GB935963A - Differential drive transmission - Google Patents

Abstract

935,963. Differential gearing; ratchet clutches. STANDARD MOTOR CO. Ltd. July 13, 1962 [July 14, 1961], No. 25537/61. Class 80 (2). [Also in Group XXXI] In a transmission comprising two aligned output shafts driven through differential gearing from a reversible input shaft, one of the output shafts is connectable to the input shaft through one of two transmission devices, according to the direction of rotation of the input shaft, each device comprising two one-way driving devices of opposite hand driven at different ratios to limit the ratio of relative rotation of the two output shafts. A driving shaft 10 drives an input shaft 17 at one of two ratios through gears 23, 21 or 25, 22 and may also drive a power take-off shaft 16. The gear 21 meshes with a gear 28 rigid with the cage 29 of a bevel differential 30, 33, 34, driving two output shafts 35, 36 which may be either vehicle axle shafts or front and rear wheel drive-shafts. The output shaft 36 has rigid therewith two gears 50, 51 of different diameters meshing with gears 48, 49, respectively, having jamming roller freewheels A, B of the same hand, selectively clutchable through teeth 66, 67 to the shaft 17 by axial movement of a clutch sleeve 69 splined to the shaft 17. A third freewheel C of opposite hand is mounted between the gears 48, 49, the inner member of the freewheel being clutchable by sleeve 69-to shaft 17 on movement of the sleeve in either direction from neutral, and the outer member 56 being clutchable by a sleeve 60 to either of the gears 48, 49. The two sleeves 69, 60 are arranged to move both in the same direction simultaneously with a shaft to forward or reverse drive. In forward drive the sleeves 60, 69 are moved to the right such that the inner members of freewheels A and C are coupled to shaft 17 and that of B is free. Rotation of the output shaft 36 at the same speed as shaft 17 is permitted by gear 49 rotating slower and gear 48 faster than shaft 17 in which case the opposite handed freewheels A and C overrun. If shaft 36 runs faster than shaft 17 due to wheelspin the speed of gear 49 will correspondingly increase until, at a predetermined ratio between the shafts 36, 17, the freewheel C locks and prevents a higher relative rotation of the shaft 36. Should the shaft 36 rotate at the same relative speed but slower, due to slippage on shaft 35, the freewheel A will lock. In reverse, the sleeves 60, 69 are moved to the left and freewheels B and C perform similar functions of limiting the relative speeds of shafts 35, 36 with respect to shaft 17. In a modification, the shaft 17 supports two freewheels, of opposite hand, each bearing an unequal size gear pair meshing with complementary gears clutchable, by three ganged dog clutches, to the output shaft 36. To prevent locking of two freewheels on sudden torque reversal the dog clutch members between the sleeve 69 and the inner members of the freewheels are provided with circumferential clearance.