A die-casting method for an oil passage groove of an automatic transmission case

Abstract

The invention belongs to the technical field of die casting molds and provides a die casting method for an oil-way groove of a housing of an automatic gearbox. The die casting method includes the steps of combining an upper die and a lower die by a clamping press to form an oil-way cavity for shaping the oil-way groove of the housing of the automatic gearbox in the die-casing die; preheating the die-casting die by an electric-induction heating device to increase temperature of the die-casting die; feeding alloy in melting furnace, melting the alloy into met completely until the oil-way cavity is filled with the liquid melt fully; holding pressure of the liquid alloy inside the oil-way cavity, and starting a supercharging mechanism after finishing the pressure holding process to supercharge the oil-way cavity so as to feed the oil-way groove which is applied with extrusion pressure. The method has the advantages that the die-casting die adopting the die-casting method is simple in structure and convenient to operate, improves production efficiency, guarantees quality of the oil-way groove, avoids defects such as shrinkage porosity and pinholes, improves casting yield and reduces manufacturing cost.

Description

technical field [0001] The invention belongs to the technical field of die-casting molds, and in particular relates to a die-casting method for an oil passage groove of an automatic transmission case. Background technique [0002] In the process of producing automatic transmission casings, the castings are usually produced by extrusion casting. Due to the different wall thicknesses, the solidification sequence will be different, and defects such as shrinkage and shrinkage will occur at the wall thickness, resulting in The quality of the product cannot meet the requirements, such as figure 1 The CVT automatic transmission case shown here has an irregular transmission oil passage on one side of the CVT automatic transmission case. The oil passage of the transmission here has a plurality of oil passage grooves 2, and the oil passage is formed by die-casting. In order to ensure the molding quality of the oil channel groove 2, it needs to be controlled. In the actual processing ...

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Problems solved by technology

[0002] In the process of producing automatic transmission casings, the castings are usually produced by extrusion casting. Due to the different wall thicknesses, the solidification sequence will be different, and defects such as shrinkage and shrinkage will occur at the wall thickness, resulting in The quality of the product cannot meet the requirements, such as figure 1 The CVT automatic transmission case shown here has an irregular transmission oil passage on one side of the CVT automatic transmission case. The oil passage of the transmission here has a plurality of oil passage grooves 2, and the oil passage is formed by die-casting. In order to ensure the molding quality of the oil channel groove 2, it needs to be controlled. In the actual processing process in the prior art, due to the long runner on the fixed mold, the cooling and solidification speed of the high-temperature liquid metal is very fast. When flowing in the runner, the temperature of the liquid metal has dropped significantly, so that the pressure transmitted from the pressure chamber cannot be maintained until the solidification of the casting is completed. In addition, since the outside of the liquid metal is in contact with the surface of the mold, the cooling speed of the outside must be Faster than the inside, the oil channel groove where the casting finally solidifies, that is, the hot joint, is often inside, and looseness often occurs at the oil channel groove of the casting, which often leads to shrinkage cavities. In addition, if machining is performed here , the internal loose structure will be exposed, and its density is difficult to meet the pressure resistance requirements of the casting, resulting in shrinkage of the oil channel groove during the die-casting molding process, directly reducing the molding quality of the oil channel groove

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