Patent GB-941980-A (GB)
Title: Variable-speed transmission
IPC: F16H47/08
Filed: 1962-03-23
Abstract: 941,980. Change speed control; fluid pressure brakes. GENERAL MOTORS CORPORATION. March 23, 1962 [April 21, 1961], No. 11152/62. Headings F2D, F2E, F2F and F2L. In an all manual control system for a tractor change speed gear having a three ratio planet gear C, D in series behind a torque converter 2 and planet reverse gear A, B, the reaction brakes 14, 21 of the latter are controlled by a separate FNR selector valve 77 and a manual valve 141 which regulates the pressure supplied to the brakes 14, 21 which may be completely slipped thereby. The exhaust 87 from the regulator valve 141 is supplied through the FNR selector valve 77 to lubricate and cool the brakes 14, 21. The three ratio gear C, D is controlled by a separate selector valve 51 supplied directly from a main pressure supply line 47 and a cut-off valve 112 is provided between the main supply line 47 and regulator valve 141 to cut the supply of pressure fluid to the regulator valve 141 and FNR selector valve 77 and thus neutralize the reverse gear A, B when the vehicle brakes 110 are applied. Ball detents 71, 96 in the valves 51, 77 respectively locate the ratio positions. Gear arrangement; reverse gear.-The reverse gear A, B comprises input suns 9, 10 driven through a torque converter 2 and the former 9 meshes planets 15 on a reaction carrier 13 whilst the latter 10 meshes planets 18 on a carrier 17 fast with a ring gear 16 of the first train A and an intermediate output shaft 11. The brake 14 holds the carrier 13 of the first train A for reverse ratio whilst the brake 21 holds a ring gear 19 of the second train B for forward ratio. Change-speed gear.-The three ratio gear C, D provides reduced, direct and overdrive ratios and the intermediate output member 11 of the preceding reverse gear form the gear input member carrying the planets 26 of a first train C and the sun 33 of a second train D. The sun 27 of the first train and planet carrier 34 of the second train are fast with a final output shaft 12. A brake 37 holds the ring gear 36 of the second train D for reduced ratio, a clutch 24 connects the input and output members 11, 12 for direct-drive and a brake 29 holds the ring gear 28 of the first train C for overdrive. Fluid system.-An input driven pump 43 supplies pressure fluid through a main pressure regulator 46 to the torque converter 2 and to the main pressure supply line 47 which feeds the three speed gear selector valve 51 directly and the FNR selector valve 77 through the cutoff valve 112 and manual pressure regulator valve 141. The cut-off valve 112 normally supplies main pressure 47 through an orifice 129 to the regulator supply line 131. When the vehicle brakes 110 are applied and sufficient pressure is developed by a master cylinder 107 in a branch line 111 on the left of the cut-off valve spool 114 to overcome the main line pressure 47 acting on the right of the spool 114, the latter moves right and a land b blocks the main supply to the FNR selector valve 77 and brakes 14, 21 thus neutralizing the reverse gear. The manual regulating valve 141 comprises a spring pressed regulating valve spool 151 which throttles the exhaust 87 from the valve. The compression of the regulating spring 152 is adjusted by manually positioning a react piston 154. The FNR selector valve 77 simultaneously supplies pressure fluid and lubricating and cooling fluid to the same brake.