Patent GB-1197140-A (GB)
Title: Torque Converter Transmission with Overdrive
IPC: F16H47/08
Filed: 1968-12-13
Abstract: 1,197,140. Variable-speed gear. FORD MOTOR CO. Ltd. 13 Dec., 1968 [20 Feb., 1968], No. 59419/68. Headings F2D, F2E and F2F. An overdrive (sun, ring, planet) gear 104, 77, 100 in parallel with an in front of a hydrokinetic (impeller, turbine, stator) torque converter 64, 66, 68 of a motor-vehicle change-speed gear, bridges the converter when the oil feed and return flow from an impeller driven pump 52 to the toroidal chamber is reversed by an engine torque and road speed rseponsive switching valve (not shown) to close a one-way valve 158 in a brake piston 136 and move the piston to engage a diaphragm spring, or fluid pressure differential, released multi-plate friction brake 126 (Fig. 1), or a dog-type synchronized brake 200 (Fig. 2) to hold the sun 104 whereby the impeller 64, driectly connected via a member 112 to the planet carrier 110, overdrives the ring gear 77 which is directly connected to the turbine output shaft 96, the turbine 66 simply idling on an over-running coupling 67. As shown, during hydrokinetic drive, oil supplied by the pump circulaters through the toroidal circuit and returns through the planetary overdrive gear to the brake piston 136 where it holds the by-pass valve 158 unseated to maintain the brake 126 released. As turbine torque develops, the turbine 66 directly drives the shaft 96 via the over-running coupling 67, the inner race of the coupling 67, i.e. the ring gear 77, rotating slower than the carrier which is directly connected via member 112 to the impeller 64, the sun 104 free-wheeling such that the planetary gear is ineffective. To condition the transmission to bridge the hydrokinetic convertor with the mechanical overdrive, the direction of oil flow through the toroidal circuit is reversed automatically via the switching valve (not shown) closing the valve 158 and pressurizing the piston/cylinder 136, 134 to engage the brake 126 and lock the sun 104. The impeller 64 now directly drives the planet carrier 110 so that the ring gear 77 is over-speeded with respect to the turbine 66 via the over-running coupling 67 such that the output turbine shaft 96 is driven by the ring gear 77 at a step-up ratio of the engine speed, the turbine 66 simply idling in the inactive toroidal circuit. A by-pass orifice (not shown) may be provided to operate when the ball valve 158 is closed to ensure that the converter is filled at all times. During hydrokinetic drive, mechanical braking on vehicle overrun coasting is effected by an overrunning brake 156 which locks the sun 104 whereby the vehicle is braked through the shaft 96 and ring gear 77 via the carrier 110 and member 112 to the engine connected impeller 64. In an alternative embodiment (Fig. 9, not shown), the sun gear (104<SP>11</SP>) is permanently fixed and the overdriven ring gear (77B<SP>11</SP>) can be selectively clutched to the turbine shaft (96B<SP>11</SP>) when a clutch (1 28B<SP>11</SP>) is engaged under toroidal circuit pressure the reverse flow of which rereleases the clutch in the same way as the release of the brake 126 in the arrangement of Figs. 1 to 8. The various alternative positive brake arrangements of Fig. 2 (as shown), and Figs. 5 to 7B inclusive (not shown), are of the synchronized dog-type having a balk-ring (164), (Fig. 5, not shown), interposed between the relatively axially movably engaged brake members 174, 178, the balk-ring having a lost-motion connection with the ring 174 whereby brake engagement is prevented until synchronism of the sun 104 is achieved.