GB911700A - Improvements in or relating to automatic transmission mechanisms incorporating torque converters - Google Patents

Abstract

911,700. Hydro-mechanical variable-speed gear. REGIE NATIONALE DES USINES RENAULT. April 7, 1959 [April 14, 1958], No. 11751/59. Class 80 (2). [Also in Group XXXI] In a vehicle having its power unit, transmission and drive wheel assembly located at the front or the rear of the vehicle, an hydraulic turbo converter 17 and an hydraulically engaged friction clutch 18 are driven in parallel by the engine through a centrifugal clutch 16 and are arranged on one side of a differential 15, a constant-mesh change-speed and reversing gear being arranged on the opposite side of the differential. The turbine 21 of the torque converter drives a shaft 12 having a gear 75 meshing a gear 76 fast on the outer race of a ratchet clutch 77 the inner race of which is loosely mounted on a shaft 13 driving the differential. The inner race has external splines 95 engaged by internal splines of a sliding pinion 83 in the position F shown to clutch the inner race to the shaft 13 to give forward drive. The sliding pinion 83 is movable to the left to mesh an idler meshing a gear 82 on the shaft 12 to give reverse. The driven disc 34 of the friction clutch 18 is fast on a shaft 11 driving shaft 13 through gears 85, 86. The clutch 18 is engaged automatically by liquid supplied to a chamber 42 under the control of the solenoid valve 60 which also controls the supply of liquid to the converter. On starting, with a manual lever 87 in its neutral, N, position, the centrifugal clutch 16 is disengaged, and closing the ignition switch also closes the solenoid valve circuit, moving the valve piston 61 to the left, thus disengaging clutch 18 and supplying liquid to the converter 17. On moving the manual lever 87 to its forward, F, or reverse, R, position, the sliding pinion 83 clutches the inner race of the ratchet clutch 77 to the output shaft 13 or meshes the reverse idler. During movement of lever 87 to position F or R a bell-crank lever 90 is temporarily actuated, which actuates a brake 91 to station shaft 12 to ensure shockless engagement. Alternatively movement of lever 87 may temporarily engage the clutch 18 and thus station shaft 12 since the driven disc 34 of the clutch is permanently geared to the drive wheels. On accelerating the engine the centrifugal clutch engages and the vehicle is driven through the converter. The output shaft 13 drives a centrifugal governor 50 which at a predetermined speed, modified according to the position of the throttle, opens a micro-switch 54 which deenergizes the solenoid, thus engaging the clutch 18 and reducing flow to the converter to a lubricating flow through a restriction 71 in a land 65 of the valve. The vehicle is now driven through the clutch 18 and gears 85, 86. In reverse, R, position, a switch 98 prevents deenergization of the solenoid valve. To provide engine braking, lever 87 is movable to a position EB, which shifts the sliding pinion 83 to its extreme right-hand position in which dog clutch teeth 96, 97 on the sliding pinion and outer race of the ratchet clutch are engaged. To ensure shockless engagement, movement of lever 87 to position EB temporarily actuates a bell-crank which opens the throttle to ensure that the ratchet clutch is engaged. In a modification, Fig. 7, the shaft 12 carries a reverse drive gear 102 and forward gears 100, 101 providing two speeds through the converter and meshing gears 103, 104 which are selectively clutched to the outer race 105 of a ratchet clutch by a clutch sleeve 111, synchronizing baulk rings 112, 113 being provided. A sliding pinion 107 is movable to the right to engage a reverse idler and to the left to engage splines 109 on the inner race 106 of the ratchet clutch for forward drive, and to the extreme left to engage teeth 114 on the outer race for engine braking. Two degrees of engine braking are provided, according as gear 103 or 104 is engaged by sleeve 111.