Abstract:
A method for manufacturing an injector having an extrusion coating, including the following steps: providing an injection module, pushing a disk-shaped alignment element onto a part of the injection module, the alignment element having a slot in order to have sufficient flexibility, welding the alignment element onto the part of the injection module, at least part of the slot also being welded shut at the same time during the welding-on step in order to stiffen the alignment element, and molding the extrusion coating onto the injection module.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an alignment element for an injector and a method for manufacturing an injector having a plug molding. 
       BACKGROUND INFORMATION 
       [0002]    Injectors are known from the related art in various embodiments. Frequently, the installation situations for injectors are different for various types of engines, in particular with regard to their alignment. However, the alignment of the injectors is important, since a different spray pattern of the injector is obtained, depending on the alignment. However, since the spray pattern has effects on the fuel consumption and exhaust gas emissions, the injector in recent engines must be very precisely aligned. One alignment option, for example, would be to provide flat polished surfaces on the injection module. However, this results in an undesirable cost increase. In addition, it may be necessary to provide a specific polished surface for each type of engine. Alternatively, an additional component having alignment surfaces could be situated on the injector. This would also have the same disadvantages as the flat polished surfaces described above, and the level of effort for the alignment is shifted to the alignment operation during installation of the additional component. In addition, recent injectors have a partial plastic extrusion coating for forming a plug-in connection. The plug-in connection could also be used here as an alignment element for the injector, but the large number of injection molds required due to the variety of engine types is likewise disadvantageous. 
       SUMMARY 
       [0003]    The method according to the present invention for manufacturing an injector has the advantage that an alignment element is provided which may be easily pushed onto a part of a preassembled injection module, so that the injection module together with the alignment element may be inserted into an injection mold in an aligned manner, and the extrusion coating may be molded on in a subsequent step. The alignment element is flexible during the pushing-on operation, and is welded to the injection module with the aid of a welding step. At the same time as the welding-on operation, a stiffening of the alignment element is carried out so that the alignment element in particular withstands the subsequent injection process. For this purpose, the alignment element is essentially disk-shaped and has at least one slot. The slot provides the flexibility during the pushing-on operation. In the subsequent welding step the slot is welded shut at the same time as the alignment element is welded onto the injection module, so that the rigidity of the alignment element which is then necessary for the injection process is present. Thus, the present invention elegantly achieves the aim that on the one hand it should be easy to push on the alignment element, which requires a reduced rigidity, and on the other hand the alignment element should be as rigid as possible for the injection process in order to avoid deformation due to a high injection pressure, and thus a misalignment in the injection mold. The alignment element which is stiffened by the welding operation in particular prevents a deformation from occurring during the injection process in such a way that the alignment element comes into contact with a wall area of the injection mold, so that it would be externally visible in the finished injector. As a result, however, the injector would no longer be leak-tight against spray water. However, according to the present invention a stiffening of the alignment element is carried out at the same time as the welding-on process of the alignment element to the preferably tubular part of the injection module, so that the alignment element may be simultaneously fastened to the injection module and stiffened in one step. 
         [0004]    For the welding-on step, the injection module together with the alignment element which is pushed onto same are particularly preferably rotated. A particularly simple welding step may be carried out in this way. 
         [0005]    According to another preferred embodiment of the present invention, a welding plane in which the alignment element is welded to the injection module does not coincide with a welding plane in which the slot is welded shut. This allows greater freedom of design of the alignment element without thus impairing the quality of the weld seam for fixing the alignment element to the injection module. 
         [0006]    The alignment element particularly preferably has a tongue, which for the stiffening is at least partially welded to a base area of the alignment element in the welding-on step. The tongue may be easily produced by a punching step, for example, in which the slot is also provided in the alignment element at the same time. 
         [0007]    The alignment element also preferably has a first and/or second tab, the first and/or second tab being situated adjacent to the tongue. The tongue is then welded to the first and/or second tab in the welding-on step. As a result of this measure, welding and thus stiffening of the alignment element in a different plane may be easily provided. 
         [0008]    The welding is particularly preferably carried out with the aid of a laser, or alternatively, with the aid of two lasers oppositely situated from one another at an angle of 180°. When two lasers are used, it is necessary to rotate the injection module by only 180°. 
         [0009]    Moreover, the present invention relates to an alignment element for an injector, which is fastenable to a preassembled injection module and is designed for alignment in an injection mold in order to apply an extrusion coating, in particular a plug molding, to the injection module. The alignment element includes a collar extending in the axial direction, a base area radially adjoining the collar, and an edge area radially adjoining the base area. In addition, a central through opening and a first slot, which is oriented in the radial direction and has a continuous design in the axial direction of the alignment element, are provided. The first slot extends radially outwardly, starting from the through opening. This results in flexibility of the alignment element, in particular in the area of the inner collar. Thus, this allows the alignment element to be very easily pushed onto a part of the injection module, which in particular is tubular. The collar is then welded to the injection component in the subsequent fastening step, and the alignment element is thus stiffened. An extrusion coating, in particular a plug receptacle, may be subsequently molded on, preferably in the area of the alignment element. The through opening is preferably elliptical. 
         [0010]    The alignment element also preferably includes at least one second curved slot which is oriented in the peripheral direction and which likewise has a continuous design in the axial direction. Providing a slot which is oriented in the radial direction and a slot which is oriented in the peripheral direction results in flexibility in the radial and axial directions as well as in the peripheral direction, so that the alignment element may be pushed on in a particularly easy manner. 
         [0011]    The first and second slots of the alignment element preferably intersect. This results in a further increase in the flexibility of the alignment element, thus making it even easier to push on the alignment element. 
         [0012]    According to another preferred embodiment of the present invention, the alignment element also includes a tongue which protrudes into one of the slots. As a result of the tongue, particularly simple stiffening of the alignment element via a welding operation may be achieved by welding the tongue to a part of the alignment element. At the same time, at least one of the slots, preferably all slots, is/are preferably shut by the welding. 
         [0013]    The alignment element also preferably includes a first and/or second tab which is/are situated at the base area, and the first and/or second tab is/are preferably situated adjacent to the tongue, and the tabs may thus be welded to the tongue during the welding step. 
         [0014]    For even greater flexibility of the alignment element, the alignment element also includes a third slot which is oriented in the radial direction and is axially continuous, and/or a fourth slot which is oriented in the peripheral direction and is axially continuous, and the first and third slot and the second and fourth slot are particularly preferably formed symmetrically with respect to a center plane through the alignment element. 
         [0015]    The alignment element also preferably includes a second slot which is oriented in the radial direction, at least one of the radial slots, as the continuous slot in the radial direction, extending from the through opening to the edge of the alignment element. As a result, the alignment element has a C shape and is no longer closed at at least one area in the peripheral direction. The alignment element may thus be spread apart in the peripheral direction, so that even greater ease of installation is achieved. 
         [0016]    In addition, at least one of the slots preferably has an expanded area. The expanded area may be curved, for example. In particular after completion of an injection pass in which the slots are filled by the injection molding material, this results in improved rigidity and reliable filling of the relatively narrow slots with injection molding material. 
         [0017]    The alignment element also preferably includes a base area which is inclined with respect to a base plane. 
         [0018]    To obtain even better permeability of the injection molding material, the alignment element preferably has a plurality of through openings, in particular circular through openings, at the base area. To also allow simple and reliable alignment of the alignment element in the injection molding die, the alignment element preferably has at least one feature at the edge area for the alignment. The feature for alignment is preferably a recess, for example a V-shaped indentation or a linear contact surface at the edge area of the alignment element. Two alignment features are particularly preferably oppositely situated from one another at an angle of 180°. 
         [0019]    To ensure that a high degree of fluid-tightness is obtained between the alignment element and the injection molding material after the injection operation, the alignment element preferably has a labyrinth configuration having at least one groove. Multiple grooves, which in particular are situated coaxially with respect to one another and extend in the peripheral direction, are preferably provided. A secure seal between the injection molding material and the alignment element may be achieved due to this labyrinth configuration. The labyrinth configuration is preferably provided on both flat sides of the alignment element. The alignment element is therefore suited in particular for applications in vehicles, in which contact with spray water or the like cannot be ruled out. 
         [0020]    Moreover, the present invention relates to an injector having an alignment element according to the present invention on which an extrusion coating, in particular for a plug, is molded on. The alignment element is preferably completely enclosed by the extrusion coating. One or multiple alignment surface(s) or the like for the alignment is/are preferably provided on the extrusion coating for an installation in an internal combustion engine. The alignment element allows alignment surfaces to be molded onto the extrusion coating in a very precise manner. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  shows a schematic, partially sectional view of an injector having a first alignment element according to the present invention. 
           [0022]      FIG. 2  shows a schematic sectional view of an injection module of the injector shown in  FIG. 1 . 
           [0023]      FIG. 3  shows a schematic top view of the alignment element. 
           [0024]      FIG. 4  shows a schematic sectional view along line B-B in  FIG. 3 . 
           [0025]      FIG. 5  shows a sectional view along line C-C in  FIG. 3 . 
           [0026]      FIG. 6  shows a perspective view of the alignment element. 
           [0027]      FIG. 7  shows a side view of the alignment element. 
           [0028]      FIG. 8  shows a schematic illustration of the welding operation of the alignment element to a part of the injection module. 
           [0029]      FIGS. 9 through 11  show illustrations of an alignment element according to a second exemplary embodiment of the present invention. 
           [0030]      FIGS. 12 through 14  show illustrations of an alignment element according to a third exemplary embodiment of the present invention. 
           [0031]      FIG. 15  shows a schematic top view of an alignment element according to a fourth exemplary embodiment of the present invention. 
           [0032]      FIG. 16  shows a perspective illustration of an alignment element according to a fifth exemplary embodiment of the present invention. 
           [0033]      FIG. 17  shows a perspective illustration of an alignment element according to a sixth exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    An injector having a first alignment element  3  according to the present invention as well as a method for manufacturing the injector are described in greater detail below, with reference to  FIGS. 1 through 8 . 
         [0035]    As is apparent from  FIG. 1 , injector  1  includes an injection module  2 , shown in greater detail in  FIG. 2 , which in the present exemplary embodiment includes a solenoid actuator  23  in order to move a valve needle  21 . The valve needle opens up or closes a valve seat  22  at one end of the injector. Injector  1  also includes a plug molding  4  (extrusion coating) which is molded onto injection module  2  shown in  FIG. 2 . Injection module  2  is a preassembled module. A disk-shaped alignment element  3  is preassembled on a tubular part  20  of injection module  2 . Injection module  2  is inserted into an injection mold with the aid of alignment element  3 , and plug molding  4  is then molded on. Plug molding  4  has an alignment surface  8  which, the same as for the actual plug-in connection, must be individually fabricated for the particular customer and his requirements. Alignment surface  8  is subsequently used for aligning the injector during the step of installing the injector in the internal combustion engine, so that the spray pattern provided by the injector corresponds to the customer&#39;s requirements. Therefore, even during the process of molding on the plug molding, injection module  2  must be correctly aligned in the injection mold so that the spray alignment of the injector subsequently matches alignment surface  8 , which is provided on the extrusion coating via the injection process. 
         [0036]    Alignment element  3  is illustrated in greater detail in  FIGS. 3 through 8 . Alignment element  3  is an essentially disk-shaped element, and has a central through opening  40 . Through opening  40  is delimited by a circumferential collar  35  which protrudes in axial direction X-X of the alignment element. Collar  35  is adjoined by a base area  36  which is inclined with respect to a base plane E of alignment element  3 , the base area being adjoined by a terminating edge area  37 . Edge area  37  is situated in base plane E of alignment element  3 . Alignment element  3  also includes a first slot  31 , a second slot  32 , a third slot  33 , and a fourth slot  34 . First slot  31  and third slot  33  extend in the radial direction, starting from a center axis of alignment element  3 , and are oppositely situated from one another at an angle of 180° (see  FIG. 3 ). Second slot  32  and fourth slot  34  extend in the peripheral direction over a circular angle of approximately 150° in each case. First slot  31  intersects second slot  32 , and third slot  33  intersects fourth slot  34 . All slots are continuous in axial direction X-X. This results in a high degree of flexibility of alignment element  3 . Flexibility results in axial direction X-X of alignment element  3 , in particular due to second and fourth slots  32 ,  34 , respectively, as well as in the radial direction with respect to the center axis, in particular due to first and third slots  31 ,  33 , respectively. 
         [0037]    Alignment element  3  also includes a tongue  30  which protrudes radially inwardly into first slot  31 , starting from edge area  37 . As is apparent in particular from  FIG. 5 , tongue  30  is still slightly bent in axial direction X-X. Alignment element  3  also includes a first tab  38  and a second tab  39 . First and second tabs  38 ,  39 , respectively, are likewise bent from base area  36  in axial direction X-X, in the same direction as tongue  30  (see  FIG. 5 ). In the process, tongue  30  contacts the two tabs  38 ,  39  at the side. As is most clearly apparent from  FIGS. 5 ,  6 , and  7 , a contact zone results between tongue  30  and the two tabs  38 ,  39  outside base plane E of the alignment element. Alternatively, a small distance which is not critical for the welding operation may be provided between the tongue and the tabs, the distance being bridged by the welding operation. 
         [0038]    Due to the high degree of flexibility of alignment element  3  in axial direction X-X as well as in the radial direction, alignment element  3  may be quickly and easily pushed onto a tubular part  20  of injection module  2 . A position of the alignment element in the pushed-on state onto tubular part  20  may also still be slightly corrected if necessary. The position of alignment element  3  is therefore important in order to ensure an alignment of injection module  2  in an injection molding die in order to mold on plug molding  4  in the correct alignment with respect to injection module  2 . In order for alignment element  3  not to be displaced during the injection process, it is welded to tubular part  20  via a weld joint, using a laser beam  7 . This results in a weld seam  5  between collar  35  of alignment element  3  and tubular part  20  (see  FIG. 8 ). For the welding operation, tubular part  20  is rotated together with alignment element  3 . As shown in  FIG. 8 , laser beam  7  no longer comes into contact with collar  35  or tubular part  20  in the area of tongue  30 , but instead comes into contact with tongue  30 , which protrudes in axial direction X-X, and protruding tabs  38 ,  39 . Tongue  30  is thus welded to tabs  38  and  39 . As is apparent from  FIG. 8 , a welding plane S 2  in which tongue  30  is welded to tabs  38 ,  39  is situated outside normal welding plane S 1  in which collar  35  is welded to tubular part  20 . Alignment element  3  is stiffened as the result of welding tongue  30  to tabs  38 ,  39 . Alignment element  3  is thus able to withstand the strong pressures during the subsequent injection process for manufacturing plug molding  4 , without alignment element  3  being bent or changed in its position. 
         [0039]    Thus, due to the shape of alignment element  3 , laser beam  7  is interrupted in the area of the tongue during the welding operation, laser beam  7  being adjusted in such a way that it is possible to weld the tongue to the tabs outside the actual focus of the laser beam. Since first slot  31  of alignment element  3  is provided in the area of tongue  30  anyway, collar  35  is shielded only in the area of tabs  38 ,  39 . However, this reduces the weld joint  5  along collar  35  only negligibly, by a width of the tabs. 
         [0040]    Thus, with the aid of a single welding operation, while rotating tubular part  20 , alignment element  3  may be welded to tubular part  20 , as well as stiffened in the area of tongue  30  and tabs  38 ,  39 . It is pointed out that a correspondingly formed tongue and correspondingly formed tabs may also be provided in the area of third slot  33  in order to automatically provide a second stiffening on the alignment element. 
         [0041]    According to the present invention, alignment element  3  may thus have sufficient flexibility for installation, so that the installation may be carried out quickly and easily, and in particular very precisely. Alignment element  3  is also subsequently stiffened at the same time as alignment element  3  is fixed to tubular part  20 , it being possible for the stiffening and fixing of the alignment element to be carried out in one step due to the tongue and the tabs of alignment element  3 . According to the present invention, the manufacture of an injector may thus be significantly simplified and reduced in cost, and at the same time the precision of a subsequent necessary alignment of the injector in an internal combustion engine may be even further improved. 
         [0042]    Further exemplary embodiments of the present invention are described below in greater detail, identical or functionally equivalent parts being denoted by the same reference numerals as in the first exemplary embodiment. 
         [0043]    An alignment element  3  according to a second exemplary embodiment of the present invention is illustrated in greater detail in  FIGS. 9 through 11 . As is apparent from the top view in  FIG. 9 , alignment element  3  of the second exemplary embodiment includes two alignment features in the form of a first and second V-shaped indentation  51 ,  52 , respectively, at edge area  37 . In addition, a plurality of circular through openings  53  is provided. The alignment element may be reliably aligned in the injection molding die via V-shaped indentations  51 ,  52 . Furthermore, during the injection process, through openings  53  ensure that the injection molding material is able to reliably and quickly enter on both sides of alignment element  3 . As is apparent in particular from  FIGS. 9 and 11 , alignment element  3  of the second exemplary embodiment may be manufactured very easily and cost-effectively, in particular since no tabs and/or tongues are provided. In addition, alignment element  3  of the second exemplary embodiment has a labyrinth configuration  50 . In this exemplary embodiment, labyrinth configuration  50  includes a circumferentially closed groove, a groove being provided on both sides of the alignment element. These two grooves ensure that very good sealing, in particular from the outside toward the inside, is possible after the injection process. Fluid-tightness of an injector in the area of alignment element  3  may thus be further improved. 
         [0044]      FIGS. 12 through 14  show an alignment element  3  according to a third exemplary embodiment of the present invention. Alignment element  3  of the third exemplary embodiment has no circumferential slots, but instead has two slots  61 ,  62  extending in the radial direction. Slot  62  is designed as a radially continuous slot from central through opening  40  to edge area  37 . Alignment element  3  thus has a C shape in a top view (see  FIG. 12 ). Slot  62 , which is continuous from collar  35  to edge area  37 , in particular provides improved flexibility in the axial direction. In addition, alignment element  3  may also be spread apart slightly in the peripheral direction, so that a particularly simple and quick installation is possible. In addition, alignment element  3  of the third exemplary embodiment has expanded areas  63 ,  64  which are provided at slots  61 ,  62 , respectively. This ensures that the injection molding material also completely fills slots  61 ,  62 , since the slots are each relatively narrow. In addition, edge area  37  and base area  36  of alignment element  3  are situated in a shared plane (see the cross section in  FIG. 13 ). 
         [0045]      FIGS. 15 through 17  show further exemplary embodiments of the present invention. In the fourth exemplary embodiment shown in  FIG. 15 , a contact surface  55  protruding in the radial direction and a V-shaped indentation  51  are provided as an alignment feature at edge area  37  of alignment element  3 . Indentation  51  and contact surface  55  are oppositely situated from one another at an angle of  180 °. The fifth exemplary embodiment of alignment element  3  shown in  FIG. 16  shows a linear contact surface  56  resulting from removal of material at edge area  37 . For further improvement in flexibility, slots  34 ,  32  extending in the peripheral direction have a first and a second radially inwardly oriented extended slot  321  and  341 , respectively. The two extended slots  321 ,  341  extend in parallel to a recessed indentation  57  which is likewise used for the alignment. In addition, no through openings are provided in the fifth exemplary embodiment. The sixth exemplary embodiment shown in  FIG. 17  likewise has a contact surface  56  resulting from removal of material at outer edge area  37  of the alignment element. However, in the sixth exemplary embodiment the extended slots of the fifth exemplary embodiment as well as the recessed indentation of the fifth exemplary embodiment are absent. The sixth exemplary embodiment may thus be manufactured very easily and cost-effectively.