DE2424590A1 - Mould assembled from segments - with joint-faces perpendicular to axis of shaft, for mfr. of cast crankshafts and camshafts - Google Patents

Abstract

The mould is assembled using mould-segments, the joint-faces of which are at 90 degrees to the axis of the shaft and aligned in a row or stacked one above the other, with the exception of the two end segments, both sides of each segment, i.e. the joint-faces, form the contours of adjacent crank-pins or the counter-weights including the webs. The mould-segments pref. include projections extending into the mould cavity to form hollow shafts and cores may be used to form oil-channels; prefabricated metal inserts can be placed in the mould; and/or more than one grade of cast-iron may be poured into the mould. By eliminating an axial joint-line, i.e. using a conventional cope and drag, axial flash-which is very difficult to remove- is eliminated together with malalignment; the flash formed in this casting method is easy to remove by grinding.

Description

Process for the production of a cast crank or. camshaft Crankshafts have bearing points protruding from the shaft body and corresponding ones Counterweights that are connected to the shaft body via connecting webs. It is known to die forge crankshafts. It is particularly advantageous Casting such parts in sand molds, as this has all the advantages of the known casting process can be used.

In particular, it is possible in this way to run the crankshafts To make the insertion of cores hollow and to significantly reduce their weight. The above remarks on rod shafts meet with corresponding modifications also on camshafts too.

In the previous production using the casting process, the model Divided lengthways and each half of the model molded. The finished casting arises this inevitably leads to a longitudinal ridge, which can only be removed by extensive post-processing is to be eliminated. Since the waves are relatively long, there is some deviation from the central axis cannot be completely ruled out. In addition, to generate the required The lateral contours of the main and pin bearing points as well as the connecting webs are inclined to the counterweights are fully executed, although this is necessary for the function of the Crankshaft is not necessary. This makes the crankshaft quite heavy, what in the interest of material and cost savings and easier construction should be avoided.

Furthermore, it is technically not possible with the known casting process Manufacture absolutely round and balanced crankshafts. It is therefore a complex one Post-treatment by balancing and machining necessary.

The described disadvantages of the casting process customary up to now, the are also present in the forging process, should be eliminated.

According to the invention there is provided a method of making a cast Kuibel or camshaft proposed in which the casting mold from perpendicular to the longitudinal axis of the workpiece to be cast divided, next to or on top of one another Shaped disks is put together, with all shaped disks except for the two End plates on both sides the contours of adjacent bearings or counterweights including their connecting webs. The number of shaped disks is by the number of bearings and counterweights protruding from the shaft plane set.

There are now surrounding burrs on the finished casting, which are lighter can be removed as a longitudinal ridge.

Deviating from the central axis can be almost completely avoided will. In addition, the shaped disks can be used to produce absolutely round crankshafts will. As a rule, post-processing by grinding will be sufficient compared to what machining is much more advantageous and cheaper. Of the most significant advantage, however, is that all Accumulations of material on the lateral contours of the bearing points and the connecting webs to the counterweights can be eliminated. It is now possible to use an advantageous casting technique, produce approximately the same-walled workpiece.

For the production of known high waves has a part of the mold disks protruding into the mold cavity in the direction of the longitudinal axis extending tenons. The shaped disks themselves and the tenons are exactly what you want Adapt the shape of the finished casting.

As usual, cores can be used to form oil channels or prefabricated Metal parts are inserted into the mold cavity to produce composite castings. The manufacture of separate cavities created by metallic fasteners are interconnected and optionally with cast iron of different quality are too full is also possible.

In this way, the associated flywheel, for example, can be used without difficulty be cast directly on.

The shaped disks can be made from green sand but also from any one hardenable sand can be produced. Boxless production is particularly useful. To protect against side pressures during pouring, slightly conical A corresponding bell made of perforated material is pushed over the outer contour of the shaped disks will. Cranking the sand ball for lateral guidance is quite advantageous.

It is easily possible to have multiple casts with a single mold produce and this via a centrally arranged pouring funnel in known Assign from below with cast iron to fill. The circulatory material per cast can be reduced in this way.

There are several for carrying out the molding process according to the invention Molding machines with different models are necessary, of which the molding disks be transported to the stacking point. By sucking the shaped disks on the This transport can do the upper model plate and swivel it to the stacking point be performed. After placing the shaped disc on the stack, the vacuum is created if necessary lifted by a slight pressure and the model plate swiveled back. The molding process can be largely automated.

Further details of the invention are from the accompanying drawing, in a single figure a partial longitudinal section through a casting mold as an embodiment represents, to be found.

The casting mold consists of mold disks 1 stacked one on top of the other, which cast off the cavity of the longitudinally running through all mold disks Part. The planes of division between the shaped disks are so that the lateral Contours of all elevations protruding from the wave by corresponding sand balls 2 can be provided with recesses. The sand balls 2 have in the illustrated Embodiment slots, which on the finished casting as narrow stiffening ribs appear in the recess. Pins 3 running in the direction of the longitudinal axis are used to manufacture hollow cast shafts.

The pouring takes place through a pouring funnel 4 and gates 5, which are to be designed according to the known rules of casting technology. One pushed on the outside Frame 6 is used to center and stabilize the casting mold.

In principle, it is also possible to use the shaped disks as permanent forms, E.g. from molds.

Claims (8)

Claims 1. Process for the production of a cast crank or ITcamshaft, characterized in that the mold is made of perpendicular to the longitudinal axis of the workpiece to be cast, divided, next to or on top of each other Shaped disks (1) is joined together, with all shaped disks (1) with the exception of the the contours of adjacent bearings or counterweights on both end plates on both sides including their connecting webs. 2. Casting mold for performing the method according to claim 1, characterized characterized in that for the production of known hollow waves a part of the Mold disks (1) protruding into the mold cavity in the direction of the longitudinal axis have extending pins (3). D. Casting mold according to claim 2, characterized in that daii in the mold cavity Cores to form oil channels are inserted. 4. Casting mold according to claim 2, characterized in that in the mold cavity prefabricated metal parts are inserted for the production of composite castings. 5. Casting mold according to claim 4, characterized in that in the mold cavity metallic connecting elements between separate cavities, optionally with Cast iron of different quality to be filled are inserted. 6. Casting mold according to claims 2 to 5, characterized in that the stacked mold disks (1) through several mold cavities form a single pouring funnel (4) to be cast workpieces. 7. Casting mold according to claims 2 to 6, characterized in that the stacked shaped disks (1) due to their slightly conical design Form a conical outer contour and that one of this outer contour corresponds Bell (6) made of perforated material is pushed over. 8. Crank or manufactured by the method according to claim 1. Camshaft, characterized in that the lateral contours of the camp and the Connecting webs to the counterweights. Recesses to avoid material accumulation have, which are interspersed with narrow stiffening ribs. Blank page