GB697431A - Improved hydraulic torque converter mechanism - Google Patents

Abstract

697,431. Hydromechanical variable speed gear. GENERAL MOTORS CORPORATION. Oct. 26, 1951 [Nov. 8, 1950], No. 25041/51 Class 80 (ii). [Also in Group XXIX] A hydraulic torque converter mechanism has a pair of turbine members one of which is connected to the output shaft and to one element of a planetary gear, and the other of which is connected to another element of the planetary gear, the third member of the planetary gear being connected to a reaction member of the converter which is mounted on a one-way detent which prevents rotation of the reaction member in the direction opposite to that of the turbine members. In operation an output shaft 42 is prevented from rotation by vehicle inertia. Upon increase in engine speed from the idling condition two reaction members R1 and R2 tend to rotate reversely but are prevented by oneway detents 29-31-49 and 29-32-41. A sun gear 44 secured to the shell 49 thereupon becomes a fixed member since the hub 29 is splined to a fixed sleeve 28. Upon further increase in engine speed a turbine member O begins to rotate, and with it an annulus gear 43 with which it is connected by drum 34 and hub 35. The annulus gear 43 drives, through planet gears 40, a planet carrier 41 which is splined to the output shaft 42. Maximum torque multiplication thus occurs and the transmission is in its "low" speed range. The blades 15 of turbine O are sharply curved so that turbine O initially overruns both impeller I and secondary turbine Oa. As the speed of rotation of the output shaft 42 increases, the speed of the turbine Oa (connected to the output shaft through the planet carrier 41) likewise increases until the drive is through the turbine member Oa without gear reduction and the converter is in its " direct "or" "high" range of operation. Upon a further increase in speed of turbines O and Oa one-way detents 29-31-49 and 29-32-51 permit first R1 and then R2 to rotate forwardly the working fluid eventually striking the rear rather than the front surfaces of the reaction blades. When R1 rotates freely no torque can be transmitted through annulus gear 43 and planetary gears 40 because of rotation of the sun gear 44, and all torque is transmitted to the carrier 41, and hence the output shaft 42, from the turbine Oa. An auxiliary impeller Ia initially overruns the main impeller I because of the high velocity of the working fluid but as the vehicle accelerates and torque multiplication decreases, the fluid velocity decreases, the speed of rotation of-the auxiliary impeller becomes the same as that of the main impeller and the two impellers become locked by a one-way clutch 18-19-20, the hub member 19 being common to both impellers. Working fluid escaping radially outwards between shells 55 and 47 and between 47 and 48 respectively flows via passage 67 between the output shaft 42 and the fixed member 28 and by a short passage 68 to a space 65 whence it is pumped by a gear pump P, (including a drive gear 63 fixed to an axial extension 56 of the impeller hub 19) through a passage 66 to the space between blades 14 of impeller I and blades 16 of impeller Ia. The shaft 42 may constitute the input shaft for further ratio reduction gearing such as a planetary gearing, certain servooperation members. of which are shown on the right of the Figure.