Abstract:
A valve seat/director unit the combines the functions of an injector valve seat and a separate spray director plate into an integral unit combining both functions. The unit is a generally flat plate having an outer portion with at least one sealing rib. A central portion includes at least one endless rib forming a valve seat and surrounding a spray director including a recessed area communicating with at least one fuel spray opening. Upper surfaces of the sealing rib(s) and valve seat are preferably flat and coplanar with one another for engagement by cooperating surfaces of an injector member and a valve member, respectively.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation-in-part of copending U.S. patent application Ser. No. 09/660,950, filed Sep. 13, 2000. Certain subject matter disclosed in that parent application is claimed in U.S. patent application Ser. No. 09/660,952 filed concurrently on Sep. 13, 2000. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to solenoid actuated fuel injectors for engines and, more particularly, to an injection valve seat/director formed as an integral dual function unit.  
         BACKGROUND OF THE INVENTION  
         [0003]    It is known in the art relating to solenoid actuated engine fuel injectors to provide a valve seat for engagement by a disk-like armature to cut off fuel flow through an injector. A separate fuel spray director may be provided with spray holes to direct an atomized spray of fuel from the valve seat into an engine. Typically, the valve seat and the spray director are separate components requiring individual forming and machining or other processing and requiring assembly in an injector with other components to form a completed structure ready for use. A simpler valve seat and spray director assembly involving less costly or reduced processing steps is desired.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention provides an improved and simplified valve seat/director unit, which combines in an integral unit the functions of a valve seat and a fuel spray director. The unit is preferably made using electroforming and/or metal etching processes. The unit may be made in layers with the same or differing materials, if desired, and with differing thickness to best accomplish the purposes of the integral unit.  
           [0005]    In an optional embodiment, a valve seat/director unit is formed as an integral multiple thickness unit for an engine fuel injector. The unit is essentially a flat plate with an outer portion including a rim or plurality of raised ribs, which are engagable with a spacer rim or other member of an injector for forming an external seal. A central portion includes a plurality of spray holes or openings surrounded on at least one side by a raised rib forming a valve seat. The seat may be varied in configuration for engagement by a solenoid valve disk or a plunger type valve as desired. The valve seat and the outer rim or ribs are preferably formed as coplanar surfaces with equal thickness through the plate. Intermediate portions of an upper surface are recessed to allow fuel flow to the valve seat but may include raised shapes for engaging a mating member.  
           [0006]    The seat/director may be formed as an integral unit in any suitable manner. However, electroforming, metal etching or a combination of both are presently preferred methods. By these methods, a dual thickness valve seat/director unit may be formed by simple processing to finished dimensions without requiring further finishing steps. A simplified, cost efficient unit is thus provided, combining the features of separate valve seats and director plates while avoiding the machining or forming and assembly steps these separate components require.  
           [0007]    These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    In the drawings:  
         [0009]    [0009]FIG. 1 is a cross-sectional view of an exemplary solenoid actuated fuel injector having an integral valve seat/director unit according to the invention;  
         [0010]    [0010]FIG. 2 is an enlarged top view of the integral unit of FIG. 1;  
         [0011]    [0011]FIG. 3 is a cross-sectional view from the line  3 - 3  of FIG. 2;  
         [0012]    [0012]FIG. 4 is an enlarged view of the portion in circle  4  of FIG. 3;  
         [0013]    [0013]FIG. 5 is an enlarged view of the portion in circle  5  of FIG. 3;  
         [0014]    [0014]FIG. 6 is a top view of an alternative embodiment of valve seat/director unit;  
         [0015]    [0015]FIG. 7 is a cross-sectional view from the line  7 - 7  of FIG. 6; and  
         [0016]    [0016]FIG. 8 is a view similar to FIG. 1 but showing a plunger type injector incorporating a valve seat/director unit according to the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    Referring first to FIG. 1 of the drawings in detail, numeral  10  generally indicates an exemplary solenoid actuated fuel injector for an engine. Injector  10  includes a non-magnetic cover  12  enclosing a solenoid coil  14 . A fuel tube extends through the coil and acts as an inner magnetic pole  16 . An outer strap  17  connects with the inner pole  16 , extends around the coil  14  and connects with an annular member forming an outer magnetic pole  18 . A nonmagnetic spacer  19  provides a seal between the inner and outer poles below the coil.  
         [0018]    The outer pole  18  includes a skirt  20  that is fixed to a lower housing  22  defining an external seal groove  24 . Housing  22  has a flat upper wall  26  that opposes and is spaced from coplanar flat lower surfaces  28 ,  30  of the inner and outer poles, respectively. The housing  22  also has a central opening  31  through the upper wall  26  and connecting with an enlarged open area below for the passage of fuel spray from the injector.  
         [0019]    Disposed between the housing upper wall  26  and the magnetic pole lower surfaces  28 ,  30  is an injection valve comprising a valve seat and spray director unit  32  formed according to the invention, and an armature/spacer member  34 .  
         [0020]    The armature/spacer member  34  includes a movable armature  36  connected by flexible legs  38  to an outer rim  40 . A spring  42  biases the armature against the seat/director unit  32  to cut off fuel flow through the injector. Armature  36  also includes fuel openings  44  through a center portion near the spring  42 . A lower surface  46  of the member  34  remains flat when the armature is seated in the closed position on the seat/director unit  32 .  
         [0021]    Referring now to FIGS.  1 - 5 , seat/director unit  32  is made as an integral body and is shaped as a circular disk, which includes a flat lower surface  48 , that seats against the flat upper wall  26  of the lower housing  22 . A thickened outer rim or concentric outer ribs  50  form a periphery of the disk while one or more raised ribs in a central portion  52  of the disk form a valve seat  54 . Spray holes  56  within the central portion form a director plate to atomize a spray of fuel passing through the holes  56 . The rim or outer ribs  50  and the valve seat  54  preferably have equal thickness dimensions and so define a flat upper surface  58  of the seat/director unit  32 . Within the valve seat  54 , between the outer ribs  50  and intermediate the valve seat and outer ribs, the upper portion of unit  32  is recessed, preferably defining coplanar recessed surfaces  60 .  
         [0022]    The disk for the seat/director unit  32  is preferably made very thin to adapt it for cost efficient manufacture by processes such as electroforming, optionally combined with metal etching. In particular, the seat/director unit  32  is made substantially thinner than the disk armature  36  of the embodiment of FIG. 1. Electroforming processes are able to provide flat sealing surfaces and accurate orifice dimensions without machining. They also use only small amounts of metal as compared to machined components which are inherently heavier.  
         [0023]    In operation of the injector in an engine, pressurized fuel is admitted to the fuel tube/inner pole  16  and flows through armature fuel openings  44  to the recessed intermediate surface  60  of the valve seat/director unit  32 , where it is blocked while the armature  60  remains seated against the valve seat  54 . When the solenoid coil  14  is energized, armature  36  is drawn upward against the magnetic poles  16 ,  18 . This opens the valve seat  54 , allowing the fuel to flow through the spray holes  56  of the integral director plate portion of unit  32 . Fuel flow continues until the coil  14  is de-energized and the spring  58  again forces the armature  36  to engage the valve seat  54 .  
         [0024]    The seat/director unit  32  of FIGS.  2 - 5  may be made by any suitable process. However, the figures show an embodiment made by a preferred method of electroforming. In this method, a mandrel is machined with a surface that forms a mold for the upper side of the unit  32  to be formed inverted on the mandrel. A suitable metal valve seat material is then formed on the mandrel by the known process of electroforming. The material fills in grooves in the mandrel to form the ribs  50  and valve seat  54  of the unit  32 . A resist applied to the mandrel at the spray hole locations prevents metal deposition there and thus accurately forms the spray holes  56 . The metal deposition on the mandrel surfaces is very even and precise, so that flat lower surface  48  of the unit  32  does not need further finishing steps. The upper surfaces are accurately molded to the desired shape by the initial shape of the mandrel. Opposite the locations of the ribs and valve seat  50 ,  54 , the lower surface  48  of the unit  32  is recessed at  61  as a result of the even deposition process. These recesses  61  have no function and are merely a result of the forming process.  
         [0025]    Other methods of forming integral seat/director units could also be used as desired. For example, the multi-thickness unit could be electroformed in layers by using resists to form the raised portions after a flat lower portion is first formed. Alternatively, an electroformed disk could be further shaped by metal etching. Any other suitable method may also be used.  
         [0026]    [0026]FIGS. 6 and 7 illustrate a modified seat/director unit  62  exemplary of alternative embodiments according to the invention. Unit  62  is a generally flat disk formed by electroforming as before. Its upper surface  64  includes outer ribs  66  and four separate oval shaped valve seats  68  surrounding annularly spaced elongated spray holes  70 . A recessed area surrounding the valve seats  68  and extending to the outer ribs  66  contains many spaced small raised portions  72  and a larger raised center  74 . These provide additional surfaces engagable by a valve disc, plunger, or other member of a suitable injector configuration. The spaced valve seats  68  allow fuel to enter the spray holes  70  from all sides of the holes when a cooperating valve member is moved away from the seats  68 . Again, the electroforming method may leave non-functional recesses  76  on the lower surface  78  of the unit  62 .  
         [0027]    [0027]FIG. 8 shows a plunger type fuel injector  80  in which the seat/director units  32  and  62  could be utilized instead of in the disk type injector  10  of FIG. 1. Injector  80  includes a reciprocable valve plunger  82  biased by a spring  84  against the valve seats  68  of a seat/director unit  62 , for example (see FIGS. 6 and 7). A lower plunger guide  86  is seated on outer portions of the unit  62 . A central hub  88  of the guide  86  extends up around the lower end of the plunger  82  to guide its motion.  
         [0028]    Energizing of a solenoid coil  90  unseats the plunger  82 , allowing fuel to flow under the plunger and through the spray holes  70  as an atomized spray. The small raised portions  72  of the outer portion of unit  62  engage and support inner portions of the disk  86 . Portions  72  on the inner portion of the disk and the larger center portion  74  are engaged by the closed end  92  of the plunger  82  to limit its force on the seats  68  in the central portion of the unit  62 . The remaining features of injector  80  are sufficiently similar in structure and operation to injector  10  as not to require further description for a full understanding of the invention.  
         [0029]    While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims.