DE202008008650U1 - Magnetic core, magnet assembly and fuel injector solenoid valve - Google Patents

Abstract

Magnet core (12) composed of at least two core elements for a magnet assembly (2) of a fuel injector solenoid valve (1), characterized in that at least one of the core elements is formed as a sintered element.

Description

State of the art

The The invention relates to a magnetic core for a magnet assembly a fuel injector solenoid valve according to the The preamble of claim 1, a magnetic assembly according to claim 15, a fuel injector solenoid valve according to claim 16 and a fuel injector according to claim 17th

From the DE 196 50 856 A1 a solenoid valve for a fuel injector is known. With the aid of the solenoid valve designed as a control valve (servo valve), the fuel pressure in a control chamber of the fuel injector is controlled. By way of the fuel pressure in the control chamber, in turn, a stroke movement of an injection valve element is controlled with which an injection opening of the fuel injector is opened or closed. The solenoid valve comprises an electromagnet, a movable armature and a valve member (control valve member) moved by the solenoid armature and urged in the closing direction by a valve closing spring, which cooperates with a valve seat of the solenoid valve and thus controls the fuel drain from the control chamber. The force is generated via the air gap field of a pot magnet, the magnetic field via an inner pole, a yoke, an outer pole, which together form a magnetic core, via an outer pole-side air gap, a movable armature plate of the armature and a innenpolseitigen air gap to a current-carrying coil (solenoid coil) closes.

It is known to form the magnetic core in several parts of solid material. In addition, one-piece, each formed as a one-piece sintered magnetic cores known. These have the advantage that the occurrence of eddy currents is minimized, resulting in a better switching dynamics. A disadvantage of the known, designed as one-piece sintered elements Magnetic cores, however, is that their geometry is not optimal to the Coil geometry is customizable.

Disclosure of the invention

Technical task

Of the Invention has for its object to propose a magnetic core, on the one hand guarantees reduced eddy currents and on the other hand others with the same external dimensions compared to known magnetic cores the use of larger coils allows.

Further The object is to provide a correspondingly optimized magnet assembly, a correspondingly optimized fuel injector solenoid valve and to propose a suitably optimized fuel injector.

Technical solution

These Task is with respect to the magnetic core with the features of Claim 1, with respect to the magnetic assembly having the features of claim 15, with respect to the fuel injector solenoid valve with the features of claim 16 and with regard to the fuel injector solved with the features of claim 17. advantageous Further developments of the invention are in the subclaims indicated. All fall within the scope of the invention Combinations of at least two of in the description, the claims and / or features disclosed in the figures.

Of the Invention is based on the idea, the magnetic core in several parts form, wherein at least one of the composite to a magnetic core Core elements is designed as a sintered element. Through the training at least one of the core elements as a sintered element can Eddy currents are reduced, resulting in a better one Efficiency one with a trained according to the concept of the invention Magnetic core equipped magnetic assembly leads and others to an improved switching dynamics of a correspondingly designed Solenoid valve. The provision of at least two core elements allows it, the pole faces of the magnetic core independently from the coil geometry to optimize. In particular, you can larger electric solenoids are used, since the coil after integration into a corresponding receiving opening of the magnetic core sections of a pole face forming core element of the magnetic core can be covered. The use of larger electrical coils allows the use of a smaller magnet armature, reducing the dynamics of a appropriately trained solenoid valve is further optimized. It is particularly preferred if electrical with the magnetic core Coils with a comparison to known coils larger wire diameter, be used in particular at the same number of turns, from which a lower electrical resistance results. This in turn decreases the power loss and optimizes the dynamics. About that In addition, lower voltages can operate one with a magnetic core formed according to the concept of the invention Well-tatteten fuel injector solenoid valve can be used.

Of particular advantage is an embodiment in which the core elements, without being glued or soldered together, are arranged adjacent to each other. By a binder-free design of the magnetic core magnetic Flow losses are minimized. If necessary, the core elements can be positively connected to each other, but this is not absolutely necessary, especially when the assembly of the magnetic core in the injector body (housing part) of a fuel injector takes place and the core elements are braced against each other in the housing of the fuel injector.

Especially preferred is an embodiment in which one of the core elements as a pole face having a pole face is formed, the one, in particular groove-shaped receiving opening for an electrical coil (magnetic coil) in sections, closes. The pole surface element is preferably used arranged at a radial distance to a Innenpolfläche Außenpolflächenelement, the receiving opening partially surmounted in the radial direction inwards. (In this case, the pole surface element as the last core element be mounted during assembly of the magnetic core).

in the With regard to the training, in particular as a sintered element trained, Polflächenelementes there are different Options. For example, it is possible form the pole surface element as a flat annular disc. In this case, it may be advantageous for the pole surface element on an adjusting piece formed in particular as a sintered element support, which in turn at one, a yoke section forming body abuts.

at an alternative embodiment, the annular Polflächenelement formed in cross-section L-shaped be, with a leg of the L-shaped cross section in the radial direction over the receiving opening extends for the solenoid. In other words the pole surface element has a cylindrical shape with internal, circumferential interior gradation.

Especially preferred is an embodiment of the magnetic core, in the pole face of the pole face element a radially outer pole surface is that with a radially inner, of the outer pole surface spaced pole face in a common, transverse to Arranged longitudinal axis of the magnetic core extending plane is, wherein axially between the Polflächenelement and the Magnet armature a residual air disc is arranged. Limit it the pole faces prefer a residual air gap between the Magnetic core and the magnetic core relative to the magnetic core adjustable. Alternatively, it is possible the outer and the inner pole surface as being transverse to the longitudinal center axis form extending, parallel shifted plane, so on a residual air disc can be dispensed with. In this case limited the higher pole face the anchor stroke and it will a residual air gap at the other (lower) pole face receive.

As explained, it is possible, the pole surface element form as a sintered element. Next to it is an embodiment feasible, in which the pole surface element made of solid material is trained. Such an embodiment is particular then advantageous if the pole surface element as a stroke stop for the magnet armature serves as solid material usually has a higher strength than sintered sintered material.

In Development of the invention is advantageously provided that a the magnetic core forming core elements as a basic body is formed, which is penetrated by a central channel. Preferably can through the central channel with the fuel injector fully assembled, Feed fuel from the control chamber to the injector return. It is particularly preferred, the main body as a sintered element train.

With Advantage is the base body constructed such that it has a annular, a yoke portion forming base plate portion has, starting from the a central channel limiting Rohhabschnitt projecting in the axial direction.

in the With regard to a tailor-made production of the core elements, it is possible at least one of the core elements, in particular the pole surface element, Grind to size after the sintering process. alternative it is according to a particularly preferred embodiment the invention possible, a sleeve-shaped Provide adjusting piece, which is axially between the base plate portion of the basic body and, in particular, designed as outer pole surface element, Polflächenelement is arranged. Very particularly preferred it is when the pole surface element as a flat annular disc is trained. By holding the adjusting piece in different axial dimensions, it is possible to Pole surface of the Polflächenelementes to position exactly in particular without a final grinding process to have to.

Especially preferred is an embodiment in which the sleeve-shaped Setting piece is designed as a sintered element.

The magnetic core is expediently designed as a pot magnet core and in this case comprises an outer pole section, an inner pole section and a yoke section connecting the outer pole section and the inner pole section in the radial direction, the outer pole section, the yoke section and the inner pole section defining a, in particular annular, slot-shaped receiving opening for a magnet coil this receiving opening be Preferably on the side facing away from the yoke portion side is partially surmounted by a Polflächenelement in the radial direction.

The Invention also leads to a magnet assembly for a fuel injector solenoid valve, comprising one according to the concept formed of the invention, multi-part magnetic core, wherein at least one of the magnetic core forming core elements as a sintered element is trained.

About that In addition, the invention leads to a fuel injector solenoid valve. This is preferably a servo valve (control valve) with which the pressure in one of an injection valve element limited Control chamber is controllable. The fuel injector solenoid valve Characterized by a magnet assembly with a concept of the Invention trained magnetic core.

Farther The invention leads to a fuel injector, in particular a common-rail injector, for injecting fuel into one Combustion chamber of an internal combustion engine. The fuel injector draws characterized by the provision of a fuel injector solenoid valve, whose magnet assembly comprises a multi-part magnetic core, wherein at least one core element of the magnetic core is formed as a sintered element is.

Brief description of the drawings

Further Advantages, features and details of the invention will become apparent the following description of preferred embodiments as well as from the drawings. These show in:

1 in an incomplete illustration, a fuel injector solenoid valve whose magnetic assembly has a two-part magnetic core,

2 an alternative embodiment of a fuel injector solenoid valve with a two-part magnetic core, the Polflächenkernelement is formed as a flat disc and

3 a further alternative embodiment of a fuel injector solenoid valve with a three-piece magnetic core.

embodiments the invention

In The figures are the same components and components with the same Function marked with the same reference numerals.

In 1 is a section of a solenoid valve 1 for controlling the fuel pressure in one of an injection valve element, not shown, in particular frontally limited, also not shown control chamber of a fuel injector shown. The solenoid valve 1 includes a magnetic assembly located at the bottom of the drawing 2 , which is preferably located in an injector head of the fuel injector. The magnet assembly 2 acts axially adjusting on an anchor plate 3 having magnet armature 4 , This is for example by one-piece training or material and / or positive connection with a merely indicated control valve element 5 connected, which cooperates with a valve seat, not shown. From a magnetic closing spring 6 in a central canal 7 the magnet assembly 2 is absorbed and attached to the anchor plate 3 is supported, the magnet armature 4 together with the control valve element 5 in the direction of a closed position, here in the drawing plane up, spring force. To open the solenoid valve 1 becomes the magnet assembly 2 , more precisely, a magnetic coil 8th (electric coil, winding) energized, causing the armature 4 is moved down in the plane of the drawing. As it turned out 1 results, the armature extends 4 , more precisely one of the magnet assembly 2 facing, annular pole face 9 the anchor plate 3 in the radial direction from the inside to the outside via an inner pole surface 10 and a radially spaced outer pole surface 11 the magnet assembly 2 , The inner pole surface 10 and the outer pole surface 11 are at core elements of a magnetic core 12 the magnet assembly 2 educated.

In the embodiment shown, the magnetic core is 12 formed in two parts and comprises an annular, contoured in cross section L-shaped main body 13 , on the binder-free also a ring-shaped, in cross-section L-shaped, designed as Außenpolflächenelement Polflächenelement 14 in the axial direction. In the embodiment shown, both the pole surface element 14 as well as the basic body 13 formed as sintered elements (sintered composite material). The main body 13 comprises a bottom plate-shaped annular disc-shaped base plate portion forming a yoke portion 15 in the axial direction of the central centric channel 7 is enforced. Over most of its axial extent becomes the central channel 7 bounded by one in the axial direction of the base plate portion 15 in the direction of the armature 4 projecting hollow cylindrical pipe section 16 ,

From the main body 13 and the pole face member 14 becomes an annular receptacle 17 for the solenoid 8th limited, the recording 17 in the direction of the magnet armature 4 is open. It can be seen that the recording 17 , or the magnetic coil 8th in the radial direction from outside to inside a piece is far overlapped by the Polflächenelement 14 , which frontally the annular Außenpolfläche 11 having. This embodiment with large magnetic coil (large radial extent) is exclusively due to the multi-part design of the magnetic core designed as a pot magnetic core 12 possible, in particular because the pole surface element 14 after mounting the solenoid 8th can be mounted and thus a mounting of the solenoid 8th not disabled. The front side of the pipe section 16 of the basic body 13 arranged, annular Innenpolfläche 10 and the front side of the pole surface element 14 trained outer pole surface 11 of the magnetic core 12 lie in a common plane that is parallel to the pole surface 9 of the magnet armature 4 runs.

In the following, the embodiments according to the 2 and 3 explained. The functioning and structure of the in the 2 and 3 shown solenoid valves 1 is essentially the same as in 1 shown and previously described nen exemplary embodiment, so that in order to avoid repetition in the following essentially only to the differences from the in 1 shown and described above embodiment is received. To avoid repetition will open 1 and the associated description.

In the embodiment of a solenoid valve 1 according to 2 for a fuel injector is the magnetic core 12 as in the embodiment according to 1 formed in two parts and consists of two core elements, namely a body 13 and a pole face member formed as an outer pole face member 14 , The latter is in contrast to the embodiment according to 1 However, not contoured in cross-section L-shaped, but formed as a flat annular disc, which on an end face of a radially outer sleeve portion 18 of the basic body 13 rests. The sleeve section 18 is concentric with the radially inner, the central channel 7 limiting pipe section 16 arranged. The main body 13 limited in both radial directions and in the plane of the drawing in the axial direction down an annular, cross-sectionally substantially rectangular contoured recording 17 for the solenoid 8th , The recording 8th is partially surmounted in the radial direction from outside to inside by the cylindrical disk-shaped pole surface element 14 , which after insertion of the solenoid 8th in the recording 7 was mounted binder-free. In the not-shown, fully assembled fuel injector, the core elements of the magnetic core 12 by corresponding clamping means, such as clamping screws and / or springs pressed together in the axial direction. The basic body is preferred 13 designed as a sintered element. The pole surface element 14 can either be made of solid material (massi vem material) or alternatively as a sintered element. In particular, when the Außenpolflächen 11 forming pole surface element 14 as a stroke stop for the magnet armature 4 is intended, an embodiment of solid material is preferred.

In the embodiment according to 3 the magnetic core is designed in three parts and comprises three core elements, namely an annular base contoured in cross-section L-shaped 13 with a base portion forming a flat portion 15 and an axially projecting, centric pipe section 16 , The in 2 as a sleeve section 18 designated portion of the magnetic core 12 is in the embodiment according to 3 from one of the main body 13 separate, sleeve-shaped setting piece 19 formed, which concentric to the pipe section 16 is formed and how the sleeve section 18 according to 2 has a smaller axial extent than the pipe section 16 , The pole surface element 14 is as in the embodiment according to 2 formed as a flat annular disc. This is supported on the end face of the setting piece 19 From and beyond the magnetic coil 8th a little way inward in the radial direction. By providing the adjusting piece 19 need the main body 13 and the pole face element 14 not be cut to size. Preferably, the setting piece 19 as well as the basic body 13 made of sintered material, so are formed as sintered elements. In particular, the pole surface element 14 may alternatively be performed as a sintered element or solid material element.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19650856 A1 [0002]

Claims (17)

Magnetic core composed of at least two core elements ( 12 ) for a magnet assembly ( 2 ) of a fuel injector solenoid valve ( 1 ), characterized in that at least one of the core elements is formed as a sintered element. Magnetic core according to Claim 1, characterized that the core elements are arranged without binding against each other are. Magnetic core according to one of claims 1 or 2, characterized in that one of the core elements as a pole surface element ( 14 ) is formed, which has a receiving opening for a magnetic coil ( 8th ) in sections, preferably in a radially outer region, closes. Magnetic core according to claim 4, characterized in that the pole surface element ( 14 ) as, in particular flat, preferably cylindrical, annular disc is formed. Magnetic core according to claim 4, characterized in that the pole surface element ( 14 ) has an L-shape section in cross-section. Magnetic core according to one of claims 3 to 5, characterized in that the pole face ( 9 ) of the pole surface element ( 14 ) a radially outer pole surface ( 9 ) which is provided with a radially inner pole surface ( 9 ) in a common, transverse to the longitudinal central axis of the magnetic core ( 12 ) extending level is arranged. Magnetic core according to one of Claims 3 to 6, characterized in that the pole surface element ( 14 ) is formed as a sintered element or solid material. Magnetic core according to one of the preceding claims, characterized in that one of the core elements as a central channel ( 7 ) having basic body ( 13 ) is trained. Magnetic core according to claim 8, characterized in that the basic body ( 13 ) is formed as a sintered element. Magnetic core according to one of claims 8 or 9, characterized in that the basic body ( 13 ), in particular a flat portion forming base plate portion ( 15 ) and axially from the base plate section (FIG. 15 ) above, the central channel ( 7 ) limiting pipe section ( 16 ) having. Magnetic core according to one of the preceding claims, characterized in that at least one of the sintered elements trained core elements, preferably all as Sinter elements formed core elements, ground to size are. Magnetic core according to one of Claims 11 or 12, characterized in that one of the core elements is in the form of a sleeve-shaped adjusting piece ( 19 ) formed axially between the base plate portion ( 15 ) and the pole surface element ( 14 ) and concentric with the pipe section ( 16 ) is arranged. Magnetic core according to claim 12, characterized in that the adjusting piece ( 19 ) is formed as a sintered element. Magnetic core according to one of the preceding claims, characterized in that the magnetic core ( 12 ) is designed as a pot magnetic core. Magnetic assembly for a fuel injector solenoid valve ( 1 ), comprising one in a magnetic core ( 12 ) according to one of the preceding claims recorded coil. Fuel injector solenoid valve, in particular servo valve, with a magnet assembly ( 2 ) according to claim 15. Fuel injector with a fuel injector solenoid valve ( 1 ) according to claim 16.