Squeeze casting die and casting method for straight toothed spur gears

Abstract

The invention discloses a squeeze casting die and a squeeze casting method for straight toothed spur gears. The squeeze casting die comprises an upper die, a middle die, a lower die, a bottom die, web plate hole cores and a shaft hole core. The upper die, the middle die, the lower die, the bottom die and the shaft hole core are coaxially arranged, the middle die is fixed to the upper end of the lower die, a sliding inner cavity is arranged on the lower die, and the bottom die is nested in the sliding inner cavity and is slidably sealed in the sliding inner cavity; the web plate hole cores and the shaft hole core are fixedly arranged on the bottom die, and positioning exhaust holes which correspond to the web plate hole cores and the shaft hole core are formed in the upper die; a sealed pouring cavity is formed among the upper die, the middle die, the lower die and the bottom die in an enclosed manner when the upper die and the middle die are closed; the web plate hole cores and the shaft hole core are inserted into the corresponding positioning exhaust holes formed in the upper die. The squeeze casting die and the squeeze casting method have the advantages of high material utilization rate of 95%, high production efficiency, zero pollution due to waste sand, energy conservation, environmental protection, small gear blank machining allowance, fine crystal grains, good mechanical property and capability of carrying out continuous operation.

Description

technical field [0001] The invention relates to the technical field of mechanical manufacturing, in particular to a squeeze casting mold for spur metal gears and a casting method thereof. Background technique [0002] Gears are an important part commonly used in mechanical equipment, usually made of metals such as steel, cast iron or non-ferrous alloys. There are mainly four kinds of gear blank manufacturing methods in the prior art: casting, forging, round steel cutting and blanking, and extrusion. [0003] The gear blank formed by forging and round steel blanking generally does not have tooth shape, and even the spoke plate is not forged. Most of its shape is just a round cake, the machining allowance is more than 4mm, the material utilization rate is less than 60%, and the processing cost is high. . [0004] There are two specific methods for producing gears by solid state extrusion method, one is hot extrusion and the other is cold extrusion. They have the advantages ...

AI Technical Summary

Problems solved by technology

[0003] The gear blank formed by forging and round steel blanking generally does not have tooth shape, and even the spoke plate is not forged. Most of its shape is just a round cake, the machining allowance is more than 4mm, the material utilization rate is less than 60%, and the processing cost is high.

The prior art discloses two molds and methods for squeeze casting gears (application numbers 200320122261.8 and 200310109211.0). The shaft hole core is installed on the upper mold, and the molten metal is squeezed under the pressure of the upper mold, so the through hole cannot be obtained. The utilization rate of the material is still low, and because the metal core needs to be squeezed into the molten metal under pressure, its life is extremely short; its pressurization method is upper part pressurization, which belongs to direct extrusion casting, so it is poured into the mold before pressurization The liquid surface in the cavity will have a ring-shaped cold gap defect during the subsequent extrusion molding, and the depth can reach 3mm, which directly affects the performance of the gear and makes the gear manufactured by this method prone to tooth breakage accidents; it requires the upper die to enter the lower Extrusion is carried out in the mold, and the matching relationship between the teeth of each upper and lower mold is difficult to guarantee. The friction resistance is very large during extrusion, which significantly reduces the effective extrusion force, resulting in shrinkage defects inside the workpiece. In short, this kind of Squeeze casting gear blanks with upper pressure have problems of cold shut and shrinkage porosity, shaft holes that cannot be penetrated, and mold life is short

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