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. A valve for metering a fluid, comprising: a valve housing, in which an internal pole is stationary-mounted; an electromagnetic actuator which includes an armature situated in an armature space and positioned on a valve needle, wherein the valve needle is operable by the actuator using the armature, the armature being guided on the valve needle, wherein the valve needle is situated inside of the valve housing and is guided along a longitudinal axis of the valve needle and/or the armature, relative to the valve housing; a first stop element that interacts with a first end face of a first stop element of the armature during operation, and a second stop element that interacts with a second end face of a second stop element 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 first stop element and the second stop element are positioned on the valve needle; a valve-closure member, which interacts with a valve-seat surface to form a sealing seat, is formed on the valve needle, wherein upon actuation of the armature, the valve-closure member is accelerated in a direction of the internal pole, and wherein when the armature strikes against the first stop element, which is a limit stop, to actuate the valve needle, the fluid is then injected through the sealing seat in an open configuration, and at least one nozzle opening, into a space; wherein the armature has at least one fluid channel, which, during operation, allows the 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 at least one fluid channel incorporating at least a portion of the spring receptacle, and wherein the at least one fluid channel runs radially outwardly in sections, along a direction, which is oriented from the first end face towards the second end face and is coaxial relative to the longitudinal axis, wherein the at least one fluid channel includes an oblique bore hole, wherein the at least one fluid channel leads through the oblique bore hole and at least a portion of the spring receptacle, wherein a coaxial direction with regard to the longitudinal axis results, which is oriented from the first end face to the second end face, wherein the oblique bore hole is formed in the armature so that it runs radially outwards along the coaxial direction and away from the longitudinal axis, so that there is an angle of inclination between the coaxial direction and an axis of oblique bore hole, and wherein the at least one 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.

2. The valve as recited in claim 1, wherein the valve includes a fuel injector for an internal combustion engine.

3. The valve as recited in claim 1, wherein a point of a first opening of the at least one 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 at least one fluid channel, away from the longitudinal axis, lying radially inwards to a maximum extent.

4. The valve as recited in claim 1, wherein the at least one fluid channel goes out to the second region of the armature space at an outlet face of the armature, and an axis of the at least one fluid channel, along which the at least one fluid channel emerges at the outlet face of the armature, is oriented perpendicularly to the outlet face.

5. The valve as recited in claim 1, wherein an 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.

6. The valve as recited in claim 1, wherein the at least one fluid channel runs continuously radially outwards along the coaxial direction.

7. The valve as recited in claim 1, wherein the at least one fluid channel includes the at least one oblique bore hole, which runs at least radially outwards along the coaxial direction.

8. The valve as recited in claim 7, wherein the oblique bore hole runs from the first end face of the armature to the second end face of the armature.

9. The valve as recited in claim 7, wherein the oblique bore hole is intersected by the spring receptacle.

10. The valve as recited in claim 7, wherein the oblique bore hole is intersected by the spring receptacle so that a base of the spring receptacle is cut by the oblique bore hole.

11. The valve as recited in claim 1, 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.

12. The valve as recited in claim 1, wherein the armature has a cylindrical form having a through-hole, wherein the armature is guided at the through-hole, on the valve needle, wherein the cylinder form of the armature has a length between the first end face of the first stop element of the armature facing the internal pole and the second end face of the second stop element of the armature facing away from the internal pole, wherein the armature is positioned in the armature space, in which the first end face borders on a first region of the armature space and in which the second end face borders on a second region of the armature space, and wherein during operation, the fuel passes through the armature over at least a portion of its length by the at least one fluid channel.

13. The valve as recited in claim 12, wherein the armature includes the spring receptacle, wherein the at least one fluid channel also includes the spring receptacle, wherein the at least one fluid channel leads through at least a portion of the spring receptacle, wherein the spring receptacle is open, wherein a spring support surface, at which the spring partially situated in the spring receptacle is supported, is formed by a base of the spring receptacle, and wherein upon actuation of the armature, the spring is shortened with respect to its starting length; so that it is insertable completely into the spring receptacle.

14. The valve as recited in claim 1, wherein the armature includes the a spring receptacle, wherein the at least one fluid channel also includes the spring receptacle, wherein the at least one fluid channel leads through at least a portion of the spring receptacle, wherein the spring receptacle is open, wherein a spring support surface, at which the spring partially situated in the spring receptacle is supported, is formed by a base of the spring receptacle, and wherein upon actuation of the armature, the spring is shortened with respect to its starting length; so that it is insertable completely into the spring receptacle.

15. A valve for metering a fluid, which is a fuel injection valve for an internal combustion engine, comprising: an electromagnetic actuator, which has an armature in an armature chamber, and which is positioned on an armature operable valve needle, so that the armature is guided on the valve needle, wherein the valve needle is situated inside of a valve housing and is guided along a longitudinal axis of the valve needle and/or the armature, relative to the valve housing; a first stop element which, during operation, interacts with a first end face of the armature on the valve needle; a second stop element which, during operation, interacts with a second end face of the armature, and limits a movement of the armature relative to the valve needle; and a valve-closure member, which interacts with a valve-seat surface to form a sealing seat, is formed on the valve needle, wherein upon actuation of the armature, the valve-closure member is accelerated in a direction of the internal pole, and wherein when the armature strikes against the first stop element, which is a limit stop, to actuate the valve needle, the fluid is then injected through the sealing seat in an open configuration, and at least one nozzle opening, into a space; wherein the armature has a spring receptacle which is open towards the first end face of the armature and into which a spring supported on the stop element is inserted, wherein the armature has at least one fluid channel which, during operation, allows fluid to be passed through between a first region of the armature space adjoining the first end face of the armature and a first region adjoining the second area of the armature space adjoining the second end face of the armature allows the fluid channel to at least partially include the spring receptacle and the fluid channel to run along one of the first end face in a direction oriented towards the second end face and coaxial with respect to a longitudinal axis, at least in sections extending radially outwards, wherein the fluid channel has at least one oblique or inclined bore which runs at least radially outwards along the coaxial direction, wherein the oblique or inclined bore intersects or is miscut with a spring mount over an entire length of the spring mount along a longitudinal axis, wherein a radially external point at a maximum distance from the longitudinal axis is outside the spring receptacle or is radially directly on the edge of the spring receptacle.

16. The valve as recited in claim 15, wherein a point of a first opening of the fluid channel that is radially at a maximum inner location from the longitudinal axis is closer to the longitudinal axis than a point a second opening of the fluid channel.

17. The calve as recited in claim 15, wherein the fluid channel exits at an exit surface of the armature towards the second region of the armature space, and wherein an axis of the fluid channel, along which the fluid channel exits at the exit surface of the armature, is oriented perpendicular to the exit surface.

18. The valve as recited in claim 15, wherein the exit surface lies in an annular surface that runs around the longitudinal axis and that the annular surface as a partial surface of a cone shell, which is rotationally symmetrical with respect to the longitudinal axis, or as a partial surface a circular disc oriented perpendicularly to the longitudinal axis.

19. The valve as recited in claim 15, wherein the fluid channel along the coaxial direction runs continuously radially outwards.

20. The valve as recited in claim 15, wherein the oblique or inclined bore runs from the first end face of the armature to the second end face of the armature.

21. The valve as recited in claim 15, wherein the oblique or inclined bore is intersected with the spring mount so that a bottom of the spring mount is cut into by the oblique or inclined bore.

22. The valve as recited in claim 15, wherein the spring receptacle includes an annular groove not adjoining the valve needle, so that a guide web is formed on the armature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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.

(2) FIG. 1 shows a schematic sectional view of a portion of a valve according to a first exemplary embodiment.

(3) FIG. 2 shows a schematic sectional view of a portion of a valve according to a second exemplary embodiment.

(4) FIG. 3 shows a schematic sectional view of a portion of a valve according to a third exemplary embodiment.

(5) FIG. 4 shows a schematic sectional view of a portion of a valve according to a fourth exemplary embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(6) 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.

(7) 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.

(8) 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.

(9) 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.

(10) 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.

(11) 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.

(12) 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.

(13) 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.

(14) 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.

(15) 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.

(16) 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.

(17) 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.

(18) 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.

(19) 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.

(20) 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.

(21) 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.

(22) 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.

(23) 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.

(24) 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.

(25) 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.

(26) 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.

(27) 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.

(28) The present invention is not limited to the exemplary embodiments described.