GB650564A - Improvements in change-speed control - Google Patents

Abstract

650,564. Change-speed gear. CHRYSLER CORPORATION. Feb. 10, 1948, No. 3859. Convention date, Nov. 13, 1939. [Class 80(ii)] [Also in Group XXXVII] A planetary overdrive unit D, Fig. 4, arranged behind a conventional manual three-speeds and reverse countershaft gear C, on a motor-vehicle, is controlled by a vacuum motor 65, Fig. 5, which, when energized, by closure of a vehicle-speed responsive centrifugal switch 120, Fig. 10, for upshift, thrusts a spring-released detent 69 into locking engagement with a slotted extension 48 on a reaction sun 47, to hold the latter for overdrive, the detent 69 being releasably locked in the gear-holding position by a lock-plunger 84 operated by energizing a solenoid 81 which also operates suction inlet and vent valves 93, 98 for simultaneously energizing the vacuum motor 65, the solenoid 81 being de-energized to vent the motor 65 to release the detent 69 and thus the reaction-sun 47, for kickdown to direct-drive through a oneway roller-clutch 52, by overtravel of the accelerator-pedal 125, Fig. 9. The latter operation is accompanied by momentary ignition-cut at a switch 165 operated by the vacuum motor 65 for torque reversal to permit release of the detent 69. Upshift to overdrive is executed by acceleratorrelease above the cut-in speed of the governor-switch 120, for a synchronized engagement of the detent 69. Gear system.-The input shaft 28, Fig. 4, of the planetary overdrive unit D is a rearward extension of the output shaft of the preceding conventional manually - controlled countershaft gear C, and rigidly carries a driving planet-carrier .42, the final output shaft 32 carrying a driven ring-gear 38. The forward extension 48 of the freelymounted reaction sun 47, in addition to having slots 49 to receive the locking detent 69 above referred to, has internal and external cam-recesses for one-way clutching engagement through rollers 52, 51 respectively either with a splined inner shaftmember 53 to provide direct-drive, or with an outer reaction-member 55 for overdrive. In direct-drive, forward drive is taken through the inner one-way clutch-rollers 52, and the outer clutch-rollers 51 are held in an inoperative position by a common cage 62 for the two sets of rollers. Under a coasting load the inner rollers 52 overrun and the cage 62 releases the outer rollers 51 which then engage to hold the sun 47 and transmit drive from the output to the input shaft at a decreased speed, the inner rollers 52 being then held off by the cage 62. With the countershaft unit C in reverse, the planetary unit drives in overdrive. In addition to its function as a reaction-member, the member 55 also acts as a balk-ring for ensuring that the sun 47 becomes stationary before the detent 69, Fig. 5, can reach its slots 49, and for this purpose the reaction-member 55 has a circumferential lost-motion spline connection 56 with the surrounding fixed casing, and is biassed in the forward direction by a single-coil spring 58. An axially projecting flange 72 of the reaction-member 55 has a single slot 73 to permit inward passage of the detent 69, and in the forward directdrive position shown, the spring 58 biasses the reaction-member 55 forwards so that a step 71 on the) detent 69 engages the trailing end of the slot 73, preventing inward movement of the detent under the suction load in the diaphragm 67. Torque-reversal, caused by accelerator-release, turns the reaction-member 55 backwards, releasing the detent step 71 at the same time as the sun-wheel slots 49 become stationary, so that the detent 69 passes inwardly to engage the slots 49 and lock the sun 47 to provide overdrive. The slotted part 48 and the detent 69 are chamfered to facilitate engagement. The detent 69 is locked in the operative position independently of suction by the lock-plunger 84 which is projected into a reduced neck 85 of the diaphragmstem by the solenoid 81 which also closes a vent-valve 98 and opens an inlet-valve 93 supplying engine-suction to the diaphragm to initiate the upshift. Control circuit.-The gear is conditioned for accelerator-release-executed upshift by the closing of the centrifugal switch 120, Figs. 9 and 10, driven by an output-shaft wheel 101, closure occurring above a vehicle-speed'of 20 m.p.h., which separates pivoted spring-loaded centrifugal masses 110 to flatten a bowed connecting-spring 114 and permit the contacts to close under spring-load. This completes circuit from the battery 159 through normally closed relay-contacts 161, the motor-energizing solenoid 81, a normally-closed manual switch 172 provided for cutting out the automatic overdrive action when not required, the governor-switch 120 and a switch 173 which is closed by a shift-rail of the main manual change-speed gear, so that the overdrive circuit is only effective in the direct-drive position. of the main gear. Energization of the solenoid 81 energizes the single-acting spring-loaded diaphragm 67 of the vacuum motor 65, Fig. 5, loading the detent 69 for movement to the overdrive lock position, which it assumes on accelerator-release. Kickdown shift. - Overtravel of the accelerator-pedal 125 beyond wide-open throttle-position closes a switch 143, completing a circuit from the battery through an ammeter 156, ignition-switch 154, a relay 152, and kickdown switch 143. The consequent energizing of the relay 152 opens the relay-contacts 161, thus de-energizing the solenoid 81, which releases the diaphragm-lock plunger 84, closes the suction-valve 93 and opens the vent-valve 98, de-energizing the diaphragm 67, which is biassed for detent-release movement by the springs 75, 78. The release movement of the solenoid-plunger 84 closes a switch 167, which completes an earthing circuit from the ignition-distributer 170 and coil 169 through the solenoid switch 167, a diaphragm-operated switch 165, which is closed in the energized position of the diaphragm, and the kickdown switch 143, thereby momentarily disabling the engine ignition system to create torque-reversal, permitting the release of the detent 69 so that the diaphragm 67 moves to the right under spring-load, ultimately breaking the ignition interrupter circuit by opening the switch 165, whereupon direct-drive is picked up through the inner clutch-rollers 52.