Patent GB-1133698-A (GB)
Title: Friction clutch having centrifugally operated valve means
IPC: F16D43/284
Filed: 1967-02-16
Abstract: 1,133,698. Friction clutches. TWIN DISC Inc. 16 Feb., 1967 [18 Feb., 1966], No. 7467/67. Heading F2C. In an hydraulically operated continuously slipping friction clutch wherein clutch plates E splined to driving and driven members A, B are urged together by pressure liquid in a servo chamber C1, the pressure in the chamber C1 is controlled to vary the slip and maintain the speed of the driving or driven member constant by a valve D housed in the constant speed member and responsive to centrifugal force. As shown, in Fig. 1, pressure liquid supplied through a duct 1 acts on the valve D in opposition to centrifugal force and the valve meters the liquid to the servo chamber C1. An orifice F continuously bleeds the chamber C1 so that when the valve D is closed the clutch engagement is reduced. Pins G compensate for the change in centrifugal force acting on the valve D due to a change in its radial position The clutch plates E are supplied with cooling liquid through ducts P, P 1 , P 2 . In Figs. 1-7 and 20 (not shown), the valve (D) is carried by the output shaft and a speed increase of the shaft causes reduced clutch engagement whilst in Figs. 10-19 (not shown) the valve (D) is carried by the input shaft and a speed increase of the shaft causes increased clutch engagement. In Fig. 3 (not shown) the supply (2) to the servo chamber which is controlled by the valve (D1) is independent from the control pressure (1) acting on the valve. In Fig. 4 (not shown) the orifice F is omitted and the valve (D1) controls both the supply and exhaust of the servo chamber. In Fig. 5 the servo chamber C1 is supplied through a duct 2 and passage I in the valve. The clutch is completely disengaged by a control, Fig. 9 (not shown), which supplies equal pressures to both ducts 1, 2 whereupon the valve D2 closes. For constant output speed operation a valve (MV) is shifted manually to increase the pressure in the duct 1 over that in duct 2. In Figs. 6 and 7 (not shown), the servo chamber is continuously supplied with pressure fluid through an orifice and the valve controls the exhaust from the chamber. In Figs. 2a and 6a an extension of the valve spool reduces the area on which the control pressure acts. In Fig. 20 (not shown) the valve is housed in the output member whilst the servo-chamber and piston are housed in the input member. Figs. 10 and 11 (not shown), are similar to Figs. 7 and 4 respectively but the valve is carried by the input member and the valve ports are arranged so that an increase of input speed causes an increase in clutch engagement and thus additionally loads the input member to maintain its speed constant. In Fig. 12 the valve D8 is carried by the input shaft and a U-section piston C surrounds an annular projection on the shaft. Pressure liquid is supplied through a duct 1 to the chamber C1 to engage the clutch and also to the valve D8. When the input shaft speed drops the valve opens to supply pressure liquid through a duct 5 to a second chamber for clutch release. An orifice F continuously bleeds the second chamber. In Fig. 13 (not shown), both the first and second chambers are continuously supplied with pressure liquid, the latter being supplied through an orifice (F) and the valve D9 vents the second chamber (6) for clutch engagement when the input speed increases. Figs. 15 and 16 (not shown), is similar to Figs. 2 and 6 but the valve is carried by the input member and the valve parts are arranged so that an increase of input speed causes an increase in clutch engagement. Figs. 17 and 18, (not shown), are similar to Figs. 16 and 15, but the servo chamber supply and control supply are independent. Fig. 19 (not shown) is similar to Fig. 17 but the servo chamber supply also acts on the other end of the valve (D13) so that the control (Fig. 9) may be used to obtain full clutch engagement. In Fig. 14 (not shown) a spring (S) acts on the control valve (D10) in opposition to centrifugal force.