... gears and we got ISO9001:2000 qualification. Helical Gear Reducer: For SR gear box, the housing is cast precisely by high ... such as metallurgy, mine, machine, energy, transportation, water conservancy, chemical industry, light industyry, printing package, pharmacy, food, textile, building ... assembled and tested critically, therefore the noise of speed reducer is low; 7. Parallel axis -bevel wheel speed ...