Recirculating-ball nut and screw set with lubricating means

A recirculating-ball nut and screw set with lubrication means;

• comprising a round screw shaft extending lengthwise, a ball nut fitting around the screw shaft to provide a slider movable along the screw shaft by virtue of balls as the screw shaft turns on an axis thereof, and lubrication means installed on at least one end of forward and aft ends of the ball nut;
• wherein the lubrication means is comprised of a holder fastened to the ball nut, and at least one lubricating plate accommodated in the holder;
• wherein the lubricating plate includes a first annular lubricating plate, and a second annular lubricating plate arranged in surface contact with the first lubricating plate so as to replenish the first lubricating plate with the lubricant;
• wherein the first lubricating plate has a tongue that extends inwardly from an inside periphery of the first lubricating plate to come partially into sliding engagement with a helical groove around the screw shaft, so that the lubricating plate makes sliding engagement with the helical groove at only the tongue when the ball nut moves back and forward with respect to the screw shaft;
• wherein the second lubricating plate is identical in configuration to the first lubricating plate without the tongue, and more than one second lubricating plate is accommodated in the holder in a manner lying on top of another;
• wherein the first and second lubricating plates are each made of a sintered resinous component of porous structure having cells impregnated with lubricant, and formed in a configuration of C-shape where a sector is removed;
• wherein the holder is engaged at any one end of forward and aft ends thereof in the ball nut, while at another end around a wiper seal;
• wherein the holder is composed of a radially reduced neck having the one end that fits in the ball nut, and a radially enlarged body formed integrally with the radially reduced neck to provide the another end engaged to the wiper seal;
• and
• wherein the radially enlarged body of the holder is made larger in outer diameter than the radially reduced neck to provide a shoulder, which comes into abutment against an associated end surface of the ball nut, and also includes a major area for accommodating therein the lubricating plate, which is made larger in inside diameter than the radially reduced neck.