RU185990U1 - DEVICE FOR OBTAINING A COXIAL LOCATION OF HOLES FOR FINGERS IN PISTON CASTING - Google Patents

Abstract

The working cycle of the chill casting machine starts from a starting position of 90 ° when the chill mold is opened. After the chill mold is heated to the set temperature, a non-stick coating is applied to the working surfaces, after which a sand-polymer rod with built-in metal rods is installed in the chill mold to form holes for the finger, and the chill mold is closed. A portion of aluminum is poured into the receiving bucket of the machine, the working volume of the chill mold is filled with the melt, then the casting is cooled and pushed out. After which the process is repeated. To comply with the technical requirements for tolerances of two holes intended for a finger in the piston body (the tolerance of the bore profile is 0.008; the tolerance of roundness is 0.008; the perpendicular tolerance is 0.08; the axle intersection tolerance is 0.3) when installing the crank mechanism, metal rods, their constituents are made on a cone up to 2 ° with the possibility of axial movement, regulation and fixation in the desired position. Approaching the indicated values in the casting, especially in large-sized products with a complex profile and precision surfaces, will allow for high-quality finishing machining and to obtain a high-quality product.

Description

The utility model relates to the field of foundry. Known - "Device for producing castings" (Patent of Russian Federation No. 20155828, B22D 18 \ 00 from 07.15.1994), "Chill mold for casting a piston with a cooling cavity", bull. No. 12 of March 30, 83. The closest to the claimed object for producing piston castings from aluminum alloys is the "Device for producing piston castings" (RF Patent No. 2418651 of 08/10/2010), containing a lower plate, a metal mold, consisting of two half-molds with a cavity and a vertical plane of the connector, a mechanism for closing and opening the molds, a rod for making a cavity in the casting and rods for making holes in the casting, a low-pressure melt casting furnace on which half-molds are installed and with a metal wire for pouring m metal from the furnace, characterized in that (the target is not specified) the rod for receiving the cavity in the casting is made of prefabricated from the side and central parts connected by magnets, and the closing and opening mechanism of the molds contains a pneumatic actuator for lifting the assembled rod and turning it 180 ° and pneumatic actuators with cylinders having double-sided pistons and rods, which serve to produce holes in the casting. Obtaining a piston in a metal form — a chill mold, is carried out as follows. The low-pressure piston casting device has a fully automated programmed control cycle, automated adjustment of the closing and opening forces of the half-molds, the operation of the pneumatic actuator for lifting the rod with the casting, 180 ° rotation to replace the casting in the holder with the rod, returning the rod, lowering it, closing half-form, change in pouring speed, pressure holding time of the molded metal. The disadvantage of this device is that it will not be suitable for the manufacture of piston castings of a more complex and massive configuration, since the chill mold, taking into account the gate system (cooling system), will not fit in the standard sizes of plates of the JD1189 chill machine (1000 × 1000). Also in this device, the holes that are made by two rods, which are the rods of double-sided pistons in the cylinders of the pneumatic chambers of the device, cannot be axially adjusted and fixed in the desired position, as in our technical solution. For example, in the manufacture of a piston for an NVD48U marine engine with overall dimensions of 17317.8 × 480, weighing 41.8 kg., With a “refrigerator”, with a cone-shaped “skirt” and with very tight tolerances for pin holes for connecting rod, diameters which should be no more than ∅125. The problem is solved as follows (Fig. 1). On the upper plate 1 and lower plate 2 of the chill machine, the upper 3 and lower 4 molds of the chill mold are fixed respectively with the place formed in them for installing the core from the sand-polymer composition 5. To form the bosses in the internal cavity of the piston and form holes in them for the finger for connecting rod, two metal rods 6 made of steel 25L according to GOST 977-88 made on a cone with the possibility of their movement along the axis using bolts 7 and subsequent fixation in the desired position. The working cycle of the chill casting machine starts from a starting position of 90 ° when the chill mold is opened. At the command of the controller, the chill mold is heated to the set temperature, a non-stick coating is applied to the working surfaces, which instantly dries, after which a sand-polymer rod with built-in metal rods is put into the chill mold to form holes for the connecting rod pin and the chill mold is closed in the set sequence. A portion of aluminum grade AK10M2N GOST 30620-98 (with shrinkage of 1.5-2.0%) is poured into the receiving bucket of the machine, the movable part of the machine is tilted by the set angle. From the receiving bucket, metal self-filling the working volume of the chill mold through the filler neck 8. After pouring, it is possible to supply cooling water to the jacket. Next, the machine returns to its original position, the chill mold opens, and the casting using the pushers 9 is pushed into the working receiver. Further, the technological process is repeated again.

Claims (1)

A device for producing a piston casting from aluminum alloys containing an upper and lower plate, a metal mold consisting of two half-molds with a cavity and a horizontal plane of the connector, a mechanism for closing and opening the mold, a rod for receiving a cavity in the casting and metal rods for receiving holes in the casting, characterized in that in order to obtain a coaxial arrangement of the profiles of the bore openings perpendicular to the axial axis of the piston itself, the metal rods for their production are made with a taper of up to 2 ° and the ability to move them along the axis with subsequent fixation.

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