HYDRAULIC TENSIONER FOR ENDLESS DRIVE Russian patent published in 1998 - IPC

FIELD: tightening-up of drive chain of internal combustion engine. SUBSTANCE: hydraulic tensioner includes housing with blind cylindrical slot and piston movably fitted in this slot. For tightening-up the chain, piston is engageable with pivot which is in contact with endless drive. Slot is provided with hole connected with pressure liquid source. Bypass valve made in form of flexible plate closes this hole. Disk is divided by cutting line into central part forming flexible plate and peripheral part connected with central connecting part. Peripheral part is held at slot bottom by means of pressure helical spring fitted in slot between piston and disk. At one end, spring has coils of constant diameter and at the second end, it has coils whose diameters increase from first end. Tensioner is provided with shoulder for limiting the return stroke of piston; this shoulder is made in side wall of slot; shoulder is also used for limiting the radial clearance between piston and side wall of slot forming calibrated passage for liquid under pressure. If required, device may be provided with fixtures preventing rotation of piston around its axis. Outer end of piston is provided with calibrated orifice for spraying the pressure liquid on endless drive, thus lubricating it and limiting and absorbing the vibrations of piston in slot. EFFECT: enhanced absorption of vibrations of drive. 11 cl, 4 dwg