Patent GB-955066-A (GB)
Title: Improvements in and relating to clutches
IPC: F16D25/063
Filed: 1962-12-12
Abstract: 955,066. Hydraulic friction clutches; clutch control. S.A. FRANCAISE DU FERODO. Dec. 12, 1962 [Dec. 12, 1961; April 7, 1962; June 22, 1962], No. 46999/62. Headings F2C, F2D and F2L. In an hydraulically operated clutch having the driving plates constituting a cylinder 10 and piston 12 assembly engaging with annular friction linings 16 on an axially flexible driven disc 14, the progression of engagement is determined by the flow of fluid from the outer chamber 18 to the inner chamber 19 through a metering passage 28, the chambers being defined between the driving plates and the inner and outer peripheries of the driven disc linings. In an embodiment, Fig. 8, in which a change-speed gear is driven from an engine through a fluid coupling or a torque-converter C, the driving shaft 15 is released from engagement with the turbine T by disengagement of the clutch E during changes of ratio. An engine shaft 31 is coupled to the casing 33 and impeller P of the torque-converter C by a flexible diaphragm 32; the reactor R being carried on a free-wheel 38 and the turbine T being rigid with the cylinder forming driving plate 10 of the clutch. The other driving plate 12 forms a piston within the cylinder 10, acted on by a Belleville spring 29 and converter casing pressure to engage the driving plates 10, 12 with the driven disc 14 rotationally rigid with the driving shaft 15. The friction faces of the plates 10, 12 are slightly conical to define, with the linings 16, inner 19 and outer 18 chambers connected by radial or spiral metering grooves formed in the linings 16. On engagement, the fluid from the outer chamber 18 passes at predetermined rate to chamber 19 to cushion the engagement of the clutch. An oil circulation is maintained between the chamber 19 and the casing through unidirectional clapper valves 47 having small calibrated orifices 48. Disengagement is produced by the introduction of pressure fluid to the chamber 19 through a hollow support 35. Operating pressure for the clutch is supplied by a pump 20, Fig. 9, through a solenoid controlled valve 22 to 25, 20 for engagement and disengagement respectively. The valve 22 is operated to disengage the clutch during gear shift by a gear lever switch 54 and in neutral gear conditions by a switch 55 on the change speed gear. In a modification, Fig. 16, the lining 16 is attached to the disc 14 through an annular lining having peripheral notches 79 housing clapper valves 73 retained in slots in the disc 14. The valves 73 have metering orifices 75 allowing only slow flow of fluid from chamber 18 through notch 79, orifice 75, the slot in the disc 14 and aperture 14a to chamber 19. On clutch disengagement, the clapper lifts to allow a fast flow in the reverse direction. In another modification, the linings 16, of paper with a small percentage of asbestos and a large percentage of cellulose, are secured to intermediate slotted washers of resin impregnated asbestos fibre; the slots housing clapper valves and opening radially inwards and outwards on different sides of the disc. The clapper valves may be secured to the plate 10 and an external duct lead from the valve to chamber 19.