Improvements in torsional vibration dynamic dampers of the type including pendular masses without return spring, for rotating shafts

摘要

664,119. Torsional vibration dampers. SARAZIN, G. F. Aug. 9, 1949 [Sept. 17, 1948 ; June 7, 1949], Nos. 20726/49 and 20727/49. Class 108(iii) In a torsional vibration damper including a plurality of pendular masses without return spring, for a rotary shaft, in which rolling contact is provided between each pendular mass and the vibrating part, i.e. a part integral with or fixed to the vibrating shaft, the means ensuring rolling contact for all the masses are disposed inside a common fluidtight envelope fixed to the vibrating shaft and containing an amount of lubricant, such that during rotation of the envelope, the means are at least partly immersed in the lubricant. In the arrangement according to Figs. 1 and 2, a plurality of blocks 4, which may be of steel, are secured laterally to a disc 2 rigid with a rotating shaft 1. Each block 4 co-operates with a mass 6 and the opposing faces 5 and 7 of the block and mass respectively are formed with roller races for a pair of rollers 8, 9. Each mass 6 is supported on a spring-loaded plunger which is slidable in a recess in the mass and which, when the damper is at rest or rotating at low speeds, bears at its outer end on a surface 9 rigid with the shaft 1. Preferably the arrangement is such that the mass makes contact with the surface 9 when the pendular amplitude of the mass exceeds 30 degrees. The plungers may be made of a self-lubricating porous metal. The damper is encased by a cover 20 which co-operates with a peripheral flange 19 on the disc 2 and sufficient lubricating liquid is contained in the casing as will, at least partly immerse the rollers 8 during operation of the damper. In a modification, Figs. 3 and 4 (not shown), each plunger is slidable in a bronze ring within the mass 6, against a spring, which is disposed around a stem portion of the plunger and a head portion which is adapted to bear on the surface 9. Transverse displacement of the rollers 8 is prevented by an annular rib projecting from each roller and which engages corresponding grooves in the block and mass. The rib may be a deformable split ring engaged in a peripheral groove of the roller. A channel, housing a lubricating wick, may be provided at either end of each mass 6, and leading from the lubricating liquid to the bottom of the adjacent roller race. In another modification, Figs. 5 and 6 (not shown), transverse displacement of the rollers 8 is prevented by plates held between the side faces of the blocks 4 and the walls of the casing. The plates may be chromium-plated spring steel. The rollers 8, may be formed as tempered steel cylinders. In another arrangement, Figs. 7 and 8, each block 4 is formed of sheet metal plate, suitably shaped to form the roller races and welded to the wall 19 of the casing which is correspondingly shaped at that point. A plunger 12 is slidable in a recess in each mass 6 against a spring 14 and carries a buffer 30, which may be of graphitized rubber and which prevents contact of the plunger 12 with the surface 9. The casing comprises elements 24 and 31, the former being welded to a peripheral flange 23 and an extension 25 of the latter, the extension 25 being secured to a member 26 rigid with the shaft. Transverse displacement of the rollers 8 which are non- circular in cross-section is prevented by peripheral bosses formed during stamping the casing. The blocks 4 and masses 6 may be formed from steel having 0.4 per cent carbon content, the blocks being obtained in a press and masses being constituted by sections of a bar. The roller races are broached without heat treatment. In a modification, Fig. 9 (not shown), the blocks 4 are dispensed with by suitably shaping the peripheral wall 19 of the casing to form the outer roller races. The casing may alsc be formed to provide a clearance at each end of each mass. In all embodiments, the rollers or the elements forming the faces may be of self-lubricating porous metal. The roller races may have a generatrix of any suitable shape.