Patent GB-1053432-A (GB)
IPC: F16H39/14
Abstract: 1,053,432. Hydraulic transmissions, change speed control. INTERNATIONAL HARVESTER CO. July 4, 1963 [July 11, 1962], No. 26515/63. Headings F2C and F2D. [Also in Division F1] In a continuously variable hydraulic transmission, in a vehicle, comprising a pump 42 and a motor 43 both of the angularly-adjustable swash-plate type and arranged coaxially one on each side of a distributing plate, wherein the pump cylinder barrel 34b rotates with the input shaft 34, the motor cylinder barrel 39 is fixed in a stationary housing 26c, and the pump and motor swash-plate backing plates 85, 51 and the distributing plate rotate with the output shaft 35, the tilt angles of both backing plates are independently hydraulically adjusted respectively by pairs of servo-cylinders 98, 99 and 86, 87 energized through follow-up valves 150, 100 coaxially disposed in the output shaft and responsive to manually adjustable hydraulic pressures. The transmission range is from forward overdrive, through direct drive and neutral, to reverse overdrive. The pump and motor swash-plates comprise thrust rings 84, 69 connected to their respective pistons by rods such as 45b, supported on the backing plates by bearings 67, 68, and respectively mounted to be rotatable with the pump cylinder barrel and rotationally fixed with the motor cylinder barrel by gimbal mountings comprising intermediate rings having perpendicularly arranged pivotal connections with the thrust rings and a pump barrel connected housing 34a and the housing 26c. The distributer plate has the usual kidney ports 159, 160 and comprises bolted-together flanges 35d, 35e respectively of bodies 35b, 35a of the servo-cylinders 98, 99 and 86, 87. The backing plates 85, 51 are trunnioned on the output shaft. The follow-up valves 150, 100 (Figs. 6, 20, not shown) each comprises a waisted plunger 116 axially moved against a spring 129 in response to pressure in a chamber 123 of a surrounding ported follow-up sleeve 102. A bracket 130 bolted to each backing plate has an inwardly extending ball end 133 eccentric of the backing plate trunnion and engaging a spherical recess 134 in the sleeve 102 through an elongated slot 135 in the output shaft. The valve 100, for example, directs pressure in a line 138 to a line 144 leading to the servocylinder 86 or a line 145 leading to the servocylinder 87, the non-energized cylinder exhausting through lines 146 or 148. The lines 138 are always under pressure when the input shaft is rotating, being fed from the kidney ports 159, 160 through one-way valves 136, 137. The kidney ports are also respectively connected to ports 30, 31 through radial ports 166, 165 in the flanges 35d, 35e and toroidal ducts 161, 162 in the casing, to provide powertake-off differential pressure for accessory motors 191 (such as bulldozer rams) through a one-way valve arrangement 192-195 which may only be dispensed with where the input shaft is unidirectional or hydraulic output braking is not required. The input power to the shaft 34 may be used entirely as powertake-off hydraulic pressure by locking the output shaft by an auxiliary brake (not shown). To provide hydraulic pressure when the pump swash-plate is not tilted and to replenish leakage losses, a conventional variable capacity charge pump 169, driven by the input shaft, draws from a sump 27, through a strainer and filter, and feeds a line 180 communicating with the ports 30, 31 through one-way valves 181, 183 respectively and with the follow-up valve control chambers 123 through lines 186, 184 and manually adjustable regulating valves 187, 188. A one-way valve arrangement 176-179 may be provided to render the charge pump effective in either direction of input shaft rotation. To prevent vehicle creeping or to place the transmission in neutral in an emergency, a by-pass line 189 having a manually controllable bleed-valve 190 connects the ports 30, 31 to short-circuit the kidney valves 159, 160. With the pump and motor swash-plates moved to the non-tilted and tilted positions respectively, the operator may control output braking, when coasting down-hill, by selective operation of the bleed valve 190, a heat exchanger for dissipation of heat generated being provided, if necessary, in the line 189.