoke made of a magnetic material having a tubular shape in which a valve seat housing hole is opened toward an end from a third through hole bored in the axial direction is mechanically and airtightly joined on the same axial center. A sleeve assembly is used and a coil is attached to the outer circumference of the sleeve assembly. A coil bobbin made of a synthetic resin material for winding is integrally molded, and a housing having one end magnetically coupled to the yoke and the other end magnetically coupled to the fixed iron core is arranged on the outer periphery of the sleeve assembly including the coil. As a result, the assembly process related to the coil bobbin, man-hours for managing delivery, inventory, etc., man-hours for loading into the assembly line,
The storage space, and especially the number of man-hours for inspecting the inner diameter of the coil bobbin, have been reduced, resulting in a significant reduction in manufacturing cost.

Further, since the coil bobbin is arranged by being out-molded on the outer peripheral portion of the joint of the abutting portions of the respective parts constituting the sleeve assembly, the abutting portion can be more surely kept airtight and the sleeve assembly and the coil bobbin can be more reliably maintained. There is no play at the joint with.

Further, since the fixed iron core, the non-magnetic tubular body, and the yoke forming the sleeve assembly are joined in a state in which their positioning is regulated in the inner and outer peripheral side directions, the respective components penetrating the inside of the sleeve assembly in particular. Through holes can be formed concentrically, which allows the fuel to flow smoothly without obstructing the flow of fuel, does not disturb the fuel injection foam, and operates the needle valve including the movable iron core. Can be performed extremely smoothly.

Further, the housing has a bottomed cup shape in which a bottom is formed at one end and the other end is opened at the opening end, and the bottom has a fixed core insertion hole and a coil bobbin which are inserted into the outer periphery of the fixed core. According to the provision of the terminal supporting portion insertion hole into which the integrally formed terminal supporting portion can be inserted, and the locking stepped portion that can be locked to the collar portion of the yoke near the opening end. Since the shape is extremely simple, the housing can be manufactured at a low cost, such as drawing a circular pipe, and can contribute to the cost reduction of the fuel injection valve.

[Brief description of drawings]

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

FIG. 2 is a vertical cross-sectional view showing the sleeve assembly of FIG.

FIG. 3 shows a state in which a coil bobbin is integrally molded with the sleeve assembly of FIG. 1 and a coil is wound around the coil bobbin.

4 is a vertical cross-sectional view of the housing of FIG.

FIG. 5 is a vertical sectional view showing another embodiment of the fuel injection valve of the present invention.

[Explanation of symbols]

 A sleeve assembly 1 fixed iron core 1A first through hole 2 non-magnetic tube 2A second through hole 3 yoke 3A third through hole 3C valve seat housing hole 4 coil bobbin 6 coil 7 housing 7C fixed iron core insertion hole 7D terminal support insertion Hole 8 Needle valve 9 Movable iron core 11 Valve seat

Claims (3)

[Claims] 1. A housing, a movable iron core magnetically attracted to a fixed iron core by a coil arranged in the housing, a valve portion formed at a front end, and a rear end integrally fixed to the movable iron core. In a fuel injection valve having a needle valve and a valve seat body having a valve seat that is continuous with a valve hole in which the valve portion of the needle valve is seated, a first through hole 1A is bored in the inside along the axial direction. A fixed iron core 1 made of a tubular magnetic material, a non-magnetic tubular body 2 made of a tubular non-magnetic material in which a second through hole 2A is bored along the axial direction, and a bore provided in the axial direction. A sleeve assembly A is formed by mechanically and airtightly joining a yoke 3 made of a magnetic material having a tubular shape, in which a valve seat housing hole 3C is opened toward the end from the formed third through hole 3A, on the same axis. And coil 6 around the outer circumference of sleeve assembly A. A coil bobbin 4 made of a synthetic resin material is integrally molded, and one end is magnetically coupled to the yoke 3 and the other end is magnetically coupled to the outer periphery of the sleeve assembly A including the coil. A fuel injection valve in which a housing 7 is arranged. 2. The fixed iron core 1, the non-magnetic tube body 2, and the yoke 3 forming the sleeve assembly are joined together in a state in which their positions are regulated in the inner and outer peripheral side directions. Fuel injection valve. 3. The housing has a bottom portion 7A at one end thereof.
And the other end is opened at the open end 7B to have a bottomed cup shape, and the bottom 7A is integrally formed with the fixed core insertion hole 7C inserted into the outer periphery of the fixed core 1 and the coil bobbin 4. The terminal support portion insertion hole 7D into which the terminal support portion 4D can be inserted is formed, and a locking step portion 7E that can be locked to the collar portion 3D of the yoke 3 is provided in the vicinity of the opening end portion 7B. The fuel injection valve according to Item 1.