DE102009055154A1 - Magnetic separation for solenoid valve - Google Patents

Abstract

A solenoid valve is proposed, in particular a fuel injection valve, with a sleeve, with a valve needle arranged in the radial direction inside the sleeve and displaceably guided, with a magnetic coil arranged in the radial direction outside the sleeve, with a magnetic core arranged in the radial direction inside the sleeve, with a magnet armature arranged axially opposite the magnet core in the radial direction inside the sleeve, the magnet armature being arranged on the valve needle, the sleeve having a small wall thickness in a thin-walled area between the magnet armature and the magnet coil, the thin-walled area having a reinforcing element for receiving Has radial forces.

Description

State of the art

The invention relates to a solenoid valve according to the preamble of claim 1 or, of a method for producing a solenoid valve according to the preamble of claim 8.

In electromagnetically actuated magnetic actuators for actuating solenoid valves, in particular of injection valves, it is often expedient to arrange a magnetic coil used for generating a magnetic field outside a region through which a fluid, in particular a fuel, flows. This facilitates assembly and prevents z. B. damage to the paint layer of the coil wire by fuel. In order to realize such a dry coil arrangement, metallic sleeves are used, which seal the fuel-filled valve interior to the coil. To withstand the fuel pressure (eg over 200 bar internal pressure), the sleeve must have sufficient wall thickness. At the same time, it must be ensured that the magnetic flux from the outside of the sleeve can reach the magnetic circuit components (armature or magnet armature and inner pole or magnetic core) arranged inside as little loss as possible. This requires a soft magnetic sleeve with the highest possible permeability, so good magnetic conductivity. However, a continuous soft magnetic sleeve has the disadvantage that a portion of the magnetic flux does not pass through as desired inner pole and armature of the magnetic circuit and the air gap arranged therebetween, but remains in the sleeve. The magnetic circuit is thus short-circuited by the sleeve, which leads to a significant reduction in the achievable magnetic force and the dynamics of the power and degradation.

To prevent the short circuit of the magnetic circuit sleeves are used, which have in the region of the armature air gap, ie in the region between armature and inner pole, no or only a small magnetic conductivity and in the zones of radial magnetic flux as good as possible magnetic conductivity. Such a "magnetic separation" can be achieved inter alia by a multi-part construction of the sleeve by an intermediate piece of non-magnetic material between two soft magnetic sleeve parts is arranged. The connection of the elements takes place by different methods such as welding (cf., for example, pamphlets DE 10 2006 014 020 A1 and DE 102 35 644 A1 ) or soldering (pamphlet DE 43 10 719 A1 ). Also, the clamping of a coated with flexible sealing material non-magnetic intermediate piece (pamphlet DE 40 29 278 A1 ) or the structural influence by local thermal treatment of the sleeve (publication DE 10 2006 055 010 A1 ) are known as solutions. Furthermore, the magnetic resistance of the sleeve in the region of the armature air gap can be increased by reducing its wall thickness in this zone.

The described methods have different disadvantages. In the case of a multi-part sleeve, the high cost of joining the parts, checking the tightness and the required post-processing z. B. due to thermal distortion considered unfavorable. The method of local thermal influence of the magnetic properties does not allow complete abolition of the magnetizability of the material, leads to a blurred separation due to the heat affected zone and causes u. U. also a delay of the sleeve. The simplest solution from the production point of view of reducing the wall thickness of the sleeve is, from a functional point of view, a rather unfavorable compromise since, for reasons of strength, a relatively large residual wall thickness is required. This significantly limits the effectiveness of the magnetic separation and thus the performance of the solenoid valve.

The object of the present invention is to provide a low-cost realizable magnetic separation with high efficiency for a magnetic circuit for actuating valves.

Disclosure of the invention

The magnetic valve according to the invention and the inventive method for producing a solenoid valve according to the independent claims have the advantage over the prior art that is achieved by the small wall thickness of the sleeve in the thin wall region optimum magnetic separation effect, since the remaining cross-sectional area even at relatively small magnetic River is in the state of magnetic saturation. It is also advantageous that the wall thickness can be selected to be comparatively thin, since the wall thickness only takes over the function of the seal and does not have to transmit the circumferential and axial forces resulting from the internal pressure. It is also advantageous that a reliable seal is ensured because the sleeve consists of a continuous component. It is furthermore advantageous that the inventive Magnel valve can also be used in applications with very high internal pressure, since the reinforcing element has a high tensile strength and a high rigidity. It is furthermore advantageous that the solenoid valve according to the invention can be realized comparatively inexpensively. Since the sleeve is in one piece, no complex handling, joining and adjustment processes are required. Furthermore eliminates a leak test. It is also advantageous that the geometry of the magnetic separation is clearly defined and sharply defined. It is also advantageous that no welding is necessary and thus no thermal distortion occurs, so that can be dispensed with a post. Preferably, the sleeve is made of a soft magnetic material, more preferably, the sleeve is made of a ferromagnetic material.

Advantageous embodiments and modifications of the invention are the dependent claims, as well as the description with reference to the drawings.

According to a preferred embodiment, it is provided that the thin-wall region comprises an annular groove. By realizing the thin-wall region as an annular groove, a simple and cost-effective production of the solenoid valve is advantageously possible.

According to another preferred embodiment, it is provided that the reinforcing element comprises a fiber material. By using the fiber material, it is advantageously possible in a simple and cost-effective manner to achieve high strength, in particular with respect to the pressure load in the radial direction in the thin-wall region of the sleeve. It is preferred that the sleeve is wrapped in the thin wall area of high-strength fibers. As a result, a comparatively high strength is advantageously achieved. It is further preferred that the reinforcing element comprises a carbon fiber material or a glass fiber material or an aramid fiber material. This makes it possible in a simple and cost-effective manner advantageously to achieve high strength of the thin-wall region with known fiber materials.

According to another preferred embodiment, it is provided that the fiber material is arranged in a fixing material. The arrangement in a fixing material, it is advantageously possible in a simple manner that a displacement of the fibers due to the axial and radial forces occurring during operation of the solenoid valve can be prevented.

According to another preferred embodiment, it is provided that the fixing material comprises a plastic material, preferably a synthetic resin material. The arrangement in a plastic or synthetic resin material, it is advantageously possible in a simple manner to realize with known matrix materials, the fixation of the fibers against unwanted displacement.

According to another preferred embodiment, it is provided that the thin-wall region has a wall thickness of at most approximately 0.2 mm, preferably at most approximately 0.1 mm. By this comparatively small wall thickness is advantageous optimum magnetic separation and thus prevention. Magnetic short circuit possible.

Another object of the present invention is a method for producing a solenoid valve. By means of this method according to the invention, it is advantageously possible in a simple manner to produce a magnetic valve with optimum magnetic separation.

According to a preferred embodiment, it is provided that an annular groove is introduced into the sleeve for the production of the thin-wall region. By manufacturing the annular groove is a solenoid valve with the advantages of the solenoid valve according to the invention can be produced in a simple manner. The annular groove is preferably introduced by a turning process. Alternatively, other manufacturing methods of the annular groove are possible.

According to another preferred development, it is provided that the thin-wall region for receiving the radial forces is reinforced with a fiber material. Due to the reinforcement with fiber material an optimal compression strength of the thin wall region can be achieved in a simple manner. Preferably, the thin wall region is wrapped with a carbon fiber or a glass fiber or an aramid fiber.

Embodiments of the present invention are illustrated in the drawings and explained in more detail in the following description.

Brief description of the drawings

Show it

1 2 schematically shows part of a solenoid valve according to a first embodiment of the present invention Magnelventils,

2 schematically a part of a solenoid valve according to a second embodiment of the present invention solenoid valve,

3 FIG. 2 schematically shows a part of a solenoid valve according to a third embodiment of the present inventive solenoid valve, FIG.

4a . 4b . 4c . 4d schematically a sequence of method steps for producing a sleeve according to a first embodiment of the method according to the invention and

5a . 5b . 5c schematically a sequence of method steps for producing a sleeve according to a second embodiment of the method according to the invention.

Embodiment (s) of the invention

In the various figures, the same parts are always provided with the same reference numerals and are therefore usually named or mentioned only once in each case.

1 schematically shows a part of a solenoid valve 113 according to a first embodiment of the present invention solenoid valve 113 , The solenoid valve 113 is in particular a fuel injection valve for liquid fuel (valve needle and return spring are not shown). The solenoid valve is rotationally symmetric with respect to the axis 112 built up. A soft magnetic, ie made of a ferromagnetic material, anchor 106 (hereinafter also magnet armature 106 called) is mounted axially displaceable and is switched on the coil 103 (hereinafter also solenoid coil 103 called) by the resulting magnetic force of a soft magnetic inner pole 111 (hereinafter also magnetic core 111 called) attracted. For a large magnetic force is desirable that the magnetic flux as completely as possible the armature air gap 107 interspersed. For this purpose, a valve sleeve 105 (hereinafter also sleeve 105 called) in the region of the armature air gap 107 with an annular groove 110 (hereinafter also groove 110 called) provided. This causes due to the low residual wall thickness 109 a reduction of the cross section, so that the magnetic flux almost completely in the armature air gap 107 and not wasted in the sleeve 105 runs.

The valve sleeve 105 consists of a soft-magnetic material to the magnetic flux as lossless radially from the inner pole 111 to a magnet pot 102 to lead. The valve sleeve 105 also has the task to seal the interior against the environment. The fuel pressure inside the sleeve 105 is usually much larger than the ambient pressure, so that the sleeve 105 pressurized and must absorb high radial forces. To reinforce the sleeve 105 , the sleeve will 105 in this area with a winding of high-strength fiber material 108 (For example, from a carbon fiber), which is fixed with a plastic matrix (eg made of synthetic resin). The fiber reinforcement absorbs the circumferential or radial forces resulting from the pressure. The occurring axial tensile force is in the illustrated first embodiment via a magnetic cover 114 and the magnet pot 102 Passed outside at the magnetic separation. The introduction of force from the sleeve 105 in the outer components via collar 100a . 100b , magnet Flat 114 and magnet pot 102 are over a thread 101 interconnected, so that the power transmission is ensured between these components.

2 schematically shows a part of a solenoid valve 113 according to a second embodiment of the present invention solenoid valve 113 , The connections between the magnet pot 102 and the sleeve 105 for transmission of the axial force are by welded joints 200 realized. The magnetic cover 114 was doing directly into the valve sleeve 105 integrated.

The illustrated embodiments in 1 and 2 are merely examples of a variety of ways to arrange dar. Alternatively, it is possible, for example, that adhesive or clamping connections between magnet pot 102 and sleeve 105 be used or that a positive connection is used by crimping.

3 schematically shows a part of a solenoid valve 113 according to a third embodiment of the present invention solenoid valve 113 , Both the axial and the radial forces are through the fiber composite material in the annular groove 110 added. For this purpose, the high-strength fibers extend not only in the circumferential direction but also in the axial direction. To the force from the sleeve 105 to allow into the fibers, has the annular groove 110 a profiling on 300 , which has an axially acting positive connection between the matrix of the fiber composite material and the sleeve 105 allows. The force is introduced in this way evenly into the fibers. To the desired orientation of the fibers in the annular groove 110 to obtain, for. B. a fabric with offset by 90 ° fiber flow are used.

4a . 4b . 4c and 4d schematically show a sequence of process steps for producing a sleeve 105 according to a first embodiment of the method according to the invention. Starting from a soft magnetic semi-finished product ( 4a ) is first the outer contour of the sleeve 105 processed ( 4b ). The next step is the ring groove 110 reinforced by the fiber composite material ( 4c ). Subsequently, the inner contour is processed 4d ). The advantage of this first embodiment of the method according to the invention is the reinforcement of the sleeve 105 through the fiber winding before the thin residual wall thickness 109 generated in the field of magnetic separation. The support effect of the fiber composite is the risk of undesirable deformation of the sleeve 105 prevented by the cutting forces.

5a . 5b and 5c schematically show a sequence of process steps for producing a sleeve 105 according to a second embodiment of the method according to the invention. Starting from a soft magnetic semi-finished product ( 5a ) are the inner and outer contour of the sleeve 105 initially completely finished ( 5b ), before in the last step the groove 110 is reinforced by wrapping with fiber material and introducing the matrix material ( 5c ). This second embodiment of the invention. Method has the advantage that after the application of the fiber composite no post-processing is required. Furthermore, it is advantageously possible that to prevent undesired deformation of the sleeve 105 by the forces occurring when attaching the fiber material, a support member, which may be cylindrical, for example, in the sleeve 105 is inserted. This support member provides a radial support during the winding process.

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 102006014020 A1 [0003]
• DE 10235644 A1 [0003]
• DE 4310719 A1 [0003]
• DE 4029278 A1 [0003]
• DE 102006055010 A1 [0003]

Claims (10)

Magnetic valve ( 113 ), in particular a fuel injection valve, with a sleeve ( 105 ), with one in the radial direction within the sleeve ( 105 ) and slidably guided valve needle, with a radially outward of the sleeve ( 105 ) arranged magnetic coil ( 103 ), with one in the radial direction within the sleeve ( 105 ) arranged magnetic core ( 111 ), with one in the radial direction within the sleeve ( 105 ) the magnetic core ( 111 ) axially oppositely arranged armature ( 106 ), wherein the magnet armature ( 106 ) is arranged on the valve needle, wherein the sleeve ( 105 ) in one between the armature ( 106 ) and the magnetic coil ( 103 ) arranged thin wall area ( 110 ) has a small wall thickness, characterized in that the thin wall area ( 110 ) a reinforcing element ( 108 ) for receiving radial forces. Magnetic valve ( 113 ) according to claim 1, characterized in that the thin wall region ( 110 ) an annular groove ( 110 ). Magnetic valve ( 113 ) according to one of the preceding claims, characterized in that the reinforcing element ( 108 ) comprises a fiber material. Magnetic valve ( 113 ) according to one of the preceding claims, characterized in that the reinforcing element ( 108 ) comprises a carbon fiber material or a glass fiber material or an aramid fiber material. Magnetic valve ( 113 ) according to one of the preceding claims, characterized in that the fiber material is arranged in a fixing material. Magnetic valve ( 113 ) according to one of the preceding claims, characterized in that the fixing material comprises a plastic material, preferably a synthetic resin material. Magnetic valve ( 113 ) according to one of the preceding claims, characterized in that the thin-wall region ( 110 ) has a wall thickness of at most about 0.2 mm, preferably at most about 0.1 mm. Method for producing a solenoid valve ( 113 ), in particular a solenoid valve ( 113 ) according to one of the preceding claims, wherein in the radial direction within a sleeve ( 105 ) is arranged a displaceably guided valve needle, wherein in the radial direction outside of the sleeve ( 105 ) a magnetic coil ( 103 ) is arranged, wherein in the radial direction within the sleeve ( 105 ) a magnetic core ( 111 ) is arranged, wherein in the radial direction within the sleeve ( 105 ) a the magnetic core ( 111 ) axially opposite armature ( 106 ), wherein the magnet armature ( 106 ) is arranged on the valve needle, wherein in the sleeve ( 105 ) a thin wall region having a small wall thickness ( 110 ) between the armature ( 106 ) and the magnetic coil ( 103 ), characterized in that in the thin-walled region ( 110 ) a reinforcing element ( 108 ) is arranged for receiving radial forces. Method for producing a solenoid valve ( 113 ) according to claim 8, characterized in that for the production of the thin wall region ( 110 ) an annular groove ( 110 ) in the sleeve ( 105 ) is introduced. Method for producing a solenoid valve ( 113 ) according to claim 8 or 9, characterized in that the thin wall region ( 110 ) is reinforced to receive the radial forces with a fiber material.

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