Patent ID: 8100024

Claim:
An external circulation type ball screw with a noise-reduction structure comprising: a screw with a groove in its outer surface; a nut with a through hole for insertion of the screw, and in an inner surface of the through hole being defined a groove which cooperates with the groove of the screw to forth a road path; at least one return member defined with a return path and mounted on the nut, and the return path of the return member, being in communication with the load path; a plurality of rolling elements circulating within the load path and the return path; and a noise-reduction cover mounted on the nut and defined with at least one groove positioned on and pressed against an outer surface of the return member, and at least one noise-reduction groove in communication with the groove of the noise-reduction cover, and a head and an end of the noise-reduction groove being aligned with and covering impacting portions of the return path of the return member where the rolling elements impact the return path; a first and a second return members are mounted on the nut, the noise-reduction cover is provided with a first groove positioned on and pressed against an outer surface of the first return member, a second groove positioned on and pressed against an outer surface of the second return member, a first noise-reduction groove connected between a head and an end of the first groove, a second noise-reduction groove connected between a head and an end of the second groove, a third noise-reduction groove connected between the heads of the first and second grooves, and a fourth noise-reduction groove connected between the ends of the first and second grooves.