EP2905460A1 - Residual air dividing disc for a magnetic assembly of a solenoid valve and method for producing a residual air dividing disc - Google Patents

Abstract

The invention relates to a residual air gap disk (10; 10a; 10b; 10c) for a magnet assembly (100) of a solenoid valve, in particular in a fuel injector (1), for setting a residual air gap between an end face of a magnetic core (12) and a valve member (16). at least indirectly actuated armature (15; 15a). According to the invention, it is provided that the residual air gap disc (10; 10a; 10b; 10c) is at least substantially rigid and has a base body (21) consisting of a ferromagnetic material and connected to a non-magnetic element (22).

Description

State of the art

The invention relates to a residual air gap disc for a magnet assembly of a solenoid valve according to the preamble of claim 1. Furthermore, the invention relates to a method for producing a residual air gap disc according to the invention.

A residual air gap disk according to the preamble of claim 1 is known from DE 10 2009 003 213 A1 the applicant known. The known residual air gap disc is made in the form of a metal foil made of a ferromagnetic or non-magnetic material and formed in the form of a circular ring. Such a residual air gap disc is used in a magnetic assembly of a solenoid valve to prevent magnetic adhesion of the armature on the front side of the magnetic core when the armature is in the magnetic core facing the end position in which the residual air gap disc forms a mechanical stop. Such an end position is typically taken in an injection valve with a magnet assembly when an at least indirectly actuated by means of the armature injection member for injecting fuel is lifted from a valve seat. Desirable are relatively small axial gaps between the armature and the magnetic core, so that in practice the residual air gap disks, for example, have a thickness of about 0.05 mm. With such a thickness of a residual air gap disk, a high flexibility of the residual air gap disk inevitably results, which complicates the handling in that a mounting of the residual air gap disk on the magnet armature or on the magnet core is relatively complex and expensive. In addition, even the installation of such thin residual air gap discs is relatively difficult due to the high elasticity and requires special tools. Furthermore, it is particularly known in such residual air gap disks, which consist of a ferromagnetic material, to provide either the magnet armature or the magnetic core on the side facing the residual air gap disk with a non-magnetic coating in order to avoid the above-mentioned adhesion of the components. However, such a coating, in particular in the region of an end face of the magnetic core or of the magnet armature, is likewise relatively complicated and cost-intensive.

From the DE 10 2009 001 706 A1 as well as the DE 10 2008 001 891 the Applicant are known further, generic residual air gap discs, which in particular have relatively large recesses or incisions, which further complicates their production and handling.

Disclosure of the invention

Based on the illustrated prior art, the invention has the object, a residual air gap disc for a magnet assembly of a solenoid valve according to the preamble of claim 1 such that a comparison with the prior art simplified handling with relatively simple and cost manufacturability of the residual air gap disc is made possible.

This object is achieved in a residual air gap disc with the features of claim 1, characterized in that the residual air gap disc is at least substantially rigid and consists of a consisting of ferromagnetic material body, which is connected to a non-magnetic element. In other words, this means that instead of a according to the prior art from a thin residual air gap to achieve the smallest possible residual air gap, the residual air gap disc according to the invention has a significantly greater thickness to allow the desired rigidity of the residual air gap disc. In order to be able to set the smallest possible residual air gap despite the relatively large thickness of the residual air gap disc, the residual air gap disk next to the non-magnetic element, instead of a In addition, consisting of a non-magnetic material, foil-like residual air gap disc, in addition, consisting of a ferromagnetic material base member which serves to allow the required stiffness of the residual air gap disc. "Substantially rigid" is understood according to the invention to mean that the residual air gap disk has such a rigidity that it can be elastically deformed either only with relatively great force and is otherwise plastically deformable.

Such a design of a residual air gap disc according to the invention makes it possible on the one hand, due to the great rigidity or thickness of the residual air gap disc, to incorporate these into the manufacturing process of the magnet assembly in a particularly simple manner and, in particular, to enable relatively simple handling. Furthermore, the high rigidity furthermore achieves the advantage that, for example, a frictional connection between the residual air gap disk and a magnetic armature or a magnetic core can be produced particularly easily.

Advantageous developments of the residual air gap disc according to the invention for a magnet assembly of a solenoid valve are listed in the subclaims.

In a preferred embodiment of the residual air gap disk, it is provided that the non-magnetic element plating is formed. The advantage of plating is in particular that a relatively simple adjustment of the thickness of the non-magnetic element is made possible, and that a connection between the base body and the non-magnetic element is made possible in an economically advantageous manner without additional connecting means.

Geometrically preferred dimensions of the residual air gap disk provide that the thickness of the main body between 0.15 mm and 1.75 mm is the thickness of the non-magnetic element between 5 μm and 75 μm. Such a dimensioning of the base body and the non-magnetic element allows for a formation of the required stiffness of the residual air gap disc and beyond the desired thin or small residual air gap between the magnetic core and the armature.

It is important that the residual air gap disc within the magnet assembly occupies a defined position that does not change during operation. Due to the high rigidity of the residual air gap disc, a large variety of possible connection techniques with the armature or the magnetic core is made possible. Thus, it is conceivable in a first embodiment that the residual air gap disc is adapted to be connected to the magnetic core by a non-positive and / or positive connection. Alternatively, however, it is also possible that the residual air gap disc is designed to be connected to the magnetic core by a non-positive and / or positive connection.

Another influencing of functional properties of the magnet assembly is when the residual air gap disk has an uneven surface shape on the side facing the magnet core or the magnet armature. Such an uneven surface shape can be used, for example, for damping the movement of the magnet armature and can be particularly easily achieved, for example, by an embossing process of the residual air gap disk.

In a further design refinement of the residual air gap disk, it is provided that the latter has an at least substantially concentric section extending concentrically with respect to a longitudinal axis of the residual air gap disk and two portions extending at least substantially parallel to one another with respect to the longitudinal axis. As a result, it is possible, in particular, to be able to attach the residual air gap disk to the magnet armature or the magnet core at the second radial portion which is axially spaced relative to the first radial portion.

Another preferred embodiment of the residual air gap disc provides that it has at least one recess or a slot. The attachment of slots or the like makes it possible in particular to carry out a forming process during the production of the residual air gap disc in a particularly secure and simple manner.

In order to influence the functional properties of the residual air gap disc such that it acts in the manner of an eddy current brake, it is provided in a development of the proposal made last, that the residual air gap disc is ring-shaped or sleeve-shaped and has a slot arranged in the radial direction, over the entire Width of the residual air gap disc extends, so that at one point a continuous radial slot is generated.

The invention also includes a method for producing a residual air gap disk according to the invention. In this case, it is provided according to the invention that a non-magnetic, likewise endless band-shaped element is applied by plating on an endless belt consisting of ferromagnetic material, and then the residual air gap disk is produced by punching out the raw strip formed by the two bands. Such a method according to the invention enables a particularly simple and cost-effective production of residual air gap disks according to the invention.

In a development of the method according to the invention, provision may be made for the residual air gap disk to be deformed at least in regions after or during the punching out of the residual air gap disk. Such deformation serves, as stated above, in particular for forming an uneven surface shape of the residual air gap disk for influencing functional properties of the magnet assembly.

Finally, the invention also includes a magnet assembly of a solenoid valve, in particular in a fuel injector, with a residual air gap disk according to the invention.

Fig. 1

einen Ausschnitt aus einem Kraftstoffinjektor im Bereich einer Magnetbaugruppe unter Verwendung einer erfindungsgemäßen Restluftspaltscheibe in einem Längsschnitt,

Fig. 2

ein Detail der Fig. 1 in vergrößerter Darstellung, ebenfalls im Längsschnitt,

Fig. 3

eine Darstellung einer an einem Magnetanker befestigten Restluftspaltscheibe im Längsschnitt,

Fig. 4

eine Draufsicht auf eine Restluftspaltscheibe und

Fig. 5

eine vereinfachte perspektivische Darstellung einer Einrichtung zum Verbinden eines Grundelements der Restluftspaltscheibe mit einem nichtmagnetischen Element,

Fig. 6

einen Teillängsschnitt im Bereich einer gegenüber Fig. 1 modifizierten Magnetbaugruppe,

Fig. 7

eine perspektivische, geschnittene Ansicht auf die Restluftspaltscheibe, wie sie bei der Magnetbaugruppe gemäß Fig. 6 verwendet wird,

Fig. 8 bis Fig. 10

jeweils in perspektivischer Ansicht Darstellung bzw. einer Seitenansicht einzelne Fertigungsschritte zum Herstellen einer mit Schlitzen versehenen Restluftspaltscheibe und

Fig. 11

eine Draufsicht auf die Restluftspaltscheibe, wie sie gemäß der Fig. 7 bis 10 hergestellt wurde.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. This shows in:

Fig. 1

a section of a fuel injector in the region of a magnet assembly using a residual air gap disc according to the invention in a longitudinal section,

Fig. 2

a detail of Fig. 1 in an enlarged view, also in longitudinal section,

Fig. 3

a representation of a fixed to a magnet armature residual air gap disk in longitudinal section,

Fig. 4

a plan view of a residual air gap disc and

Fig. 5

a simplified perspective view of a device for connecting a basic element of the residual air gap disc with a non-magnetic element,

Fig. 6

a partial longitudinal section in the area opposite Fig. 1 modified magnet assembly,

Fig. 7

a perspective, sectional view of the residual air gap disc, as in the magnetic assembly according to Fig. 6 is used,

Fig. 8 to Fig. 10

each in a perspective view representation or a side view of individual manufacturing steps for producing a slotted residual air gap disc and

Fig. 11

a plan view of the residual air gap disk, as shown in the Fig. 7 to 10 was produced.

The same elements or elements with the same function are provided in the figures with the same reference numerals.

In the Fig. 1 a solenoid assembly 100 of a solenoid valve is shown, which is part of a fuel injector 1 for injecting fuel into the Combustion chamber of an internal combustion engine, in particular in the combustion chamber of a self-igniting internal combustion engine. The magnet assembly 100 is arranged within a housing 11, in particular the injector housing, and comprises at least one magnetic core 12 in the form of a disc in the exemplary embodiment, in which a magnetic coil 13 is inserted in an annular circumferential depression. The magnetic core 12 and the magnetic coil 13 cooperate with a likewise substantially disk-shaped magnet armature 15, which merges on the side facing away from the magnetic core 12 in a pin-shaped portion 16, the valve member is in the form of a nozzle needle or at least indirectly with a valve member ( Nozzle needle) is operatively connected to release the nozzle needle for releasing not shown injection openings in the housing 11 and to close.

The magnetic core 12 has a centrally disposed through hole 17 which is penetrated by a compression spring 18, one end abuts the end face of the armature 15 and this pushes away in the direction of the magnetic core 12 to the (not shown) injection openings through the valve member close. When the magnet coil 13 is energized, the armature 15 is pulled against the spring force of the compression spring 18 in the direction of the magnet core 12. In order to avoid a magnetic adhesion of the armature 15 to the magnetic core 12, in particular in a subsequent, required to close the injection openings return movement of the magnet armature 15 when the solenoid 13 is not energized, between the armature 15 facing the front side of the magnetic core 12 and the armature 15 is a residual air gap disc according to the invention 10 arranged.

The substantially ring-shaped or disc-shaped residual air gap disc 10, as in particular with reference to the Fig. 2 It can be seen from a consisting of ferromagnetic material body 21 and connected to the main body 21, consisting of non-magnetic material element 22. Preferably, the element 22 is disposed on the magnet armature 15 facing side. The main body 21, which has, for example, a thickness between 0.15 mm and 1.75 mm, consists for example of sheet metal or steel and ensures the inventively desired stiffness of the residual air gap disk 10. In contrast, the non-magnetic element 22, formed in the form of a plating 23 and connected to the main body 21, for the magnetic separation between the armature 15 and the magnetic core 12. The non-magnetic element 22 is made of a stainless steel material or the like. and has a thickness between 5μm and 75μm.

In addition, based on the presentation of the Fig. 4 can be seen, the residual air gap disc 10, for example, arranged on a pitch circle diameter, small recesses 24 or a slot 25, a plurality of thin slits o.ä. exhibit.

In the in the Fig. 1 and 2 illustrated embodiment of the residual air gap disc 10, this is firmly connected to the magnetic core 12. In the illustrated embodiment, the residual air gap disc 10 for this purpose by way of example, and not limiting, extending in the longitudinal direction, radially encircling edge 26 which engages in a formed on the magnetic core 12, also radially circumferential recess 27 in the form of a groove, for example, caused by a crimping tool or similar

In addition, it is mentioned that instead of a (completely) radially encircling edge 26, it may also be provided that the edge 26 is merely in the form of webs or the like. is formed, wherein the webs are preferably arranged at equal angular intervals to each other. Furthermore, the attachment of the residual air gap disk 10 can additionally or alternatively take place on the inner circumference of the magnetic core 12.

The connection between the residual air gap disk 10 and the magnetic core 12 is thus designed as a non-positive and / or positive connection.

In the Fig. 3 a residual air gap disk 10a is shown, in which the residual air gap disk 10a is connected to the magnet armature 15a. The connection between the residual air gap disk 10a and the magnet armature 15a takes place analogously to the connection between the residual air gap disk 10 and the magnetic core 12 in the case of Fig. 2 by a radially encircling edge 28 of the residual air gap disc 10a, which projects in regions radially inwardly into a recess 29 of the magnet armature 15a. Also in the in the Fig. 3 illustrated embodiment thus takes place a positive and / or positive connection between the residual air gap disc 10a and the armature 15a. In the residual air gap disk 10a, the element 22 is arranged on the side facing away from the magnet armature 15a.

In the Fig. 5 is a part of a manufacturing device 50 for producing inventive residual air gap disks 10, 10a shown. In particular, the production device 50 comprises two mutually parallel and cooperating press rolls 51, 52. The two press rolls 51, 52 are overlapping, stored in the form of endless belts 53, 54 sections of the main body 21 and the non-magnetic element 22, wherein by a corresponding formed arrangement of the two press rolls 51, 52 with a small gap between the two press rolls 51, 52, the non-magnetic element 22 is rolled onto the ferromagnetic body 21, this process is called plating. In this case, an intimate connection of the material of the main body 21 with the material of the non-magnetic element 22 takes place. After passing through the two press rolls 51, 52, the residual air gap disks 10, 10a are punched out of the (one-piece) raw strip 55 by a stamping process. In addition, provision may be made for the residual air gap disks 10, 10a, either already during the stamping process or by a downstream tool, to be provided with an uneven surface in order to influence the functional properties of the magnet assembly 10, for example damping properties.

From the 6 and 7 a modified residual air gap disc 10b can be seen, the two, arranged approximately parallel to each other, extending in the radial direction sections 31, 32, and one, the two sections 31, 32 interconnecting, concentric with a longitudinal axis 33 of the residual air gap disc 10b arranged section 34 , While, a larger radial extent having portion 31 is disposed on the magnetic core 12 on the front side facing the armature 15, not shown, the portion 32 is crimped against a trained in the magnetic core 12 contact shoulder 35 to the residual air gap disc 10b both in axial, and in radial direction to be attached to the magnetic core 12.

In the 8 to 11 the preparation of a relation to the residual air gap disc 10b again modified residual air gap disc 10c is shown, which differs from the residual air gap disc 10b, that at the two sections 31, 32 a plurality, preferably approximately equal angular intervals to each other arranged, extending in the radial direction slots 36, 37 formed are. It is also essential that the residual air gap disc 10c is not closed in the circumferential direction, but has a likewise extending in the radial direction slot 38 which extends over the entire width b of the annular or sleeve-shaped residual air gap discs 10c.

Based on Fig. 8 It can be seen that in a first manufacturing step in the raw strip 55a, the slots 36 and 37 are punched out. Furthermore, a defined portion of the length I is punched or cut from the raw strip 55a, which serves to form a residual air gap disc 10c. In the Fig. 9 it can be seen that the sections 31 and 32 and 34 are subsequently formed by a rolling process, ie the corresponding section of the raw strip 55a is formed without cutting. Last will be according to the Fig. 10 the portion of the Rohbands 55a passed over a plurality of rollers 39, such that from the rectilinear portion of the Rohbands 55a this as shown in the Fig. 11 is provided with a radius r, which corresponds to the distance between the longitudinal axis 33 and the portion 34. After insertion into the magnetic core 12, the section 32 can be folded against the contact shoulder 35.

The residual air gap disc 10, 10a, 10b, 10c described so far as well as the described method for producing the residual air gap disk 10, 10a can be modified or modified in many different ways without deviating from the idea of the invention. In particular, the residual air gap disks 10, 10a can also be provided with corresponding (continuous) slots 38, so that they act in the manner of an eddy current brake. Also, the residual air gap discs 10b, 10c with embossments or the like. be provided for surface modification to reduce the tendency to adhere to the mating element cooperating with the residual air gap disc 10b, 10c.

Claims (12)

Residual air gap disc (10; 10a; 10b; 10c) for a magnet assembly (100) of a solenoid valve, in particular in a fuel injector (1), for adjusting a residual air gap between an end face of a magnetic core (12) and an armature actuating a valve member (16) at least indirectly (15; 15a),
characterized,
that the residual air gap disc (10; 10a; 10b; 10c) is at least substantially rigid design and made of a ferromagnetic material body (21), which is connected to a non-magnetic member (22). Residual air gap disc according to claim 1,
characterized,
in that the non-magnetic element (22) is plating (23). Residual air gap disc according to claim 1 or 2,
characterized,
in that the thickness of the main body (21) is 0.15 mm to 1.75 mm and the thickness of the non-magnetic element (22) is 5 μm to 75 μm. Residual air gap disc according to one of claims 1 to 3,
characterized,
that the residual air gap disc (10; 10b; 10c) is adapted to be connected to the magnetic core (12) connected by a non-positive and / or positive connection. Residual air gap disc according to one of claims 1 to 3,
characterized,
in that the residual air gap disk (10a) is designed to be connected to the magentanker (15a) by a non-positive and / or positive connection. Residual air gap disc according to one of claims 1 to 5,
characterized,
that the residual air gap disc (10; 10a; 10b; 10c) on the magnetic core (12) or the armature (15; 15a) side facing an uneven surface shape. Residual air gap disc according to one of claims 1 to 6,
characterized,
in that the residual air gap disc (10b, 10c) has at least one section (34) extending at least substantially concentrically with a longitudinal axis (33) and two sections (31, 32) which extend radially relative to the longitudinal axis (33). Residual air gap disc according to one of claims 1 to 7,
characterized,
that the residual air gap disc (10; 10a; 10b, 10c) has at least one recess or slot (36 to 38). Residual air gap disc according to claim 8,
characterized,
that the residual air gap disc (10c) annular or formed sleeve-shaped and has a radially extending slot (38), the continuous slot (38) is formed and separates the residual air gap disc (10c) in the circumferential direction. Method for producing a residual air gap disk according to one of claims 1 to 9,
characterized,
in that a non-magnetic element (22) which is likewise endless (54) is formed by plating on a base body (21) made of ferromagnetic material and designed as an endless belt (53), and in that subsequently the residual air gap disk (10; 10a) by punching out of the two bands (53, 54) existing Rohband (55; 55a) is generated. Method according to claim 10,
characterized,
that after or during punching the residual air gap disk (10; 10a; 10b; 10c) is deformed at least in certain areas. Magnetic assembly (100) of a solenoid valve, in particular in a fuel injector (1), having a residual air gap disc (10; 10a; 10b; 10c) according to one of claims 1 to 9.

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