Patent GB-1051901-A (GB)
IPC: F16H47/06
Abstract: 1,051,901. Change-speed control. VOLKSWAGENWERK A.G. Jan. 16, 1964 [Jan. 18, 1963], No. 2072/64. Heading F2D. In a control for a motor vehicle change-speed epicyclic gear wherein shift is dependent on the speed difference between the pump and turbine of an hydrodynamic torque converter, the pump 15 and turbine 16 of the converter are respectively connected to the housing la and the rotor 1b or inner gear 1d of a vane (Fig. 3) or gear (Fig. 4) type pump which pressurizes both a shift control line 59 and a clutch and brake actuating line 60. Gear arrangement.-Planets 73 on an output carrier 74 mesh a ring 71 connected to the turbine 16 and a sun 72 which may be friction clutched at 64 to the pump 15 for hydromechanical split-torque High drive to the carrier or band-braked at 26 for series Low drive through the torque converter and the reducing epicyclic gear. The pump 15 is connected to an engine crankshaft 70 and the carrier 74 drives an output bevel wheel 78 through a following two-speed gear 75 and a bevel pinion 77. Fluid control system.-The pump 1 draws from a sump 10 through two suction lines 63a, 63b and discharges to the lines 59, 60. An arrangement of valves 2-9 (Fig. 3) or a frictionally dragged changeover slide valve (Fig. 4) maintains constant direction of feed when the relative pump rotational direction changes due to negative converter slip. Safety valves 19, 17 are provided in the lines 59, 60, the valve 17 relieving through a cooler 18. Needle valves 11, 13 in the lines 59, 60 have nozzle needles of expansible metal in conical seats so as to be temperature responsive and thereby compensate for viscosity change. The valves 11, 13 may be controlled by handles 12, 14. Adjustment of the valve 11 alters the amount of converter slip required for shift. The valve 13 may be controlled by the vehicle accelerator pedal to adapt the pressure in line 60 to engine load. A nozzle 32 in the line 60 feeds oil for vehicle lubrication. The clutch 64 comprises interleaved friction discs acted on by a doubleacting presser piston 23 having different areas respectively acted on by pressures in lines 61, 62. The band brake is acted on, through a link 58, by a double-acting piston 27 having different areas also respectively acted on by pressures in the lines 61, 62. The lines 59, 60 are connected to a valve housing 28 accommodating two valve members 21, 29. With the valve member 29 connecting the lines 60, 62, the valve member 21, which is stepped to provide hysteresis, is rightwardly moved by a spring 22 to connect the pressure in the line 60 to the line 61 to engage the clutch 64 and release the brake 26 for splittorque High drive, and is leftwardly moved by increasing pressure in the line 59 or by an overriding pulling-eye 21a to cut off pressure in the line 61 to release the clutch 64 and apply the brake 26 for series Low drive. The valve member 29 is actuated, by a notched disc 31 and against a spring 30, to interrupt drive for manual engagement in the two-speed gear. Pressure reservoirs may be provided in the line 59 to compensate for too-energetic accelerate pedal depression resulting in sudden gear change.