GB867965A - A fluid coupling - Google Patents

Abstract

867,965. Hydraulic couplings. SCHWITZER CORPORATION. Jan. 4, 1960 [July 31, 1959], No. 190/60. Class 69 (2). An hydraulic coupling for the cooling fan of an internal combustion engine comprises a housing 12, 13 which is formed with a fluid containing chamber having opposed faces 19, 19a and is rotatably mounted and axially movable on a driving shaft 10, a pair of discs 23, 29 rotated by the driving shaft and having their outer side surfaces, which carry friction facings 33a, 33b in face-to-face relation with the faces of the housing, and a temperatureresponsive element 26 connected to one of the plates for movement thereof and consequent movement of the housing to vary the clearance between the opposed faces of the housing and discs and the torque transmitted by the shearing motion of the fluid in the chamber. The disc 23 is secured to the driving shaft 10 and has apertures 25 receiving projections 32 on the disc 29 so that the discs are rotated together. The disc 29, which is resilient, is mounted on a sleeve 27 axially movable in response to a change in temperature by the element 26, such as described in Specification 507,501, the sleeve sliding over a piston 28 restrained from axial movement by a member 22 in a bore in the driving shaft. In operation, the drive from the shaft 10 is transmitted by the shearing action of the fluid, such as silicone oil, in the chamber to the housing 12 which is provided with threaded bores 16 for the attachment of the cooling fan. A rise in the temperature of the cooling air acts on fins 40a to transmit the increase in temperature to the element 26 which moves the sleeve 27 to the left so that the frictional facing 33b on the disc 29 comes into wet clutch contact with the housing which is consequently moved to the left to decrease the thickness of the fluid film between the frictional facing 33a on the disc 23 and the housing part 12 so that the torque transmitted by the coupling is increased. Spring tags 39 on the disc 23 prevent a predetermined minimum clearance between the discs being reduced so that the torque transmitted by the coupling is not reduced beyond a predetermined minimum. The plates 23, 29 are provided with apertures to permit the toroidal circulation of fluid in the chamber as described in Specification 841,203. Cooling fins 17, 18 are provided on the houring parts 12, 13.