GB517519A - Improvements in hydromechanical power transmission means for vehicles - Google Patents

Abstract

517,519. Hydraulic transmission of power. TENNANT, W. J. (Aktiebolaget Ljungstroms Angturbin). July 7, 1938, No. 20197. [Class 69 (ii)] [Also in Group XXIV] In hydromechanical gearing particularly for a railway vehicle, in which a driven shaft 15 can be selectively clutched to a driving shaft 10 either by a clutch-disc 12 providing a wholly mechanical drive, or by a clutch-disc 13 providing a combined hydraulic and mechanical drive, the driven shaft 15 is at all times connected to the driven wheel 26 of the hydraulic gearing, e.g., a converter 24, by continuously meshing toothed gearing, e.g., 29, 16, including a one-way clutch 28, and the driving wheel 25 of the hydraulic gear is also connected to the engine through.another toothed gear-pair 21, 22. The provision of the one-way clutch 28 allows the hydraulic converter 24 to be stationary whilst the mechanical drive is in operation. The speed at which a change-over from hydraulic to mechanical drive is to be made in accelerating the vehicle from rest, which determines the starting tractive effort of the vehicle can be arranged to be any desired percentage of the maximum speed by a suitable choice of velocityratio for the wheels 29, 16, which latter are arranged to be readily exchangeable so that the gear can be adapted to suit different purposes as by the provision of greater or less starting tractive effort. By a suitable choice of ratio for the toothed gearing 21, 22 between the driving wheel 25 of the hydraulic converter and the clutch-disc 13 a given converter can be arranged to suit engines of different speeds. The driven shaft 15 drives the vehicle axle 19 through an idler 17. In a modification, Fig. 3, not shown, the clutch 12, 13 and gear-pair 21, 22 are arranged as a unit remotely positioned from the converter 24 and gear-pair 29, 16, and connected thereto through jointed shafts. The modification shown in Fig. 4 is the same as that in Fig. 2 with the exception that a two-speed mechanical gear is arranged between the driven wheel 26 of the converter and a parallel shaft 40 which drives the wheel 16 through a one-way clutch 41. A one-way clutch 42 is also included in the lowspeed pair 36, 38 of this two-speed gear, and overruns when the high-speed pair 37, 39 is clutched in at 43. In the form shown in Fig. 5, separate converters 24, 24<1> individually drive axles 19, 19<1> respectively through gear-pairs 53, 55; 53', 55<1> and one-way clutch 54, 54'. The wholly mechanical drive may, as shown, be to one axle 19' only, through a train 56, 53', 55<1>, or the axles may be connected together by a shaft 57. The hydraulic converter 24, Fig. 2, has fixed guide-vanes and may have adjustable impeller blades.