GB435389A - Improvements in and relating to power transmission systems for transmitting progressively variable drive - Google Patents

Abstract

435,389. Hydro-mechanical variablespeed gearing. SWAN, J. G., 14, Old Square, Lincoln's Inn, London. Feb. 20, 1934, No. 5626. [Class 80 (ii)] Comprises a combination of a Vulcantype hydraulic coupling with an epicyclic train arranged to prevent undesirably rapid variations in the torque transmitted when filling or emptying the coupling. Two epicyclic elements 28, 8, Fig. 4, are connected to a vaned coupling member 9 fast on a driving- shaft 1 and to a loose coupling member 10, respectively. The third epicyclic element 3 is fast on a driven shaft 2. The arrangement is such that, during transmission, the loose coupling member 10, that is the one not coupled to the driving-shaft 1, is caused to rotate in the same direction as the driving- shaft irrespective of the speed of the driven shaft 2. The slip in the coupling in the arrangement of Fig. 4 is 50 per cent when the driven shaft is stalled, the loose coupling member 10 rotates faster than the driving- member 9, and the torque in the coupling is less than that transmitted. Means for emptying and filling the coupling when rotating is essential to the invention. Drain ports 16 are controlled by a ring valve 17 moved axially by suitable means. Filling is controlled by a valve 18 in a duct leading to an annular channel 19. Radial ports 21 in the shaft 1 communicate with an axial bore 22 which leads to radial ports 23 opening within a sleeve 13 which connects the coupling member 10 to the gear element 8. Radial ports 24 then lead liquid into the coupling. Air vents 25 assist rapid emptying and filling. In Fig. 3 is shown a form in which the planet carrier 28 is secured to the loose coupling member 10 instead of to the driving coupling member 9 as in Fig. 4. In this form, the slip in the coupling is 40 per cent when the driven shaft 2 is stalled, the loose coupling member 10 rotates slower than the driving-member 9, and the torque in the coupling is greater than that transmitted, so that the coupling is made large. A form in which the epicyclic train comprises interengaging spur gears is also described. Specifications 384,022 and 402,185, [both in Group XXIX], are referred to.