Patent GB-916638-A (GB)
Title: Variable speed transmission for automotive vehicles
IPC: F16H47/08
Filed: 1959-03-31
Abstract: 916,638. Hydro-mechanical variable-speed gear; change-speed control. BORG-WARNER CORPORATION. March 31, 1959 [March 31, 1958], No. 10925/59. Class 80 (2). [Also in Groups XXIX, XXXI and XXXIV] In a combined variable-speed and differential gear for rear mounting in an automobile, a torque converter having an impeller 38 connected to an input shaft 27, and three turbines, 39, 40, 41, is combined with compound planetary sun-ring trains 31, 32 to drive a differential crown-wheel 56 through a gear output pinion 55, the torque converter and planetary trains being arranged on opposite sides of the road wheel axles. As shown, the compound planetary trains are arranged forward of the road wheel axles. A sun 61 of train 31 is connected to a first turbine 39 through a one-way clutch 51, a carrier 64 of train 31 and a ring 66 of train 32 are connected together and to a second turbine 40, a ring 62 of train 31 and a carrier 68 of train 32 are connected together, to the output pinion 55, and, through a friction clutch 37 to a third turbine 41, and a sun 65 of train 32 may react through a one-way detent 69 friction-braked at 35 or may be directly frictionbraked at 34. A reactor 42 reacts on a one-way detent and its blade incidence is variable by fluid-pressure for increased torque multiplication in the converter. For forward drive clutch 37 and brake 35 are engaged; initially drive is from the first turbine 39 only through the one-way clutch 51 to the sun 61, the two trains 31, 32 functioning as a compound reducing train reacting on the sun 65. With speed increase the second turbine 40 takes the drive exclusive of the turbine 39 and drives the ring 66 for reduced but higher speed drive through the train 32, the one-way clutch 51 releasing. With further speed increase the third turbine 41 takes over and drives the output pinion directly, the one-way clutch 51 and detent 69 releasing. With sufficient decrease in engine torque and increase in vehicle speed the reactor 42 is released and converter coupling point is reached. Hill braking is obtained by engaging clutch 37 and brake 34, and since the turbines 41 and 40 are respectively directly driven and over-driven by the output pinion 55 the torque converter acts as an hydrodynamic brake. For reverse, the carrier 64 is friction braked at 36, the first turbine 39 driving the ring 62 and hence the output pinion reversely. Additional torque for reverse may be obtained by engaging clutch 37, the second turbine 40 braked with the carrier 64 causing the converter fluid to drive the output-connected third turbine 41 reversely. The friction brakes and clutch are fluidpressure engaged. In Fig. 7 (not shown), for hill braking the clutch 37 and a friction brake acting on the first turbine 39 and replacing the brake 34 are engagod, the braked first turbine tending to force backward rotation on the output-connected third turbine. This braking torque may be increased by increased throttle opening for higher impeller speeds. Fig. 8 (not shown) differs from Fig. 7 in that a two-speed sun-ring planetary gear is arranged between the carrier 68 and the output pinion 55, the torque converter is forward of the road wheel axles, and the clutch 37 is replaced by a permanent shaft connection. The two-speed gear comprises a sun which may be friction braked, or friction clutched to a ring which is connected to the carrier 68, and a carrier connected to the output pinion 55. For forward " economy " range the brake 35 is engaged, and the sun and ring of the two-speed gear are clutched together to provide solid 1/1 ratio between the carrier 68 and output. For forward low speed " performance " range the brake 35 is engaged and the sun of the two-speed gear is braked to provide speed reduction between the carrier 68 and output. For hill braking, similar to Fig. 7, the first turbine is braked and the third turbine 41 is connected to output through the locked-up or speed-reducing twospeed gear. For reverse, the carrier 64, at 36, and the two-speed sun are braked. In Fig. 11 (not shown) the ring of the twospeed gear of Fig. 8 is braked, or clutched to the sun which is connected to the carrier 68, hill braking being effected as in Fig. 2. In Figs. 1, 3 and 4 (not shown), the combined variable-speed and differential gear is supported at the rear of an X-type framed chassis. The input shaft 27 is connected to the forward engine by a universally-jointed propeller shaft, and half-axles extending from the differential are connected through universal joints, to swing axles which carry the rear road wheels, support the chassis on coil springs, and are restricted to vertical swinging by limit straps.