Self-alignment spacer for a ball screw device

[0028] For better understanding the operation and the function of the first embodiment, references should be made again to FIG. 6-9.

[0029] Since the stuffing 40 is stuffed into the receiving space 32 of the spacer 30 which is located off-center in the spacer 30, the specific gravity of the stuffing 40 is greater than that of the spacer 30, so that the center-of-gravity of the spacer 30 is eccentrically positioned. When the clearances between the respective balls 20 are accumulated at the upper and the lower sides of the screw shaft 50, the eccentric center of gravity of the spacer 11 will produce a force T (like a tumbler) to prevent the spacer 11 from tipping over. When the clearances between the respective balls 20 are accumulated at the both lateral sides of the screw bolt 50, the eccentric center of gravity of the spacer 11 will cause the spacer 11 to tumble down on the surface of the screw shaft 50, however, when the spacer 11 moves to the upper or the lower sides of the screw sha

[0030] Referring to FIGS. 10-12, which show the present invention, at either side of the respective spacers 60 is formed an arc-shaped recess 61 in response to the surface of the ball 20, in the spacer 60 is formed an annular passage 62 which surrounds the center of the spacer 60.

[0031] A stuffing 70 is a liquid having a specific gravity greater than that of the spacer 60 and occupies a part of the annular passage 62, so that the center-of-gravity of the spacer 60 is eccentrically positioned.

[0032] Since the stuffing 70 is a liquid and only occupies a part of the annular passage 62 of the spacer 60, it will keep flowing, during the movement of the spacer 60, to adjust the center of gravity of the spacer 60 continuously. When the clearances between the respective balls 20 are accumulated at the upper and the lower sides of the screw shaft, the liquid-like stuffing 70 will adjust the center of gravity of the spacer 60, thus producing a force T to prevent the spacer 60 from tip over. Sin