Patent GB-827290-A (GB)
Title: A speed responsive change-speed gear control system
IPC: F16H61/02
Filed: 1956-03-01
Abstract: 827,290. Change-speed control; variablespeed gear. EATON MANUFACTURING CO. March 1, 1956 [March 2, 1955], No. 6443/56. Class 80 (2). An electric control system for a changeratio planetary gear in a motor-car comprises an output shaft-driven generator producing an electric signal proportional in magnitude to the speed of rotation of the shaft and an accelerator pedal-operated control varying the electric signal inversely as the accelerator pedal is depressed to increase the engine speed &c., the resulting signal selecting the gear ratio. Gearing.-A driving shaft 120 carries a drum 124 which can be clutched by energizing coils 26, 28 to clutch members 126, 128 fast with a shaft 130 and a quill shaft 134, respectively. The shaft 130 carries a sun-gear 138 meshing a planet pinion 150 carried on an output shaft 154. The quill shaft 134 is formed at its end with a second sun-gear 136 meshing a planet pinion 140 rotatable in a drum 144 prevented from rotating in one direction by a one-way detent 160. The planet pinion 140 also meshes an internally-toothed annulus 146 carried by the output shaft 154, and the planet pinion 150 meshes internal teeth formed in the drum 144. For a first, reduced, forward speed, the coil 26 is energized to clutch the drum 124 to the member 126, and thus drive the sun-gear 138. Reverse rotation of the drum 144 is prevented by the one-way detent 160, so that a reduced drive is obtained at the output shaft 154, the second sun-gear 136 rotating idly. To obtain a second reduced ratio, a solenoid 30 is energized to open a valve 180 so that a diaphragm motor 176 is connected to a source of vacuum, and a brake 174 is applied to station the quill shaft 134. The sun-gear 138 drives as before, but the sun-gear 136 is now held stationary, so that the drum 144 rotates in the forward direction, as allowed by the one-way detent 160. To obtain direct drive, the coil 28 is energized as well as the coil 26, the brake 170 is released, and the gearing rotates as a unit. To obtain reverse, a selector member 186 is operated to engage a plunger 182.with teeth 184 on the outside of the drum 144, which is thereby held stationary. The coil 28 is energized to connect the drum 124 to the clutch member 128, the sun-gear 136 is thus driven, and the output shaft 154 driven backwardly. Control.-The gearing is controlled by a selector switch formed by three parts 110, 112, 114, operated simultaneously and having four positions, corresponding to neutral, forward drive with automatic change of ratio, reverse drive, and forward drive in low ratio only. An alternating generator 34 provides a current having a voltage proportional to the speed of rotation of the output shaft 154. Current from the generator 34 is fed to a solenoid 36 within which a core 56 is adjustably positioned according to the setting of an accelerator pedal 50, to vary the impedance. From the solenoid 36, a line leads to a rectifier 38 and inductance 40, a capacitor 32 being in parallel with this circuit. When the selector switch 110 &c. is in the position for forward drive with automatic selection of ratio, the generator circuit is connected by the part 112 of the switch to a circuit containing a " kick-down " switch 44 and two relays B, C. On starting the vehicle from rest, a battery 14 supplies current through an ignition switch 16 to the part 110 of the selector switch, and thence via a rheostat 22, the setting of which is determined by the accelerator pedal 50, to the selector switch part 114 and the coil 26, to couple the driving shaft 120 and drum 124 to the sun-gear 138 for forward drive. As the vehicle moves off, increasing depression of the accelerator pedal 50 so adjusts the rheostat at 22 that the flow of current to the coil 26 is increased to give increasing clutch engagement. As the speed of rotation of the output shaft 154 increases, the voltage of the alternating generator 34 goes up, and thus increases the voltage applied to the two relays B, C which are in the position shown. The relay B is arranged to operate at a smaller applied voltage than the relay C. When the output shaft 154 rotates at a sufficient speed, the relay B operates to close pairs of contacts B 1 , B 2 . The relay C at this point remains as shown. Closure of the contacts B 1  supplies current from the battery 14 and contacts C 2  to the solenoid 30 operating the valve 180 to connect the diaphragm motor 176 to the source of vacuum, and thus apply the brake 174 for the second ratio. As the speed of the output shaft 154 increases still further, the corresponding increase of voltage produced by the alternating generator 34 ultimately reaches such a value that the relay C is operated, to open pairs of contacts C 1 , C 2 , and close a pair of contacts C 3 . Opening of the contacts C 1  serves to disconnect the common earthing connection of the clutch coils 26, 28 from ground. Opening of the contacts C 2  breaks the circuit to the solenoid 30, and thus allows the valve 180 to close so that the brake 170 is released. Closure of the contacts C 3  connects the coil 28 direct to ground, so that the two clutch coils 26, 28 are now fed in series through the rheostat 22. The gearing then rotates solidly as a unit for direct drive. Depression of the accelerator pedal 50 increases the impedance in the coil 36 by adjusting the position of its core 56 and thus reduces the potential of the circuit, thereby increasing the road speeds at which the relays B, C operate. Below a certain predetermined speed, kick-down of the accelerator pedal 50 to its point of full depression opens the switch 44 to break the circuit to the relay C, and thus restore conditions for second speed operation of the gear. An adjustable resistance 48 is arranged in parallel with the switch 44, so that above a certain speed, the voltage of the generator 34 as applied through the resistance 48 is sufficient to keep the relay C in its operating condition with the switch 44 open, and thus prevent a kick-down shift. To obtain reverse, the selector switch is moved to its third position, so that current is supplied from the battery 14 through the rheostat 22 to the switch part 114 and thence to the coil 28, to drive sun-gear 136, and simultaneously the selector rod 186 is automatically operated to engage the plunger 182 with the teeth 184 on the outside of the drum 144. In order that the vehicle may be rocked out of mud or snow by rapid engagement and disengagement of low forward ratio and reverse ratio, a fourth position is provided for the selector switch, when the rheostat 22 is connected to the coil 26, to connect the driving shaft 120 and the drum 124 to the sun-gear 138, the plunger 182 remaining engaged with the teeth 184. The selector switch can then be moved rapidly between its third and fourth positions. Specification 602,512 is referred to.