Patent GB-1119405-A (GB)
Title: Improvements in or relating to friction clutches
IPC: F16D13/68
Filed: 1965-07-23
Abstract: 1,119,405. Damped resilient couplings. SOC. ANON. FRANCAISE DU FERODO. 23 July, 1965 [4 Aug., 1964; 6 May, 1965], No. 31608/65. Heading F2U. In a friction-damped, torsionally resilient connection providing limited relative circumferential displacement between a friction-lined clutch disc 16 and a splined hub 10, the damping is dependent on torque transmission, being applied only after an initial sector of said displacement during which a torsionally resilient means acts alone. As shown, a counter-disc 18 is spaced from and secured to the disc 16 by pillars 19. Friction washers 15 are interposed between the disc 16 and counter-disc 18 and free auxiliary webs 12 which flank a hub web 11 and are secured together by pillars 13 passing, with an initial circumferential clearance " J " through slots 14 in the hub web periphery. The pillars 19 pass, with an initial circumferential clearance " G " greater than that " J," through slots 20, 21 respectively in the hub web and the auxiliary web peripheries. Two alternating sets of springs 22, 25 are respectively tangentially disposed in windows 23, 24 and 26, 27 of the hub web and of the auxiliary webs and disc and counter-disc. The springs 25 are prestressed and have an initial clearance " J " in the hub web windows 26. On increase in torque transmitted between the hub 10 and the clutch disc 16, initially, in a first displacement sector, the springs 22 act alone in opposition and the friction washers are inoperative, until the clearance " J " between the pillars 13 and the slots 14 and the springs 25 and the windows 26 is taken up, whereupon, continuing in a second displacement sector, both sets of springs 22, 25 act together in opposition and relative circumferential displacement between the auxiliary webs and the disc and counter-disc applies the friction damping of the washers 15, the second displacement sector being terminated when the limiting clearance " G " between the web slots 20 and the pillars 19 is taken up. The opposite procedure takes place on decrease in transmitted torque. In an alternative embodiment, only one friction washer 15 may be provided and the set of springs 25 may be dispensed with. In Figs. 11, 12 (not shown), instead of the pillars 13 the auxiliary webs are connected by offset lugs cut-out therefrom. The Figs. 15, 16 (not shown) embodiment is similar in operation and construction to that shown being distinguished in that: the one or two friction washers 15 are interposed between the hub web and the auxiliary webs; the clearance for the springs 25 is arranged between the latter and the disc and counter-disc windows; the clearance between the pillars 19 and the hub web slots 20 is greater than that between said pillars and the auxiliary web slots 21; the pillars 13 securing the auxiliary webs together are extended to co-operate, with clearance, with apertures in the disc and the counter-disc; and the springs 25 act as driving means for the auxiliary webs during the first displacement sector. The Figs. 13, 14 (not shown) embodiment is similar to that shown except that the disc and counterdisc are disposed immediately adjacent the hub web and are flanked by two pairs of auxiliary webs; the disc and counter-disc and the outer two auxiliary webs are secured together by pillars passing with clearance " G " through slots in the hub web and passing through slots in the auxiliary webs; friction washers are interposed between the auxiliary webs, and between the inner auxiliary webs and the disc and counter-disc; and studs extending axially from the hub web periphery co-operate with slots in the peripheries of the inner auxiliary webs for driving the latter after a free circumferential displacement to take up clearance " J." In Figs. 24, 25, wherein the auxiliary webs are dispensed with, friction washers 115A, 115B are interposed between a hub web 111 and respectively a clutch disc 116 (or, as shown, a disc 116a secured to the clutch disc) and a counter-disc 118. First and second sets of springs 220 are provided alternately arranged. The second spring set may be prestressed, and, as described, the windows for this set are circumferentially extended in the hub web. The washer 115A is fast with the web 111 and has in one face radial notches 230 accommodating bosses 231 of the counter-disc 118. The washer 115B is arranged so as to be inoperative during the first displacement sector. At the onset of the second displacement sector, the bosses 231 become operative and contact the flanks of the notches 230 so as to apply a frictional damping which progressively increases as the bosses 231 ride up the notch flanks, the damping by the washers 115B being also operative and increased due to the connecting pillars 119 between the discs 116, 11 Or and the counterdisc 118. The second set of springs are inoperative throughout the first displacement sector. In alternatives to this embodiment, each washer may comprise boss-cooperating notches, and the bosses and notches may be carried respectively by the washers and discs. To provide differing characteristics during forward or reverse torque transmission, i.e. driving or overrunning, different value clearances may be provided in respect of the pillars and/or springs, the windows may be suitably arranged, and in Figs. 24, 25 the notch flanks may be given different profiles on each side of the bosses or may be suitably displaced with respect thereto.