Motor vehicles with power take-off

摘要

1,101,968. Variable speed control. GENERAL MOTORS CORPORATION. 27 June, 1966 [16 July, 1965], No. 28605/66. Headings F2C and F2D. In a motor vehicle wherein an engine (2) drives the vehicle wheels (5) through a hydrodynamic torque converter 4 and change gear (4a) and also drives an accessory (6 through a hydrostatic transmission (8, 9), the torque converter has variable-angle reactor blades 18 movable by a servo-piston 30 under the control of a valve 44 between a first position providing maximum torque-converter capacity and a second position providing reduced torque-converter capacity which allows both the vehicle and accessory to be driven simultaneously without reduction of engine speed. Axial movement of the piston 30 acts through cranks 32 to vary the angle of the reactor blades 18. As shown a passage 35 permits converter pressure to urge the piston 30 right against the pressure supplied to the chamber 36 from the valve 44. Pressure from a line 50 supplied through a restriction 72 to a chamber 62 moves the spool of valve 44 down against the bias of a spring 46 to exhaust the chamber 36 whereupon converter pressure moves the piston, 30 right and reduces the angle of the blades 18 for high capacity converter operation. For low capacity converter operation a valve 80 is opened to supply pressure air from a source 81 to a piston 84 which moves up together with a plunger 86. A projection 86a of the plunger 86 opens a ball valve 74 to vent the chamber 62 at 68 and permit a spring 46 to move the valve spool 44 upward and thus supply regulated pressure to the chamber 36 which pressure moves the piston 30 left to increase the reactor blades angle. The pressure is regulated by the pressure acting in a chamber 56 opposing the action of the spring 46. The regulated pressure and thus the high angle blade position may be adjusted by changing the number of washers 58 below the spring 46. In Fig. 2a (not shown) the ball valve (741) is normally held closed by the plunger (861) and is opened by cutting off the air supply. In Fig. 3 (not shown) the reactor blade angle of a twin-turbine torque converter is urged toward a high-angle position by converter pressure and towards a low-angle position by pressure liquid supplied from the valve (140). The piston (154) controlling the ball valve (144) is operated by pressure liquid from the hydrostatic transmission (8, 9) driving the accessory. With the ball valve (144) closed a low regulated pressure is supplied to a chamber (112) which opposes the converter pressure on the piston (106) to determine the high angle low capacity position of the reactor blades. When the ball valve (144) is open a high pressure is supplied to the chamber (112) to move the blades to their low angle high capacity position.