DE2146663A1 - Fuel injectors with electromagnetic control - Google Patents

Description

DK. ERICH NEW BUILDING _{8 MUNICH}

PATKXTANWAT ^ T *? 1 Λ R R R *} PHONE «mi« 224337 r. 202501

S MUNICH 20 - POST BOX 31 t IHOOOO TELEGBAMMADIIEBSE!

ZWKIBKÜCKBNSTBASSB 10 ^

(NKBEN I) XX DKUTSCHIIi PAT B W TA Κ T)

U / G-2692

17th September 1971

Description.

to the patent application

SOCIETE DES PROCEDES MODERNES D'INJECTION SOPROMI 133 Avenue du Marechal Foch, 78 Les Mureaux / France

concerning

Fuel injectors with electromagnetic control

The invention relates to improvements in electromagnetically controllable injection nozzles which are equipped with injection elements for internal combustion engines .

It is known to carry out the injection with the aid of electromagnetically controllable injection nozzles, which are located close to the inlet connection, specifically upstream of these, in order to carry out an indirect injection. If the injection nozzles are located directly on the cylinder head of the engine, direct injection can be carried out. Each electromagnetically controllable injection nozzle determines the dosage of the fuel

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material for each cylinder in accordance with a recorded, electrical control signal, the duration of which a per se known electronic device is determined as a puncture of the running conditions of the engine. As a result, the injection nozzles have to operate at a considerable speed. For example, is the injection duration between 0.2 to 1.5 ms for diesel engines and 0.8 to 4 ms for internal combustion engines to inject fuel quantities of 7 mm to 40 mnr.

W Although ee does not present any particular difficulties,

to generate an electrical signal for control, according to the requirements of the motor, it is very difficult to to obtain a corresponding injection quantity, which is identical for a signal of the same duration at each injection element is. The manufacturing tolerances in the dimensions of the injection elements are transferred into changes in the movement of the Needle for the injector, in changes in the channel cross-sections for the fuel as well as in changes

fc in the magnetic properties of the controller. Consequently Each injection nozzle must be set on a calibration device and, with the help of suitable means, on one if possible the same characteristic can be brought, with the required accuracy in the range of 1 #.

Electromagnetic injectors of the type known and used in the art commonly operate

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with a point or with a needle, which is opposite an opening is effective to determine the amount of fuel. The needle is one with the movable armature Electromagnet connected. The movable anchor, which is designed in the form of a laminated anchor body, is opposite the fixed anchor. The lifting movements of the needle are in the range of 0.1 mm and will formed by the difference between the start and end gap. The opposing faces the fixed armature and the movable armature as well as the elements of the injector in which it is attached are straightened before they are assembled. The width of the start and end gap becomes determined in the injection elements by means of two intermediate layers or washers, which between the lower and the upper elements and are inserted between the fixed and movable anchor bodies.

The amount of fuel injected also depends on the speed of response, which is given at a given electromagnetic force depends on the support cross-section of the needle and on the force of the return spring, since the electromagnet at the opening has to overcome the force created by the pressure of the fuel on the needle tip and which is exerted by the force of the return spring. Because the power of the electromagnet from the distance depends on the start and end gap, it is obvious

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voices.

that any change in this area will affect the properties of injectors of this type in a corresponding manner changes.

It should also be noted that the base between the fixed and movable anchor bodies represents an end stop, which is why the rapid rise and fall movements of the injection needle cause an impact bring about. As a result, the amount of liquid injected is not linear with time, but is subject to the peculiarity "that vibrations or wave movements with a rapid increase, with a relative maximum and with a relative minimum arise. This curve shape is due to the impact movements the needle at its stops. The usable part is only after the minimum of the curve, which can be essentially linear got to. There is therefore a threshold above which it is not possible to use the known injection nozzles injected quantity to be loaded with sufficient accuracy

In injection nozzles of the known type there is also a certain delay in closing, which on the adhesive connection of the movable anchor to the pad located at the end of the web and to the adhesive connection this is due to the fixed anchor. the

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Liquid is completely removed with this arrangement the space between the various mentioned elements pressed out when the movable armature the Has reached the end of its upward movement. This delay is variable and depends on the individual components, on the condition of the washer or base, on its wear and tear, on the response or excitation time of the injector, etc. Changes follow from this the amount injected in each case.

However, the most significant disadvantage with injectors of the described form is therein to see that the stop or at the end of the path. Washer cannot withstand repeated knocks can and is destroyed very quickly. This of course disables the injector. Also can the initial gap of known type injectors change greatly when the injector is clamped to the engine or attached. The reason is that this clamping is very difficult to do with precision can be.

Based on this, the object of the present invention is to avoid the disadvantages of known injection nozzles and fuel injectors with electro-magnetic control, in particular for fuel engines

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to create, with an anchor stationary in an upper Component of the fuel injector is attached and the fuel inlet and electrical terminals of the Winding of the electromagnet used for control are connected to the upper component, with a movable one Armature in the form of a movable plate made of laminated, ferromagnetic material, which is in a lower Component of the injection nozzle, arranged opposite the stationary armature and connected to the needle of the injection ^ organes is connected, the opposing surfaces of the fixed and the movable armature as well as the components of the injector in which they are attached, prior to assembly of a surface straightening are subjected, while the initial and the final gap between the opposing surfaces through a base between the lower component and the upper component of the injection nozzle is determined.

The injection nozzle of the type described above is characterized according to the invention in that the opposing surfaces of the fixed armature and the movable armature are spaced apart at the end of the upward movement of the movable armature by a pressurized layer of the fuel, the fuel acts as a hydraulic stop that the fuel is supplied via a central channel in the fixed armature and only to the

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Side edges of the bev / egbarton anchor escapes to the opening of the injection nozzle to get, and that the hydraulic stop thereby the width of the Endspeltes and the upward movement of the needle on the difference in the opening of the start and end gap limited.

The structure and characteristics of the injector according to of the invention are characterized in that:

the fixed anchor is formed by ferromagnetic lamellae, which consist of a package of three legs, wherein the ends of the legs are opposite the movable armature, that the middle leg of the winding is surrounded that a lateral groove is provided on both sides of the fixed armature and recesses connect between the three legs in the form of a rectangle that the area of this rectangle with respect to those The movable armature is designed to balance the hydraulic and magnetic forces taking into account the force of a return spring for to set the movable armature, and that an auxiliary groove in the middle leg, the middle channel and the recesses between the three legs connects to the distribution of the fuel in the recesses and in the grooves to facilitate;

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that the "movable armature with a hollow, cylindrical and in the lower component a displaceable needle is connected so that the needle runs in a conical end, which cooperates with a corresponding conical seat of the lower component that a return spring is provided inside the needle and on the one hand on the needle and on the other hand on the lower component with the help of a Cuerstiftes and an abutment piece in the needle, the transverse pin having a longitudinal bore the needle penetrates>

that the fixed anchor made of ferromagnetic lamellae is formed in the form of a package of three legs, the ends of the legs being the movable armature opposite that the middle leg is surrounded by the winding, that the one middle recess having, movable armature has an area which with respect to the total areas of the opposing Areas of the movable and the fixed armature is designed to balance the hydraulic and magnetic forces in consideration of the force of a return spring for the movable armature to manufacture ^

that the fixed anchor is attached by gluing in the upper component, that the upper component from the lower Component through a washer that defines the initial gap

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disc and by a tubular strut made of non-magnetic material is separated that the two components held together by a tubular housing are, with the edges of the housing bent in the direction of the upper component and the lower component are to prevent excessive compression of the washer and the stiffener, and that the lower element is used to attach the injection nozzle; and

that the stationary anchor is arranged displaceably in the upper component, that the stationary anchor from the lower Component by means of a washer defining the width of the initial gap and by means of a tubular one Stiffening made of non-magnetic material is separated, with the contact between the fixed armature, the Washer, the stiffener and the lower component

is ensured by a spring, which is located between the fixed anchor and the base of the upper element is that the tight connection between the lower component and the upper component is formed by a nut is, which is supported on a shoulder of the lower component and on a threaded part of the upper component is screwed, where e the end of the upper component rests on the other surface of the shoulder, and that the The injection nozzle is fastened with the aid of the upper component and the nut with the aid of a clamp .

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The invention is explained on the basis of the attached exemplary embodiments with reference to the drawings.

Pig. 1 of the drawings is a sectional view of an injection nozzle according to a first embodiment of the invention;

Pig. 2 is a sectional view taken from line II-II in FIG Pig. 1;

Pig. Fig. 3 is a sectional view taken from line 1II-III in Pig »2; and

Pig, Fig. 4 is a sectional view of an injection nozzle according to a second embodiment of the invention.

The injection nozzle shown in FIGS. 1, 2 and 3 of the drawings is essentially formed by an upper element 2 and a lower element 6. This w or two elements, components are held together by a housing. 1 The edges of the housing are bent over and bear against the upper and lower surfaces of the upper element 2 and the lower element 6. The connection 2a for fuel is provided on the upper element 2 of the injection nozzle. Within the connection there is a centrally running line 2b, which

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opens into a ^ through hole 2c. This cross hole connects the line 2b with a central hole 3a in the stationary Armature 3 of the magnetic control circuit. In the upper element 2 there are also electrical terminals 13 Using a rubber seal 14 attached. The seal has a lump 14a, which through the clamps 13 is pressed outwards and compressed. A complete seal is thereby brought about by means of bracing on the upper element 2. The fixed one Anchor is formed by a block of a magnetic material laid in a lamellar shape and has both outer legs 3c and 3f as well as a middle leg 3d. A winding 4 surrounds the center leg 3d. The totality is attached in the upper element 2 by means of gluing, all voids being filled by a suitable resin 18 are. Recesses 20 are provided between the legs 3c, 3d and 3f below the winding 4 and are connected to one another by means of cast-in grooves and by means of a countersunk groove 3b. It thereby becomes the connection the central bore 3a with the created in this way Cavities or depressions guaranteed. A rectangle is obtained, which by the grooves 19 and is formed by the recesses 20. This rectangle is in its dimensions according to the fuel pressure calculated. The lower element 6 receives the movable armature 7, which is made through the armature body 7a laminated magnetic material and through the needle 7b

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is formed. The needle serves as a result of its cylindrical Arrangement for guiding the movable armature and controls the injections with the help of its conical end 7g. The end 7g works with a corresponding, conical seat 6g in the lower element 6 together. A "stiffener 5 made of tirinagnetic material is pulled up on the lower element 6 and is supported on a shoulder 6f. Die.Nadel 7b has a central bore 7d, in which a return spring 16 and a stop guide for the spring are located. ) The stop guide is through a shaft 8 and through a spherical head 8a is formed. The head 8a for its part rests on a transversely extending pin 15 which penetrates the needle 7b through the transverse bore 7c. The return spring 16 rests on the head 8a and on the shoulder 7f of the needle 7b. The lower end of the shaft 8 is guided in the bore 7e. the The lamellae of the anchor body 7a are glued and also with the aid of a transversely extending pin 17 attached to the movable armature. The fuel becomes the seat via the bore 6a and the annular chamber 6b the needle 7b out. The atomization of the fuel takes place via the opening 6c, which is made in one piece through the with the needle 7b existing tip 7h is reduced to an annular surface. With the help of the thread 6e, the injection nozzle attached to the engine. For this purpose, a pin wrench is used, which is inserted into the opening 6d

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is introduced. The opposing surfaces of the anchor 3 fixed in the upper element 2 and the Anchor body 7a, which is arranged in the lower element 2, when the stiffener is in its position before the final assembly of a straightening or grinding subjected, so that the existing at the beginning Gap determined during honing with the aid of a washer 10 between the upper element and the stiffener 5 ". sealing gaskets 9 are in the corresponding Grooves and inserted on the housing 1 and, as already mentioned, are enclosed. The clamping or enclosing is done with a certain amount of care to prevent the upper element, the lower Element and especially the washer 10 and the stiffener 5 are too tightly pressed together. A pressure on the latter two elements would remove the originally existing gap and thus the upward movement of the needle the injector considerably. In other words, such a change in the size of the original Gap cannot be accepted as it cannot determine the performance of the injection nozzle would affect. For this reason, the injector is screwed to the engine by placing the key on the bottom Element 6 is applied.

It should be pointed out that the vertical position in the straightening of the surfaces mentioned is not a considerable one

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It plays a role because the parallel relationship of the two surfaces through the base or the washer 10 is determined. In addition, the movable armature 7 is prevented from rotating by the pin 15. As these different Elements are no longer dismantled after their alignment, there is no mistake as to the position of the movable armature 7 with respect to the lower element 6 and the stiffener 5 concerns. When assembling, it is only necessary to ensure that the movable armature ^ with the anchor body 7a exactly with respect to the fixed

Anchor 3 is introduced. The laminated elements must aligned parallel to each other, with a tolerance of 3 to 5 degrees is possible.

As a result of the assembly described above, the pressurized fuel fills all of the channels 2b, 2c, 3a, 6a and 6b as well as the recesses 20 and the grooves 19 and 3b.

w When winding 4 picks up an electrical signal,

then the movable armature 7 is pulled toward the fixed armature 3; those located between the opposite ones Liquid located on surfaces of the fixed armature 3 and the movable armature 7 is expelled. With a certain remaining gap, the magnetic forces and the force of the return spring 16 as well as the Pressure of the liquid on the movable armature 7 in the same

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weight. The movable armature 7 holds under 'a certain Distance to the fixed anchor 3 · This distance represents the Kestspalt and depends on the one through the Grooves 19 »3b and formed by the recesses 20 Area and the pressure of the fuel. For the order of magnitude, it should be stated that the through the washer 10 formed, original gap can have a value of 0.1 mm, while the remaining gap has a width of 0.02 mm. The upward movement of the needle is therefore 0.08 mm. During the upward movement of the movable Armature 7, there is a certain damping in the course of the movement by adding the fuel between the surfaces of the lamellae 7a and the fixed anchor 3> since the fuel is only on the edges or sides of the movable armature 7 can escape. The movable armature 7 stops at the end of its path and is under pressure through the Blocked fuel located, which is introduced via the bore 3a. There is no contact between the fixed armature 3 and the movable armature 7 So there is no mechanical wear, since there is no contact or no contact between the aforementioned Components can arise. The wear of the conical head 7g at its conical seat 6g is extreme low, as these components are made of a very hard material and have large dimensions. It follows that the amount of fuel at the beginning of the opening increases very sharply and finally the linear part of the curve

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for the amount of fuel reached. As already mentioned, the amount of fuel no longer runs over a first maximum, a relative minimum and finally m * ¥ over a linear part, as was previously the case with known injection nozzles you can even use this part of the curve for the injections. Since the space between the opposing surfaces of the fixed armature 3 and the movable armature 7 is filled with liquid under pressure, the injection nozzle closes immediately and without interruptions after the current in the winding 4 is interrupted. The liquid can in fact fill up this space without difficulty, since the movable armature 7 moves away from the fixed armature 3. With the aid of the arrangement according to the invention, a so-called hydraulic stop is obtained, which at the same time has a simple damping effect. This effect is only available during opening and not at the moment of closing. The response time of the injector is also improved; the amount of fuel is reproducible even in the non-linear part of the curve. Furthermore, there is no mechanical wear and tear on the parts because they do not touch. Finally, the uncontrollable changes in the initial gap during assembly are practically excluded due to the special assembly by means of precise flanging or edging.

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In Pig. 4 of the drawings shows an injection nozzle which is particularly suitable for diesel engines. This injection nozzle is provided in the same way with an upper element 2 'in which the fixed armature 3 is located. In the present case, however, the fixed or stationary armature 3 is surrounded by a jacket 18 'made of cast resin and is provided in the upper element 2 ^{1 so} that it can be moved. Applied against the stiffener by means of a spring 26, an annular seal 27 surrounds the fixed anchor in order to prevent the fuel from escaping on the outer area of the fixed anchor. The fuel can therefore only flow through the central bores 3a. The winding 4 is fastened to the fixed armature 3 in the same way by means of adhesive bonding, while all cavities are filled with resin 18 ¹ . The upper element 2 'rests against a shoulder 6 * f of the lower element 6' and is tightened against this shoulder by means of a nut 21 so that the shoulder 6 'is between the contact surface of the nut and the cylindrical extension 2'b of the lower Element 2 ^{1 is} clamped. The movable armature 7 'has an armature body 7'a and a needle which is equipped with a cylindrical guide 7'b. An extension 7'e of the needle rests on a conical, sealing seat 7'g and is equipped with a tip 7'h. The return spring 16 is fastened in the middle channel 7'd of the needle and is located on the one hand on the contact surface 7'f in the interior of the needle and on the other hand on a port set 8 ^!

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supports. The port set 8 ′ can be displaced in the bore of the needle and is supported on the adjusting screw 23 by means of a shaft 22. With the aid of the adjusting screw 23, the preload of the return spring 16 can be precisely adjusted. The set screw 23 is self-locking, since a pin 23a made of nylon penetrates or cuts the thread. The set screw is sealed with the aid of a cover screw 24 and a seal 25. The fuel arrives at connection 2 ^! a, ^ the hole 3'a in the fixed anchor, the hole 6'a in the

lower element 6 ¹ , the annular space 6'b and the annular space 6'h in the opening 6'c of the injection nozzle. The conical end 7'g of the needle interacts with a corresponding, conical seat 6'g on the lower element 6 '.

As in the case of the exemplary embodiment explained above, the armature body in the form of laminated, magnetic material 7'a is fastened to the movable armature 7 ¹ by means of adhesive. The fastening is supported by I.U. pins 17. The reinforcement 5 is clamped in the inner element 6, while the washer 10 is located between the reinforcement 5 and the fixed armature 3 and defines the initial gap of the magnetic circuit In order to achieve a uniform distribution of the fuel on the armature body, a groove 7 ^f k is milled in. Assuming that the injection pressures are considerably higher when a diesel engine is used

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as in the case of engines with controllable spark ignition, then it is not necessary to use a comparably large area on which the full pressure of the fuel is exercises.

The fixed armature 3 has neither a recess nor a groove, while the movable armature only is provided with a central channel 7'd as well as with a smaller groove 7'k a size of 2 mm. The groove 7'k exceeds the diameter of the bore or of the channel 7'd only very slightly. The washer 10, which determines the original gap is in the case of an injector for a diesel engine 0.15 mm thick. The one caused by the pressure of the liquid and the balance of the magnetic forces and the residual gap formed by the forces of the return spring is much more important than in the exemplary embodiment explained above, because there is a much higher amount of fuel. As a result, the gap has a width or an opening of 0.04 mm.

It should be noted that the injection nozzle according to FIG. 4 of the drawings on the cylinder head of the diesel engine is attached. In doing so, the contact surface 21a of the nut is placed against a corresponding surface of the cylinder head at. One uses a clamp or a collar ring, which is attached to the upper surface 2'c of the element 2 ' starts.

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The forces used when fastening or bracing the injection nozzle in the cylinder head are considerable, since the combustion pressures in the diesel engine are very high; Due to the special construction of the injection nozzle according to the invention, however, no influence of these forces on the position or position of the gap can be determined in its start and end position. The forces are transmitted through the cylindrical extension 2'b of the upper element 2 ¹ to the element 6 ^l f of the lower element and from there directly to the contact surface of the nut. Neither the fixed anchor 3> the washer 10, nor the reinforcement 5 or the lower element 6 'are exposed to this fastening or tensioning force. So no deformation is to be expected; no compaction of the reinforcement 5 and the washer 10 can be observed in such a way that uncontrollable changes in the start or end gap occur in the course of the fastening. The injection nozzle works precisely and repeatably and cannot be influenced by external influences during assembly or use. The setting or calibration of the injection nozzles, if this is necessary, can be limited to minimal corrections of the properties or characteristics. This is done either by individually changing each control signal for the associated injection nozzle or by changing the preload of the return spring 7 with the aid of the adjusting screw 23.

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sad

All information and characteristics contained in the documents, in particular the spatial design of the Subject of the application, are claimed as essential to the invention, insofar as they are compared to the state of the art are new.

Expectations

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Claims (6)

2H6663 Expectations Fuel injection nozzle with electromagnetic control, in particular for fuel engines, whereby an anchor stationary in an upper component of the fuel injector is attached and the fuel inlet and the electrical terminals of the winding of the for Control serving electromagnets are connected to the upper component, with a movable armature in the form fc a movable plate made of laminated, ferromagnetic material, 'which in a lower component of the Injection nozzle, arranged opposite the fixed armature and connected to the needle of the injection element is, the opposing surfaces of the fixed and the movable armature as well as the Components of the injection nozzle in which they are attached are subjected to surface straightening prior to assembly, while the start and end gap between the opposing surfaces by a pad between the lower component and the upper component of the injection nozzle is determined, characterized in that, that the opposing surfaces of the fixed armature (3) and the movable armature (7) at the end of the upward movement of the movable armature through a pressurized layer of fuel in the Are kept spaced apart, with the fuel - 23 209820/0543 acts as a hydraulic stop that the fuel is supplied via a cement channel (3a) in the stationary anchor is and escapes only at the side edges of the movable armature to get to the opening (6c) of the injection nozzle, and that the hydraulic stop thereby determines the width of the end gap and the upward movement of the needle on the difference in the opening of the The start and end gap are limited. 2. Fuel injection nozzle according to claim 1, characterized in that the fixed armature (3) is formed by ferromagnetic lamellae, which consist of a package of three legs (3c, 3d, 3f), wherein the ends of the legs are opposite the movable armature, that the middle leg (3d) from the winding (4) is surrounded that a lateral groove (19) on both Sides of the fixed anchor (3) is provided and recesses (20) between the three legs in the form connect a rectangle that the area of this rectangle is designed with respect to that of the movable armature (7) is to take into account the balance between the hydraulic and magnetic forces Force of a return spring (16) for the movable armature (7) to set, and that an auxiliary groove (3b) in the middle leg (3d) the middle channel (3a) and the recesses (20) connects between the three legs in order to distribute the fuel in the recesses and in the grooves to facilitate. 209820/0543 - 24 - 3. Fuel injection nozzle according to claim 2, characterized in that the movable armature (7) is connected to a hollow, cylindrical needle (7b) displaceable in the lower component (6), that the needle runs in a conical end (7g), which with a corresponding conical seat (6g) of the lower Component (6) cooperates that a return spring (16) is provided in the interior of the needle (7b) and on the one hand on the needle and on the other hand on the lower component with the help of a cross pin (15) and a contact ™ piece (8) in the needle, the cross pin a longitudinal bore (7c) penetrates the needle. 4. Injection nozzle according to claim 1, characterized in that the fixed armature (3) is formed from ferromagnetic lamellae in the form of a package of three legs (3c, 3d, 3f), the ends of the legs facing ^{the movable armature (7 1)} that the middle leg (3d) is surrounded by the winding (4), that the movable armature (7 ') having a central recess (7'd) has a surface which, with respect to the total surfaces of the opposing surfaces of the Ewegbaren and the stationary armature is designed to produce the equilibrium between the hydraulic and magnetic forces, taking into account the force of a return spring (16) for the movable armature (7 ¹ ). 209820/0543 - ² ^ - 2H6663 5. Injection nozzle according to claim 3, characterized in that the fixed armature (3) by means of Bonding in the upper component (2) is attached, that the upper component from the lower component (6) through an initial gap fixing washer (10) and separated by a tubular strut (5) made of non-magnetic material is that the two components are held together by a tubular housing (1), the edges (1a) of the housing are bent in the direction of the upper component and the lower component in order to be too tightly compressed the washer (10) and the stiffener (5) to prevent and that the lower element (6) is used to fasten the injection nozzle to prevent any occurring when the nozzle is clamped To prevent tension on the injector. 6. Fuel injection nozzle according to claim 4, characterized in that the stationary armature (3) is arranged displaceably in the upper component (2 '), that the stationary armature from the lower component (6') by means of a washer (10) which defines the width of the initial gap and is separated by means of a tubular stiffener (5) made of non-magnetic material, the contact between the stationary anchor (3)> the washer (10), the stiffener (5) and the lower component (6 ¹ ) by a spring (26) is guaranteed, which is located between (June fixed anchor and the base of the upper element (2 ¹ ) that the tight connection between 209820/0543 -26- - ze - 2UB663 dun lower component and the upper component is formed by a nut (2λ ), which is supported on a shoulder (6T) of the lower component (6 ¹ ) and is screwed onto a threaded part (Z * b) of the upper component, the end of the upper component rests on the other surface of the shoulder, and that the injection nozzle is fastened with the aid of the upper component and the nut with the aid of a clamp, without having to accept tensions on the magnetic circuit, on the washer, on the reinforcement and on the lower component . 209820/0543 BAD ORIGIN * ¹