DE102016213984A1 - Magnetic circuit, solenoid-operated suction valve and high-pressure fuel pump - Google Patents

Abstract

The invention relates to a magnetic circuit (1) for an electromagnetically operated suction valve (2) of a high-pressure fuel pump (3) comprising an annular solenoid (4) for acting on a between two end stops (5, 6) liftable anchor (7) and a at least one end stop (5, 6) forming body (8), which is at least partially made of a magnetic or magnetizable material. According to the invention, the end stops (5, 6) define an armature movement space (9) which is completely formed inside the body (8). Furthermore, the invention relates to an electromagnetically operated suction valve (2) for a high-pressure fuel pump (3) and a high-pressure fuel pump (3) with such a suction valve (2).

Description

The invention relates to a magnetic circuit having the features of the preamble of claim 1. Furthermore, the invention relates to an electromagnetically operated suction valve for a high-pressure fuel pump with a magnetic circuit according to the invention and a high-pressure fuel pump with a suction valve according to the invention.

State of the art

From the DE 10 2014 200 339 A1 is an electromagnetically controllable suction valve for a high pressure pump of a fuel injection system, in particular a common rail injection system, known with a magnetic circuit comprising an annular magnetic coil for acting on a liftable armature and a pole core. The pole core lies opposite the armature at a working air gap and thus forms a first end stop for the armature. A second end stop is formed by a valve screw which surrounds the armature at least in sections and serves to attach the suction valve to the high-pressure pump. The pole core and the valve screw are connected by means of a sleeve, which is welded on the one hand to the pole core, on the other hand with the valve screw. Since the welding seams are heavily loaded by striking the armature on the pole core or on the valve screw, it is proposed, in order to relieve the weld seams, to axially bias the pole core in the direction of the armature. In this way, the robustness of the component connections should be increased, so that the risk of premature failure of the component connections is reduced.

Based on the above-mentioned prior art, the present invention seeks to further increase the mechanical strength of a magnetic circuit for an electromagnetically actuated suction valve of a high-pressure fuel pump. In addition, the magnetic circuit should be easy to produce.

To solve the problem, the magnetic circuit with the features of claim 1 is proposed. Advantageous developments of the invention can be found in the dependent claims. Furthermore, an electromagnetically operated suction valve with a magnetic circuit according to the invention and a high-pressure fuel pump with a suction valve according to the invention are specified.

Disclosure of the invention

The proposed for an electromagnetically actuated suction valve of a high-pressure fuel pump magnetic circuit comprises an annular magnetic coil for acting on a liftable between two end stops armature and at least one end stop forming body, which is at least partially made of a magnetic or magnetizable material. According to the invention, the end stops define an armature movement space that is completely formed within the body. That is, the body has an axial extent greater than that of the armature travel space. At the same time the armature movement space is limited in the radial direction and in at least one axial direction of the body.

Since the body is at least partially made of a magnetic or magnetizable material, it is capable of replacing a pole core and / or a valve body. In addition, one of the connection of pole core and valve body serving sleeve is dispensable. This means that the number of components is reduced and assembly is facilitated. In particular, the assembly step of welding the sleeve to the pole core or the valve body is eliminated. The omission of the welds also has the consequence that the robustness of the magnetic circuit is increased.

In addition, there are no sealing points for sealing the usually medienbeaufschlagten anchor movement space. In particular, the medium may be fuel when the magnetic circuit is for actuating a suction valve for a high-pressure fuel pump. In particular, the one-piece body delimiting the armature movement space ensures that the magnet coil arranged radially outward with respect to the body does not come into contact with the medium received in the armature movement space. As a result, the effort that is usually required to produce the desired tightness in "dry" solenoid, significantly reduced.

The components of the magnetic circuit are preferably arranged such that the armature moving space forming body passes through the annular magnetic coil. The armature movement space is therefore - at least in sections - to lie within the magnetic coil. The magnetic circuit is thus particularly suitable for the realization of a magnet assembly operating according to the plunger-rod principle.

According to a preferred embodiment of the invention, the armature moving space forming body has been manufactured in an additive manufacturing process, preferably in a 3D printing process. Additive manufacturing processes, such as 3D printing, allow the body to build up around another component. For example, the body may be built around an anchor member, so that a further assembly step is omitted. Furthermore, the body can be designed such that it engages around the anchor on both sides. In this way, a body can be created, which forms both end stops for the anchor. The production of the body in a 3D printing process also has the advantage that a large number of different materials can be used, so that the most functional selection of materials can be made.

Preferably, the body is made of at least two, preferably at least three different materials. The different materials are preferably used in different areas and / or sections of the body. The material can then be optimally adapted to the respective function of a region or section in this case.

As part of the magnetic circuit, the body must be made of a magnetic or magnetizable material, at least in sections or in sections, so that the magnetic flux is ensured. The material is therefore to be selected in particular with regard to its magenta properties. However, materials with particularly good magnetic properties are generally less resistant to wear, so that they are less suitable for the formation of mechanically highly loaded stop or guide surfaces. By using different materials this conflict of objectives can be solved.

For example, a serving as an end stop for the anchor area or section of a particularly hard, wear-resistant material to be made in order to minimize the wear in this area or section by the abutting anchor. Alternatively or additionally, an area or section serving to guide the armature can be made of a material which proves to be particularly resistant to wear in relation to the frictional forces occurring in the guide. Incidentally, the body may be made of a magnetic or magnetizable material to ensure a high magnetic flux.

In a further development of the invention it is proposed that the body has a sleeve-shaped portion which is made of a material which is neither magnetic nor magnetizable, adjacent to the sleeve-shaped portion in the axial direction on both sides of sections, each made of a magnetic or magnetizable material are. A body constructed in this way can replace a pole core, a valve body and a sleeve connecting the pole core with the valve body, which usually also serves at the same time for the magnetic separation of pole core and valve body and is accordingly made of a material which is neither magnetic nor magnetizable. All three components, namely pole core, valve body and sleeve, are thus formed by a single body, whereby the number of components is significantly reduced. Furthermore, the assembly of the magnetic circuit is facilitated because it applies less components to connect. At the same time, the number of sealing points decreases, which must be sealed by additional measures.

Alternatively or additionally, it is proposed that the body is made in regions, preferably in the region of at least one end stop, from a material which is neither magnetic nor magnetizable. The arrangement of such a material in the region of an end stop can be counteracted by a magnetic gluing of the armature to the end stop. The non-magnetic or non-magnetizable material therefore preferably forms an abutment surface serving as an end stop for the armature. With an appropriate choice of material damping effects in the area of an end stop can be achieved at the same time, so that the robustness of the magnetic circuit continues to increase.

Preferably, the body of the magnetic circuit has a the armature movement space in the axial direction limiting annular collar to form an end stop for the armature. The annular collar leaves an opening through which a portion of the armature or a contact pin connected to the armature can be guided for contacting a valve tappet. Thus, the valve stem can be actuated directly via the magnetic circuit.

The annular collar may at least partially be made of a material that is neither magnetic nor magnetizable. This applies in particular to a region of the annular collar which delimits the armature movement space. The annular collar or the body forming the annular collar is thus able to replace an end stop serving as a stop plate, which is usually inserted into the armature movement space and supported on an annular collar of the valve body. Such a trained annular collar counteracts a magnetic sticking of the armature to the end stop. Furthermore, the wear in the area of the end stop on the collar can be reduced if a material is chosen which is also particularly hard and wear-resistant.

Analogous to a stop plate produced in the 3D printing process, a residual air gap disk can be formed in the region of the further end stop. In order to counteract magnetic sticking of the armature to the further end stop, a material which is neither magnetic nor magnetizable is preferably used for this purpose.

Furthermore, it is proposed that the body has an inner peripheral surface delimiting the armature movement space in the radial direction. About the inner peripheral surface of the body, a guide of the anchor can be effected. Preferably, the inner peripheral surface has recesses which expand the armature movement space. The recesses reduce the contact area of the armature with the body, so that the wear due to friction is reduced. Furthermore, the recesses form pockets in which the medium present in the armature movement space can accumulate, which favors the construction of a lubricating film. Recesses in the form of longitudinal grooves promote a pressure compensation within the armature movement space during a stroke movement of the armature.

Since solenoid-operated suction valves represent the preferred field of application for a magnetic circuit according to the invention, an electromagnetically actuated suction valve for a high-pressure fuel pump with such a magnetic circuit is also proposed. Due to the increased mechanical strength of the magnetic circuit and the robustness and thus the life of the suction valve can be increased. At the same time, the suction valve is easy to produce, since the assembly cost is significantly reduced.

Preferably, the armature moving space forming body passes through the annular magnetic coil. In this way, a compact construction in the axial direction is achieved, which reduces the space requirement of the suction valve.

Further, a fuel high pressure pump for a fuel injection system is provided with a suction valve according to the invention. The suction valve is preferably integrated in a housing part of the high-pressure fuel pump, so that a particularly compact construction arrangement is achieved.

A preferred embodiment of the invention will be explained in more detail with reference to the accompanying drawings. This shows a schematic longitudinal section through an electromagnetically actuated suction valve with a magnetic circuit according to the invention, wherein the suction valve is integrated in a housing part of a high-pressure fuel pump.

Detailed description of the drawing

The illustrated electromagnetically operated suction valve 2 serves to fill a high-pressure element space 18 a high-pressure fuel pump 3 with fuel. The suction valve 2 is this in a housing part 15 the fuel high-pressure pump 3 integrated, in which also the high-pressure element space 18 is trained. A valve lifter 16 of the suction valve 2 in a hole 17 of the housing part 15 is guided in a liftable manner, opens into the high-pressure element space 18 , allowing fuel from a low-pressure space 22 via inlet bores 23 and a valve seat 21 in the high-pressure element space 18 can flow. In the conveying mode of the high-pressure fuel pump 3 is the in the high-pressure element space 18 existing fuel is compressed and via an exhaust valve 19 a high-pressure accumulator (not shown) supplied. Meanwhile, the suction valve 2 closed, with a valve spring 20 the valve lifter 16 in the valve seat 21 draws.

For actuating the valve tappet 16 has the suction valve 2 a magnetic circuit 1 on, which is an annular solenoid 4 and one the solenoid 4 assertive body 8th includes. The body 8th forms an anchor movement space 9 for one between two end stops 5 . 6 lifting anchor 7 out, completely in the body 8th is included. The body 8th thus also forms the two end stops 5 . 6 out. This is possible because the body 8th has been produced in a 3D printing process, with the structure around the anchor 7 took place around. A further in the body 8th recorded spring 24 that the anchor 7 in the direction of the valve lifter 16 loaded, is subsequently through a central bore 26 of the anchor 7 been used. Then it is in the hole 15 a contact pin 26 been pressed, which the contacting of the valve stem 16 serves. The valve seat side end stop 5 is accordingly by a ring collar 13 of the body 8th formed, which is a passage of the contact pin 26 allowed.

The ring collar 13 is in the area 13 ' Made of a material that is neither magnetic nor magnetizable. In this way, the ring collar acts 13 . 13 ' a magnetic gluing of the anchor 7 at the end stop 5 opposite. The area 13 ' has also been printed in the manufacture of the body 8th , The same applies to a sleeve-shaped section 10 of the body 8th which is the lead of the anchor 7 is also made of a material that is neither magnetic nor magnetizable. Because the sleeve-shaped section 10 should be a magnetic separation between the two adjacent sections 11 . 12 cause, which are made of a magnetic or magnetizable material. In this way it is ensured that the magnetic flux across the armature 7 occurs when the solenoid coil 4 is energized. The leadership of the anchor 7 is over an inner peripheral surface 14 of the sleeve-shaped portion 10 causes.

When energizing the magnetic coil 4 builds up a magnetic field whose magnetic force the anchor 7 against the spring force of the spring 24 in the direction of the section 12 of the body 8th draws. This dissolves the contact pin 26 from the valve lifter 16 and the valve spring 20 can do the valve lifter 16 in the valve seat 21 to draw. Is the energization of the solenoid 4 finished, presses the spring 24 the anchor 7 in the direction of the ring collar 13 of the body 8th , wherein the contact pin 26 for contact with the valve lifter 16 passes and this against the spring force of the valve spring 20 from the valve seat 21 lifts.

The one-piece executed body 8th combines several functions in one component. In particular, it replaces a pole core and a valve body, which are connected via a sleeve and at the same time magnetically separated. The body 8th This is made of different materials. The production is preferably carried out in a 3D printing process, which allows the use of different materials and the production of nested components. In particular, the body can 8th around the anchor 7 to be built around.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014200339 A1 [0002]

Claims (9)

Magnetic circuit ( 1 ) for an electromagnetically operated suction valve ( 2 ) a high-pressure fuel pump ( 3 ) comprising an annular magnetic coil ( 4 ) affecting one between two end-stops ( 5 . 6 ) lifting anchor ( 7 ) and at least one end stop ( 5 . 6 ) training body ( 8th ), which is at least partially made of a magnetic or magnetizable material, characterized in that the end stops ( 5 . 6 ) an anchor movement space ( 9 ) completely within the body ( 8th ) is trained. Magnetic circuit ( 1 ) according to claim 1, characterized in that the body ( 8th ) has been produced in an additive manufacturing process, preferably in a 3D printing process. Magnetic circuit ( 1 ) according to claim 1 or 2, characterized in that the body ( 8th ) is made of at least two, preferably at least three different materials. Magnetic circuit ( 1 ) according to one of the preceding claims, characterized in that the body ( 8th ) a sleeve-shaped section ( 10 ), which is made of a material that is neither magnetic nor magnetizable, wherein the sleeve-shaped portion ( 10 ) in the axial direction on both sides sections ( 11 . 12 ), each made of a magnetic or magnetizable material. Magnetic circuit ( 1 ) according to one of the preceding claims, characterized in that the body ( 8th ) in regions, preferably in the region of at least one end stop ( 5 . 6 ), is made of a material that is neither magnetic nor magnetizable. Magnetic circuit ( 1 ) according to one of the preceding claims, characterized in that the body ( 8th ) one the anchor movement space ( 9 ) in the axial direction limiting annular collar ( 13 . 13 ' ) for forming an end stop ( 5 ) having. Magnetic circuit ( 1 ) according to one of the preceding claims, characterized in that the body ( 8th ) one the anchor movement space ( 9 ) in the radial direction limiting inner peripheral surface ( 14 ), wherein preferably in the inner peripheral surface ( 14 ) the anchor movement space ( 9 ) widening recesses, for example in the form of longitudinal grooves, are formed. Electromagnetically operated suction valve ( 2 ) for a high-pressure fuel pump ( 3 ) with a magnetic circuit ( 1 ) according to any one of the preceding claims, wherein preferably the body ( 8th ) the annular magnet coil ( 4 ). Fuel high pressure pump ( 3 ) for a fuel injection system with a suction valve ( 2 ) according to claim 8, wherein preferably the suction valve ( 2 ) in a housing part ( 15 ) of the high-pressure fuel pump ( 3 ) is integrated.

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