GB654082A - Improvements in or relating to torque-meters in gear drives - Google Patents

Abstract

654,082. Measuring torque. ROLLSROYCE, Ltd. Oct. 31, 1947, Nos. 29161/47 ond 5521/48. [Class 106 (ii)] [Also in Group XXIV] In an arrangement for measuring torque in a gear-train comprising a lay-shaft 16, Figs. 1 and 3, free for limited axial movement, and supporting a gear 15 which develops axial thrust when torque is transmitted through the gear-train, thrust bearing means 17, supporting the lay-shaft, is carried in non-rotatable axially movable housing means 30 including a cylinder element 32 in which slides a fixed piston element 130, pressure fluid is supplied to the element 32 to oppose the axial thrust and escapes through an exit port such as 138, the area of which is determined by the relative position of elements 32, 130, and the pressure in the cylinder element is measured, e.g. by a gauge 42, Fig. 4, calibrated to indicate torque. As shown, the torque transmitted through reduction gearing between a gas-turbine engine and an airscrew is measured. The engine drives a helical-toothed pinion 12, Figs. 1 and 4, meshing with three helical gears 15 or 40 on shafts 16 or 41 which also carry straight-toothed gears 19 meshing with an internally toothed ring 20 supported to allow limited play transversely to its axis on a flange 23 carried by the airscrew shaft 24. Only one of the shafts 16 or 41 has the housing means 30, Fig. 3, fixed to the outer race of the thrust ball bearing 17, and the associated piston and cylinder, the space between which is sealed by rings 135, 136, and supplied with fluid through ports 140 by a gear pump 37 driven by the shaft. The area of escape ports 138 is controlled by cylinder ring 136, the cylinder moving until this area is such that the fluid pressure balances the axial thrust. Assuming equal torque transmission through each shaft 16 or 41, the total torque and thus the total power transmitted through the gearing can be obtained. In a modification, the play between the ring 20 and flange 23 is eliminated and there is a piston-and-cylinder device for each shaft 16 or 41. Only one device, however, may have the controlled exit ports 138, the gear pump driven by the corresponding shaft supplying equal fluid pressure to all three devices. Where the gears transmit different proportions of the total torque the effective thrust areas of the corresponding piston-andcylinder devices are dimensioned accordingly.