Patent GB-1033294-A (GB)
Title: Improvements in or relating to hydraulic transmissions
IPC: F16H45/00
Filed: 1963-04-16
Abstract: 1,033,294. Friction clutches; change-speed and reversing gearing control; controlling clutches; hydraulic couplings. S.A. FRANCAISE DU FERODO. April 16, 1963 [April 13, 1962; Nov. 22, 1962; March 15, 1963], No. 14958/63. Headings F2C, F2D and F2L. An hydrokinetic coupling device C (torque converter or coupling) having an impeller P driven from a bell housing 13 and a turbine T driving an output shaft 11 through an hydraulically actuated friction clutch E, having driving plates 20, 22 forming respectively a cylinder and piston between which may be engaged a driven plate 26, is supplied with oil from a pump through a conduit 38 in the vicinity of the axis which acts to selectively engage the clutch E before passing to the coupling device C. The oil flows from an impeller driven pump 150 through a clutch control valve 48 and conduit 38 to radial fan-shaped passages 41 to pressurize a chamber 34 to cause engagement of the friction clutch in conjunction with a Belleville washer 23, which also serves to rotationally couple the plates 22, 20. Oil from the chamber 34 passes into the torque converter by passage 37 and from the convertor by passage 62 to a one-way pressure-reducing valve 91 thence from the inner compartment 31 of the clutch through a duct 46 to a tank 51. By passing direct to the clutch chamber 34 the oil is prevented from being heated by work in the converter. For clutch release the supply is stopped by the electro-valve 48, under the energization of a gear lever break switch 59 or a neutral switch 60 in a following change-speed gear, the valve 91 closes and centrifugal pressure build-up within the outer clutch chamber 30 releases the clutch. Pressure is maintained in the system by a relief valve 53 which first charges an accumulator 52 for rapid engagement. In a modification, the shaft 11 is solid and oil flowing along its outer surface escapes for clutch engagement through a blank spline. A second embodiment, Fig. 5, has the output clutches with driven plates 122, 125 driving forward 147, 148, 149 and reverse 150, 151 gearing; the clutches being biased to disengaged positions by Belleville springs 152, 153 and engaged by oil from a pump 129 passing by ducts 171, 173, 174 through orifice 158 to a common chamber 126. Metering orifices 156, 157 bleed oil to the clutch interior chambers 127, 128 which are vented through ducts 164, 165, 166, 167 leading to a forward/reverse selecting valve 131. A mechanically actuated shutter 176 may be interposed in the converter circuit to vary the torque absorption, particularly in conjunction with the vehicle brakes. In a third embodiment (not shown) twin friction clutches drive concentric shafts to provide forward and reverse gear to a coaxial output shaft; the hydraulic clutch control circuit being simplified. A fourth embodiment, Fig. 7, has one clutch driving an inner shaft 111 directly from the bell housing 113 and the second clutch driving a concentric shaft 112 from the converter turbine 117, the two shafts 112 and 113 being the inputs to a two speed and reverse gear providing four forward and two reverse speeds with a speed sensitive brake 243 to hold the layshaft 242 at low speeds. The clutches are engaged by oil pressure in a common chamber 126 bleeding through one-way restrictors 230, 291. Actuation of both clutches for interruption of drive during change is controlled by solenoid valve 259 actuated by a gear shift lever break switch 255 and actuation for selective engagement is controlled by a second solenoid valve 260 energized through a contact 263 responsive to output shaft speed through a governor 264 controlled by a spring 265, the loading of which is dependent upon intake manifold depression in diaphragm chamber 272 and throttle pedal position through linkwork 269, 267; the position of the fulcrum 268 1  being dependent on the engagement of the high or low gear range by sliding dog member 251. In a further modification of the single clutch arrangement, the bell housing is divided into separate compartments, each supplied individually with oil.