JPH09170523A - Fuel injection valve for internal combusion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce wearing at a stopper plane in contact with each other by enlarging the stopper plane of valve by the addition of form of the valve in this region larger than an annual plane geometrically produced by the difference of diameters between a valve spindle and a pusher. SOLUTION: By coupling a valve 1 to a valve support 7 with an intermediate disc 3, a valve spring 29 charging the valve 11 toward the valve seat 17 in the closing direction is disposed to the valve support 7. The valve spring 29 is engaged to the pusher 37 through the valve spring shoe 33 to form a stopper plane 39 at the transition of cross section between the pusher 37 and the spindle 21. The stopper plane 39 is enlarged by the addition of form of the valve member 11 in this region larger than the annual plane geometrically produced by the difference of diameters between the valve spindle 21 and the pusher 37. This allows the wearing in the stopper plane 39 in contact with each other to be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for an internal combustion engine, in which a valve body is provided, and a piston-shaped valve member is guided in the valve body so as to be axially movable. , The valve member has a valve sealing surface at the end on the combustion chamber side, and the valve member cooperates with a valve seat provided on the valve main body at the valve sealing surface, A valve holder is provided which is axially connected to the valve body via a disc, and a valve spring is arranged on the valve holder to load the valve member in the closing direction towards the valve seat. The valve spring is engaged with a pressing member of the valve member, which protrudes into the intermediate disc through the spring bearing and has a reduced diameter, and has a shaft with a large diameter of the valve member and a pressing member with a small diameter. A stopper surface is formed at a cross section transition portion between the valve member and the member, and the stopper surface is a valve member. In order to limit the maximum opening stroke,
The present invention relates to a type which cooperates with a position fixing stopper on an intermediate disk.

[0002]

PRIOR ART German Patent Application Publication No. 440
In a fuel injection valve for an internal combustion engine of the above-mentioned type, which is known from U.S. Pat. No. 8,245, a piston-shaped valve member is guided in a valve body so as to be axially slidable. The valve member has a valve sealing surface at one end thereof which cooperates with a valve seat at the end of the valve body which projects into the combustion chamber of the internal combustion engine. In this case, an injection port that opens to the combustion chamber is provided downstream of the valve seat surface.

The valve body is axially clamped to the valve holder at the end opposite to the combustion chamber by means of a tensioning nut. In this case, the end surface of the valve body and the valve holder are fixed. An intermediate disc is clamped in between. A valve spring, which loads the valve member in the closing direction toward the valve seat, is arranged on the valve holder, and the valve spring projects through the spring bearing into the through-opening of the intermediate disc and has a diameter of It engages the depressing member of the reduced valve member. In this case, the annular step at the cross-section transition between the large diameter valve member shaft and the small diameter pressing member forms the stopper surface of the valve member, which limits the maximum opening stroke. In order to do so, it cooperates with a fixed stopper formed by the end faces of the intermediate disc.

However, this known fuel injection valve has the following drawbacks. That is, in a known fuel injection valve,
At the contact surface between the valve member stopper surface and the position-fixed stopper, mechanical and corrosive wear occurs strongly, and such wear impairs the service life of the entire injection valve.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is therefore to improve a fuel injection valve for an internal combustion engine of the type mentioned at the outset to reduce wear on the stopper surfaces which abut one another. Is to provide.

[0006]

In order to solve this problem, in the structure of the present invention, the stopper surface formed in the cross-section transition portion between the shaft of the valve member and the pressing member in the valve member is By giving the shape of the valve member in the range,
It is larger than the annular surface which is geometrically shaped by the pure difference in diameter between the shaft of the valve member and the pressure member.

[0007]

The fuel injection valve according to the present invention having the above-described structure has the following advantages as compared with the known fuel injection valve. That is, in the fuel injection valve according to the present invention, the effective stopper area between the valve member stopper surface and the position-fixed stopper can be increased by giving the valve member an appropriate geometrical shape. If the abutment forces are the same, the pressure load on the stopper surface and thus the resulting wear can be significantly reduced.

In order to increase the valve member stopper surface in this way, according to the first embodiment of the present invention, the portion of which the cross section is enlarged as compared with the shaft of the valve member is the shaft and the pressing member. The region of the valve element which is enlarged in cross section is preferably designed as an annular collar, for example. The lever arm for the abutment force acting on the intermediate disc is in this case displaced radially outwards and thereby becomes smaller, which results in a displacing tilting movement, the so-called “turning over or inverting” of the intermediate disc. (Umstuelpen) "can be reduced, or can be completely avoided if the stopper surface is large enough. And in this way,
It is possible to effectively prevent dent-like wear and corrosion.

It is also possible for the stop surface of the valve member to be made elastic, so that in an advantageous configuration of the invention, a radially projecting ring-shaped integral molding is provided in the transverse direction of the valve member. The end portion of the integrally formed portion on the outer side in the radial direction is provided in the surface transition portion and is integrally formed so as to project in the axial direction with respect to the annular shoulder portion between the valve member shaft and the pressing member. . In this case, the contact force is reduced not only by increasing the contact area but also by elastically deforming the valve member stopper surface.

Another embodiment of the enlarged stopper surface in the valve member is to provide a surface inclined in the direction of travel. For this purpose, in a further advantageous configuration of the invention, the cross-section transition between the valve member shaft and the pressure member is designed conically. The position-locking stop, which co-operates with this tilted stop surface of the valve member, is in this case constructed with a complementary shape to this stop surface. The advantages of such a conical stopper surface are as follows. That is, with this structure, the introduction of the radial force component,
The associated positive crimping of the intermediate disc on the valve body avoids lifting of the intermediate disc from the valve body on the basis of the axial force component and thus a gap between them. In this case, the cone angle of the valve member stopper surface and the cone angle of the position-fixed stopper may have the same magnitude, or may have a small difference (seating angle difference (Sitzwinkeldifferenz)). Good.

In a further advantageous embodiment, a central cylindrical extension which projects into a corresponding corresponding receiving opening of the valve body is provided on the combustion chamber-side end surface of the intermediate disc.
It is possible to avoid relative sliding of the intermediate disc in the valve body in the radial direction.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of a fuel injection valve according to the invention, which is shown in a longitudinal sectional view in FIG. 1 and in a partially enlarged view in FIG. 2, has a valve body 1, The valve body 1 is
A cap nut 5 is used together with the intermediate disk 3 to axially clamp the valve holder 7. A piston-shaped valve member 11 is axially slidably supported in a valve hole 9 of the valve body 1, and the valve member 11 has a valve sealing surface 13 on the end surface on the combustion chamber side. . This valve sealing surface 13 of the valve member 11
Cooperates with the valve seat 17 of the valve body 1, that is, the valve seat 17 formed at the end 15 of the valve hole 9 closed on the combustion chamber side and directed inward, A plurality of injection ports 19 are provided in the. Shaft 21 of valve member 11
The valve hole 9, which serves as a guide hole for, is enlarged at one location to form a pressure chamber 23, in the region of which the valve member 11 has a pressure shoulder 25,
The pressure chamber 23 is connected via a pressure passage 27 to a connecting piece (not shown) in the valve carrier for connecting the injection conduit extending from the injection pump. In this case, the pressure chamber 23 is connected to the valve seat 17 via an annular gap 28 between the valve member 11 and the wall of the valve hole 9.

The valve holder 7 is provided with a spring chamber 31 in the form of a blind hole open towards the intermediate disc 3 for receiving a valve spring 29 which is embodied as a compression coil spring. At the bottom (not shown) of the spring chamber, the valve spring 29 is supported at its one end. Intermediate disk 3
The other end of the valve spring 29, with a defined pre-stress, engages the pressing member 37 of the valve member 11 projecting into the through-opening 35 of the intermediate disc 3 via the spring bearing 33. I am using. In the exemplary embodiment valve element 1 is preferably used
The pressure member 37, which is constructed in one piece with 1, has in this case a reduced diameter with respect to the shaft 21 of the valve member 11,
The cross-sectional transition surface between the shaft 21 and the pressing member 37 then forms a stopper surface 39 on the valve member 11, which stopper surface 39 limits the maximum opening stroke movement of the valve member 11. , Cooperates with the position-fixing stopper 41. The stopper 41 is formed by the lower end surface of the intermediate disc 3 facing the valve body 1.

In this case, in order to obtain the largest possible contact surface between the stopper surfaces 39, 41, the cross section of the valve member 11 is enlarged in the transition range between the shaft 21 and the pressing member 37. This enlargement of the cross section is achieved in the first embodiment shown in FIGS. 1 and 2 by the annular collar 43 on the valve member 11. This ring collar 43
Has an enlarged diameter compared to the axis 21 of the valve member, in which case the valve bore 9 likewise has a cross section for receiving the annular collar 43 in the area adjacent to the intermediate disc 3. It has an enlarged part. The upper annular end face of the annular collar 43 facing the intermediate disc 3 now forms a valve member stop face 39, which is between the shaft 21 of the valve member and the pressing member 37. Greatly expanded compared to the pure diameter difference.

In the second embodiment shown in FIG. 3, the valve member 1
The stopper surface 39 of No. 1 is arranged on the ring-shaped elastic integrally molded portion 45, and the radially outer edge of this integrally molded portion 45 is an annular step portion between the shaft 21 and the pressing member 37. Compared to, it projects in the axial direction. In this case, the upper annular end surface of the integrally molded portion 45 forming the stopper surface 39 is configured as follows. Thus, in this case, this annular end face comes into flat contact with the position-locking stop 41 after the spring-elastic displacement movement when the maximum opening stroke position of the valve member 11 is reached.

In the third embodiment shown in FIG. 4, the valve member shaft 21 and the pressing member 37 forming the valve member stopper surface 39.
The transition surface between and is inclined toward the stroke direction of the valve member 11. The stop surface 39, which is preferably conical, co-operates with a fixed stop surface 41, which in this case is also conical towards the stop surface 39 with a complementary shape on the intermediate disk 3, which serves as a stop. The surface 41 is a concentric cylindrical extension 4 of the intermediate disc 3.
7, it is arranged on the end face facing the valve body 1. In this case, the valve body 1 has a correspondingly shaped receiving opening 49 on the end face facing the intermediate disc 3.
An extension 47 is axially and radially supported in the receiving opening 49.

The fuel injection valve according to the invention operates in a known manner. That is, in this case, the valve member 11 is lifted from the valve seat 17 against the closing force of the valve spring 29 and communicates with the injection port 19 when the fuel under high pressure acting on the pressure shoulder 25 of the valve member 11 is supplied. Open the cross section of the opening. This opening movement is limited by the contact of the stop surface 39 of the valve member 11 with the position-fixed stop 41, in which case the stop surface 39 is enlarged in order to reduce wear.

The injection is terminated by the end of the high pressure supply to the injection valve, which causes the valve spring 29 to push the valve member 11 back into contact with the valve seat 17.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of a fuel injection valve according to the present invention, in which an enlarged stopper surface is formed by an annular collar of a valve member.

FIG. 2 is a vertical cross-sectional view showing an enlarged range of an annular collar shown in FIG.

FIG. 3 is a vertical cross-sectional view showing a second embodiment of the fuel injection valve according to the present invention, in which the enlarged stopper surface is formed by an annular elastic integrally molded portion.

FIG. 4 is a longitudinal sectional view showing a third embodiment of the fuel injection valve according to the present invention, in which the enlarged stopper surface is formed by a transition surface inclined in the stroke direction.

[Explanation of symbols]

1 valve body, 3 intermediate disk, 5 cap nut, 7
Valve retainer, 9 valve hole, 11 valve member, 13 valve sealing surface, 15 end portion, 17 valve seat, 19 injection port,
21 shafts, 23 pressure chambers, 25 pressure shoulders, 2
7 pressure passage, 28 annular gap, 29 valve spring,
33 spring receiver, 35 through opening, 37 pressing member,
39 stopper surface, 41 stopper, 43 annular collar, 45 integral molding part, 47 extension part, 49 receiving opening

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Heinz-Arno Mart Germany Weil der Stadt Brammerberg Strasse 43

Claims (7)

[Claims] 1. A fuel injection valve for an internal combustion engine, comprising a valve body (1) in which a piston-shaped valve member (11) is guided so as to be axially movable. The valve member (11) has a valve sealing surface (13) at the end on the combustion chamber side, and at the valve sealing surface (13) the valve member (11) forms the valve body (1). ) Valve seat (1
7) and a valve retainer (7) axially connected to the valve body (1) via an intermediate disc (3).
And a valve member (1
A valve spring (29) is arranged which loads 1) in the closing direction towards the valve seat (17), said valve spring (29)
Is pressed into the intermediate disc (3) via the spring bearing (33) to reduce the diameter of the valve member (11).
7), engaging a stopper surface at the cross-section transition between the large diameter shaft (21) of the valve member (11) and the small diameter pressing member (37). A valve member (11) of the type in which the stop surface cooperates with a fixed stop (41) on the intermediate disc (3) in order to limit the maximum opening stroke of the valve member (11). The stopper surface (39) formed at the cross-section transition portion between the shaft (21) of the valve member and the pressing member (37) at The shaft (21) and the pressing member (3
7) A fuel injection valve for an internal combustion engine, characterized in that it is larger than the annular surface which is geometrically shaped by the pure difference in diameter between it and. 2. An enlarged stopper surface (39) of the valve member (11) and a pressing member (37) by means of a portion whose cross section is enlarged compared to the shaft (21) of the valve member. The fuel injection valve according to claim 1, which is formed in a range of a transition portion between the fuel injection valve and 3. The enlarged cross-section of the valve member (11) is designed as an annular collar (43).
The fuel injection valve according to claim 2. 4. A portion of the valve member (11) whose cross section is enlarged is formed by a ring-shaped elastic integrally-molded portion (45), which is located outside of the integrally-molded portion (45) in the radial direction. The rim has a shaft (21) of the valve member and a pressing member (3).
7) projecting axially beyond the step formed between it and the integrally formed part (45) under the action of the opening force in the valve member (11) after the maximum opening stroke movement has been carried out. 3. Flat contact with a fixed stopper (41).
A fuel injection valve as described. 5. The stop surface (39) with an enlarged cross section in the valve member (11) is configured as a surface inclined towards the stroke direction of the valve member (11). Fuel injection valve. 6. The stopper (41) for fixing the position of the intermediate disc (3) is constructed by being inclined with a complementary shape with respect to the stopper surface (39) of the valve member (11). Fuel injection valve. 7. The intermediate disc (3) has a central cylindrical extension (47) on its end face facing the valve body (1), the extension (47) comprising: 7. The fuel injection valve according to claim 6, which projects into a corresponding corresponding receiving opening (49) of the valve body (1).