Patent GB-728206-A (GB)
Title: Improvements in propulsion systems for vehicles
Inventor: CLERK ROBERT CECIL
IPC: F16H37/00
Filed: 1950-08-23
Abstract: 728,206. Differential gear. GYREACTA TRANSMISSIONS, Ltd. Aug. 13, 1951 [Aug. 23, 1950], No. 29713/53. Divided out of 728,122. Class 80 (2). [Also in Group XXXI] A vehicle propulsion system comprises means for driving both the front and rear road wheels of the vehicle via a shaft which transmits the whole of the driving torque, means for applying braking effort to both the front and rear road wheels by the application of reverse torque to the shaft, the system being provided with means whereby a major part of the forward driving torque in the shaft is applied to the rear road wheels and a minor part of the forward driving torque is applied to the front road wheels, and also with means whereby a major part of the reverse torque in the shaft is applied to the front road wheels and a minor part of this torque is applied to the rear load wheels. In the arrangement according to Fig. 1, in which planetary gear trains I and II are provided between an intermediate shaft 82, which is or may be, coupled to the output shaft of the gear-box of a vehicle, and a coaxial output or propeller shaft 145 directed to the vehicle rear wheels, a planet carrier 146 of train I and a planet carrier 147 of train II are connected together and to shaft 82, and a sun-wheel 148 of train I and an annulus gear 149 of train II are fast with the shaft 145. An annulus gear 150 of train I journalled on shaft 82 carries a duplex chain-wheel 151 and a sun-wheel 152 of train II is journalled on the shaft 145 and carries a single chain-wheel 153. The planet carrier 146 carries planet pinions 154 co-operating with the sun-wheel 148 and annulus gear 150 of train I, and the planet carrier 147 carries planet pinions 155 co-operating with sun-wheel 152 and annulus gear 149 of train II. Train I, which is effective during retardation of the vehicle has a ratio between tooth members of the annulus gear 150 and sun-wheel 148 proportional to the effective weight distribution as between the front and rear wheels of the vehicle at the highest rate of retardation, whereas train II, which is effective during acceleration has a ratio as between the annulus gear 149 and sunwheel 152 proportional to the effective weight distribution between rear and front wheels at the highest rate of acceleration. Chains drivably connect the wheels 151 and 153 to sprockets 156 and 157 respectively journalled on an output or propeller shaft 158 for the front wheels. A camming element 159 on the shaft 158 cooperates with two sets of rollers 160, 161 and a cage 162, the rollers 160 co-operating with a drum 163 fast with the sprocket 156, and the rollers 161 co-operating with a drum 164 fast with the sprocket 157. In operation, driving torque applied to drum 164, in forward driving, constrains the rollers 161 to jam between the drum and the element 159, to transmit drive to the shaft 158, but due to a balancing effect of the pinions 153, a proportionately greater torque is transmitted to the annulus gear 149, through pinions 153. Reversal of torque in shaft 82, frees the rollers 161, but jams the rollers 160 between the element 159 and drum 163 by transmission of the reverse torque to the drum 163 through the sprocket 156 and annulus gear 150, the torque load at the latter being balanced through pinions 154 by a proportionately lower torque at sun-wheel 148 on shaft 145. The shaft 158 may extend alongside the vehicle engine. In the arrangement according to Fig. 3, applicable where weight transfers during acceleration and retardation are substantially equal, the intermediate shaft 82 is solid with a carrier 165 carrying pinions 160 which mesh with a sun-wheel 167 fast with a transfer gear 168. An annulus gear 169 is solid with a transfer gear 170. The gears 168, 170 mesh respectively with idler gears 171, 172 which mesh with gears 174, 175 journalled on a rear wheel propeller shaft 176. Oppositely acting unidirectional clutches 180, 181 drivably connect gears 171, 172 alternatively with gears 177, 178 and front wheel propeller shaft 179, and clutches 182, 183 connect gears 174, 175 alternatively to the shaft 176, the arrangement being such that the greater part of forward driving torque by shaft 82 is transmitted via gears 169, 170, 171 and 172 to shaft 176, while the lesser part is transmitted via wheel 167, gears 168, 171, 177 and 178 to the shaft 179. Upon reversal of torque in shaft 82, the greater part is transmitted from gear 169 via gears 170, 172, 177 and 178 to shaft 179, and the lesser part via gears 168, 171 and 174 to shaft 176. The shafts 176 and 179 are offset from shaft 82, and shaft 179 may extend alongside the engine. Reversal of torque on shaft 82 may be effected by interruption of engine fuel supply, or by the application of regenerative braking.