GB854007A - Improvements in or relating to hydraulic transmissions - Google Patents

Abstract

854,007. Hydraulic transmission of power. SVENSKA ROTOR MASKINER A.B. Aug. 13, 1958 [Aug. 16, 1957], No. 26005/58. Class 69 (2). An hydraulic transmission comprises an hydrodynamic torque converter in the form of a number of blade rings arranged to act as pump 70, reaction and turbine members 76, 74, 72, a releasable mechanical direct coupling 94, 96 operable to couple the pump and turbine members, and an hydrostatic coupling arranged in series with the torque converter. The turbine blade rings 72, 74 are arranged on a disc 78 connected to rotate with a shaft 80, which may be the propeller shaft of the transmission, and the reaction blade ring 76 connected to rotate with a shaft 84 which is actuated by a counter-directed torque so as to remain stationary or connected by gearing to the shaft 80. The pump blade ring 70 is connected to a set of clutch discs 94 energizing a second set of discs 96 connected to the shaft 80. The clutch is engaged by hydraulic pressure supplied through ducts 88, 90 acting on a piston 86 to press the discs against a surface 98 on the converter, and disengaged upon release of the pressure in the ducts by the pressure in the converter acting on the other side of the piston. The pump blade ring 70 is rigidly attached to the housing 18 of the coupling which is provided with recesses 26 containing pairs of gears 28, 30 serving as gear pumps, one gear of each pair co-operating with a gear 16 mounted on a shaft 14 located by needle rollers on a journal 22 on the housing 18 and connected to a shaft 10 driven by an engine so as to permit axial and eccentric movement therebetween by a disc 12. A pressure chamber 46 is disposed radially-outwardly of the gears so that hydraulic pressure therein acts on the gears in the opposite direction to the centrifugal force acting on the wheel, and each chamber is connected by a circulation duct 54 and relief valve 56 to a central chamber 44, in turn connected by ducts 62 with the working chamber of the torque converter which is continuously supplied with liquid from a separate pump. The valves 56 are individually adjustable and may be arranged so that their bodies 58 are free or spring-urged inwardly, outwardly or parallel to the axis of the coupling to provide, with the centrifugal force acting in the bodies, different output characteristics to the coupling. The gear pumps may be arranged such that one gear of each pair is spaced further from the centre of the coupling than the other by the depth of the gear teeth, or the axes of the gears may be the same distance from the centre of the housing and the radius of one gear differ from that of the other by the depth of the teeth of the gears. Alternate pumps may be arranged to operate upon opposite rotation to permit the coupling to operate on forward and reverse rotation. Leakage past the sides of the gears is prevented by sealing plates 48 which are urged towards the sides of the gears by springs and/or liquid pressure supplied from the chambers 46. Specification 854,006 is referred to.