Ball screw device

The utility model provides a ball screw device, it is helpless to the sealed structure that lubricated unnecessary lubricating grease fell in the nut in the within range high efficiency that can not disperse in order to possess to make, and makes the ascending grooving orientation in footpath of sealing member be opposite direction for lead screw axle helicla flute orientation. Ball screw device (1) has lead screw axle (10), nut (20) and a plurality of ball. Install sealing member (30) on at least one tip in the tip of ball screw device on the moving direction of nut. The sealing member has: convex part (31), it surrounds outer peripheral face of lead screw axle, and gets into to the lead screw axial screw groove (11) in the inboard, tube -shape portion (32), expose in its axial outside at the nut. Be equipped with grooving (34) in the tube -shape portion of sealing member, this grooving is opposite direction in the ascending grooving orientation in the footpath of sealing member for lead screw axle helicla f