GB1045972A - Improvements in or relating to gear boxes for motor vehicles - Google Patents

Abstract

1,045,972. Change speed gear. ZAHNRADFABRIK FRIEDRICHSHAFEN A.G. April 16, 1963 [April 27, 1962], No.14870/63. Heading F2D. In a change speed gear of the kind wherein a four ratio countershaft gear C is in series with a two-ratio and reverse sun-ring planet gear E, ratio shift in both gears is effected by a single shift lever 120. Gear arrangement.-In Fig. 3 an input pinion 72 is in permanent mesh with a pinion 81 fast on a countershaft 85. Pinions 82, 83, 84 fast with the countershaft 85 are in permanent mesh with pinions 76, 77, 78 which are selectively clutched by synchronized clutches 79, 80 to an intermediate shaft 73. The input and intermediate shafts 72, 73 may be clutched together at 80 for direct drive in the countershaft gear. The countershaft may be extended to the rear of the gear-box to provide a power take off. The planet gear comprises planets 88 meshing a sun gear 86 fast with the shaft 73 and a ring gear 87 which latter is held by a brake 92b for reduced ratio, clutched at 93b to the planet carrier 90, 91 for direct drive and clutched at 96a to an output shaft 74 for reverse, whilst the planet carrier 90, 91 is clutched at 91a to the output shaft for reduced ratio and held by the brake 92b for reverse ratio. A disc 94 connects the brake sleeve 92 and clutch sleeve 93 for conjoint axial movement. The ratios of both gears are selected so that final ratios are in a geometric progression. In Figs. 1 and 2 (not shown) the countershaft gear is identical with that shown in Fig. 3 and in Fig. 1 the planet gear comprises planets 31 meshing a long sun gear 33 fast with the intermediate shaft 35 and ring gear 30. The planet carrier 38 and ring gear 30 are axially shiftable as a unit to effect ratio shift. In the position shown the ring 30 is held by a brake 37a and the planet carrier 38 is clutched at 34b to the output shaft 34 for reduced ratio. For direct drive the ring-carrier unit is moved right and a coupling ring 36 connects the sun gear 33 to the output shaft 34 whilst for reverse ratio the ring-carrier unit is moved left whereupon the planet carrier 38 is held by a brake 92, 38b whilst the ring gear 30 is clutched at 38a, 37b to the output shaft 34. In Fig. 2 (not shown) except for a direct drive clutch between the intermediate and output shafts, the planet gear is identical with that shown in Fig. 3. Control.-Ratio shift in the countershaft gear is effected by shift rods 130, 131 under the control of a shift finger 140. - For ratio shift in the planet gear the shift finger 140 is moved left or right beyond the shift rods 130, 131 whereupon it acts through rods 141 or 142 to open a valve 121 or 122 which supplies pressure air through a line 124 or 124a to a servomotor 125 fast with a rod 150 having a projection 150a engaging a shift rod 132. The servomotor 125 and shift rod 132 are thus moved up for reduced ratio and down to the position shown for direct ratio. When direct or reduced ratios are established a projection 153 on the rod 150 engages stops 151, 152 and a cam 128 opens a valve 126 or 127 which supplies pressure air through a line 129 or 129a to close the valve 121 or 122. For reverse ratio the shift finger 140 is moved right beyond the movement required for shift to direct drive whereupon it pivots the rod 150 so that the projection 153 clears the stop 151 and opens the valve 121 to move the servomotor piston 125 and rod 132 to their lowest positions which establishes reverse ratio.