tailieunhanh - Tài liệu Diezel 1410 P13

Function and type. The main diesel engines are directly connected to the main generators which furnish power to the main motors or battery through the control cubicle. | 13 REDUCTION GEARS A. REDUCTION GEAR UNITS 13A1. Function and type. The main diesel engines are directly connected to the main generators which furnish power to the main motors or battery through the control cubicle. Two types of main drive installations are now in use in modern fleet type submarines. The older type which is at present used in about 95 percent of our submarines consists of four main motors arranged in pairs to drive each of the propeller shafts through a reduction gear. This type of installation uses a single control cubicle. The latest type of main drive installation consists of a split control cubicle and two large slow-speed double-armature motors which are directly connected to the propeller shaft. Each section of the split control cubicle is designed primarily to control propulsion on its particular side. It is possible however to tie the two sides of the split cubicle together and therefore use port engines on the starboard screw and vice versa. This description of reduction gears is limited to the older type installation. Each reduction gear reduces the high main motor speed of approximately 1300 rpm to the propeller shaft speed of 280 rpm. The ratio of reduction is determined by the maximum efficiency obtainable from the propellers without loss of power at varying motor and propeller speeds. The gears are single reduction double helical type a right- and left-hand helix being used to balance the fore and aft components of the tooth pressure. The reduction gear assembly consists essentially of two main motor pinions forged and cut integral with the pinion shafts one main gear or bull gear which is connected to the propeller shaft and a lubricating oil pump gear which is geared to the inner pinion shaft. The forward ends of the pinion shafts are connected to their respective motors through flexible couplings. Each pinion shaft is supported by a cylindrical type bearing at each end. The main gear is pressed and keyed to the gear shaft. The aft