Patent ES-349154-A1 (ES)
Title: Transmission mechanism
IPC: F16H37/04
Filed: 1968-01-11
Abstract: A motor vehicle transmission includes a planetary train comprising a driving sun 76 fast on a shaft 16, a driven planet carrier 79 fast on a shaft 17, and a ring gear 77 which, for reduced drive, is held by a multi-disc brake 83 engaged by air pressure acting on an annular piston 110 acting through a Belleville spring lever 111, whilst for direct drive the ring is clutched to the sun gear 76 by a multi-disc clutch 82 engaged by an annular spring 88 and released by air pressure acting on an annular piston 91. General.-The transmission provides 8 forward ratios and a reverse ratio and comprises a simple counter shaft gear unit 15-16 having three reduced, one reverse ratios and direct drive, followed by the planetary gear lever 21 selecting the respective counter shaft unit ratio and controlling an air pressure system, Fig. 6, to establish a predetermined ratio in the planetary unit. Overall first-fourth ratios are obtained by selecting respectively first-fourth in the countershaft gear unit with reduced drive in the planetary gear unit, whilst overall fifth-eighth ratios are obtained by selecting respectively first-fourth ratios in the countershaft gear unit with direct drive in the planetary gear unit. Overall reverse is obtained by selecting reverse in the countershaft gear unit with reduced drive in the planetary gear unit. Gearing.-The input shaft 15 drives a countershaft cluster 42-44 through a wheel pair 47, 41. Freely mounted first and second speed wheels 52, 51 are clutched to the intermediate shaft 16 by a core synchronized balked double jaw-clutch 68, a similar clutch 67 connecting wheels 50 and 47 to the intermediate shaft for third speed and direct drive respectively. For reverse, an idler 60, meshing the wheel 44, is slid into mesh with wheel 53 splined to the shaft 16. Control.-The gear lever 21 has a ball-andsocket joint 206 with the gear-box and is restrained to pivot about two axes respectively parallel, and at right angles, to the intermediate shaft 16 by a pin-and-slot (210, 211), Fig. 4 (not shown), and is formed with a bi-furcated end, either leg 201, 202 of which may engage a shift fork 30 on a shift rod 22 and controlling the synchronizing clutch 67, and a shift collar (31), Fig. 3 (not shown), on a shift rod (23) which also carries shift fork 32 controlling the synchronizing clutch 68, the alternative engagement of these forks by either leg 201 or 202 conditioning the planetary gear set for reduced or direct drive respectively, as herein described. The leg 201 also may engage a shift fork (33) on a shift rod (24) and controlling the reverse idler 60. Cross-shifting the gear lever 21, i.e. to engage an adjacent fork or collar, or to engage the same fork or collar with a different leg, slides a plate 215, through a slot in which the lever passes, and a rod 220 carried by the plate, the rod 220 adjusting a valve 231 in the air pressure system of the planetary gear unit by means of a ball 270 co-operating with grooves 260, 263 in the rod. When the manual lever is positioned to select overall first-fourth, the ball 270 lies in groove 260 as shown, but for overall fifth-eighth the ball co-operates with the land between grooves 260 and 263. For reverse, the ball lies in groove 263. The three shift rods are provided with notches 25 and ball detents 26 to position them axially, and an additional known mechanism (212) is provided to interlock them to prevent the engagement of more than one ratio. The rod 220 is formed with four grooves (222), Fig. 5 (not shown), cooperating with a detent mechanism (not shown) and corresponding to the positions of the rod between overall first and second, third and fourth, fifth and sixth, and seventh and eighth. Additional grooves 261, 262 co-operating with a ball detent 265 are also provided in the rod 220 to locate the rod axially when moving the manual lever forward fifth speed position from established fourth. Operation.-As shown, one of the overall first-fourth ratios has been selected and the ball lies in groove 260, main line pressure 235 from an air compressor 230 flows via the valve 231, urged downwards by spring 254 and line pressure, and line 238 to a directional valve 232 which opens against spring 283 to allow pressure in line 241 to build up to disengage clutch 82, and only after reaching, e.g. 60 p.s.i., to shift the spool 291 of valve 233 to connect line pressure 238 to the brake apply line 240 which also, on reaching, e.g. 10 p.s.i., urges spool 291a of valve 234 to the left to connect line pressure 235 to line 239 which, together with spring 283 urges spool 280 of valve 232 to the right to connect lines 239 and 241 to maintain the clutch disengaged and the spool 291 of valve 233 urged to the left to engage the brake 83. The clutch 82 is therefore released before brake 83 is engaged, and the planetary gear is in reduced drive. On moving the lever 21 to select one of the overall fifth-eighth ratios, rod 220 is moved axially so that ball 270 co-operates with the land between grooves 260, 263 and through a spring 271 urges the spool 251 of valve 231 up against line pressure 235 and spring 254 to close the valve and exhaust line pressure 238 through port 250. Air pressure is then exhausted from the brake and from valve 234 through line 240 and valve 233, and the brake is immediately released. Spring 295a now moves spool 291a of valve 234 to disconnect line 239 from line pressure 235 and connect it to exhaust at 296 to exhaust line 241 and hence allow spring engagement of the clutch 82, spring 245 urging spool 291 of valve 233 back to the right. The brake 82 is therefore released before the clutch is engaged, and the planetary gear is then in direct drive. On moving the lever 21 to engage reverse, the rod 220 slides further to the left and ball 270 engages groove 263 and reduced drive in the planetary gear is again obtained.