GB927394A - Improvements relating to torque transmssion devices - Google Patents

Abstract

927,394. Homopolar machines; automatic speed control. J. SAYERS. July 3, 1959 [July 3, 1958 (2)], Nos. 21279/58 and 21282/58. Classes 35 and 38 (4). A device for transmitting torque between two coaxial shafts 10, 11, Fig. 1, includes two homopolar machines 14, 15 respectively acting as a generator and a motor when the shafts 10, 11 form the respective input and output members, and the machines have a common stator field structure which includes a central annular polepiece 16 and respective excitation windings 20, 21 and rotary armatures 29, 31 connected to the respective shafts; an electrical circuit 40 interlinked with the two magnetic circuits 22, 23 created by the windings 20, 21 exists through the two rotors and part of the stator structure by way of electrical brush means which may be of the liquid mercury type forming the subject matter of Specifications 927,395, 927,396 and 927,397, which are referred to. All portions 27, 28, 16a of the rotors and stator structure lying within a toroidal zone bounded by the electrical circuit 40 and which also convey the working fluxes of the magnetic circuits 22, 23 are formed wholly of interleaved sets of high and low magnetic reluctance laminations 34 33, Fig. 2, at least one set being of low resistivity. The laminations, e.g. of copper and low carbon steel are united together by fusion and have set up in them by rotation of the armature 29 a voltage which causes a current to flow in the circuit 40. Whilst the device may comprise only the two machines, it is shown associated with a differential gearing which includes an input bevel gear 30 fixed to the shaft 10 and to the generator armature 29, and an output bevel gear 58 bolted to the motor armature 31 and connected to the output shaft 11 via bevel gears 56 carried by stub shafts 55 on a cage 32 fast with the shaft. In operation, the torque transmission is shared between the machines and the gearing, and when the fluxes 22, 23 are equal and opposite as shown, and the shaft 10 is rotated the torque is transmitted as the two armatures 29, 31 rotate at equal speeds in opposite directions. If now either flux 22 or 23 is reduced the output shaft will rotate in a direction which is respectively the same as, or opposite from, that of the input shaft. The device, which is shown as 87 in Fig. 5, may be applied to the transmission in a land vehicle, e.g. a motor car, wherein an I.C. engine 88 drives via shafts 10, 11 the road wheels 93a, and a tachogenerator 90 and an amplidyne 92a, 92b which provide control and excitation of the windings 20, 21. The car throttle 91 controls both the engine fuel control 88a and the tachogenerator excitation current provided in a winding F1 by a battery B1. The characteristics of the tachogenerator 90, the amplidyne 92a, 92b and the displacement of the slider of resistor R1 for a given throttle displacement may be so arranged that the conversion effected by the device 87 tends to produce a predetermined engine speed for that throttle setting irrespective of the load encountered by the road wheels.