GB863532A - Fluid coupling - Google Patents

Abstract

863,532. Hydraulic couplings. SCHWITZER CORPORATION. Feb. 12, 1959 [Feb. 17, 1958], No. 4902/59. Class 69 (2). An hydraulic coupling for transmitting torque from an engine crankshaft 10 to an accessory, such as a fan, comprises a housing 21, 22 having walls spaced from the side surfaces 19 and rim 18 of a rotor 11, and fluid circulating means 13, 17, 41 and 42 on the rotor and housing for maintaining a film of fluid between the rim of the rotor and the housing to lubricate the surfaces and damp vibrations transmitted to the rotor while transferring torque between the rotor and the housing by means of the shearing action of the fluid. The thickness of the film of fluid is between 0.002 inch and 0.0035 inch at the rim 18 and between 0.0035 inch and 0.0085 inch at the side surfaces 19. The rotor is mounted on the crankshaft of the engine and extending through the rotor are passages 13, 14 which, together with a spiral groove 17 on the rim and tangential slots 41, 42 in the rotor or housing, form the fluid circulating means, the fluid moving toroidally when the coupling is transmitting torque. The toroidal movement of the fluid and fins 36 assist in cooling the fluid. The housing part 22 is in the form of a piston urged towards the rotor by a spring 31, 32. During operation, as the speed of the rotor increases, the centrifugal force of the fluid moves the piston 22 outwardly to increase the space between the walls of the housing and the rotor, and hence increase the slip therebetween. The accessory is driven by V-belts engaging grooves 34 in the housing. Seals 37, 38 serve to support the housing when the coupling is stationary, the fluid then being at a level 44. The surfaces 18, 19 of the rotor may be given an anti-friction coating.