VALVE FOR METERING A FLUID

Abstract

A valve includes an electromagnetic actuator, which has an armature in an armature space and guided on a valve needle operable by the actuator using the armature. A first and a second stop element that interact with a first and second end face, respectively, of the armature are situated on the valve needle. The armature has a spring receptacle, which is open towards the first end face of the armature, and into which a spring is inserted. The armature has at least one fluid channel, which, during operation, allows fluid to pass through between first and second regions of the armature space at the first and second end faces, respectively, of the armature. The fluid channel incorporates at least part of the spring receptacle. Sections of the fluid channel run radially outwards along a direction oriented from the first to the second end face and coaxial to a longitudinal axis.

Claims

1-10. (canceled)

11. A valve for metering a fluid, comprising: an electromagnetic actuator which includes an armature situated in an armature space; a valve needle operable by the actuator using the armature, the armature being guided on the valve needle; a first stop element that interacts with a first end face of the armature during operation, and a second stop element that interacts with a second end face of the armature during operation, situated on the valve needle, the first stop element and the second stop element limiting a movement of the armature relative to the valve needle, the armature having a spring receptacle which is open towards the first end face of the armature, and into which a spring supported at the first stop element is inserted; wherein the armature has at least one fluid channel, which, during operation, allows fluid to pass through between a first region of the armature space bordering on the first end face of the armature and a second region of the armature space bordering on the second end face of the armature, the fluid channel incorporating at least a portion of the spring receptacle, and wherein the fluid channel runs radially outwardly at least in sections, along a direction, which is oriented from the first end face towards the second end face and is coaxial relative to a longitudinal axis.

12. The valve as recited in claim 11, wherein the valve is a fuel injector for an internal combustion engine.

13. The valve as recited in claim 11, wherein a point of a first opening of the fluid channel, away from the longitudinal axis, lying radially inwards to a maximum extent, is located closer to the longitudinal axis than a point of a second opening of the fluid channel, away from the longitudinal axis, lying radially inwards to a maximum extent.

14. The valve as recited in claim 11, wherein the fluid channel goes out to the second region of the armature space at an outlet face of the armature, and an axis of the fluid channel, along which the fluid channel emerges at the outlet face of the armature, is oriented perpendicularly to the outlet face.

15. The valve as recited in claim 11, wherein the outlet face lies in an annular surface running about the longitudinal axis, and the annular surface is in the form of a partial surface of a conical envelope axially symmetric with regard to the longitudinal axis, or is in the form of a partial surface of a circular disk oriented perpendicularly to the longitudinal axis.

16. The valve as recited in claim 11, wherein the fluid channel runs continuously radially outwards along the coaxial direction.

17. The valve as recited in claim 11, wherein the fluid channel includes at least one oblique bore hole, which runs at least radially outwards along the coaxial direction.

18. The valve as recited in claim 17, wherein the oblique bore hole runs from the first end face of the armature to the second end face of the armature.

19. The valve as recited in claim 17, wherein the oblique bore hole is intersected by the spring receptacle.

20. The valve as recited in claim 17, wherein the oblique bore hole is intersected by the spring receptacle in such a manner, that a base of the spring receptacle is cut by the oblique bore hole.

21. The valve as recited in claim 11, wherein the fluid channel includes a first coaxial blind-end bore, which runs in the coaxial direction, starting from the first end face of the armature, and a second coaxial blind-end bore, which runs contrary to the coaxial direction, starting from the second end face of the armature, wherein the first coaxial blind-end bore and the second coaxial blind-end bore intersect each other inside of the armature, and with regard to the longitudinal axis, the second blind-end bore is situated radially further outwards than the first blind-end bore.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Preferred exemplary embodiments of the present invention are explained in greater detail in the following description, with reference to the figures, in which elements corresponding to each other are provided with matching reference numerals.

[0018] FIG. 1 shows a schematic sectional view of a portion of a valve according to a first exemplary embodiment.

[0019] FIG. 2 shows a schematic sectional view of a portion of a valve according to a second exemplary embodiment.

[0020] FIG. 3 shows a schematic sectional view of a portion of a valve according to a third exemplary embodiment.

[0021] FIG. 4 shows a schematic sectional view of a portion of a valve according to a fourth exemplary embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0022] FIG. 1 shows a schematic sectional view of a portion of a valve 1 for metering a fluid, according to a first exemplary embodiment. Valve 1 may take the form of, in particular, a fuel injector 1. One preferred application is a fuel injection system, in which such fuel injectors 1 take the form of high-pressure injectors 1 and are used for direct injections of fuel into assigned combustion chambers. In this connection, liquid or gaseous fuels may be used as fuel. Accordingly, valve 1 is suitable for metering liquid or gaseous fluids.

[0023] Valve 1 includes a housing (valve housing) 2, in which an internal pole 3 is stationary-mounted. In this exemplary embodiment, a valve needle 5 situated inside of housing 2 is guided along a longitudinal axis 4, relative to housing 2.

[0024] An armature (magnet armature) 6 is positioned on valve needle 5. In addition, a stop element 7 and a further stop element 8 are positioned on valve needle 5. Stop faces 7, 8 are formed on stop elements 7, 8. In this connection, upon actuation, armature 6 may be moved along longitudinal axis 4, relative to valve needle 5, between stop elements 7, 8, in which case a free travel 9 of the armature is predetermined. In this case, longitudinal axis 4 may be referred to as longitudinal axis 4 of valve needle 5 and/or as longitudinal axis 4 of armature 5. Armature 6, internal pole 3, as well as a magnetic coil not shown, are parts of an electromagnetic actuator 10.

[0025] A valve-closure member 11, which interacts with a valve-seat surface 12 to form a sealing seat, is formed on valve needle 5. Upon actuation of armature 6, it is accelerated in the direction of internal pole 3. When armature 6 strikes against limit stop 7 of stop element 7 and thereby actuates valve needle 5, fuel may then be injected through the open sealing seat and at least one nozzle opening 13 into a space, in particular, a combustion chamber.

[0026] Valve 1 includes a restoring spring 14, which moves valve needle 5 via stop element 7 into its starting position, in which the sealing seat is closed.

[0027] Armature 6 is based on a basic cylindrical form 20 having a through-hole 21; armature 6 being guided at through-hole 21, on valve needle 5. In this connection, basic form 20 of armature 6 has a length 24 between a first end face 22 of armature 6 facing internal pole 3 and a second end face 23 of armature 6 facing away from internal pole 3. Armature 6 is positioned in an armature space 16. In this connection, first end face 22 borders on a first region 17 of armature space 16. In addition, second end face 23 borders on a second region 18 of armature space 16. During operation, the passage of fuel through the armature over at least a portion of its length 24 is rendered possible by at least one fluid channel 15.

[0028] Armature 6 includes a spring receptacle 25. In this connection, fluid channel 15 also includes spring receptacle 25. Thus, fluid channel 15 leads through at least a portion of spring receptacle 25. Spring receptacle 25 is open at end face 22 of armature 6. A spring support surface 26, at which a spring 27 partially situated in spring receptacle 25 is supported, is formed by base 26 of spring receptacle 25. Spring 27 is also supported at stop face 7 of limit stop 7. Upon actuation of armature 6, spring 27 is shortened with respect to its starting length; it being able to be inserted completely into spring receptacle 25.

[0029] In this exemplary embodiment, spring 27 is also formed to have ground spring ends 43, 44. This provides an even more effective seat. In addition, this results in reduced wear, as well as more uniform application of force, to armature 6 at spring support surface 26, on one side, and at limit stop 7 of stop element 7, on the other side.

[0030] In this exemplary embodiment, a guide segment 28 is formed on armature 6. Due to this, the guide length of armature 6 on valve needle 5 is equal to length 24 of armature 6 between its end faces 22, 23.

[0031] In this exemplary embodiment, the guidance of valve needle 5 relative to longitudinal axis 4 and/or relative to housing 2 is carried out via stop element 7. In this connection, stop element 7 is guided in a guide region 30 at an inner bore 31 of internal pole 3. In one modified refinement, valve needle 5 may also be guided additionally or alternatively via armature 6. In this connection, at least part of the outside 32 of armature 6 extends to inner side 33 of housing 2. In this refinement, an annular gap between stop element 7 and internal pole 3 may then be produced in place of guide region 30.

[0032] In this exemplary embodiment, fluid channel 15 includes an oblique bore hole 50. In this connection, fluid channel 15 preferably has exactly one oblique bore hole 50. Fluid channel 15 then leads through oblique bore hole 50 and at least a portion 51 of spring receptacle 25.

[0033] In this exemplary embodiment, a direction 19 coaxial with regard to longitudinal axis 4 results, which is oriented from first end face 22 to second end face 23, in an orientation contrary to an opening direction 52, in which valve needle 5 is actuated during the opening of valve 1.

[0034] Oblique bore hole 50 is formed in armature 6 in such a manner, that it runs radially outwards along coaxial direction 19, that is, away from longitudinal axis 4; an angle of inclination 54 between coaxial direction 19 and an axis 53 of oblique bore hole 50 resulting in the drawing plane. However, the embodiment of oblique bore hole 50 is not limited to the axis' 53 being situated in the same plane as longitudinal axis 4 of valve needle 5, as is the case in the depicted exemplary embodiment having the plane given by the drawing plane.

[0035] In addition, in this exemplary embodiment, oblique bore hole 50 runs from first end face 22 of armature 6 to second end face 23 of armature 6. In this connection, a first opening 55 of fluid channel 15, which borders on first region 17, is situated in end face 22, while a second opening 56, which borders on second region 18, in situated in second end face 23. The oblique bore hole 50 running from first end face 22 to second end face 23 of armature 6 allows for an advantageous hydraulic connection between first region 17 and second region 18. The positioning of first opening 55 close to longitudinal axis 4 allows the fluid, in particular, the fuel, to flow from inner bore 31 of internal pole 3 into fluid channel 15 in an advantageous manner. The positioning of second opening 56 of fluid channel 15 away from longitudinal axis 4 allows an inner portion 57 of second end face 23, at which armature 6 interacts with second stop face 8, to be preselected to be sufficiently large in correspondence with a specified and, if desired, large, second stop face 8, without second opening's 56 being situated in this inner portion 57 and/or without fluid channel's 15 intersecting this inner portion 57 of second end face 23. This allows a large damping surface to be produced between second stop face 8 and second end face 23.

[0036] Since oblique bore hole 50 is intersected by spring receptacle 24 over an entire length 58 of spring receptacle 25 along longitudinal axis 4, favorable flow characteristics and a first opening 55 of fluid channel 15 even more enlarged with respect to spring receptacle 25 are produced. In this connection, in particular, a point 60, at which first opening 55 is at a maximum radial distance from longitudinal axis 4, is even outside of spring receptacle 25. On the other hand, a point 61, at which first opening 55 is at a minimum distance from longitudinal axis 4, is still at the edge of spring receptacle 25. In addition, points 62, 63 are apparent at second opening 56, in which case point 62 is situated at the edge of second opening 56, at a maximum distance away from longitudinal axis 4, and point 63 is situated at the edge of second opening 56, at a minimum distance from longitudinal axis 4. Viewed radially, point 62 is further away from longitudinal axis 4 than point 60. Viewed radially, point 63 of second opening 56 is also further away from longitudinal axis 4 than point 61 on the edge of first opening 55. In addition, a centroid 64 of first opening 55 is situated radially closer to longitudinal axis 4 than a centroid 65 of second opening 56.

[0037] In this exemplary embodiment, oblique bore hole 50 is formed in such a manner, that base 26 of spring receptacle 25 is intersected by oblique bore hole 50. Therefore, spring receptacle 25 may be used in an advantageous manner for allowing the fuel to pass through, and may be integrated in fluid channel 15 along its entire length 58.

[0038] FIG. 2 shows a schematic sectional view of part of a valve 1 according to a second exemplary embodiment. In this exemplary embodiment, at the second end face 23 of armature 6, in which second opening is situated, second opening 56 or a partial surface 56 is oriented perpendicularly to axis 53 of oblique bore hole 50. In this connection, partial surface 56 of armature 6 may be formed, using a circular groove 85 or individual countersinks. In particular, partial surface 56 may initially be formed at second end face 23 of armature 6, and oblique bore hole 50 may then be drilled, starting from second end face 23. This allows a drill bit to impinge upon partial surface 56 of armature 6 at right angles. Consequently, this produces, in particular, a modification to the first exemplary embodiment described with the aid of FIG. 1; the modification being optimized with regard to manufacturing and, in particular, being used for improving the drilling. Through this, fracture of a drill bit may also be prevented, since the drilling does not occur at an angle to a surface.

[0039] In this connection, with regard to a plurality of oblique bore holes to be produced on armature 6, which are formed in accordance with oblique bore hole 50, in particular, it is advantageous for partial surface 56 to take the form of a groove, which runs around longitudinal axis 4, and from which individual oblique bore holes 50 then start out in a circumferentially distributed manner.

[0040] FIG. 3 shows a schematic sectional view of part of a valve 1 according to a third exemplary embodiment. In this exemplary embodiment, a bevel 66, which cuts second end face 23 at its outer diameter 42, is formed on armature 6. Bevel 66 then lies between second end face 23 and outside 32 of armature 6. Bevel 66 is preferably formed at a right angle to axis 53 of oblique bore hole 50. First of all, this embodiment has the advantage that optimization of manufacturing is achieved, as is accordingly described in light of FIG. 2. In addition, inner portion 57 of second end face 23, at which armature 6 interacts with stop face 8, may be formed to have a maximum size. This produces a particularly high degree of structural latitude. Thus, in the specific application, a very high degree of hydraulic damping may be attained.

[0041] FIG. 4 shows a schematic sectional view of a portion of a valve 1 according to a fourth exemplary embodiment. In this exemplary embodiment, fluid channel 15 has a first coaxial blind-end bore 71 and a second coaxial blind-end bore 72. Starting from first end face 22, first coaxial blind-end bore 71 runs in coaxial direction 19. Starting from second end face 23, second coaxial blind-end bore 72 runs contrary to coaxial direction 19. The two blind-end bores 71, 72 intersect each other inside of armature 6. In this case, viewed along longitudinal axis 4, a region of intersection 73 may be situated close to base 26 of spring receptacle 25. This produces favorable flow conditions. Blind-end bores 71, 72 and at least a portion 51 of spring receptacle 25 may then be used during the passage of the fluid through armature 6. In this exemplary embodiment, as well, this advantageously allows spring receptacle 25 to be integrated at least partially into fluid channel 15. Viewed in coaxial direction 19, in the region of intersection 73, the fluid is guided radially outwards along longitudinal axis 4. This also allows the fluid to be introduced advantageously into fluid channel 15, starting from inner bore 31 of internal pole 3 and, at the same time, provides advantageous damping at second stop element 8.

[0042] Thus, in particular, it is advantageous that a point 60 of a first opening 55 of fluid channel 15, lying radially far outwards from longitudinal axis 4 to a maximum extent, is closer to longitudinal axis 4 than a point 62 of a second opening 56 of fluid channel 15, lying radially far outwards from longitudinal axis 4 to a maximum extent. In addition, it is advantageous for a centroid 64 of a first opening 55 of fluid channel 15 to be situated closer to longitudinal axis 4 than a centroid 65 of a second opening 56 of fluid channel 15.

[0043] In the exemplary embodiments put forward, which are described, in particular, in light of FIGS. 2 through 4, it is advantageously feasible that at an outlet face 80 of armature 6, fluid channel 15 goes out to second region 18 of armature space 16; an axis 81 of fluid channel 15, along which fluid channel 15 emerges at outlet face 80 of armature 6, being oriented perpendicularly to outlet face 80. In this manner, it is possible, inter alia, to form fluid channel 15 from this side, using a bore hole, which may be introduced into the armature perpendicularly to outlet face 80, thereby improving producibility. In this connection, outlet face 80 may lie in an annular surface 82 running about longitudinal axis 4; the annular surface 82 taking the form of a partial surface 82 of a conical envelope 83 axially symmetric with regard to longitudinal axis 4, or the form of a partial surface 82 of a circular disk 84 oriented perpendicularly to longitudinal axis 4. This is possible, for example, by forming a circular groove 85 or a bevel 66.

[0044] The present invention is not limited to the exemplary embodiments described.