GB765668A - Improvements relating to hydraulic couplings - Google Patents

Abstract

765,668. Hydraulic couplings. ROLLSROYCE, Ltd. Feb. 17, 1955 [Feb. 17, 1954], No. 4726/54. Class 69 (2). A hydrokinetic coupling is automatically emptied under conditions of rapid acceleration and/or rapid deceleration. A coupling comprises an impeller 13 and a runner 12 and the working liquid drains into a rotating reservoir containing a stationary scoop tube 25 for returning the liquid to the working chamber 22. The reservoir is divided by a partition 24 rotating with the impeller into spaces A, B, the liquid draining into the space A before entering the space B which contains the scoop 25. The partition 24 is formed with radial vanes dividing the space A into a number of auxiliary chambers and is provided with passages 32, 32A for each auxiliary chamber. The passages 32, 32A are located adjacent the trailing faces of the vanes. At a uniform speed leakage flow from the chamber 22 passes into the space A and thence through the passages 32, 32A into the space B to keep the entry of the scoop 25 immersed. If the impeller 13 is rapidly accelerated the liquid in the space A lags with respect to the vanes and the passages 32A, 32 are successively uncovered, discontinuing the flow to the reservoir space B, and thus return flow through the scoop to the working chamber 22 ceases. Valves 35 may control drain passages 21 between the working chamber 22 and the space A, the valves opening to permit increased flow from the working chamber upon acceleration. If the transfer passages 32, 32A are adjacent the leading faces of the vanes replenishing flow is interrupted during periods of rapid deceleration. Two chambers such as A may be provided in series so as to interrupt replenishing flow during both acceleration and deceleration. Flow between the scoop and the working chamber may be controlled by a thermostatic device as described in Specification 765,667.