JP2002371939A - Magnet valve for controlling injection nozzle of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the assembly of a magnet valve for controlling the injection valve of an internal combustion engine comprising an armature having an electromagnet 29, an armature plate 28, and an armature pin 27 slidably supported in a slide guide member 34, a control valve member 25, and a shoulder part 33 formed in an armature pin and in which the shoulder part limits the opening stroke of the armature pin when the magnet valve is opened by the contact of the slide guide member on a stopper surface 37 and the armature plate is pivoted on the armature pin slidably in the closing direction of the control valve member under the action an inertial mass. SOLUTION: The shoulder part formed on the armature pin is supported on the stopper surface 37 of the slide guide member through the intermediate member 50 of an integrated structure or a multiple-structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a magnet valve of the type defined in the preamble of claim 1 for controlling an injection valve of an internal combustion engine.

[0002]

2. Description of the Related Art A magnet valve known, for example, from DE-A-197 08 104 A1 is used for controlling the fuel pressure in the control pressure chamber of an injection valve, for example an injector of a common-rail injector. The movement of the valve plunger is controlled by the fuel pressure in the control pressure chamber to open or close the injection opening of the injection valve. The known magnet valve comprises an electromagnet, a movable armature located within a casing part, and
A control valve member movable together with the armature and loaded in a closing direction by a closing spring, the control valve member cooperating with a valve seat of the magnet valve to allow fuel to flow out of the control pressure chamber; Control.

A disadvantage of the magnet valve in which the armature plate and the armature pin are integrally formed is a so-called armature bounce. When the electromagnet is shut off, the armature and the control valve member together with the armature are accelerated by the closing spring toward the valve seat to close the fuel outlet passage from the control pressure chamber. The impact of the control valve member on the valve seat causes undesired bouncing and / or vibration of the control valve member on the valve seat, which impairs the control of the injection process. Thus, in a magnet valve known from DE-A-197 08 104 A1, the armature is formed in a two-part structure consisting of an armature pin and an armature plate slidably mounted on said armature pin. As a result, the armature plate continues to move against the clamping force of the return spring in the event of a collision between the control valve member and the valve seat. Thereafter, the return spring returns the armature plate again to the starting position adjacent to the armature pin stop.

Although the two-part construction of the armature effectively dampens the inertial mass and thus reduces the kinetic energy of the armature hitting the valve seat, which causes the armature to bounce, the armature plate remains in place of the magnet valve. Violently vibrates (post-vibration) on the armature pin after closing of the armature. Since control of the magnet valve produces a defined injection quantity only when the armature plate does not vibrate, means for reducing the vibration of the armature plate are required. This is particularly necessary, for example, to reduce the time interval between the pilot injection and the main injection. For this purpose, the technique described in DE-A-197 08 104 A1 provides an over-travel stop in the form of an over-travel adjustment plate or an inertial travel travel distance adjustment plate mounted on a sliding guide. In addition, the overstroke adjusting stopper limits the stroke length in which the armature plate can be moved along the armature pin. An over-stroke adjusting plate is immovably (stationarily) arranged in the casing of the magnet valve between the armature plate and the sliding guide member for guiding the armature pin. Upon approach of the armature plate to the overstroke adjustment plate, a hydraulic damping chamber is created between the opposed flat surfaces of the armature plate and the overstroke adjustment plate. Fuel in the damping chamber creates a force opposite to the movement of the armature plate. Thereby, the vibration (post-vibration) of the armature plate is strongly attenuated.

In the known magnet valve, the necessary over-travel of the armature plate must be adjusted when the magnet valve is assembled in the casing of the magnet valve, in which case the control valve member and the valve seat are connected. The distance (stroke) by which the armature plate can be moved (moved) against the force of the return spring after contact is adjusted by the thickness of the over-stroke adjusting plate. Disadvantages of this magnet valve are that the incorporation of the over-stroke adjusting plate below the return spring of the armature plate is complicated and time-consuming. In order to incorporate the overstroke adjusting plate below the return spring of the armature plate, a complicated keyhole-shaped notch is required in the overstroke adjusting plate. In addition, since the overstroke adjustment plate also affects the spacing between the pole face of the electromagnet and the armature plate, changing the thickness of the overstroke adjustment plate impairs the residual air gap, which makes assembly difficult. .

[0006]

A magnet valve according to the invention having the features of claim 1 eliminates the disadvantages of the prior art and allows a very simple assembly of the armature plate. Advantageously, the armature is pre-assembled outside the assembly line of the injection valve with the armature plate, the armature pin, the return spring and the intermediate member, and the required travel distance of the armature plate on the armature pin Alternatively, the overstroke distance is adjusted outside the casing of the injection valve by selection of the thickness of the intermediate member. With the knowledge of the axial dimensions of the armature plate, the slide guide member and the armature pin, the correct thickness for the intermediate member is determined. The armature unit (construction group) assembled and completed in advance is assembled in the casing of the magnet valve in the following process. During this installation, the maximum opening stroke of the armature pin is adjusted by means of an adjusting plate arranged between the sliding guide and the inner shoulder of the magnet valve housing.

[0007] Advantageous refinements and embodiments of the invention are possible by means of the dependent claims. It is particularly advantageous if the intermediate element is formed as a sickle plate, which is inserted laterally into the armature pin.

[0008] Advantageously, a retaining sleeve or a retaining sleeve which is fitted over the sliding guide member prevents the sickle plate from coming off (sliding down) from the armature pin. A securing sleeve or a retaining sleeve is preferably mounted or connected to the slide guide via a locking element.

[0009]

FIG. 1 shows the upper part of a fuel injector of the prior art, which is suitable for use in a fuel injector with a fuel accumulator, and An accumulator is continuously supplied with high pressure fuel by a high pressure feed pump. The illustrated fuel injection valve has a valve casing 4, which has a vertical hole (a hole extending in the axial direction), and a valve plunger 6 in the vertical hole.
With the valve plunger at one end,
Acts on a valve needle arranged in the nozzle body, not shown. A valve needle is arranged in the pressure chamber, and the pressure chamber is supplied with high-pressure fuel through a pressure hole. During the opening stroke movement of the valve plunger 6, the valve needle is lifted by the high fuel pressure in the pressure chamber, which always acts on the pressure shoulder of the valve needle. As a result, fuel is injected into the combustion chamber of the internal combustion engine through the injection opening connected to the pressure chamber. By the downward movement of the valve plunger 6, the valve needle is pressed against the valve seat of the fuel injection valve in the closing direction and the injection process is terminated.

The valve plunger 6 is guided into the cylinder bore at the end opposite to the valve needle, the cylinder bore is formed in the valve member 12 and the valve member is inserted into the valve casing 4. ing. End face 13 of valve plunger 6
Closes the control pressure chamber 14 in the cylinder bore, and the control pressure chamber is connected via an inflow passage to a high-pressure fuel connection (not shown). The inflow passage has a substantially three-part structure. A hole extending radially through the wall of the valve member 12 and forming an inlet throttle 15 on a part of the wall thickness on the inner wall side is always connected to a ring chamber 16 surrounding the outer circumference of the valve member. The ring chamber itself is always connected to the high-pressure fuel connection. The control pressure chamber 14 receives, via an inlet throttle 15, a high fuel pressure acting in the fuel accumulator. A hole is provided coaxially with the valve plunger 6 and extends from the control pressure chamber 14 into the valve member 12, and the hole forms a fuel outflow passage 17.
The fuel outlet passage has an outlet throttle 18 and a pressure relief chamber 19.
The pressure relief chamber is connected to a low fuel pressure connection (not shown), and the low fuel pressure connection is connected to the fuel return passage of the fuel injection valve. The outlet of the fuel outflow passage 17 from the valve member 12 is provided in the region of a portion 21 which is conically recessed at the end located outside the valve member 12. The valve member 12 is firmly fastened to the valve housing 4 with a screw member 23 at the flange section 22.

A valve seat 24 is formed in the conical portion (recessed portion) 21, and the valve seat cooperates with a control valve member 25 of a magnet valve 30 for controlling the injection valve. The control valve member 25 includes the armature pin 27 and the armature plate 2
The armature is connected to a two-part armature in the form of 8, which cooperates with the electromagnet 29 of the magnet valve 30. The magnet valve 30 further has a housing part 60 for receiving the electromagnet 29, which is firmly connected to the valve housing 4 by means of a screw-in connection 7. In the known magnet valve, the armature plate 28 is supported on the armature pin 27 kinematically movable against the initial load (clamping force) of the return spring 35 under the action of its own inertial mass. In the stationary state, the return spring is pressed against the stop ring 26 fixed to the armature pin. The return spring 35 is supported at the other end by a stroke adjusting plate 70, which is supported by a slide guide member 34, which guides the armature pin 27. The sliding guide member 34 has a flange 32 which, together with a stroke adjusting plate 70 and another adjusting plate 38, tightens the shoulder 42 of the valve housing 4.
And the annular edge 41 of the casing part 60 is tightly fastened. Armature pin 27, armature plate 2
8 and the control valve member 25 connected to the armature pin,
It is always loaded in the closing direction by the closing spring 31 supported by the casing, so that the control valve member 25 is in contact with the valve seat 24 in the normally closed position. Upon excitation of the electromagnet, the armature plate 28 and the armature pin 27 are attracted by the electromagnet, whereby the outflow passage 17 is opened toward the pressure release chamber 19. The armature pin 27 has a ring shoulder 33 at the end opposite to the electromagnet 29;
The ring shoulder comes into contact with the ring-shaped stopper surface 37 of the slide guide member 34 when the electromagnet is excited, and the control valve member 25
To limit the opening process. An adjusting plate 38 arranged between the flange 32 and the clamping shoulder 42 serves for adjusting the opening stroke.

The opening and closing of the fuel injection valve is performed by the magnet valve 30 as described below. As already explained, the armature pin 27 is always loaded in the closing direction by the closing spring 31, so that the control valve member 25 contacts the valve seat 24 in the closed position when the electromagnet is not energized. The control pressure chamber 14 is closed relative to the pressure relief chamber 19, so that the high pressure acting in the fuel accumulator via the inlet passage in the control pressure chamber is formed very rapidly. The pressure in the control pressure chamber 14 causes a closing force on the valve plunger via the end face 13 of the valve plunger 6 and thus on the valve needle, which on the other hand is greater than the force acting in the opening direction. Has become. When the control pressure chamber 14 is opened toward the pressure release chamber 19 by opening the magnet valve, the pressure in the control pressure chamber 14 having a small volume drops significantly rapidly, because the pressure between the control pressure chamber and the high pressure side is reduced. The reason is that there is an inflow restrictor 15 in FIG. As a result, the high pressure of the fuel high pressure acting on the valve needle in the opening direction of the valve needle is exceeded, so that the valve needle is moved upwards, whereby at least one injection opening is opened for injection. On the other hand, when the magnet valve 30 closes the fuel outflow passage 17, the pressure in the control pressure chamber 14 is again formed by the fuel replenished through the inflow restrictor 15, so that the original closing force is generated. Then, the valve needle of the fuel injection valve is closed.

When closing the magnet valve, the closing spring 3
1 attaches the armature pin 27 together with the control valve member 25 to the valve seat 24
Pressing toward The stop of the control valve member and thus the armature pin at the valve seat, i.e. the stopping causes an elastic deformation of the armature pin and the disadvantage of the control valve member based on the fact that the armature pin acts as a power storage device. A significant bounce or vibration occurs, in which case a portion of the energy is transferred back to the control valve member, which bounces from the valve seat 24 with the armature pin. Accordingly, the known magnet valve shown in FIG. 1 uses a two-part armature comprising the armature pin 27 and the armature plate 28 which can be disconnected from the armature pin. This reduces the inertial mass from hitting the valve seat 24, but undesirably vibrates the armature plate 28. For this reason, in the known magnet valve shown in FIG. 1, an over-stroke adjusting plate 70 is provided between the armature plate 28 and the sliding sleeve 34. FIG. 1 shows a state in which the magnet valve is closed by shutting off the electromagnet 29. The over-stroke adjusting plate 70 has a complicated keyhole-shaped opening 71 for the armature pin. Such an opening 71 is necessary so that during assembly the armature plate 28 is moved through the opening 71 with the tubular portion 65 and then the sickle plate 26 is inserted into the armature pin 27. The over-stroke adjusting plate 70 limits the moving distance of the armature plate 28 along the armature pin 27 to a predetermined dimension d.
The vibration movement of the armature plate 28 causes the over-stroke adjusting plate 7
0, and the armature plate 28 is quickly re-engaged again with the stop 2 formed as a sickle plate
It is returned to the starting position adjacent to 6 (the position shown in FIG. 1). The adjusting plate 38, the flange 32 of the slide guide member 34, and the over-stroke adjusting plate 70 are fastened and fixed in the magnet valve casing. The thickness of the over-travel adjustment plate 70 affects the spacing between the armature plate 28 and the electromagnet 29. Therefore, the production of known magnet valves and injection valves equipped with such magnet valves is just expensive,
And it is troublesome.

FIG. 2 shows an embodiment of the magnet valve according to the present invention. The same members are given the same reference numerals. In the magnet valve according to the invention, the maximum opening stroke of the armature pin 27 is adjusted by means of an adjusting plate 38. The annular flange 32 of the slide guide member 34 is
Tightening the annular edge 41 of the casing part 60 and the casing part 4 via the adjusting plate 38 and another adjusting plate 70 a for adjusting the distance between the pole face of the electromagnet 29 and the armature plate 28. It is tightened between the shoulder 42. The adjustment plate 70a is the armature plate 2
It does not adjust the overstroke distance of 8.

To facilitate understanding of the present invention, FIG.
Armature plate 28, armature pin 27, return spring 35,
The armature unit comprising the intermediate member 50 and the slide guide member 34 is shown in an enlarged manner. The assembly of the armature unit may advantageously take place outside the casing of the fuel injector. In FIG. 3, the armature pin 27 is shown in a position corresponding to a state where the armature plate 28 is pulled by the electromagnet 29 and the magnet valve is completely opened, unlike FIG. The armature plate 28 is pressed by a return spring 35 onto a stopper 26 a formed by an annular protrusion of the armature pin 27. The end of the armature pin 27 opposite to the electromagnet has a ring shoulder 3 facing the sliding guide member.
3 with the ring shoulder in contact with an intermediate member 50 which is fitted over the armature pin. Intermediate member 50
Are supported by a ring-shaped stopper surface 37 of the slide guide member 34. When the magnet valve is opened, the intermediate member 50 is opened.
By stopping, ie supporting or receiving, the ring shoulder 33 at the stop surface 37, the maximum opening stroke of the armature pin 27 and the control valve member 25 connected to the armature pin is limited. The intermediate element may be formed in one piece or in a plurality, and in particular in the form of a plate. In the embodiment shown here, the intermediate member
And as shown in FIG. 5, a sickle plate (Sichels
cheibe). A sickle-shaped plate, ie, the distance c between the opposing surfaces 51, 52 of the intermediate member 50,
That is, the over-travel distance d of the armature plate 28 is defined by the thickness c. The inner diameter g of the sickle-shaped plate is configured to be slightly larger than the groove diameter of the ring groove 44 of the armature pin 27, and the sickle-shaped plate is inserted into the ring groove. The width of the ring groove 44 is set to be larger than the thickness c of all the sickle plates used. An axial dimension a of the armature plate, an axial dimension b of the sliding guide member, and an axial dimension (distance or interval) f from the armature pin stopper 26a to the ring shoulder 33 are preset. .

F = a + b + c + d + e (Formula)
In other words, from the relation d + e = fabc, d + e
Is determined depending on the thickness c of the sickle plate (intermediate member). The amount of d + e comprises the sum of the maximum opening stroke e of the armature pin and the maximum overstroke distance d of the armature plate 28 before contacting the stopper surface 36 of the sliding guide member 34. Once the maximum opening stroke e to be adjusted is determined, the maximum overstroke distance d of the armature plate 28 is exactly produced during assembly (pre-assembly) of the armature unit, depending on the thickness c of the sickle plate 50. Can be squeezed. The sickle-shaped plate 50 inserted into the armature pin,
The position in the radial direction is secured by the sleeve 80, that is, it is positioned in the radial direction. The sleeve 80 is shown in FIG.
And in FIG. The inner diameter of the sleeve 80 is larger than the outer diameter h of the sickle plate 50. Sleeve 8
0 has a rib 83 projecting inward at one end. An axially extending notch 82 allows the sleeve 80
Is formed with a locking element 81. Sleeve 80
However, as shown in FIG. 2 and FIG.
4 is inserted into the tubular portion 45 on the side opposite to the stopper surface 36, and the locking element 81 is engaged in the concave portion 46 of the outer peripheral wall of the tubular portion 45. In this case, the sleeve 81 slides along the outer periphery of the sickle plate 50 to house the sickle plate 50 therein, whereby the sickle plate 5
0 secures the radial position.

The pre-assembled armature unit (FIG. 3) is inserted into the valve casing, as shown in FIG. The thickness of the adjustment plate 38 is selected to accurately maintain a predetermined maximum opening stroke e between the control valve member 25 and the valve seat 24. The spacing (j, see FIG. 1) between the armature plate 28 and the electromagnet is defined by the adjustment plate 70a.

As described above, when the magnet valve is closed, the closing spring (armature spring) 31 presses the control valve member 25 into the valve seat 24 via the armature pin 27, and the armature plate 28 is moved. It continues to move along the armature pin 27 against the tightening force of the return spring 35 and comes into contact with the stopper surface 36 of the slide guide member 34. The tubular part 6 of the armature plate 28 protruding toward the sliding guide member
5, the surface 66 facing the stop surface 36 (FIG. 3) cooperates with the stop surface 36 to form a hydraulic damping chamber. Face 6
The fuel in the damping chamber (gap) between 6 and the stopper surface 36 effectively damps the collision or vibration of the armature plate. In the magnet valve according to the invention, the stop surface 36 is preferably flat (ebene Flaech
e) is formed. Compared to a conventional magnet valve (FIG. 1) in which the armature plate is brought closer to the adjustment plate 70 with the opening 71, an improved damping effect is achieved in the magnet valve according to the invention shown in FIG. This is because the damping chamber is formed widely.

As a modification of the illustrated embodiment, the intermediate member (intermediate piece) may be constituted by a plurality of plates or disks. Intermediate members that are not plate-like are also conceivable. If the intermediate member is held on the armature pin in a form-fitting manner, i.e. based on shape constraints, the sleeve for holding the intermediate member in the radial direction may be omitted. The intermediate member is configured to be elastically deformable, and the ring groove 44 of the armature pin is formed.
It may be possible to fit it inside like a clip.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an upper portion of a fuel injection valve provided with a magnet valve according to the related art.

FIG. 2 is a sectional view of an upper portion of an embodiment of the magnet valve according to the present invention.

FIG. 3 is a sectional view of the armature unit of the embodiment of FIG. 2;

FIG. 4 is a sectional view of an embodiment of the intermediate member.

FIG. 5 is a plan view of the intermediate member of FIG. 4;

FIG. 6 is a side view of the sleeve partially broken along the line AA of FIG. 7;

FIG. 7 is a plan view of the sleeve of FIG. 6;

[Explanation of symbols]

Reference Signs List 4 valve casing, 6 valve plunger, 7 coupling member, 12 valve member, 13 end face, 14 control pressure chamber, 15 inflow restrictor, 16 ring chamber, 17 fuel outflow passage, 18 outflow restrictor, 19 pressure relief chamber, 2
1 part, 22 flange section, 23 screw member,
24 valve seat, 25 control valve member, 26 stop ring, 27 armature pin, 28 armature plate,
29 electromagnet, 30 magnet valve, 31 closing spring, 32 flange, 33 ring shoulder, 34 sliding guide member, 35 return spring, 36, 37 stopper surface, 38 adjustment plate, 41 annular edge, 4
2 fastening shoulder, 45 tubular part, 50 intermediate member, 60 casing part, 70 stroke adjustment plate, 65 tubular part, 66 surface, 80 sleeve,
81 locking element, 82 notch, 83 rib

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Tillman Miele, Germany Weiplingen-Maisenweg 6 F-term (reference) 3G066 AA07 AB02 AC09 BA51 BA56 CC05U CC63 CE22 DA10

Claims (11)

[Claims] A magnet valve for controlling an injection valve of an internal combustion engine, comprising an electromagnet (29), an armature plate (2)
8) and a movable armature comprising an armature pin (27) slidably mounted in an opening (40) of a stationary slide guide (34) for opening and closing the fuel passage (17). A control valve member (25) movable with the armature and cooperating with the valve seat (24), and a shoulder formed at the end of the armature pin (27) opposite the electromagnet (29). (33), the shoulder of which opens the armature pin when the magnet valve is opened, and adjusts the opening stroke of the armature pin to the valve seat (2) of the sliding guide member (34).
4), the armature plate (28) moves under the action of the inertial mass in the direction of closing of the control valve member (25). 27), a shoulder (33) formed on the armature pin (27) has a sliding guide member (35) with an intermediate member (50) interposed therebetween. A magnet valve for controlling an injection valve of an internal combustion engine, the magnet valve being supported by a stopper surface (37) of the internal combustion engine. 2. An over-stroke distance (d) of the armature plate (28) during a predetermined maximum opening stroke (e) of the armature pin (27) causes the control valve member (25) and the valve to close when the magnet valve is closed. After contact with the seat (24), the armature plate (28) is slid along the armature pin (27) under the action of the inertial mass of the armature plate to provide a sliding guide member (3).
2. The magnet valve according to claim 1, wherein the valve is adapted to be indirectly or directly supported in 5) by adjusting the selection of the intermediate member. 3. An intermediate member (50) comprising an armature pin (2)
The magnet valve according to claim 1 or 2, wherein the magnet valve is formed as a plate piece that can be inserted into (7). 4. The magnet valve according to claim 3, wherein the intermediate member (50) is formed as a sickle plate. 5. A means (8) for securing the radial position of the sickle plate (50), said means preventing the sickle plate from coming off the armature pin (27). Item 6. The magnet valve according to Item 4. 6. The means (8) for securing the radial position of the sickle plate (50) comprises a sleeve mounted on the sickle plate and fixed to the slide guide (34). Item 6. A magnet valve according to Item 5. 7. A sleeve (80) having a sliding guide member (3).
4), a tubular portion (4) projecting toward the valve seat (24).
7. The magnet valve according to claim 6, wherein the inner diameter of the sleeve is slightly larger than the outer diameter of the sickle plate. 8. A sleeve (80) is provided with a locking means (81), said locking means for fixing the sleeve,
8. The magnet valve according to claim 7, wherein the valve engages in a recess formed in the tubular portion of the slide guide. 9. An armature plate (28) is formed on the armature pin (27) against the clamping force of a return spring (35) supported by a sliding guide member (34). Movably mounted between a first stop (26a) and a second stop, said second stop being another stop of the sliding guide member (34) facing the electromagnet (29). 9. The magnet valve according to claim 1, wherein the valve is formed by a surface. 10. The slide guide member having another stopper surface (3).
6) and the surface (66) of the armature plate (38) facing said another stopper surface, by means of the armature pin (2).
10. A magnet valve according to claim 9, wherein a hydraulic damping chamber is formed for damping the movement of the armature plate (28) along (7). 11. An armature pin (27), an armature plate (28), a sliding guide member (34) and an intermediate member (50).
Consists of the casing part (6) of the magnet valve (30) as a pre-assembled group of components.
11. The method according to claim 1, wherein the insertion is performed within 0).
The magnet valve according to any one of claims 1 to 4.