Full range automatic torque converter of hydrostatic type

摘要

1,101632. Hydrostatic transmissions. TOYOTA CENTRAL RESEARCH & DEVELOPMENT LABORATORIES Inc. 30 March, 1965 [18 Aug., 1964], No. 13481/65. Headings F2C and F2D. An hydrostatic transmission has a primary pump with one part connected to an input shaft through a one-way clutch and a second part connected to an output shaft, and a secondary pump having a part selectively clutchable to the input shaft for over-drive and reverse and clutchable to the output shaft for reduced drive. As shown, an input shaft 1 is connected through a one-way clutch 60 to a sun 6 of a planetary gear pump B having a planet carrier 3 fast with an output shaft 5. A swash-plate type secondary pump A has a tiltable non-rotatably mounted swash-plate 20 and a cylinder barrel 17 in permanent splined connection with a clutch sleeve 24 slidable to engage a key 25 on the input shaft or to engage internal teeth 14 formed on an extension of the output carrier 3. A stationary valve plate 13 is disposed between the pumps A, B. An hydraulically engaged friction clutch E is provided for direct drive. For reduced drive the swash-plate is set to its maximum inclination and the cylinder barrel 17 is clutched to the carrier 3. The gear ratio is increased as the inclination of the swash-plate is reduced, until direct drive is obtained when the swash-plate is vertical, in which position the swash-plate actuates a valve to engage the clutch E. For over-drive the cylinder barrel 17 is clutched to the input shaft and the swash-plate is tilted in the opposite direction. For reverse the cylinder barrel 17 is clutched to the input shaft and the swash-plate is tilted the same way as for reduced drive. In a modification the double positive clutch 24 is replaced by two friction clutches between the cylinder barrel and the input shaft and between the cylinder barrel and the output carrier. In this case both clutches can be engaged for direct drive, the clutch E being dispensed with. In another modification the primary pump B is replaced by a swash-plate type pump having a cylinder barrel connected to the input shaft through a one-way clutch and a non-adjustable swashplate mounted on the output shaft. Control system. Manual shift.-A steering column mounted lever controls mechanically interconnected rotary valves S1-S4. In the position shown the valves S1-S4 are in their normal drive positions and the transmission is in under-drive. For over-drive the lever is shifted momentarily clockwise from its position D to a position H and pressure fluid from the working circuit is fed from a port h to the left-hand side of a piston 43a to shift the valve 42 to the right in which position fluid from a supply pump is supplied to a servo 50 to shift the servo piston to the right and shift the clutch 24 to its overdrive position. Fluid from the port h is also supplied to the left-hand end of a swash-plate actuating servo 75 to reverse the tilt of the swash-plate. To shift from overdrive to underdrive the manual lever is shifted momentarily anticlockwise from its D position and liquid from the port h is supplied to the right-hand side of piston 43a to return the valve 42 to its left-hand position and is supplied to the right-hand end of the swash-plate servo 75 to return the swash-plate to its underdrive position. For reverse drive the valves S1-S4 are rotated through 180 degrees from the position shown. Fluid from the supply pump is directed by a valve S1 to the left-hand side of the clutch servo 50, and a pump 73 (see below for the further details) supplies to the right-hand side of the swashplate servo 75 so that the clutch and the swash-plate assume their reverse drive positions. Automatic shifts.-The transmission input and output shafts drive a differential arrangement, the output member of which drives the pump 73 so that the direction in which the pump discharges depends on whether the output shaft is rotating more slowly than the input shaft or vice versa. The output member of the differential arrangement also co-operates with a follower 37 actuating the valve 42 upon a reversal of the direction of rotation of the differential output member. Thus the swashplate and the clutch are shifted to their appropriate positions according to the conditions obtained.