GB484296A - Improvements in variable-speed gears with epicycloidal trains, particularly for automobiles - Google Patents

Abstract

484,296. Variable speed gearing. FORICHON, A. July 30, 1936, No. 21168. Convention date, July 31, 1935. [Class 80 (ii)] A variable-speed gear has two planet wheels of different diameter freely rotatable as one upon an axle revolved by the driving shaft, one planet meshing with a sun connected directly to the driven shaft and the other with a sun which can be controlled to give three forward speeds, viz., when it is fixed against rotation ; when it is coupled directly with the driving shaft and another when it is connected to the driven shaft through a reversing gear train. The invention is described in connection with a gear box having three forward speeds and a reverse. On the driving shaft 1 is mounted a plate 2 carrying axles 3 of integral planets 4, 5, the planets 4 engaging a sun 6 on an intermediate shaft 7, and the planets 5 a sun 8 integral with a sleeve 9 loosely mounted on shaft 7. On sleeve 9 is loosely mounted a sleeve 10 integral with a plate 11 carrying axles of planets 12. These engage a sun 13, integral with sleeve 9, and also a, ring 14 carried by a plate 15 the hub of which has internal ribs 16 engaging external grooves 17<1> of the output shaft 17, the plate being displaceable along the shaft. In Fig. 1, the plate is shown engaging teeth on a disc 18 keyed on shaft 7, so that shafts 7, 17 are rigidly interconnected. Control is effected by hydraulically actuated friction clutches. The liquid, which may be the lubricating oil, is drawn through a duct 19<1> by a pump 19 and delivered through pipe 21 to a distributer 22 having a slide valve 22<3>. A byepass 23 with spring- loaded valve 21<1> is provided, to ensure a return when valve 22<3> is in the position shown. When this valve is moved to the right, liquid is admitted to a cavity 26, Figs. 1, 3, behind an annular piston 27 loaded by a spring 30 and carrying a clutch member 29. When the valve is moved to the left, oil is delivered through ducts 25, 31, 32 to a cavity 33 a wall 34 of which slides on guides 2<1> on plate 2, is loaded by a spring 35 and carries a clutch member 36. A free-wheel device 38 between sleeve 10 and a fixed wall 39 ensures that the sleeve 'will rotate only in the forward direction. The sleeve 10 carries a toothed ring 41 adapted to be engaged by a projection 44 on a bolt 42 carrying a fork 45 engaging the member 15, which, together with the bolt, is actuated by a lever 43. Slidably mounted on sleeve 9 is a plate 46 carrying clutch member 47, 48. A plate 49 with peripheral clutch surface is rigidly secured to the driving plate 2. Other types of clutch members may be employed. For all forward speeds, the bolt 42 and member 15 occupy the position shown in Fig. 1. For first speed, all the clutches are out, the axles of planets 12 are held against reverse rotation, and drive takes place in part through planets 4, sun 6, and intermediate shaft 7, and in part through planets 5, sun 8 and reversing train 13, 12, 14. For second speed, the valve 22<3> is moved to the right to move piston 27 to the left and hold plate 46 against surface 53 of the casing. The planets 5 then revolve over fixed sun 8 and the drive is then through planets 4, sun 6 and shaft 7. For third speed, i.e. direct drive, the valve is moved to the left and pressure is transmitted through ducts 25, 31, 32 to wall 34 causing the plates 2, 46, 49 to be clutched together. For reverse drive, the bolt 42 is moved to lock the toothed member 41 and the member 15 is separated from disc 18. The valve 22<3> is kept in the position for direct drive and therefore the train 4 ... 8 rotates as a whole and drives sun 13 and this rotates pinions 12, whose axles are now fixed, ring 14 and member 15. To bring about an uninterrupted change from third to second speed a second free wheel may be placed between plate 46 and sun 8 or, the orifices 28‹, Fig. 3, in the piston 27 and which work over guide pins 28<1>, Fig. 1, may be elongated, to permit the piston to move through a small angle to cover more or less the inlet 24 for the oil. Springs 50 return the piston against the driving torque.