Abstract:
A method of producing and stacking components from individual layers which are punched, cut or the like out of a hardened material strip. According to the method, layers are removed from a hardened material strip, the removed layers are pressed back into the material strip and pressed out of the latter in a subsequent station (ii). They are then inserted into a stack magazine in which the individual layers are centered and assembled to form a component, the component then being removed from the stack magazine.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a method for the production and layering of components consisting of individual layers which are punched out, cut out or the like from a material strip, the layers, after being punched out or the like, being pressed back into the material strip again, and to an apparatus for this purpose. 
     Components, for example for automobiles, such as connecting rods, cams, gearwheels, toothed rings or the like, are produced either by the casting method or by being punched out or cut out from a relatively thick material strip. A precision cutting device of this type is described, for example, in EP 0,183,648. 
     With reference to a full cam, a known process chain for producing the latter will be described below. First, a blank is separated from a material strip by the punching press. A solid lubricant is applied to this blank. Heating of the blank, preforming and annealing are subsequently carried out. 
     A solid lubricant is then applied once again, and the semifinished product is preformed and finally ready-formed. Calibration and inductive hardening then take place, after which reaming and chamfering are carried out to obtain the finished cam. The cam is then joined onto a tube, so that a camshaft is produced. The latter is ground. A method of this kind is highly complicated. 
     Furthermore, DE-A-38 41 205 describes the production of workpieces from metal. Reference is made primarily to the production of a connecting rod, in terms of construction the connecting rod being broken down into individual simple part profiles, and these being produced by precision cutting and, by being layered, being assembled together to form the finished part and connected to one another. This therefore relates to the production of a part of complicated design from different part profiles having different contours. 
     It is known, for example, from DE 27 50 742, to separate sheet metal parts from a sheet metal band material by means of shears and subsequently to layer them one on top of the other in a stacking device. 
     Strasser F. “Gewindebohren in sehr kleinen Blechausschnitten in: Werkstatt und Betrieb”, [“Screw tapping in very small sheet metal cutouts in: Workshop and Factory”], volume 93, 1960, number 3, page 155, describes perforating and cutting out workpieces in follow-up cuts, said workpieces, after being cut out, not falling downward through the die plate opening, but, instead, being pressed back into the sheet metal strip again by a spring-actuated striking ram. 
     SUMMARY OF THE INVENTION 
     By contrast, the object of the present invention is to produce simple components consisting of a plurality of identical layers in a simple and cost-effective way and to position said components exactly in relation to one another. 
     To achieve this object, the layers are pressed out of the material strip in a subsequent station and are inserted into a stack magazine, in which the individual layers are centered and connected to form the component, before the latter is discharged from the stack magazine. 
     This means that components of relatively great thickness can be produced from individual thin hardened lamellae by the latter being layered. Preferably, these layers are connected to one another by riveting in a further machining method. 
     The individual lamellae have the shape of the part, and the number of individual lamellae gives the cam height. Since the lamellae are very thin (for example, 0.1-2 millimeters), they can be punched out of already hardened material, so that there is no longer any need for subsequent hardening or grinding. The layered component is a finished part. The material may already have a hardness of up to and above 63 HRC. 
     Furthermore, it is possible, by punching the thin lamellae, to produce cams having very small cross sections between the inner and the outer contour. The cams may also have very small holes of, for example, 1 millimeter. These holes serve for weight reduction or mass equalization or may be used as a receptacle for a rivet. 
     Moreover, it is possible, by punching the thin lamellae, to adhere to tolerance qualities of class  6  for inner and outer shapes. Above all, the production costs are also reduced, since the method sequence according to the invention requires only few work steps. 
     There is scarcely any need for additional investment. The layered cam has already met stringent requirements in the engine and is distinguished by a high degree of damping, low noise generation and the least possible wear, since, as a result of the lamellae, a capillary action occurs and lubricating oil is constantly carried onto the operating surfaces. 
     The core of the apparatus for carrying out the method is a punching press, in the die of which the inner and the outer shape of the layer are cut simultaneously during the overall cut. A follow-up die would also be possible, but the tolerances between the inner and the outer shape become too great. 
     The cut part is pressed back into the punching screen. 
     The inner shape waste falls through the cutting punch and corresponding shafts in the machine table of the punching press and is discharged downward. 
     The punching die is followed by an assembly station, in which the individual layers are collected in a stack magazine. At the same time, a bundling ram presses the individual lamellae (layers) out of the punching screen in synchronism with the plunger stroke of the punching press. 
     According to the invention, the entire process takes place either in a timed feed unit or on a rotary indexing plate. 
     After a specific number of punching strokes, which corresponds to the number of layers for producing a component (cam), the rotary indexing plate switches one position further or the stack magazine is transported to the next station in the timed feed unit. An empty stack magazine at the same time extends beneath the bundling ram. 
     In the following station, at least one rivet is supplied to the stack magazine, in the next station the layers are centered and riveted, and in the next station the finished component is pressed out of the stack magazine, for example by a ram, passes onto a band or the like and is transported for final assembly. 
     The material strip preferably comes from a coil winder, with its own drive, into the punching press, a corresponding band loop control being provided here. The punching machine itself is an automatic precision puncher with entry feed, band lubrication, etc. Depending on the number of components required, the method according to the invention is possible with a single-drop die, but also with multiple-drop dies, thus resulting in additional cost effectiveness. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Further advantages, features and details of the invention can be gathered from the following description of preferred exemplary embodiments and with reference to the drawing in which: 
     FIG. 1 shows a diagrammatic illustration of an apparatus according to the invention for the production and layering of components, 
     FIG. 2 shows a top view of a diagrammatically illustrated timed feed unit in the apparatus according to FIG. 1; 
     FIG. 3 shows a diagrammatically illustrated method sequence for layered components; 
     FIG. 4 shows a detail, illustrated on an enlarged scale, from a punching press according to FIG. 1 in the region of the die; 
     FIG. 5 shows a top view of a material strip for forming the components, 
     FIG. 6 shows a diagrammatic illustration of a further exemplary embodiment of an apparatus according to the invention for the production and layering of components; 
     FIG. 7 shows a perspective view of a cam produced by the method according to the invention; 
     FIG. 8 shows cross sections through the cam along the line VIII—VIII in FIG. 7 with various rivets; 
     FIG. 9 shows a perspective view of a further exemplary embodiment of a cam produced by the method according to the invention; 
     FIG. 10 shows a cross section through the cam according to FIG. 9 along the line X—X. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     According to FIG. 1, an apparatus R for the production and layering of components has a coil winder  2 , a punching press  3 , an only partially indicated timed feed unit  1  and a waste winder  4 . 
     A material strip  5  is unrolled clockwise from a coil winder  2  which is provided with its own drive. This material strip  5  passes a light barrier  6  which indicates when the material strip  5  sags too low. The material strip  5  thereafter enters a material entry  7  of the punching press  3  and there passes a lubricating appliance  8 , via which lubricating oil comes onto the surfaces of the material strip  5 . 
     The material strip  5  runs next through a die H for cutting out or punching the inner and outer shapes of component layers  30 , of cam layers in the present exemplary embodiment. 
     A detail of the die H is illustrated on an enlarged scale in FIG.  4 . It consists of a top part O and a bottom part U. 
     The top part O, which is vertically movable, has a plunger  10  which can be seen more clearly in FIG.  1 . This plunger  10  is followed by a chucking plate  11  and, after this, a cutting plate  12 , in which, in turn, an ejector  13  and two inner shape rams  14 ,  15  are guided. These inner shape rams  14 ,  15  serve for punching inner shapes out of the cam layers  30 . The ejector  13  is under the pressure of thrust bolts  16 ,  17 . 
     The bottom part U of the die H is assigned a machine table  18 . A chucking plate  19  rests on the latter. A stripping plate  20  is under the pressure of thrust bolts  21 ,  22 . A cutting ram  23 , which has conical shafts  24 . 1 ,  25 . 1 , is provided in the chucking plate  19  and the stripping plate  20 . The inner shape waste punched out of the cam layer  30  by the inner shape rams  14 ,  15  travels downward through shafts  24 . 2 ,  25 . 2  in the machine table  18  out of the die H. After punching, the parts are pressed into the punching screen again immediately. For this purpose, the forces act on the ejector  13  and the stripping plate  20 . A band guide  26  corresponding to the material thickness serves for ensuring that the punching screen, together with the parts which have been pressed back, is fed to the next machining station. 
     FIG. 5 shows a top view of the material strip  5  for forming the cam layers  30 . The parts falling away as inner shape waste  27 ,  28  are indicated by hatching. Furthermore, the first stage of the timed feed unit  1  can be seen, in which a bundling ram  29 , illustrated in FIG. 1, has pressed the punched cam layer  30  into a stack magazine  31 . The stack magazine  31  may be preceded by an intermediate magazine, into which the bundling ram  29  presses out individual parts. 
     A top view of the complete timed feed unit  1  is illustrated in FIG.  2 . It has a level A and a level B. The material strip  5  is transported on the machine table  18  to the level A. At this level A, the individual method steps of layering and riveting, which are illustrated in FIG. 3 by stations II-V, take place. 
     In station II, the punched cam layers  30  are pressed out of the material strip  5  into the stack magazine  31  by means of the bundling ram  29 , and the cam  9 , which consists of a plurality of such cam layers  30 , is formed in this way. FIG. 3 shows the station II in section and, above, the ready-layered cam  9  in its stack magazine  31 . 
     After a predetermined number of cam layers  30  forms the cam  9 , the timed feed unit  1  pushes the stack conveying magazine  32  further to the next station III in the direction of the arrow, while another stack magazine  31  comes into the station II, in order to form the next cam  9 . 
     In station III, a rivet  33  A, B is supplied, while the individual cam layers  30 , of which the cam  9  consists, are subsequently centered in station IV by means of a centering bolt  34  exactly filling the inner shape, in order thereby to acquire an exact cam shape. When this has been achieved, riveting is carried out. 
     In station V, the ready-stacked and riveted cam  9  is pressed out of the stack magazine  31  by means of a ram  35 , deposited onto a transport band  36  and transported for final assembly. 
     The empty stack magazines  31  are then lined up, lowered onto the level B by means of the lowering unit  37 , transported to the lifting unit  38  and raised to the level A again by means of a lifting unit  38 . At this level, they are once again available for receiving cam layers  30  in front of the station II. Lowering to the level B takes place so that the stack magazines  31  can pass through under the feed  47 . 
     The material strip  5 , from which the individual cam layers  30  have been punched out, then runs through a feed  47  and is wound up by means of the waste winder  4  to form a waste coil. 
     FIG. 6 illustrates diagrammatically a further exemplary embodiment of an apparatus R 1  for the production and layering of components. This apparatus R 1  likewise has a coil winder  2  and a punching press  3  which are followed, however, by a rotary indexing plate  39 , an exit feed  42  and shears  43  which cut off a waste screen  44  from the punching screen. 
     In station II, on the rotary indexing plate which rotates about an axis, the punched cam layers  30  are pressed out of the material strip  5  into the stack magazine  31  by means of the bundling ram  20 , and the cam  9 , which consists of a plurality of these cam layers  30 , is formed in this way. 
     Further machining is subsequently carried out in stations III-V, as described above, but on the rotary indexing plate  39 . 
     The material strip  5 , from which the individual cam layers  30  have been punched out, arrives, via a deflection  41 , at the exit feed  42  and is cut off by means of the shears  43 , so that a waste screen  44  falls into a collecting container not shown in any more detail. 
     FIGS. 7 to  10  in each case show completely layered and riveted cams  9  and  9 . 1  produced by the methods according to the invention. The number of cam layers  30  determines the cam thickness  45 . 
     Various rivets for connecting the cam layers  30  are illustrated in cross section in FIG.  8 . Thus, FIG. 8 a  shows a hollow rivet  33 .B 1  and FIG. 8 b  a solid rivet  33 .B 2 . It is also possible for the rivet  33 .A 1  to be left hollow in the riveting region only, as shown in FIG. 8 b . FIG. 8 d  also shows a fourth possibility for a rivet  33 .A 2  with a collar. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 List of reference numerals 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  1 
                 Timed feed unit 
               
               
                   
                  2 
                 Coil winder 
               
               
                   
                  3 
                 Punching press 
               
               
                   
                  4 
                 Waste winder 
               
               
                   
                  5 
                 Material strip 
               
               
                   
                  6 
                 Light barrier 
               
               
                   
                  7 
                 Material entry 
               
               
                   
                  8 
                 Lubricating appliance 
               
               
                   
                  9 
                 Cam 
               
               
                   
                 10 
                 Plunger 
               
               
                   
                 11 
                 Chucking plate 
               
               
                   
                 12 
                 Cutting plate 
               
               
                   
                 13 
                 Ejector 
               
               
                   
                 14 
                 Inner shape ram 
               
               
                   
                 15 
                 Inner shape ram 
               
               
                   
                 16 
                 Thrust bolt 
               
               
                   
                 17 
                 Thrust bolt 
               
               
                   
                 18 
                 Machine table 
               
               
                   
                 19 
                 Chucking plate 
               
               
                   
                 20 
                 Stripping plate 
               
               
                   
                 21 
                 Thrust bolt 
               
               
                   
                 22 
                 Thrust bolt 
               
               
                   
                 23 
                 Cutting ram 
               
               
                   
                 24 
                 Shafts 
               
               
                   
                 25 
                 Shafts 
               
               
                   
                 26 
                 Band guide 
               
               
                   
                 27 
                 Inner shape waste 
               
               
                   
                 28 
                 Inner shape waste 
               
               
                   
                 29 
                 Bundling ram 
               
               
                   
                 30 
                 Cam layer 
               
               
                   
                 31 
                 Stack magazine 
               
               
                   
                 32 
                 Stack conveying magazine 
               
               
                   
                 33A, B 
                 Rivet 
               
               
                   
                 34 
                 Centering bolt 
               
               
                   
                 35 
                 Ram 
               
               
                   
                 36 
                 Transport band 
               
               
                   
                 37 
                 Lowering unit 
               
               
                   
                 38 
                 Lifting unit 
               
               
                   
                 39 
                 Rotary indexing plate 
               
               
                   
                 40 
                 Entry feed 
               
               
                   
                 41 
                 Deflection 
               
               
                   
                 42 
                 Exit feed 
               
               
                   
                 43 
                 Shears 
               
               
                   
                 44 
                 Waste screen 
               
               
                   
                 45 
                 Cam width 
               
               
                   
                 46 
                 Axis 
               
               
                   
                 47 
                 Feed 
               
               
                   
                 48 
               
               
                   
                 49 
               
               
                   
                 50 
               
               
                   
                 51 
               
               
                   
                 52 
               
               
                   
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                 75 
               
               
                   
                 76 
               
               
                   
                 77 
               
               
                   
                 78 
               
               
                   
                 79 
               
               
                   
                 R 
                 Apparatus 
               
               
                   
                 H 
                 Die 
               
               
                   
                 O 
                 Top part 
               
               
                   
                 U 
                 Bottom part 
               
               
                   
                 A 
                 Level 
               
               
                   
                 B 
                 Level