Patent GB-833273-A (GB)
Title: Constant speed drives
IPC: F16D33/16
Filed: 1957-10-18
Abstract: 833,273. Variable speed gear; clutch combinations. FORD MOTOR CO. Ltd. Oct. 18, 1957 [Oct. 18, 1956], No. 32685/57. Class 80 (2). [Also in Group XXIX] Constant speed of an output member 32, driven through variable ratio planetary or fluid (see Group XXIX) gearing by a variablespeed input 21, is obtained by controlling the ratio of the variable gear in response to variations from a fixed datum in the delivery of a positive displacement pump 23 driven by the output member 32. In the planetary form shown in Figs. 1 and 2 such variations are sensed by a pressure-responsive valve 33 which operates a throttle valve 34 in the delivery 38 of a positive displacement meter pump 22 driven through a pulley 31 by a reaction sun 29 of the planet train whereby the pump 22 applies an appropriate resistance to the reaction sun 29 to permit it to run at the varying speeds necessary to result in constant output speed as the input varies. The gear-train comprises input ring 21; intermeshed planets 27 on a floating carrier; an output sun 24 on an inner shaft carrying the pump-driving pulley 32; and the reaction sun 29 fast with the meter pump driving pulley 31. The sensing valve 33 receives output pressure 49 from the output driven pump 23 which it feeds through a bleed 51 to act rightwards in the valve 33, and through passages 52, 56 to act rightwards also in the throttle valve 34. In operation, when the output speed and hence delivery 49 of the pump 23 increases above the constant value, the pressure sensing valve 33 moves right to connect the right end 43 of the throttle valve 34 to output pump suction through ports 44, 47 of the pressure sensing valve, permitting pressure 56 to move the throttle valve 34 right, to open the delivery 38 of the reaction meter pump 22 to suction at 39, thereby permitting the reaction sun 29 driving that pump to rotate at a higher speed, with consequential reduction in the output speed. When output speed falls below the constant value, the pressure sensing valve 33 moves left, supplying pressure 56 through the port 44 to the right end of the throttle valve 34 which is moved left to throttle the delivery 38 of the meter pump 22, thus reducing reaction speed and correspondingly increasing output speed. In Fig. 3 (not shown), the train comprises input and output suns meshing stepped planets on a reaction carrier which drives the meter pump of the Gerator type concentric with the output shaft. In Fig. 6 (not shown) the train is similar to that of Fig. 1 but the reaction sun is drivingly connected to output through a concentric hydrodynamic fluid coupling which is variably filled through a valve controlled by a Venturi 91 (Fig. 5) in the delivery of the output driven pump. In Fig. 5, the turbine 84 of a fluid coupling 86 is driven by an input pulley 87 through an overrunning clutch 83 until the speed of the second input pulley 82 which rotates at twice the speed of the pulley 81, reaches a speed whereby an impeller 87 is capable of driving the turbine 84 over-running the clutch 83. The constant-speed output shaft may drive such accessories in an automotive vehicle as air conditioning units, water or oil pumps, and generators, whilst the constant pressure from the output pump may supply such accessories as power steering, brakes and window lifts.