GB305527A - - Google Patents

Abstract

305,527. Junkers, H. Feb. 6, 1928, [Convention date]. Flywheels. - In apparatus for damping the torsional oscillations of rotary shafts in which a part rigid with the shaft is coupled to a freely rotatable revolving mass by frictional devices or by dash-pot apparatus, the heat generated in the damper is transmitted to circulating liquid which is cooled by external means. In Fig. 1, a disc 2 is fixed on the shaft and is surrounded by two freely mounted discs 3, 4 carrying heavy rotating masses 6, 7. The disc 2 is provided with braking surfaces 8, 9 which are engaged by corresponding surfaces on the outer discs 3, 4, pressure being applied by means of springs 12. Small radial passages for the circulation of the liquid are machined in the braking surfaces. liquid from the cooler 37 is led through a pump 38, pipe 39, passage 20 in the shaft and radial holes 22, 23 to the spaces between the discs 2, 3, 4 from which it passes between the friction surfaces to the outer passages 26 and chambers 29, 30 formed by annular check plates 31, 32. It then falls into the bottom of the fixed casing 35. Since the points of exit 33, 34 of the liquid from the damper are further from the centre of the shaft than the point of admission, the circulation of the liquid is assisted by centrifugal force. Further assistance can also be obtained by shaping the grooves in the friction faces after the manner of the vanes of centrifugal pumps. The grooves in the faces may be replaced by closed passages in the metal below the surfaces. In Figs. 3 and 4, the circulating liquid also forms the damping medium and is obtained from the crank case of an internal-combustion engine, to the crank shaft of which the damper is applied. The central disc 50 secured to the crank shaft is provided with circumferential and radial partitions forming a number of outwardly facing pockets. The freely mounted revolving mass 58 is carried by two discs 56, 57 having vanes 59 which project into the pockets. Movement of the vanes 59 in the pockets due to vibration, pumps liquid through small gaps 62, 63 in the direction indicated by the arrows. The oil delivered by the usual force pump 74 is led to the bearings of the drilled crank shaft and also to the damper through the passage 91. The oil leaves the damper through the passage 92 and returns to the sump. In a modification having an independent circulating system, the heavy revolving mass is arranged inside the casing and carries vanes which project radially outwards into pockets.