Gear case die-casting technology and gear case die-casting dies thereof

Abstract

The invention provides a gear case die-casting technology which includes the smelting step, the die-casting and exhaust step and the die stripping step. In the die-casting and exhaust step, melt is divided by a runner and then is injected upwards into die cavities from the bottoms of dies, and after the melt is injected into the die cavities, gas in the cavities is exhausted upwards to exhaust tanks in the tops of the dies until the cavities are filled with the melt. The invention further provides the gear case die-casting dies used for implementing the gear case die-casting technology. The runner of a pouring mechanism is connected with the bottoms of the cavity of the fixed die through a flow gate, and the exhaust tanks are formed in the tops of the cavities of the fixed die and the movable die. A die-casting technology of pouring melt from top to bottom is changed, the die-casting technology of pouring melt from bottom to top is implemented, gas is exhausted via the exhaust tanks in the tops by the utilization of the upward gas exhaust property, secondary mixing caused when the gas encounters with the downwards flowing melt in the gas exhaust process is avoided, and the problems of air holes and cracks in the gravity casting process are solved.

Description

technical field [0001] The invention relates to the field of die-casting technology, in particular to a die-casting process suitable for a micro tiller gearbox body and a mold thereof. Background technique [0002] The traditional die-casting method of metal products usually includes the following steps: mold closing, keeping the movable mold in contact with the fixed mold, so that the cavity for molding the metal product is formed; mold locking, locking the two halves of the mold; gravity casting filling, pouring the molten metal Inject into the cavity so that the molten metal fills the cavity; unlock and split the mold, when the molten metal filled in the cavity is hardened into a metal product, separate the movable mold and the fixed mold; eject, on the rear surface of the movable mold The ejector plate is close to the movable mold so that the metal product is ejected from the movable mold by the ejector pins fixed to the ejector plate. [0003] This casting method has t...

AI Technical Summary

Problems solved by technology

[0003] This casting method has the following defects: when the molten metal is injected into the cavity, the gas present in the cavity or the gas injected into the cavity with the molten metal cannot be exhausted to the outside but mixed with the molten metal. Incomplete filling defects occur in metal products, resulting in pores and cracks, which make the strength and quality of metal products deteriorate

At present, the existing casting molds on the market have vent holes on the top for exhausting, but since the injection of molten metal and the removal of gas are all set on the top of the mold, the molten metal will be encountered during the gas evacuation process, resulting in molten metal. The secondary mixing of metal and air, the removal effect of pores is not ideal

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