VARIABLE-SPEED DRIVE UNIT VALVE Russian patent published in 2003 - IPC

FIELD: mechanical engineering; adjustable stepless drives. SUBSTANCE: invention relates to control systems of variable-speed drive. Proposed unit contains variable- speed drive of such type in which coupling is provided by rolling over toroidal rolling surface and double-acting pistons are used to control rollers and pressure differential created by end loading variable-speed drive and control device is employed designed for changing pressure differential created by end load according to changes of resulting pressure acting from side of pistons controlling the rollers. Pistons controlling the rollers are double-acting ones being controlled by pressure differential in hydraulic control means and valves coupled with first and second hydraulic circuits. First valve serves to supply liquid at higher pressure into circuits leading to higher pressure chamber of the means creating end load. Second valve serves to deliver liquid at lower pressure to circuits leading to compensating chamber of means creating end load. Coefficient of adhesion between contact surfaces of roller and disk in variable-speed drive unit is maintained constantly lower than limit value at which adhesion will be lost. EFFECT: enlarged operating capabilities. 13 cl, 9 dwg