Patent GB-972629-A (GB)
Title: Variable-ratio power transmission mechanisms
IPC: F16D41/067
Filed: 1963-10-10
Abstract: 972,629. Hydromechanical change-speed gear; ratchet and friction clutches; disc brakes. GENERAL MOTORS CORPORATION. Oct. 10, 1963 [Oct. 22, 1962], No. 39963/63. Headings F2C, F2D and F2E. An hydrodynamic torque converter having an impeller 12, Fig. 1, is provided with first and second turbines 14, 16 and a stator 17 carried by a one-way detent 18, the first turbine 14 driving from stall at high torque through a shaft 22, a step-down gear train 27, 28 and a friction ratchet clutch 31 to a drive-shaft 29, the second turbine 16 remaining at first virtually inactive until a moderate speed has been achieved, when it drives through a shaft 24 and a step-up gear train 33, 32 to the drive-shaft 29, the ratchet clutch 31 now overrunning. With still further increase in speed, torque transmission through the first turbine 14 ceases, while that transmitted through the second turbine 16 decreases slightly. A gear 20 fast with the impeller 12 drives a power take-off 20<SP>7</SP>. Ratchet clutches.-The friction ratchet clutch 31 comprises an outer race 58, Figs. 2, 3, bolted to the gear 32 and formed with a series of cam pockets 62 each receiving a roller 61. A cage 64 having slots for the rollers 61 is rotatably mounted by bronze bearing rings 67, 68 fastened in the outer race 58. Long springs 71, 78 at each side of the cage 64 are connected at their ends 72, 74 between the cage and the bearing rings, and serve to bias the cage so that it turns and, through its cam pockets 62, forces the rollers 61 radially inwards against the cylindrical surface of an inner race 59. At starting and while the first turbine 14 is operational, the gear 32 transmits torque from the outer race 58 through the clutch rollers 61 to the inner race 59 &c., and the direction of drive is such that the cam pockets 62 wedge the rollers against the inner race 59. When the second turbine 16 takes over drive, the ratchet clutch is rotating at such speed that centrifugal force acts upon the rollers 41 and moves them radially outwards within their cam pockets 62 completely clear of the inner race 59 to disengage the clutch, turning the cage 64 against the bias of its springs 71, 78. Change-speed gear.-The drive shaft 29, Fig. 1, is fast with two sun gears 36, 46 and with the input side of a direct-drive hydraulically operated multidise clutch 52, carrying on its outside an output ring gear 43 meshing a gear 54 on a final output shaft 56. A low-speed forward drive is established by engaging an hydraulically-operated multidisc brake 49 to station a ring gear 48 meshed by planet pinions 47 in a carrier 42 fast with the output ring gear 43. Direct drive is established by disengaging the brake 49 and instead engaging the clutch 52. Reverse is established by disengaging the direct drive clutch 52 and instead engaging an hydraulically-operated multidisc brake 39 to station a carrier 38 mounting planets 37 meshing the sun gear 36 and also meshing a ring gear 41 fast with the carrier 42. Friction clutches.-The direct drive clutch 52, Fig. 4, comprises interleaved multidiscs 53 between a hub 51 and a pin 121 fast in a housing 116 integral with the output ring gear 43, engaged by admitting hydraulic pressure to act upon a ring-shaped piston 125 against the bias of a Belleville spring 126. Lubricating change-speed gears; lubricating clutches.-Oil is supplied through a chamber 95, Fig. 4, a shaft duct 98 and ports 99, 97 to the gearing and the planet pinion spindles 107. An extension 100 of the shaft duct 98 supplies a port 100<SP>7</SP> to lubricate the planet carrier 42, and also to lubricate the plates 53 of the clutch 52. Disc brakes.-The two multidisc brakes 39, 49, Fig. 4, are mounted upon a fixed casing member 106 and each has its own servo piston 103, 109 moved to the operative position by hydraulic pressure against the bias of disengaging springs (not shown) to station the ring gears 38, 48.