Metal working – Method of mechanical manufacture – Prime mover or fluid pump making
Reexamination Certificate
1999-02-18
2001-02-06
Cuda Rosenbaum, I (Department: 3726)
Metal working
Method of mechanical manufacture
Prime mover or fluid pump making
C029S525060, C029S527700, C072S327000
Reexamination Certificate
active
06182360
ABSTRACT:
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.
REFERENCES:
patent: 2750742 (1979-05-01), None
patent: 3841205 (1990-06-01), None
patent: 0 183 648 (1986-06-01), None
F. Strasser, “Gewindebohren in sehr Kleinen Blechausschnitten” (screw tapping in very small sheet metal cutouts), vol. 93, No. 3, p. 155, 1960.
Bachman & LaPointe P.C.
Cuda Rosenbaum I
Feintool International Holding AG
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