GB881313A - Gearbox - Google Patents

Abstract

881,313. Change-speed gear. ROLLSROYCE Ltd. May 25, 1960 [June 1, 1959], No. 18706/59. Class 80 (2). [Also in Group XXXI] Gearing for use in two-engined Diesel locomotives comprises first and second input shafts, an output shaft which is driven by a differential gear, and gear change means for selectively transmitting the drive from the first and second input shafts either to the same or to opposite sides of the differential gear. As shown, a bevel gear differential having a planet carrier 39 fast with a driven shaft 16 has one of its sun gears 25 fast with a shaft 23 driven through a hydrodynamic torque converter (not shown) from one of the Diesel engines, the other sun gear 38 being carried by a sleeve 37 surrounding the driven shaft and prevented from reverse rotation by a one-way detent 44 of general similar construction to a Legge clutch. Fast with the first engine-driven shaft 23 and the sun gear 25 is a gear 29 meshed by a gear 30 carried by a shaft 24 driven through a hydrodynamic torque converter by the second Diesel engine and connected for rotation therewith by a ratchet clutch 32 of the Legge type. A gear 34, mounted for rotation upon the second engine drive shaft 24 but adapted to be clutched thereto by a positive dog sleeve 36, meshes a gear 35 secured to the sleeve 37 and a sun gear 38. If both the Diesel engines rotate their shafts 23, 24 and the clutch 36 is disengaged, the Legge clutch 32 engages and the torque of the shaft 24 is transmitted through the gears 30, 29 to the sun gear 25, which latter also receives torque directly from the shaft 23, the one-way detent 44 preventing reverse rotation of the sun gear 38. Accordingly a low ratio drive is obtained. If, however, the positive clutch 36 is engaged, the drive from the second engine shaft 24 is transmitted through the gears 34, 35 to the sun gear 38, and the Legge clutch 32 overruns, as also does the one-way detent 44. Accordingly both sun gears 25, 38 are driven, and a relatively high ratio is obtained. If the Diesel engine driving the shaft 24 should become inoperative, then the locomotive may be driven through the shaft 23, the one-way detent 44 preventing the sun gear 38 from rotating backwardly. If, during operation of the gearing in the high ratio, the engine driving the shaft 23 fails, the speed of rotation of the gear 30 decreases until the Legge clutch 32 engages, so that drive is still momentarily transmitted to both sun gears 25, 38. Due to the increase load placed on the engine driving the shaft 24, its speed is reduced, and automatic means (not further described) shuts down the engine and disengages the dog clutch 36. Drive is then taken up again from the shaft 24 through the Legge clutch 32, the gears 30, 29 and sun gear 25, the one-way detent 44 again restraining the sun gear 38 from reverse rotation. The driven shaft 16 is connected to the rail wheels of the locomotive through a reverse and reduction gear (not further described).