GB630508A - Improvements relating to epicyclic power transmission mechanisms - Google Patents

Abstract

630,508. Change-speed epicyclic gearing. NORMANVILLE, E. J. DE. March 20,1947, No. 7669. [Class 80 (ii)] In a change-speed epicyclic gearing for motor vehicle transmissions having interengaging planets 9, 10 engaging, the one a driving sun 2 and a driven annulus 7 and the other a reaction sun 11, brakable members 18, 19, 20 are provided for controlling the rotation of the sun 11,-one of the brakable members, 19, being connected to the sun 11 through a unidirectional clutch 21 so as to allow drive in one speed ratio under free-wheel as well as engine braking conditions. As shown, applied to a three speed and reversing gearing, the planet carrier 8 and sun 11 respectively are rigid with the annulus 13 and planet carrier 12 of a second epicyclic train the planets 14 of which mesh the annulus 13 and a second reaction sun 15 to which brake drums 19, 20 are connected through a one way roller clutch 21 and directly respectively. The member 20 may be engaged by a clutch member 22 on the input shaft 1 for a third speed direct drive. Stationing of the sun 15 through either of the brake drums 19, 20 gives second speed under one or other of the above conditions, and further brake drums 18, 17 are provided on the planet carriers 12, 8 to station these for first and reverse speeds respectively. The drum 19 is normally stationed during direct drive to facilitate changing down therefrom and to minimise brake wear. The brake drum 20 may be dispensed with, the clutch member 22 engaging the drum 19 instead. In a two speed and reverse gear, Fig. 3 (not shown), the second train is dispensed with, the dual brakable members being applied to the reaction sun of the principal train. In either of these gearings, compound planet pinions may be incorporated to give a reverse ratio differing from that of the first speed. The invention is applicable to transmissions incorporating a fluid torque converter or coupling.