Patent GB-460838-A (GB)
Title: Improvements in hydraulic torque converters
IPC: F16H45/02
Filed: 1935-04-29
Abstract: 460,838. Hydraulic transmission of power. DODGE, A. Y. April 29, 1935, No. 805/37. Convention date, April 30, 1934. Divided out of 460,764. [Class 69 (ii)] In a hydraulic torque converter comprising an impeller, a turbine, and a reaction member the outlet of the turbine is in direct communication with the inlet of the impeller and also in indirect communication therewith through the reaction member ; when the speed of the turbine approximates to that of the impeller liquid is byepassed directly from the turbine to the impeller without passing through the reaction member, the proportion of liquid so byepassed increasing as the speed of the turbine approximates more closely to that of the impeller. In one form, Fig. 1, the pump blades 53 are carried by a casing 52 bolted to a flywheel 51 secured to a flange on the crank-shaft 50 of an internalcombustion engine driving the vehicle ; the turbine blades 54 are secured to a sleeve 55 rotatably mounted on a shaft 62 ; the reaction member blades 92 are carried by a casing 93 secured against rotation. In a modification, Fig. 2, a clutch for obtaining direct drive at a predetermined speed of the turbine is provided in the core space, comprising friction shoes 135 pivoted on the core ring 138 of the turbine and adapted to engage the core ring 137 of the pump. Liquid passes along the hollow shaft 62<a> and thence through 158, 159, 160, 161 into a space 162 and is then carried centrifugally through passages 163 into the working circuit. When the latter is full, liquid discharges through passages 164 ; should the pressure in the working circuit become too great liquid is forced through the gap 167 into the chamber 166 whence it discharges through passages 165. In a modification, Fig. 4, resilient guide vanes 245 are provided between the turbine blades 54 ; at low speeds of the turbine relatively to that of the impeller, the velocity of flow in the working circuit is so large that the blades are deflected against their resiliency into a radial position in which they are not affected by centrifugal force, the liquid then flowing through the reaction blades 92; when the speed of the turbine increases the flow is diminished and the blades move into the position shown by centrifugal force, the liquid then flowing direct from turbine to impeller with no torque conversion. The turbine blades 54 are carried bv two members 248, 249 the back of the blades being thus exposed to the impeller shell 51 ; the three elements of the converter carry rings 250, 251, 253 comprising an auxiliary core which separates the two paths of flow open to the liquid. The passages widen axially as they approach the axis so that despite their convergence radially towards the axis their cross-section is substantially uniform. The cross-sections however decrease slightly in the direction of flow and the inlets are larger than the preceding outlets ; relative sizes are given. In a modification, Fig. 6, the impeller blades 53 are supplemented by resilient blades 275 free at their outer ends and connected to a ring which is acted upon by a spring arranged in the core ring to maintain the blades 275 in the position shown ; the liquid is thus directed backwardly at low impeller speeds whereby only a small torque is exerted on the turbine, thus facilitating the changing of gear which is necessary at low speeds. At higher impeller speeds the force of the liquid deflects the blades 275 into a radial position this being assisted by the centrifugal force on the blades themselves. In a modification, Fig. 11, the blades comprise sheet metal stampings tongued to engage their respective shells and secured by spot welds as at 300 and by arc welds as at 301. The reaction member blades are curved and inclined to the axis of the converter so as to exert considerable resistance to flow therethrough. An inlet 163 provided in the material of the vanes or comprising tubes carried thereby opens at a point of low pressure.in the circuit ; liquid discharges under considerable pressure at 303 ; vanes 303<1> provided on the impeller housing 52 exist a centrifugal pressure opposing the discharge pressure ; an adjustable gooseneck tube 304 enables the quantity of liquid in the circuit to be varied. In a modification, Fig. 12, the impeller blades 53 extend nearer to the axis than the turbine blades 54 and are wider axially at their central portions than the turbine blades whereby a considerable circulation of liquid is obtained even when the impeller and turbine are rotating at almost the same speed. Auxiliary impeller blades 275 as described above are provided. Figs. 13-17 (not shown) illustrate a reaction member formed from stamped buckets which are assembled together so that parts of them comprise the shell of the reaction member while other parts form the blades ; the reaction blades are formed by two sets of buckets and the half-blades may meet edge to edge or be staggered. The impeller and turbine blades may be similarly formed. Fig. 18 (not shown) shows the shape of the turbine blades in relation to the reaction member blades which present a helically curved surface to the liquid. In a modification, Fig. 19, a friction clutch 465 is provided between the driving casing 52 and the impeller shell 466 ; at a predetermined speed of the driving casing 52 weighted arms 468 move under centrifugal force against a torsion spring to engage the clutch 465 whereupon the impeller is driven. At high speeds the axial thrust due to the liquid flow moves the turbine casing 477 to the left against a spring 476, the turbine casing 477 being then connected by a friction clutch 475 to the flywheel 51 so that a direct drive is obtained. A thrust bearing 481 is provided between the reaction 'member 93 and turbine shell 477 so that the reaction member 93 is also moved to the left, whereby a clutch 482 is disconnected and the reaction member is free to rotate. The three elements of the converter are provided with different members of blades, three members being prime to each other. The converter may be combined with mechanical variable speed gearing to form a transmission as described in Specification 460,764 [Group XXIV].