Patent GB-1498013-A (GB)
Title: Control valve system and valve arrangement therefor
IPC: F16H41/24
Filed: 1974-12-18
Abstract: 1498013 Hydrodynamic transmission control; change-speed gear; friction clutches SRM HYDROMEKANIK AB 18 Dec 1974 [14 Feb 1974] 54770/74 Divided out of 1498011 Headings F2C F2D and F2W A valve for controlling the direction of fluid flow through a hydrodynamic torque converter thereby to govern the mode of operation of the converter consists of valve discs 130, 144, Fig. 5, coacting with seats at either end of a member 154, valve discs 140, 132 coacting with seats at either end of a member 152, and an axially movable stem 174 on which the discs are mounted. The torque converter has an impeller 54, Fig. 1, a turbine 52 mounted on a shaft 18, and a reaction ring 50 which in one range of operation acts as a turbine and transmits torque to the shaft 18 through a hollow shaft 6 and planetary gearing 16, the planet carrier being held by a brake 14, and in another range is held stationary by a brake 12. The shaft 18 is connected to an output shaft 36 through forward/reverse planetary gearing 44 controlled by a clutch 46 and brake 48. A pump 20 driven by the rotary casing 22 of the torque converter delivers fluid to an inlet port 1146 of the control valve, and when an electromagnetic valve (not shown) in a housing 158 is energized to apply pressure to a servopiston 142 to raise the valve stem 174, lifting the valve disc 144 from its seat, fluid passes to a port 1154 and thence through passageways 86, 88, 90 to the working chamber 92 of the torque converter from which it exits through maximum pressure valves 96, a one-way valve 100, and passageways 102, 104, 110 leading to a port 1156 of the control valve where it lifts the valve disc 132 to pass through a duct 162 and heat exchanger 62, and return to the pump inlet. The pressure difference across the impeller 54 due to the passage of fluid through the valves 96 causes the impeller to be clutched at 56 to the rotary casing 22 which is connected to the engine flywheel 32. When the control valve is reversed by energization of an electromagnetic valve (not shown) in a housing 156, the pump 20 circulates fluid through the torque converter in the opposite direction, a pressure difference across a maximum pressure valve 114 then causing engagement of a lock-up clutch 58 so that the shaft 18 is driven directly by the engine, the clutch 56 being released by the passage of fluid between its engagement surfaces. When the control valve is in its intermediate setting shown in Fig. 5 the pump delivery is vented to the heat exchanger through a maximum pressure valve (not shown). In this setting a restricted flow is delivered to the torque converter through passages 118, 122, 124, 128, returning to the control valve port 1156 from which it escapes by lifting the valve disc 132. The valve disc 130 maintains sufficient pressure in the working chamber 92 of the torque converter for hydraulic braking. The Specification also discloses a control system employing two additional valves of the kind shown in Fig. 5 for controlling the brakes 12, 14 and the clutch 46 and brake 48, the system including a manual selector, a kickdown switch, and means for sensing the input and output speeds of the torque converter.