JPH09189279A - Fuel injection valve for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a fuel injection valve for an internal combustion engine at a low cost by forming an adjustment constituent member which can be accessed (approached) from the outside with extremely ease in its structure. SOLUTION: In a fuel injection valve for an internal combustion engine in which the pre-load of a valve spring 12 is changed by an adjustor 20 arranged between the end of the valve spring 12 on a side opposite to a valve member and the stationary supporting surface 26 of a casing, an adjusting member is composed as a sleeve 21 inserted to the inside of the receiving opening 22 of the casing 6, a guide 23 is projected from an end surface 28 faced to the inside of the casing 6 of the sleeve 21, and a spacer member which can be replaced is arranged in the guide 23. One end of the spacer member projected from the guide 23 in the axial direction where a valve member 2 is extended is brought in contact with the supporting surface 16 of the casing 6, and the other end thereof is brought in contact with a thrust member 14.

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, including a valve member which is axially slidable in a valve casing, and a valve spring which loads the valve member in a closing direction. A preload of the valve spring being variable by means of an adjusting device arranged between the end of the valve spring facing away from the valve member and the stationary supporting surface of the casing. The adjusting device comprises an adjusting member transversely to the valve axis and insertable externally into the casing, the adjusting member comprising a stationary supporting surface of the casing and a valve of the valve spring. Thrust member that abuts the end opposite to the member
(Druckstueck), and the preload (or preload) of the valve spring is defined by the dimension of the adjusting member in the axial direction of the valve member.

[0002]

2. Description of the Prior Art In a fuel injection valve for internal combustion engines of this type, which is known from DE-A-2554987, a piston-like valve element is guided axially in a valve body. There is. The valve member is fastened to the holder via an intermediate disc and together with the holder forms a valve casing. The valve member has a valve sealing surface at its combustion chamber end, at which the valve member cooperates with an inwardly projecting valve seat provided on the valve body. Downstream of this valve seat, on the downstream side, an injection opening opens into the combustion chamber of the internal combustion engine to which fuel is to be supplied. The valve member is loaded in the closing direction by a valve spring at the end opposite to the valve seat, the valve spring acting on the valve member via a spring seat, which abuts against the valve seat. Let
The valve spring, which is arranged in a spring chamber in the valve casing, is supported on the other hand by means of a thrust member on a stationary bearing surface of the casing, in which case the thrust member and the casing are adjusted in order to adjust the preload of the valve spring. An adjusting device is provided between it and the fixed support surface, which adjusting device is accessible externally in a favorable manner. In the known injection valve, this adjusting device is designed as a wedge-shaped slider, which is arranged between the thrust member and the supporting surface via a lateral notch which extends transversely to the valve member axis. The position of the thrust member can be adjusted through the depth of penetration of the slider. Another solution for the adjustment described in the above-mentioned known specification is to insert a support pin radially between the thrust member and the support surface, on the outer peripheral surface of which the flat pin of non-uniform size. The axial position of the thrust member and thus the pre-loading force of the valve spring by rotating the support pin. In this known solution,
It has the drawback that it requires a relatively expensive adjusting structure and that the thrust member is not centered with sufficient accuracy.

[0003]

The object of the present invention is therefore to eliminate the disadvantages of the known devices described above.

[0004]

According to the invention, which has solved this problem, the adjusting member is constructed as a sleeve which is inserted into a receiving opening in the casing and is directed towards the inside of the casing. And a replaceable spacer member disposed within the guide portion, wherein the spacer member has one end protruding from the guide portion in an axial direction in which the valve member extends, It is in contact with the support surface and the other end is in contact with the thrust member.

[0005]

The fuel injection valve for an internal combustion engine according to the invention having the features of claim 1 has a structurally very simple construction of the adjusting structure which is accessible from the outside. However, this has the advantage that it can be manufactured at low cost. According to the invention, the adjusting member is expediently designed as a sleeve,
A guide portion is arranged on an end surface of the sleeve that projects into the casing, and a replaceable spacer member is inserted in the guide portion, and the spacer member directly contacts the thrust member and the casing supporting surface. ing. In this case, the adjustment of the opening pressure directly based on the preload force of the valve spring is possible in a simple manner by replacing the spacer member, and the spring force can be adjusted by the axial dimension of this spacer member. ing. At the same time, in order to ensure that the thrust member for guiding the valve spring is centered, a molded portion is provided on the end of the thrust member opposite to the spring and on the casing supporting surface. The spacer member is adapted to be engaged with these molded parts. In the adjusted spring preload, the spring force is such that the central position of the spacer member does not change. When the spacer member is removed or replaced, a sleeve can be used to radially untighten it against the spring force and remove it.
For this purpose, the sleeve is provided with an annular take-out groove. According to a particularly advantageous design, the spacer element is designed as a sphere. The sphere is easy to manufacture,
It is easy to integrate based on position independence. By using the sleeve of the adjusting device at the same time as a connection for the leak-out conduit, an additional connection sleeve can be dispensed with in an advantageous manner. In this case, due to the different connectability of the sleeve,
The position of the leak oil connection can be changed. In this case, the shape of the fuel connection, which is locked or clipped in the radial direction, is particularly advantageous. Because with such a shape,
This is because the fuel connection can be installed and removed very easily. In this case, such an advantageous fuel connection can be used not only for the fuel injection valve, but also for the fuel injection pump or another fuel conduit connection. In this case, instead of using a ball, another locking member or a lockable spring tongue may be used. Another advantage is obtained by directly contacting the end surface of the sleeve of the injection device with the outer peripheral surface of the thrust member. In this case, the two contact surfaces are provided with complementary moldings, preferably grinding parts on the longitudinal axis extending in the axial direction of the valve member, which provides anti-rotation of the thrust member and thus wear reduction. can get.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, advantageous embodiments of the present invention will be described with reference to illustrated examples.

1 to 3 show different views of an embodiment of a fuel injection valve according to the invention for an internal combustion engine.
This fuel injection valve has a valve body 1 in which a piston-shaped valve member 2 is axially slidably guided. In this case, the valve body 1 is retained by the nozzle nut 3 and by interposing the intermediate disc 4 in the axial direction, whereby
It is tightened against the holding body 5 to form a valve casing 6. The valve member 2 has at its end on the combustion chamber side a conical valve sealing surface 7 by means of which the valve member 2 is mounted on the valve seat body 1 in a known manner. It cooperates with a valve seat 8 which projects in a flange-like manner towards one side. An injection opening 9 is provided downstream of the valve seat 8 on the downstream side, and the injection opening 9 projects into the combustion chamber of the internal combustion engine to be supplied.

The valve member 9 is loaded at its end opposite to the valve seat 8 in the closing direction by a valve spring 12 via a spring bearing 10. A valve spring 12 that presses the valve member 2 against the valve seat 8 and abuts it is arranged in a spring chamber 13 in the valve casing 6 and is supported on the side opposite to the valve member by a cylindrical thrust member 14. The thrust member 14 is
The valve spring 12 is guided via the central pin 15.

The thrust member 14 itself is indirectly supported by a bearing surface 16 of the casing 6 which axially limits the spring chamber 13, which bearing surface 16 forms a stationary abutment surface. In order to adjust the preloading force of the valve spring 12 on which the opening pressure of the injection valve is directly dependent, an adjusting device 2 is additionally provided between the thrust member 14 and the casing support surface 16.
0 is provided. The adjusting device 20 shown in plan view in FIG. 3 has a sleeve 21. The sleeve 21 has a receiving opening 22 which is arranged in the casing 6 transversely to the axis of the valve member and which is inserted from the outside. At the end face 28 that projects into the casing 6, the sleeve 21 has a guide portion 23 formed in the shape of a ring or tongue that projects in the axial direction.
A spacer member is guided in a circular notch inside the three. This guide member is configured as a ball 24 in the illustrated embodiment. The sphere 24 projects from the guide portion 23 in the axial direction of the valve member 2, the first upper end of the sphere 24 is in contact with the support surface 16 of the casing 6 and the second lower side of the sphere. Of the thrust member 14 is in contact with the end surface 26 of the thrust member 14 opposite to the valve member. A recess 27 is provided in the bearing surface 16 and in the thrust member 14 for securely holding the sleeve 21 in the receiving opening 22, which is preferably configured as a lateral hole, and for centering the thrust member 14.
Is provided in the upper end surface 26 of the valve, the center of the recess 27 is located in the valve member axis, and the ball 24 is engaged in the recess 27 by the preload force of the valve spring 12. Stop and hold here.

In this case, the receiving opening 22 is the sleeve 21.
The end surface 28 of the thrust member 14 is located below the guide portion 23.
It intersects with the spring chamber 13 in such a manner as to come into contact with the outer peripheral surface of the. In this case, the contact surfaces of the thrust member 14 and the end surface 28 that contact each other are formed by complementary molding portions,
It advantageously has a grinding surface oriented in the longitudinal direction of the valve member axis, which ensures that rotation of the thrust member 14 is avoided. In order to seal the spring chamber 13 against the outside, a sealing ring 30 is also clamped between the sleeve 21 and the wall of the receiving opening 22. The seal ring 30 is guided in a groove formed on the outer peripheral surface of the sleeve 21 in a known manner. In order to extract the leaked fuel (leakage oil) from the spring chamber 13, the sleeve 21 has two hose connecting pipe pieces 32 on its outer end surface,
The hose connecting pipe pieces 32 are connected to leak-leading hoses (not shown), and these hose connecting pipe pieces 32 are connected to the spring chamber 13 via the axial holes 33 provided in the sleeve 21. It is connected. Alternatively, the connection for the leak conduit may be configured as a threaded sleeve with a central thread in the sleeve 21. An annular groove 34 is further formed in the part of the sleeve 21 projecting from the casing 6 for engaging the removal tool.

In order to adjust the opening pressure in the fuel injection pump according to the invention, that is to say to adjust the preload force of the valve spring 12, the sleeve 21 acts against the spring force of the valve spring 12 via a take-off tool. A sphere 24, which is taken out of the casing 6 radially with respect to the valve member axis and thereby adjusts the spacing between the support surface 16 and the thrust member 14, is replaced by another sphere having a different diameter. In this case, the inner diameter of the guide portion 23 is designed according to the maximum possible sphere diameter.

Alternatively, it is also possible to permanently (for example integrally) provide a spacer member on the guide part. In this case, different guide parts with different spacer members must be provided.

Finally, the sleeve 2 with the new ball 24
1 is inserted in the receiving opening 22, in which case the ball locks in the recess 27, thereby fixing the position of the sleeve 21. Through the diameter of the ball 24, which can be easily exchanged, the preloading force of the valve spring 12 and thus the opening pressure of the injection valve can be externally adjusted in a simple manner.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing a part of FIG. 1 showing a position of a cross section different from that of FIG.

FIG. 3 is a sectional view of the adjusting device for adjusting the preload of the valve spring shown in FIG.

[Explanation of symbols]

1 valve body, 2 valve member, 3 nozzle nut, 4
Intermediate disc, 5 holding body, 6 valve body, 7 valve sealing surface, 8 valve seat, 9 injection opening, 10 spring bearing,
12 valve springs, 13 spring chambers, 14 thrust members, 15 central pin, 16 casing support surface,
20 adjusting device, 21 sleeve, 22 receiving opening, 23 guide portion, 24 ball, 26 end face,
27 recesses, 28 end faces, 30 seal rings,
32 hose connecting piece, 33 axial hole, 34 annular groove

Claims (11)

[Claims] 1. A fuel injection valve for an internal combustion engine, comprising:
It has a valve member (2) which is axially slidable in a valve casing (6) and a valve spring (12) which loads the valve member (2) in the closing direction. ) Has a preload at the end of the valve spring (12) opposite the valve member,
It is adapted to be changed by means of an adjusting device (20) arranged between the stationary supporting surface (16) of the casing, which adjusting device (20) is transverse to the valve axis,
It has an adjusting member which can be inserted into the casing (6) from the outside, which adjusting member is opposite the stationary support surface (16) of the casing (6) and the valve spring (12) from the valve member. It is tightened between a thrust member (14) which abuts on the side end, and the preload of the valve spring (12) is defined by the dimension of the adjusting member in the axial direction of the valve member. Of the type, the adjusting member is configured as a sleeve (21) inserted into a receiving opening (22) of the casing (6), the end surface (28) of the sleeve (21) facing inward of the casing. ), A replaceable spacer member is arranged in the guide portion (23), the spacer member being arranged in the axial direction of the valve member (2) and extending in the axial direction. ) Sticking out from One end is
Fuel injection valve for an internal combustion engine, characterized in that it is in contact with the support surface (16) of the casing (6) and the other end is in contact with the thrust member (14). 2. A support surface (16) for the casing (6),
A recess (27) is provided on the end surface (26) of the thrust member (14) opposite to the valve spring (12), and the contour of the spacer member is locked in the recess (27). The fuel injection valve according to claim 1, wherein 3. The fuel injection according to claim 2, wherein the spacer member is constructed as a sphere (24), which sphere (24) is arranged in a ring-shaped guide part (23). valve. 4. A receiving opening (22) in the sleeve (21) extending transversely to the axis of the valve member (2) opens into a spring chamber (13) for receiving a valve spring (12). Is
The fuel injection valve according to claim 1. 5. Casing (6) of the fuel injection valve, preferably
A fuel conduit connection for insertion therein having a sleeve (21) insertable in a receiving opening (22), the sleeve (21) having at least one connection for a fuel conduit. In particular, in the type in which a leak-out conduit is provided, the sleeve (21) has at its end on the casing side a molding member (24) projecting in the axial direction, which molding member (2)
4) is characterized in that the sleeve (21) is adapted to cooperate with a spring-tensioning member under preload so as to be releasably locked after insertion in the receiving opening (22), Fuel conduit connection. 6. The connection for the leak-out conduit of the sleeve (21) is connected to the spring chamber (13) of the fuel injection valve via a leak hole (33) provided in the sleeve (21). The fuel conduit connection of claim 5, wherein: 7. The fuel conduit connection according to claim 5, wherein the connection for the leak-out conduit is in the form of a hose connection piece (32). 8. The connection for the leak-out conduit is designed as a threaded sleeve, which preferably has a central thread in the sleeve (21). The fuel conduit connection of claim 5, wherein: 9. A sealing member, preferably a sealing ring (30), between the sleeve (21) and the wall of the receiving opening (22).
The fuel injection valve according to claim 1, wherein the fuel injection valve is tightened. 10. The end face (28) of the sleeve (21) projecting into the casing (6) has a thrust member (1).
4) is in contact with the outer peripheral surface, and the contact surfaces of the end surface (28) and the thrust member (14) that come into contact with each other are provided with notches that complement each other, and these notches serve as thrust members ( 2. The fuel injection valve according to claim 1, wherein the thrust member (14) is prevented from rotating when the sleeve (21) abuts against the sleeve 14). 11. An annular groove (34) is provided in the part of the sleeve (21) projecting from the receiving opening (22) into which the removal tool is engaged. The fuel injection valve according to claim 1.