Patent GB-1040199-A (GB)
Title: Automatic control device for a change-gear transmission
IPC: F16H61/02
Filed: 1965-05-24
Abstract: 1,040,199. Change-speed control. DR ING h.c.F. PORSCHE KOMM. GES. May 24, 1965 [May 23, 1964], No. 21823/65. Heading F2D. An automatic variable-ratio gear has hydraulically applied clutches and brakes engaged under the control of a shift valve 82 which is positioned by pilot liquid supplied by a valve 41 which has a valve spool 42 positioned by an output driven governor 40 acting on the spool through a spring 46, the valve 41 also having a valve sleeve 43 positioned in accordance with depression of the accelerator pedal 69, the spool 42 and sleeve 43 being coupled by a ball detent 53 so that axial movement of the sleeve moves the spool axially with consequent tensioning of the spring 46 thus modifying the output speed at which the spool will be shifted relative to the sleeve. Gearing.-The variable-ratio gear is formed by two compounded epicyclic trains driven from an hydrodynamic torque converter 1 (Fig. 1, not shown) with a lock-up clutch 13, the trains having a common sun gear 26 which can be stationed by a brake 35 for second gear or be clutched to the input (turbine) shaft by a clutch 18 for third gear (direct drive), a first ring gear 27 clutched to the input shaft for forward drive, a first planet carrier and a second ring gear 38 connected to an output shaft 30, and a second planet carrier which is stationed by a brake 36 for first gear. Control.-An input driven pump 21 supplies pilot liquid through a line 71 to the valve 41, which in the position shown directs liquid through lines 78, 79 to either side of a piston 81 fast with the shift valve 82 which is spring urged to its central position in which liquid supplied by the pump 21 to a line 84 is supplied to the servos of the forward clutch 17 and brake 35 to give second gear. Downward movement of the spool 42 relative to the sleeve 43 under the control of the governor 40 opens line 78 to exhaust so that pressure in line 79 shifts the valve 82 to the right and clutches 17, 18 are engaged to give third gear. Upward movement of the spool 42 from the position shown shifts the valve 82 to the left to engage the clutch 17 and brake 36 for first gear. The sleeve 43 is fast with a bracket 56 which is guided in a helical groove 59 in a fixed bushing. The sleeve has a pin-and-slot connection 62, 64 with a stem of the spool 42 which in turn has a pin-and-slot connection 63, 65 with a lever 66 which is rotated on depression of the accelerator pedal 69. Depression of the accelerator pedal thus rotates the spool 42 and sleeve 43, and through the helical groove 59 shifts the sleeve 43 axially. The spring-pressed ball detent 53 causes the spool 42 to shift axially, tensioning the spring 46, so that the relative positions of the spool and sleeve are unaltered until the tension of spring 46 is sufficient to cam the ball 53 out of a groove 51 thus permitting the spool to shift under the action of the spring 46 until the ball 53 engages the next groove 51. The ball 53 is biased into the grooves 51 by a spring 54 reacting against a cam surface 57 formed on the fixed bushing 58 so that the loading of the spring 54 is dependent on the position of the valve sleeve 43.