GB765081A - An hydraulic change speed device - Google Patents

Abstract

765,081. Hydraulic variable-speed devices. CAMBI IDRAULICI BADALINI SOC. PER AZIONI. Aug. 30, 1954 [May 21, 1954], No. 25133/54. Class 69(2). An hydraulic variable-speed device having a pump and an engine, both of swash-plate type, arranged coaxially one on each side of a distributing plate has a supplementary rotary pump driven by the driving shaft and supplying oil to the distributing plate to make up leakage. The inclination of the swash plates is controlled by a handwheel which moves a plunger in piston and'cylinder means connected to the swash plate of the pump. The swash plates 5, 8 are connected by a link 36. The pump 2, driven by a shaft 4 through a splined sleeve 32 engaging the casing 6 of the pump, has connecting rods 42 engaging the swash plate 5. The pump drives the engine 3, the casing 7 of which is stationary on a reaction shaft 12. Connecting rods 53 of the engine drive the swash plate 8 connected to a casing 9 having an extension 10 forming the driven' shaft. The distributing plate 11 rotates with the casing 9. The pump and engine casings are spring pressed against the plate. Recesses 97, 98 (Fig. 6) in the plate form distributing ports between the pump and engine, and liquid from the supplementary rotary pumps 16 (Fig. 3) passes via a filter 126, a duct 127, the interior of the shaft 12 and recesses 82 to a duct 99 (Figs. 3<SP>1</SP> and 6) in the plate. Valves 100, 101 admit the oil to either recess 97 or 98 depending on the pressure therein. Each valve is operated by the difference of the pressures on its opposite faces. Further valves 103, 104 exhaust excess liquid via a spring-loaded valve 107 to a reservoir in the bottom of a stationary casing 1. The casing has an intake 111 to the pump 16. The angle of the swash plates 5, 8 is controlled by a handwheel 136 connected by a linkage 140, 141, 146, 147 to a plunger 153 in piston and cylinder means 149, 152 connected to the swash plate 5 by a link 154. For each position of the plunger 153 there is a corresponding position of equilibrium of the piston 152 and of the swash plate 5. The portion 151<SP>1</SP> of the cylinder 149 is supplied with liquid from the pump 2 via the plate 11, and passages 158, 158<SP>1</SP> and 159 connect the opposite sides of the piston. For any position of the plunger 153 the piston is in equilibrium when its passage 158<SP>1</SP> is between the passage 159 and a recess 160 connected to exhaust.