WO1994000686A1

WO1994000686A1 - Perforated injection plate for a valve and process for producing it

Info

Publication number: WO1994000686A1
Application number: PCT/DE1993/000481
Authority: WO
Inventors: Ferdinand Reiter; Martin Maier
Original assignee: Robert Bosch Gmbh
Priority date: 1992-06-27
Filing date: 1993-06-04
Publication date: 1994-01-06
Also published as: DE4221185A1

Abstract

A curved perforated injection plate for a fuel injection valve having at least one cylindrical injection aperture inclined obliquely to the longitudinal axis of the valve is known. The injection apertures are parallel to the longitudinal valve axis and produced by stamping the initially plane perforated injection plate, which is then bent at one end of the valve into a conical shape so that the cylindrical injection apertures are inclined in relation to the longitudinal valve axis. The novel perforated injection plate (22) also has at least one injection aperture (27) initially parallel to the longitudinal valve axis. The plate (22) is then plastically deformed at its central region (29) containing the injection apertures (27), by deep drawing, so that the injection apertures (27) are inclined in relation to the longitudinal valve axis (2) and are of a truncated conical shape, increasing in size in the direction of flow. This provides good preparation and high flow stability of the stream of medium provided through the at least one injection aperture (27). The perforated injection plate is especially suitable for injection values of fuel injection devices in internal combustion engines.

Description

Orifice plate for a valve and method of manufacture

State of the art

The invention is based on an orifice plate for a valve or a method for producing an orifice plate according to the preamble of claim 1 and claim 9. JP-OS 3-111 660 discloses a curved orifice plate with a plurality of Cylindrical spray orifices inclined relative to the longitudinal axis of the valve. In this known perforated spray disk, the spray openings are first formed in a flat sheet metal section by stamping. In a subsequent process step, the spray orifice plate is bent by means of a bending tool around the injection-side, frustoconical end of a fuel injection valve, so that the perforated plate is given an approximately conical shape which is rounded in the region of the tip of the cone. However, this known spray hole disk has the disadvantage that, despite the deformation of the spray hole disk, the spray openings maintain their cylindrical shape obtained by stamping. In the case of such cylindrical spraying openings produced by punching, good preparation and good jet stability of the fuel dispensed through the spraying openings is not always guaranteed, since there is a risk that in the edge region of the spraying openings when the fuel emerges fuel collects in the spray openings, which then drips off or is carried away at a later time.

Advantages of the invention

The spray-perforated disk according to the invention with the characterizing features of claim 1 has the advantage over the prior art that good jet stability and good preparation of the medium jet emitted by the at least one spray orifice result and fluttering of the jet is avoided.

The method according to the invention for the production of a spray hole disk with the characterizing features of claim 9 has the advantage of allowing a particularly simple and inexpensive manufacture of the spray hole disk with spray cone-widening spray openings. By forming the at least one spray opening parallel to the longitudinal axis of the valve, the spray openings can be formed very precisely and with only a slight burr formation. A tool used to form the spray openings need not be changed as a function of the angle of inclination of the spray openings with respect to the longitudinal axis of the valve. The deep-drawing of the spray hole disk leads to the widening of the spray openings formed in the central region of the spray hole disk.

The measures listed in the subclaims enable advantageous further developments and improvements of the spray perforated disk specified in claim 1 and of the method specified in claim 9.

For a particularly simple design of the frustoconical extensions of the spray openings, it is advantageous if the central region of the spray orifice plate is domed in the direction facing away from the valve seat surface. It is particularly advantageous if the at least one spray opening is formed by punching by means of a punch which acts parallel to the longitudinal valve axis or by eroding by means of an eroding electrode acting parallel to the longitudinal valve axis, so that the spray openings are very precise and simple in a cost-effective manner are formed with only a slight burr formation.

drawing

Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. FIG. 1 shows a partially illustrated fuel injection valve with an injection orifice disk according to the invention in accordance with a first exemplary embodiment, FIG. 2 shows the production of an injection orifice disk in accordance with the invention in accordance with the first exemplary embodiment, FIG. 3 shows the injection orifice disk in accordance with the first embodiment before it is plastically deformed, 4 shows the spray hole disk according to the first embodiment after its plastic deformation, FIG. 5 shows a partial view of the spray hole disk shown in FIG. 4 in the direction of arrow X in FIG. 4, FIG. 6 shows a spray hole disk according to a second embodiment in front of it plastic deformation, FIG. 7 shows the spray hole disk according to the second embodiment after its plastic deformation, and FIG. 8 shows a partial view of the spray hole disk according to the second embodiment in the direction of arrow Y in FIG. 7, FIG 10, the spray hole disk according to the third embodiment after its plastic deformation, and FIG. 11 a partial view of the spray hole disk according to the third embodiment in the direction of arrow Z in FIG. 10. Description of the embodiments

In FIG. 1, for example, a valve in the form of an injection valve for fuel injection systems of mixture-compressing spark-ignition internal combustion engines is partially shown. The injection valve has a tubular seat support 1, in which a longitudinal bore 3 is formed concentrically with a valve longitudinal axis 2. In the longitudinal bore 3 is e.g. Tubular valve needle 5 arranged, which at its downstream end 6 with a e.g. ball-shaped valve closing body 7 is connected. The injection valve is actuated in a known manner, for example electromagnetically. An indicated electromagnetic circuit with a magnetic coil 10, an armature 11 and a core 12 is used for the axial movement of the valve needle 5 and thus for opening against the spring force or closing of the injection valve. The armature 11 is connected to the end of the valve body 7 facing away from the Valve needle 5 connected and aligned with the core 12.

A guide opening 16 of a valve seat body 18 is used to guide the valve closing body 7 during the axial movement. The circumference of the valve seat body 18 has a slightly smaller diameter than the diameter of the longitudinal bore 3 of the seat carrier 1. On its one lower end face facing away from the valve closing body 7 page 19 is the valve seat body 18 with a bottom part 21 of an example Pot-shaped spray plate 22 concentrically and firmly connected, so that the bottom part 21 with its upper end face

20 bears against the lower end face 19 of the valve seat body 18. The connection of valve seat body 18 and spray orifice plate 22 takes place, for example, by a circumferential and tight, e.g. first weld seam 24 formed by means of a laser. This type of assembly poses the risk of undesired deformation of the base part

21 in the region of its at least one, for example four, spray openings 27 formed by erosion or stamping. The base part 21 of the spray orifice plate 22 is domed in a central region 29, in which the spray openings 27 are formed, in the direction of the valve closing body 7 facing away from the dome. The spray openings 27 are inclined outwards in the flow direction of the fuel with respect to the longitudinal valve axis 2 and run perpendicular to the plane of the central region 29 of the base part 21.

At the bottom part 21 of the pot-shaped spray disk 22 is followed by a circumferential retaining edge 31 which extends in the axial direction facing away from the valve seat body 18 and is conically bent outwards up to its end 32. The holding edge 31 has at its end 32 a larger diameter than the diameter of the longitudinal bore 3 of the seat support 1. Due to the smaller diameter of the circumference of the valve seat body 18 compared to the longitudinal bore 3 of the seat support 1, only lies between the longitudinal bore 3 and the easy Holding edge 31 of the spray-perforated disk 22, which is designed to be conically curved outwards, exerts a radial pressure, the holding edge 31 exerting a radial spring action on the wall of the longitudinal bore 3.

The insertion depth of the valve seat part consisting of valve seat body 18 and cup-shaped spray orifice plate 22 into the longitudinal bore 3 of the seat support 1 determines the presetting of the stroke of the valve needle 5, since the one end position of the valve needle 5 when the solenoid coil 10 is not excited due to the valve closing body being in contact 7 is fixed to a valve seat surface 34 of the valve seat body 18. The other end position of the valve needle 5 is determined when the solenoid 10 is excited, for example by the armature 11 resting on the core 12. The path between these two end positions of the valve needle 5 represents the stroke. At its end 32, which bears against the longitudinal bore 3 of the seat support 1, the holding edge 31 of the spray perforated disk 22 is connected to the wall of the longitudinal bore 3, for example by a circumferential and tight second weld seam 36. The second weld 36 is formed exactly like the first weld 24, for example by means of a laser. A tight welding of valve seat body 18 and spray hole disk 22 as well as spray hole disk 22 and seat support 1 is necessary so that the medium used, for example a fuel, does not pass between the longitudinal bore 3 of the seat support 1 and the circumference of the valve seat body 18 can flow directly into a suction line of the internal combustion engine through the spray openings 27 or between the longitudinal bore 3 of the seat support 1 and the holding edge 31 of the cup-shaped spray hole disk 22. There are thus two fastening points on the cup-shaped spray perforated disk 22. One attachment point is the first weld seam 24 with the valve seat body 18 and the second attachment point is the second weld seam 36 with the seat support 1.

The spherical valve closing body 7 interacts with the valve seat surface 34 of the valve seat body 18 which tapers in the shape of a truncated cone and is formed in the axial direction between the guide opening 16 and the lower end face 19 of the valve seat body 18. As shown on the left of the longitudinal valve axis 2 in FIG. 1, the guide opening 16 has at least one flow passage 38 which between the valve interior 40 bounds in the radial direction through the longitudinal bore 3 of the seat support 1 and a flow in the flow direction Guide opening 16 and the valve seat surface 34 of the valve seat body 18 formed annular groove 42, which is in the open state of the valve with the spray openings 27 of the spray plate 22 in connection. For the exact guidance of the valve closing body 7 and thus the valve needle 5 during the axial movement, the diameter of the guide opening 16 is designed such that the spherical valve The closing body 7 projects through the guide opening 16 with a small radial distance.

A protective cap 45 is arranged on the periphery of the seat carrier 1 at its downstream end facing away from the magnet coil 10 and is connected to the periphery of the seat carrier 1 by means of a latching connection 46. The protective cap 45 rests with a first end radial section 47 on a lower end 48 of the seat support 1. In the direction facing the magnet coil 10, the first radial section 47 of the protective cap 45 is first adjoined by an axially extending parallel section 49 and by a second radial section 50 pointing radially outward. A sealing ring 51 is arranged in an annular groove 53, the side surfaces of which, through an end face 54 of the second radial section 50 of the protective cap 45 facing the magnetic coil 10, and through a radially outwardly facing contact surface 55 of the seat support 1 and the groove base 57 of the circumference of the seat support 1 are formed. The sealing ring 51 serves to seal between the circumference of the injection valve and a valve receptacle, not shown, for example the intake line of the internal combustion engine.

FIG. 2 shows, in a highly simplified manner, the structure for plastically deforming a sheet metal section 60 forming the spray orifice plate 22 by means of deep drawing. The sheet metal section 60, which has at least one, for example four, spray openings 27 formed parallel to the longitudinal axis 2 of the valve, is held by a die 62, which is shown in simplified form, and by means of a deep-drawing tool 64 on its bottom part 21 in the central region having the spray openings 27 29 deformed in such a way that the central region 29 of the base part 21 forms, at least in the region of the spray openings 27, for example a spherical cap section facing the end 32 of the holding edge 31 of the later spray perforated disc 22. The diameter 66 is a die opening 67 into which the middle region 29 of the sheet metal section 60 is pressed by means of the deep-drawing tool 64, depending on the deep-drawing tool 64 and the desired axial extent of the spherical cap section of the central region 29.

3 shows a sheet metal section 60, in which, by means of punching, parallel to the valve longitudinal axis 2, that is to say perpendicularly to the upper end face 20 of the sheet metal section 60, punch 70 acts in the central region 29, for example four spray openings 27, e.g. are formed at the same distance from one another and to the longitudinal valve axis 2, as in FIG. 5, which shows a view of the spray orifice plate 22 shown in FIG. 4 according to the first exemplary embodiment according to the invention shown in FIG. 1 in the direction of arrow X in FIG. 4 is. In the area of the spray openings 27, for example the pot-shaped sheet metal section 60, as is also shown in FIG. plastically deformed by means of deep drawing such that the central region 29 of the base part 21 in the assembled valve in the valve seat body 18 is curved in the shape of a spherical cap. As a result of this deep-drawing process, the four spray openings 27, for example, are inclined outwards in relation to the longitudinal axis 2 of the valve in the direction of flow of the medium and widen in the shape of a truncated cone in this medium flow direction, that is to say the cross section of the spray openings 27 starts from the upper end face 20 to a bottom end Spray face 23 of the spray plate 22 always larger.

The second exemplary embodiment according to the invention shown in FIGS. 6 to 8 differs from the first exemplary embodiment according to the invention shown in FIGS. 1 to 5 essentially only in that in the sheet metal section 60 or the spraying orifice plate 22 in the central region 29 only two spray openings 27 are provided and that these spray openings 27 are are produced parallel to the valve longitudinal axis 2, that is perpendicular to the upper end face 20 of eroding electrodes 72. The two spray openings 27 can be seen, for example, along one in the plane, as shown in FIG. 8, which shows a view of the spray hole disk 22 shown in FIG. 7 according to the second exemplary embodiment according to the direction of the arrow Y in FIG of the bottom part 21, the central longitudinal axis 75 of the spray hole disk 22, which intersects the longitudinal valve axis 2, and is formed at the same distance from the longitudinal valve axis 2. When using such an orifice plate 22, two individual medium jets are sprayed off. As a result of the deep-drawing process, spray openings 27 that widen in the shape of a truncated cone again arise in the medium flow direction.

In the third exemplary embodiment according to the invention shown in FIGS. 9 to 11, as in the second exemplary embodiment according to the invention shown in FIGS. spherical cap-shaped central region 29 of the base part 21, for example, two cone-shaped spray openings 27. The two spray openings 27 are formed in a half 80 of the bottom part 21, which is delimited by a transverse axis 77 running perpendicular to the central axis 75 and intersecting the valve longitudinal axis 2, at the same distance from the longitudinal valve axis 2 and are at the same distance from the through the central axis 75 passing through the longitudinal axis 2 of the valve, as shown in FIG. 11, which shows a view of the spray orifice plate 22 in the direction of the arrow Z in FIG. 10.

In the method according to the invention for the production of a spray perforated disk 22, a sheet metal section 60 is thus first produced, for example with a peripheral holding edge 31 and a flat bottom part 21. Then in the sheet metal section 60, for example by stamping or eroding, the at least one spray opening 27 parallel to the valve longitudinal axis 2 formed, the punch 70 and the eroding electrodes 72 act parallel to the valve longitudinal axis. Subsequently, the sheet metal section 60 is deformed into a spherical cap shape in a central region 29 having the spray openings 27 by means of a deep-drawing tool 64, for example in the direction of the end 32 of the holding edge 31. In such an orifice plate 22, the spray openings 27 are inclined outward in the medium flow direction with respect to the valve longitudinal axis 2 and widen in the shape of a truncated cone in the medium flow direction.

The method according to the invention has the advantage of forming the spray openings 27 in a very precise manner and of ensuring a slight burr formation of the spray openings 27. In order to change the inclination of the spray openings 27 with respect to the longitudinal valve axis 2, it is not necessary to change the punching tool having the punch 70. It is easier, e.g. to vary the embossing depth when deep-drawing sheet metal section 60.

Claims

Expectations

1. Spray hole disk for a valve, in particular for an injection valve for fuel injection systems of internal combustion engines, with a movable valve closing body, a valve axis, a valve seat surface interacting with the valve closing body, with a spray hole disk arranged downstream of the valve seat surface, which is in a central region is curved in the direction facing away from the valve seat and has at least one spray opening which is inclined relative to the valve axis, characterized in that the at least one spray opening (27) is formed in the curved, central region (29) and its cross section widens conically in the direction facing away from the valve seat (34).

2. spray-perforated disc according to claim 1, characterized in that the central region (29) of the spray-perforated disc (22) is domed in a dome shape.

3. Orifice plate according to claim 1 or 2, characterized in that in the orifice plate (22) four spray openings (27) are formed at the same distance from each other.

4. spraying disc according to one of claims 1 to 3, with at least two spray orifices, characterized in that the Absprühöff¬ openings (27) in the spraying disc (22) with the same distance to the valve ngsachse (2) are formed.

5. spray-perforated disc according to one of claims 1 to 4, which has a central axis passing through the longitudinal axis of the valve and at least two spray openings, characterized in that the spray openings (27) are at the same distance from the central axis (75).

6. spray hole disc according to claim 5, characterized in that the spray openings (27) in one half (80) of the spray hole disc (22) are formed.

7. spray plate according to claim 4, which has a central axis passing through the valve axis, characterized in that the two spray openings (27) are formed on the central axis (75).

8. spray perforated disk according to claim 5, characterized in that two spray openings (27) are formed on the central axis (75).

9. A method for producing a spray hole disk, in particular a spray hole disk designed according to one of claims 1 to 8, characterized in that a sheet metal section (60) is produced in a first method step, in a second method step in the sheet metal section ( 60) at least one spray opening (27) is formed in a central region (29) perpendicular to an upper end face (20) of the sheet metal section (60) and in a third process step the sheet metal section (60) is deep drawn to form a spray perforated disk (22) deformed and the Spritzloch¬ disc (22) is arched in the central region (29).

10. The method according to claim 9, characterized in that the at least one spray opening (27) is formed by stamping.

11. The method according to claim 9, characterized in that the at least one spray opening (27) is formed by eroding.

12. The method according to claim 9 or 11, characterized in that the central region (29) is dome-shaped.

13. The method according to any one of claims 9 to 12, characterized gekenn¬ characterized in that in the sheet metal section (60) four spray openings (27) are formed with the same distance from each other.

14. The method according to any one of claims 9 to 13, characterized gekenn¬ characterized in that in the sheet metal section (60) at least two Abspritzöff¬ openings (27) with the same distance to the valve longitudinal axis (2) are formed.

15. The method according to any one of claims 9 to 14, characterized gekenn¬ characterized in that in the sheet metal section (60) at least two spray openings (27) are formed which are the same distance from a central axis (75) passing through the valve longitudinal axis (2) ) have.

16. The method according to claim 16, characterized in that the Ab¬ spray openings (27) in one half (80) of the spray orifice plate (22) are formed.

17. The method according to claim 14 or 15, characterized in that in the sheet metal section (60) two spray openings (27) are formed on a central axis (15) passing through the longitudinal valve axis (2).