Title of Invention

VALVE WITH COMBINED VALVE SEAT BODY AND PERFORATED INJECTION DISC

Abstract

The invention relates to a valve, in particular a fuel injection valve for fuel injection systems of internal combustion engines, having a valve seat surface (17), which is formed on a valve seat body (14) and interacts with an actuable valve closure member (8) to form a sealed seat, and also having a perforated injection disc (15) which has at least one injection orifice (18). According to the development of the invention, the valve seat body (14) and the perforated injection disc (15) are formed in one piece from a planar, deformable workpiece (16). The workpiece (16) is shaped in the form of a cup, in such a manner that, in the region of the valve seat surface (17), it bears in a sealing manner against the unactuated valve closure member (8) in the closed position of the valve (1) and, in a region d<. wnstream of the valve seat surface (17), forms the perforated injection disc (15) having at least one injection orifice (18).

Full Text

Valve With combined valve seat body and perforated injection disc Prior art The invention is based on a valve, in particular a fuel :injection valve for fuel injection systems of internal qombustion engines, in accordance with the. preamble of Claim 1. DE 42 21 185 Al has already disclosed a fuel injection valve in which the valve seat body is produced by means of a metal-removing manufacturing process. In the region of the valve seat, the * valve seat body must undergo a precision finishing operation after the metal-removing machining, in order to achieve the accuracy which is required for the sealing function during interaction with a ball-shaped valve closure member. A separately produced perforated injection disc is connected to the valve seat body in a sealing manner by welding. The welded joint has the disadvantage that the action of heat may lead to an undesired deformation. The known two-part combination of valve seat body and perforated injection disc requires a relatively high production expenditure both for production of the valve seat body and the perforated injection disc and for mounting these components on a valve seat support of the fuel injection valve. The relatively high processing expenditure and the relatively high material costs lead overall to relatively high manufacturing costs. Advantages of the invention The valve according to the invention having the characterizing features of Claim 1 has the advantage over the prior art that the valve seat body and the perforated injection disc are integrated in a one-piece combined component, it being possible to produce this combined component from a planar, deformable workpiece, e.g. a sheet-metal part, in a simple, material-saving manner by means of a deep-drawing process. Particularly in large-scale series production, this results in a significant saving on costs., Forming the valve seat body and the perforated injection disc from a single , metal . sheet leads not only to easy machining and a low weight} of the combination of valve seat body and perforated injection disc, but also to a reduction in the material requirement. Furthermore, the sealing properties are improved. '■ ' ' '. Advantageous developments of, and improvements to, the ■■ ■ ■- ■ valv& described in Claim 1 are possible by means of the :' measures listed in the subclaims. * ' . i i. i It is advantageous to provide a preferably polyhedral ' guide section upstream of the valve seat surface, so that the valve closure member is guided axially during its opening and closing movements. The polyhedral design of the guide section ensures unimpeded flow of the medium flowing through the valve as far as the sealing valve seat surface. It is likewise advantageous for the planar, deformable workpiece, on which the valve seat surface and the perforated injection disc are formed, to be bent over downstream of the guide section, so that a fastening section of the planar, deformable workpiece runs in the direction of flow towards a surrounding end of this workpiece. This has the advantage, firstly, that the surrounding end of the workpiece is readily accessible in order for it to be fastened to the valve seat support, for example by applying a weld seam. Secondly, this has the advantage that the workpiece can be displaced in the valve seat support, in order to adjust the opening lift of the valve, by means of a displacement tool acting from the injection side, without the workpiece becoming jammed in the valve seat support * :! After fastening the workpiece to the valve seat; support, the position of the valve seat, and hence the ' valve lift and/or the maximum flow rate of the valve can still be adjusted easily by means of the displacement tool. In the process, the workpiece is deformed plastically to a minor extent only in regions remote from the seat. i Et is advantageous here if the displacement tool is adapted to the shape of the workpiece, so that the displacement tool acts only on the fastening section and/or the turn section of the workpiece, in order to avoid deformation of the valve seat surface, or of the section forming the perforated injection disc, during :he displacement operation used to adjust the lift. Drawing exemplary embodiments of the invention are illustrated .n a simplified manner in the drawing and are explained .n more detail in the following description. In the Irawing: 'ig. 1 shows an exemplary embodiment of the invention m the basis of a fuel injection valve which is shown [iagrammatically in a partial sectional representation, 'ig. 2 shows a section on the line II-II in Fig. 1, ig. 3 shows a further.exemplary embodiment of a valve hown diagrammatically in a partial representation, ogether with a displacement tool for adjusting the alve '" lift, and Fig. 4 shows yet another exemplary mbodifment of a valve, shown in a diagrammatic partial epre^entation, together with a displacement tool for djustjing the valve lift. Descx-iption of the exemolary embodiments Fig. 1 diagrammatically depicts, by way of example, a ivalve in; the form of a fuel injection valve for fuel injection systems of mixture-compressed, spark-ignition "internal combustion engines, in a partial representation. However, the present invention can be employed not only for fuel injection valves but also for other types of valves for liquid or gaseous media. i i. The fuel injection valve 1 has a tubular valve seat support 3 which is partially surrounded by an injection-moulded plastic casing 2. A longitudinal bor^ 5 is formed in the valve seat support 3, concentrically with respect to the longitudinal axis 4 of the valve. In the longitudinal bore 5 there is arranged a valve needle 6, which in the exemplary embodiment is tubular and at its downstream end 7 is connected to a valve closure member 8, which in the exemplary embodiment is ball-shaped, for example by welding at a weld seam 9. The fuel, which flows in, for example, via the interior of the valve needle 6, can pass unimpeded into the longitudinal bore 5 via lateral openings 10 and can flow to the valve closure member 8. The fuel inj ection valve 1 is actuated in a known manner, for example electromagnetically. An electromagnetic circuit, which is only indicated and comprises a magnet coil 11, an armature 12 and a core 13 which is surrounded by the magnet coil 11, serves to move the valve needle 6 axial ly and thus to effect opening counter to the spring force of a return spring (not shown) . The armature 12 is connected to that end of thej valve needle 6 . which is remote from the valve :closur4 member 8 and is aligned with the core 13. >■ i i i The valve closure member 8 interacts with a valve seat surface 17 formed on a valve seat body 14 to form a sealed seat. Injection orifices 18, for injecting the medium, in the exemplary embodiment the fuel, flowing through the valve, are made in a perforated injection disc 15. According to the invention, the valve seat . body 14 and the perforated injection disc 15 are integrated in a on£-piece, planar, deformable workpiece 16. The one-piece, planar workpiece 16 is preferably a sheet-metal part, which is made into the cup shape illustrated in Fig. 1 by deep-drawing. The workpiece 16 is formed f rustoconically in the region of the valve seat body 14, so that the ball-shaped valve closure member 8 bears in a sealing manner against an encircling contact line on the valve seat surface 17. In order to improve the sealing closure between the valve closure member 8 and the valve seat surface 17, the valve seat surface 17 may be finished after the deep-drawing of the workpiece 16 by means of a suitable finishing process, e.g. by polishing, so that the necessary dimensional accuracy is achieved. That section of the workpiece 16 which forms the perforated -injection disc 15 is situated downstream of that section of the workpiece 16 which forms the valve seat body 14. In the region of the perforated injection disc 15, the workpiece 16 is curved in the shape of a dome in the direction of flow, so that the injection orifices, of which there are preferably several, for example four, are inclined outwards with respect to the longitudinal axis 4 of the valve. This improves the injection characteristics of the fuel injection valve 1 refined in accordance with the invention. The dome-shaped curvature of that section of the workpiece 16 which forms the perforated injection disc 15 also means that the workpiece 16 does not bear against the ball-shaped valve closure member 8 in the region of the injection orifices 18. ■'i ' . .., ■ i A guide section 19 is provided upstream of that section of the workpiece 16 which forms the valve seat body 14. In t>rder better to illustrate the geometry of the workpiece 16 in the guide section 19, Fig. 2 shows a section on line II-II in Fig. 1. The ball-shaped valve closure member 8, which is embedded in the guide section 19 of the workpiece 16, can be seen. The workpiece 16 is of polyhedral design in the guide :sectioiji 19 and has a plurality of guide surfaces 20, which jin combination form a polyhedron with rounded corners 21. The; polyhedron may, for. example, have five corners 21 and five guide surfaces 20. In order to guide the valve closure member 8, the guide surfaces 2 0 'bear ; against the valve closure member 8 at contact | locations, 22. The result is thus flow apertures 23 ,-. betjweon^ the contact locations 22, which flow apertures :'allow the; medium, in the exemplary embodiment the fuel, l' flowing through the valve to pass unhindered as far as 'I ; the valve seat surface 17. i: As can be seen from Fig. 1, upstream of the guide section 19 the planar, deformable workpiece 16 is bent over, in the exemplary embodiment through 180°, in a turn section 24, so that a radially outer fastening section 25, which adjoins the turn- section 24, extends, parallel to the direction of flow of the medium flowing through the fuel injection valve 1, towards a surrounding end 2 6 of the workpiece 16. In the exemplary embodiment illustrated in t Fig. 1, the fastening section 25 bears over its entire axial length against the inner wall of the longitudinal bore 5 in the valve seat support 3, and is connected to the valve seat support 3 at the surrounding end 26 in a form-fitting and sealing manner, preferably by means of a weld seam 27. The sealing connection between the workpiece 16 and the valve seat support 3 ensures that the medium flowing through the fuel injection valve 1 does not circumvent the sealed seat and flow between the valve seat support 3 and the workpiece 16. The end 26 of the workpiece 16 is situated downstream of the injection orifices 18, so that accessibility of the surrounding end 26 in order , to apply the weld seam 27 is ensured. The large-area contact between the fastening section 26 and the valve seat support 3 allows the heat produced on the valve seat support 3 during the welding operation to be dissipated, so that overheating of the guide section 19, of the section forming the valve seat body 14 and of that section of the workpiece 16 which forms the perforated injection disc 15 is avoided. This counteracts deformation of these|regions when the workpiece 16 is being welded to the valve seat support 3. The injection orifices 18 may be made in the workpiece 16 in a manner known per se, by punching, drilling, laser : drilling, eroding or any other suitable manufacturing process. The injection orifices 18 may eith|erL jbe made in the as yet undeformed blank of the wbrkpiec^ 16 ; or may be made in the already deformed workplace 16 at a later time. Figs. 3 and 4 show further ; exemplary "embodiments of a fuel' injection valve 1, which is illustrated only partially and in section, the fastening section 25 and the valve seat support 3 in each case being modified with, respect to the exemplary embodiment illustrated in Fig. 1 and described above. In the exemplary embodiment shown in Fig. 3, the diameter of the longitudinal bore 5 provided in the valve seat support 3 is larger than in the exemplary embodiment shown in Fig. 1. The fastening section 25 of the workpiece 16 is divided up into three regions: a first axial section 25a, which adjoins the turn section 24 in the direction of flow, a second axial section 25c, which adjoins the surrounding end 2 6 and bears against the inner wall of the longitudinal bore 5, and a radial section 25b, which connects the first and the second axial sections 25a and 25c with a radial component. In this exemplary embodiment too, the 1 I surrounding end 2 6 of the workpiece 16 is welded to the valve seat support 3 at a sealing, encircling weld seam 27. This exemplary embodiment has the advantage over the exenplajry embodiment illustrated in Fig. 1 firstly that the distance between the weld seam 27 and the guide section; 19 atid also the sections forming the valve seat bociy 14 and the perforated injection disc 15 is lengthened by the radial section 2 5b, which additionally counteracts thermal deformation of the abovementioned regions while the weld seam is being applied. Furthermore, the geometric shaping of the workpiece 16 illustrated in Fig. 3 has the additional considerable advantage that a displacement tool 40, which serves to adjust the lift of the fuel injection valve 1 according to the invention, can act unimpeded on the radial section 25b of the fastening section 25. The depth to which the workpiece 16 is inserted in the longitudinal bore 5 in the valve seat support 3 determines the initial setting of the lift of the valve needle 6, since one limit position of the valve needle 6 is fixed, when the magnet coil 11 is not excited, by the valve closure member 8 bearing against the valve seat surface 17. The other limit position of the valve needle 6, with the magnet coil 11 excited, is fixed, for example, by the armature. 12 bearing against the core 13. The distance between these two limit positions of the valve needle 6 represents the valve lift. The displacement tool 40 is of bell-shaped design, so that those regions of the workpiece 16 which form the valve seat body 14 and the perforated injection disc 15 penetrate into a bell-shaped recess 41 in the displacement tool 40 when the displacement tool 40 acts 1 on tthe radial section 25b. This prevents deformation of the ; guide section 19 and of the regions forming the i ' i valve seat body 14 and the perforated injection disc 15 during the axial displacement /of the workpiece 16 in the longitudinal bore 5 in the valve seat support 3 for the purpose of adjusting the lift. The second axial section 25c has a slightly greater diameter than the internal diameter of the longitudinal bore 5, so that the second axial section 25c presses in a spring-loaded manner against the inner wall of the longitudinal bore 5 and locks the workpiece 16 in the longitudinal bore 5. The exemplary embodiment depicted in Fig. 4 differs from that illustrated in Fig. 3 in that the first axial section 2 5a of the fastening section 2 5 of the workpiece 16 is made longer and the radial section 25b and the second axial section 2 5c are made shorter. At the injection-side end of the valve seat support 3, the longitudinal bore 5 in the valve seat support 3 is designed as a stepped bore and has a step 5b which adjoins the step 5a on the injection side and has a widened diameter. The second axial section 25c is welded to the widened stepped bore 5b, while the first axial section 2 5a bears in a spring-loaded manner against the step 5a of the longitudinal bore 5. This embodiment too provides good dissipation of the heat generated on the valve seat support 3 during welding, thus | counteracting thermal deformation of the guide section 19 and of the regions forming the valve seat body 14 and the perforated injection disc 15. ; i In this exemplary embodiment too, the displacement tool ■ J , ■ 40 pan: ^ct on the radial section 25b of the fastening j ' i ■'", ' '■ 'sjectiQn i! 25 6f the workpiece 16, that region of the ■. i workpiece 16'which forms the perforated injection disc 15 penetrating into a trough 42 provided for this purpose in the displacement tool 40. In order to provide resistance to wear, the workpiece 16 may either be made from a hard base material or may be hardened in regions or everywhere. It is also conceivable to protect the workpiece 16 by applying a coating of hard material, for example of TiN, at least at the regions which are subject to wear. WE CLAIM : 1. A valve, in particular fuel injection valve for fuel injection systems of internal combustion engines, having a valve seat surface which is formed on a valve seat body and interacts with an actuable valve closure member to form a sealed seat, and having a perforated injection disc which has at least one injection orifice, charactenzed in that the valve seat body (14) and the perforated injection disc (15) are formed in one piece from a planar, deformable workpiece (16), which is shaped in the form of a cup in such a manner that, in the region of the valve seat surface (17), it bears in a sealing manner against the unactuated valve closure member (8) in the closed position of the valve (1) and, in a region downstream of the valve seat surface (17), forms the perforated injection disc (15) having at least one injection orifice (18). 2. The valve according to Claim 1, wherein the planar, deformable workpiece (16) is a sheet-metal part and can preferably be deformed by deep-drawing. 3. The valve according to Claim 1 or 2, wherein the planar, deformable workpiece (16) is curved in the shape of a dome in the region of the perforated injection disc (15). 4. The valve according to one of Claims 1 to 3, wherein the valve closure member (8) is formed in the shape of a ball or part of a ball and the valve seat surface (17) is frustoconical. 5. The valve according to one of Claims 1 to 4, wherein the planar workpiece (16), upstream of the valve seat surface (17), is formed into a guide section (19) which guides the movement of the valve closure member (8) when the latter is actuated. 6. The valve according to Claim 5, wherein guide surfaces (20), which are in contact with the valve closure member (8) at contact locations (22), and flow apertures (23), which are arranged between the contact locations (22), are provided on the guide section (19). 7. The valve according to Claim 6, wherein the valve closure member (8) is designed in the shape of a ball or part of a ball and the guide section (19) is polyhedral, preferably with rounded corners (21). 8. The valve according to one of Claims 5 to 7, wherein the planar, deformable workpiece (16) is bent over, upstream of the guide section (19), in a turn section (24), so that a fastening section (25), which adjoins the turn section (24), extends, essentially parallel to the direction of flow of the medium flowing through the valve (1), in the direction of a surrounding end (26) of the planar, deformable workpiece (16). 9. The valve according to Claim 8, wherein the valve (1) has a valve seat support (3) with a longitudinal bore (5), into which the planar, deformable workpiece (16) can be inserted and can be joined to the fastening section (25), preferably by welding. 10. The valve according to Claim 9, wherein the planar, deformable workpiece (16) can be displaced, by means of a displacement tool (40), in the longitudinal bore (5) of the valve seat support (3) in order to adjust the valve lift. 11. The valve according to Claim 10, wherein the displacement tool (40) is adapted to the shape of the workpiece (16) in such a manner that it acts only on the fastening section (25) and/or on the turn section (24). 12. The valve according to one of Claims 1 to 11, wherein the planar, deformable workpiece (16) is hardened, at least in the region of the valve seat surface (17), in particular by coating with a layer of hard material. 13. A valve, in particular fuel injection valve for fuel injection systems of internal combustion engines substantially as herein described with reference to the accompanying drawing.

Documents:

2574-mas-1997-abstract.pdf

2574-mas-1997-claims duplicate.pdf

2574-mas-1997-claims original.pdf

2574-mas-1997-correspondance others.pdf

2574-mas-1997-correspondance po.pdf

2574-mas-1997-description complete duplicate.pdf

2574-mas-1997-description complete original.pdf

2574-mas-1997-drawings.pdf

2574-mas-1997-form 1.pdf

2574-mas-1997-form 26.pdf

2574-mas-1997-form 3.pdf

2574-mas-1997-other documents.pdf