Patent ID: 6176149
Filing Date: 2001-01-23
Classification: F16C,F16H,Y10T

Abstract:
A ball screw, comprising: a screw shaft having an outer peripheral surface; a ball screw groove on the outer peripheral surface; a ball nut having an axis, a thick wall, and an inner peripheral surface; another ball screw groove on the inner peripheral surface of the ball nut, spaced uniformly from said axis and opposed to the ball screw groove on the outer peripheral surface of the screw shaft; a plurality of balls, of uniform size and having spherical surfaces, installed in a series along a helix between said ball screw grooves, each ball in the series being adjacent two other balls in the series; and a ball circulation mechanism provided in the ball nut for transferring balls from one location on the ball screw to another location on the ball screw;wherein a spacers having at each end thereof a concave surface complementary to the spherical surfaces of the balls, is disposed between the balls of each pair of adjacent balls;wherein the thick wall of the ball nut has opposite ends axially spaced from each other, each said end having a recess for receiving an adapter inserted into the recess in a direction parallel to said axis; andwherein the ball circulation mechanism comprises; a through hole which extends in parallel to the axis of the ball nut inside said thick wall of the ball nut, the through hole having opposite ends; and a pair of adapters, one adapter being located adjacent each end of the ball nut, each said adapter having one open end provided with a tongue portion for scooping up balls from, and returning balls to, the ball screw grooves, and another open end connected to, and in communication with, an end of the through hole, and the adapters being fitted respectively in said recesses in the axially spaced oposite ends of the thick wall of the ball nut.