The invention discloses a gearbox rear shell
casting method. The method includes the steps that modeling
material selection is conducted; parting face selection is conducted;
casting position determining is conducted; one box is adopted for containing one part; the
casting shrinkage rate is set; the pattern draft is set; a sand core is designed, wherein a positioning core head is arranged on the sand core, resin self-hardening sand is adopted for manufacturing the sand, and an exhaust channel is formed in the sand core; a casting manner is selected, wherein a sealed intermediate injection typecasting
system is adopted, a semispherical
sprue base is arranged, and a funnel-shaped
sprue cup provided with a foam type
ceramic filter net is arranged; a chilling block is arranged; the sizes of inner frames of an upper box and a lower box are the same;
smelting is conducted; casting forming is conducted; and heat treatment is conducted. By means of the gearbox rear shell casting method, sequential solidification is achieved at the defect position of a casting, a compact structure is formed, in addition, grains at the position are refined, and the mechanical performance of the casting canbe improved; and during casting, large impurities can be intercepted on the outer surface of a filter, micro impurities are adsorbed on the wall face of a channel, a
metal liquid flowing manner is changed into a laminar flow manner from a turbulent flow manner, and the probability that filtered
metal is further oxidized is lowered.