Patent GB-634866-A (GB)
Title: Dynamo-electric machines employed as generators and starting motors for internal-combustion engines
IPC: F02N15/06
Filed: 1947-07-29
Abstract: 634,866. Turning-gear. BENDIX AVIATION CORPORATION. July 29, 1947, No. 20476. Convention date, Aug. 28, 1946. [Class 7 (v)] In dynamo-electric machines employed as generators and starting motors for internal-combustion engines of the kind comprising means for increasing the speed of a machine relatively to engine speed when operating as a generator as compared with its speed relatively to engine speed when operating as a motor, the starter means including an engine clutch element connected to and rotatable with the engine and a starter clutchmember adapted to engage the engine element and the clutch member being rotated to start the engine by the machine operating as a motor and being disengaged after the engine has started, the machine is driven from the engine when the latter is running above a given speed, by driving means exterior to and independent of the mechanism by which the clutch member is connected to the engine element when starting the engines. The machine may be connected to the starter mechanism by which the clutch member and engine element are connected for the purpose of starting the engine and the machine may be driven from the engine by driving means exterior to and independent of the starter mechanism when the engine speed attains a given value. An axially stationary nut 10, Fig. 1, is in threaded connection with a screw shaft 12, which latter has splined to it the spring- loaded clutch member 14, provided with a friction and oil seal member of neoprene, for engagement with and rotation of the engine elements secured to an engine shaft 38. The nut 10 is coupled to a drum 22 through an adjustable multiplate friction clutch 24, the right-hand wall of the drum 22 carrying planet gears 30 on trunnions 31, which gears engage an orbital gear 26 fixed to the starter casing 90, and a sun gear 42 journalled from the end wall of the drum 22. A driving shaft 32 which extends through the clutch member 14 is splined to the engine elements 36. The right-hand end of the sun gear is formed with a separate gear 40 which engages a pinion 52 connected by means of a shaft 46 to a speed-reducing gear 54. A hollow armature shaft 56 aligned with the driving shaft 32 is part of the dynamo-electric machine 58 and may be connected to the latter shaft by a centrifugal clutch 77. A spring-loaded pinion 68 is rotated with but slidable on the inner end of the hollow armature shaft 56, whilst a meshing rod 75 is axially slidable within the armature shaft 56 for moving the pinion 68 against its spring loading - into engagement with the speed-reducing gear 54. The meshing rod 75 is actuated by a solenoid 76 which is connected in series with the machine 58 when the latter operates as a series motor. Upon closing a switch 148, Fig. 2, a coil 156 is energized and contacts 150 and 152 closed, thereby connecting a battery 144 and motor field-winding 61 in series with the armature of the machine. At the same time the solenoid 76 is energized and axially moves the meshing rod 75 to cause the pinion 68, Fig. 1, to mesh with the speed-reducing gear 54 and so through pinion 52, gear 40, sun gear 42 and the reaction Between the planet gears 30 and the stationary orbital gear 26 to effect both rotation of the drum 22 and, due to the clutch 24 which also absorbs any reaction due to backfiring of the engine, the nut 10, which results in leftward axial movement of the screw shaft 12 and engagement of the clutch member and engine element. Upon further leftward movement of the screw shaft being limited by abutment of shoulders 27 and 29 on the screw shaft and nut respectively, the clutch member 14 commences to crank the engine. When the engine starts, its element 36 overrides the clutch member 14 and upon switch 148, .Fig. 2, being opened, the member 14 is cammed back to the position shown in Fig. 1. The driving shaft 32 is now rotated at engine speed and upon a predetermined speed being attained the centrifugal clutch 77 becomes operative and drives the machine 58 as a generator utilizing a shunt field winding 59 to charge the battery 144 through a voltage regulator 146, Fig. 2. In a modification, the driving shaft is connected indirectly to the engine shaft by means of speedincreasing gearing inside the crank case of the engine to be started and by changing the ratio of the other gears in the starter casing 90 the engine cranking speed may remain unchanged whilst the speed at which the machine is driven as a generator is increased. In another modification, the gearing inside the crank case of the engine to be started is replaced by sun-and-planet gears housed inside the clutch member which is consequently made larger in diameter.