GB446166A - Improvements in or relating to variable speed gearing - Google Patents

Abstract

446,166. Variable - speed gearing. SZEKELY, O. E., 818, Church Street, Elmira, New York, U.S.A. July 21, 1934, No. 21427. [Class 80 (ii)] In an infinitely-variable epicyclic change-speed gear, the driving member carries a planet pinion engaging a gear on the driven member and a smaller gear on the reaction member, which is connected back to the driving member by a gear pump, the outlet of which is throttled to produce a drag effect. In the form shown, the casing 25 on the driving shaft 20 is connected to the driven shaft 40, (1) by planet pinions 46 engaging a gear 45 on the driven shaft and a reaction gear 48 connected through a gear pump 49, 60 back to the casing 25 and (2) by gear pump 50, 60, Each of the pumps draws oil from a sump in the main casing and discharges it into a common chamber 110 from which it returns to the sump through a throttle 112. When the throttle is wide open, the shaft 40 and gear 50 are stationary and the gear 48 rotates forwards at rather more than twice the speed of the driving shaft. As the throttle 112 is closed by a control, the gear 48 is retarded by the pump 49, 60, thus producing a forward torque on the driven gear 45, while a further forward torque is applied to the gear 50 by the pump 50, 60 until when the throttle is closed the pumps are locked and direct drive is obtained. Owing to the common discharge chamber 110, the loads on the two pumps are always equal. The spindles 61 of the pinions 60 of the pumps are held in plates 26, 52 integral with the driving casing 25 and carrying blades 26a, 52a which pick up oil from the sump and deliver it to the pumps through openings 67. Since the gear 48 is smaller than the gear 45 a high starting torque is obtained. A freewheel clutch 41 is provided between the driven shaft 40 and the gear 48 to prevent overrunning and allow engine braking. An ordinary reverse drive may be obtained by opening the throttle 112 wide and connecting the driving casing 25 to the driven shaft through gears 82, 89, 89a, a shiftable gear (not shown), and a gear 90.