GB873451A - Improvements relating to the control of change-speed transmissions for automotive vehicles - Google Patents

Abstract

873,451. Change-speed control. REGIE NATIONALE DES USINES RENAULT. June 4, 1958 [July 8, 1957], No. 17852/58. Class 80 (2). [Also in Group XXXI] The gear ratio given by expanding pulley gearing 4 ... 6 in a motor vehicle is controlled by a differential valve 11 acted upon by a manually-operated ratio shift lever 16, movement of the shift lever to a new position causing the valve to supply oil from an engine-driven pump 14 to servomotors 9 which adjust the axial position of the slidable pulley flanges 4a of the driving pulleys, movement of the flanges 4a reacting back through cams 18 upon the differential valve 11 to shut off the supply of oil when the axial movement has been completed, the differential valve also being actuated by a speed-responsive pump 23 driven from the roadwheels 7 of the vehicle and supplying oil through a pipe 22 to a servomotor 21 which, when the vehicle comes to rest, moves a cam 20 to position the differential valve 11 so that the gearing is adjusted to give its highest ratio, i.e., the lowest gear. Tension in the belts 5 between the driving and driven expanding pulleys 4, 6 is maintained by oil pressure supplied from an accumulator 36 through a pipe 35 to servomotors 37 acting through thrust-plates 38 upon the axially slidable flanges of the driven pulleys. An engine 1 drives through a centrifugal clutch 2 to a forward-reverse gear 3 (not further described) and through bevel gearing to the ex. panding pulleys 4, the driven expanding pulleys 6 transmitting drive through fixed ratio reduction trains 8 to the half-shafts 24 and the vehicle road wheels 7. The speed-responsive pump 23 is driven through chains and sprockets 25 by one of the half-shafts 24.