Patent GB-636139-A (GB)
Title: Motor vehicle power transmission assembly
IPC: F16H47/06
Filed: 1947-07-31
Abstract: 636,139. Hydro-mechanical variable speed gearing ; friction clutches. GENERAL MOTORS CORPORATION. July 31, 1947, No. 20786. Convention date, Oct. 21, 1943. [Class 80 (ii)] [Also in Group XXXI] A motor vehicle power transmission assembly comprises an engine E, Fig. 1, mounted transversely of the vehicle, a transmission mechanism mounted obliquely the mechanism being connected to the engine through bevel gearing intermounted obliquely, the transmission mechanism being connected to the engine through bevel gearing intermediate the ends of the mechanism at which ends are respectively located a hydraulic torque converter T and clutch mechanism C for effecting drive alternatively directly or indirectly through the converter, and a forward and reverse gear unit G. With -the arrangement shown the change from indirect to direct drive is effected by engine speed responsive means, change from direct to indirect drive is effected by depression of the accelerator pedal to about full throttle opening or by the engine speed responsive means and the clutch C is moved into a disengaged position on movement of the gear lever out of its in-gear positions. the transmission mechanism is contained in a casing consisting of parts 100a, 100b, 100c, 100d, each removable to allow inspection of parts contained therein, and a removable cover plate 100f for inspection of a one way clutch R. The drive of the rear mounted engine from the engine shaft 1 is through a vibration damper D to an input shaft 2. The shaft 2 carries a bevel gear 5 meshing with the gear 6 carried on a sleeve 7 which carries the clutch drum 8 of the clutch C comprising a clutch plate 31 on the hub 9 of the main transmission shaft 10, a clutch plate 32 mounted on the hub 12 of a sleeve 11, and a presser plate 33. The presser plate is moved to place one or neither of the clutch plates 31, 32, into contact with the drum 8 by bolts (not shown) on a ring 34 on the outer edge of a conical spring disc 63 mounted on guide pins 35 and fulcruming on bosses on the drum 8 on rotation of an eccentric 61 by means of a lever 62 connected to a servo piston and cylinder 70, 71. When the clutch plate 32 is engaged with the drum 8, the drive is transmitted through the sleeve 11 to the impeller 15 of the hydraulic torque converter T, whose rotor 17 is connected through the one-way clutch R to the shaft 10, and when the clutch plate 31 is engaged, the drive is transmitted directly through the hub 9 to the shaft 10. The shaft 10 carries a driving gear 19 in the forward and reverse gear G. The gear 19 meshes with a gear 20 on a lay shaft having another gear 21 engaging a reverse idler gear 22. A slider gear 40 actuated by a fork 41 has external teeth 40a which can engage the gear 22 and internal teeth 40b which can alternatively engage teeth 19a on the gear 19, the teeth 40b being in permanent engagement with a driven gear 25 on the output shaft 30. The shaft 30 is engaged with a universal joint U, Fig. 1, to the propeller shaft 50 having a universal joint 160 to a differential on the driving axle 170. Control gear. The fork 41 is controlled through linkage 42... 44 by a hand lever 140, Fig. 4, riding in an E-shaped slot, the notches in the slot corresponding to forward, neutral and reverse gear drives. When the lever 140 is in the slot connecting the notches, it makes the switch S2. The servo piston and cylinder 70, 71 controlling the clutch is operated by air pressure admitted through the solenoid valve V from an air supply tank. A switch S4 is controlled by a governor 150 driven by a gear 30<1>, Fig. 2, from the shaft 30. A switch S1 is made and broken by a solenoid controlling a pin 76. A switch S3 is broken by operating the accelerator pedal 120 to at or about its full throttle position until it depresses a spring loaded plunger 130, the pedal being connected by linkage 121 ... 124, lost motion device L and link 125 to an arm 83a operating the switch S3 and connected by a link 84 to a fuel injector 85 which can also be controlled by a piston 80 in a cylinder 81 through linkage 82 ... 84. Control gear operation. With the vehicle at rest and a master switch S made, the lever 140 is put into the forward drive notch, and the vehicle moves forward with the drive through the hydraulic torque converter T. As the speed of the drive increases the switch S4 is made by the governor 150 and current flows from earthed battery B through master switch S, switch S4, and normally closed switch S3 to actuate the solenoid valve V admitting air pressure into line 75, thus causing movement of the pistons 70, 80. Movement of the piston 80 causes a closing of the 'engine throttle until the line 78 is charged with air by the piston 70 passing its port. Then a spring 86 operates on the piston 80 when the air pressures are equalised in the cylinder 81 causing a return of the throttle to its previous position. This release of the throttle synchronises with the movement of the presser plate 33 to the position shown in Fig. 2 when the clutch plate 31 is engaged with the drum 8 due to upward movement of the piston 70 and the drive from the engine is then direct. The change from direct to indirect drive can be effected either by further depression or relaxation of the pedal 120. Further depression of the pedal 120 causes the link 83a to break the switch S3 so that the solenoid valve V is deenergized and a spring 72 in the cylinder 71 moves the piston 70 downward with corresponding movement of the presser plate 33 until the engine drive is through the torque converter. Relaxation of the pedal 120 causes reduced speed of drive which causes the governor 150 to break the switch S4 thus de-energizing the solenoid valve V with the consequential reversion to drive through the torque converter. With the engine in indirect drive, to change gear the lever 140 is moved out of its notch thus closing the switch S2. Current then actuates the solenoid controlling pin 76 moving it to the right and thus closing the switch S1 and allowing the solenoid valve to be actuated causing temporary relaxation of the throttle by the piston 80 and the piston 70 to be moved upward. With the pin 76 moved to the right it stops upward movement of the piston 70 by a lug 73 engaging it at the position when neither clutch plate 31, 32 is engaged with the drum 8. Then the lever 140 can now be moved into the notch for the required gear drive.