Abstract: A circulator comprises a circulating body and an extending rib. The circulating body is formed with an arc-shaped circulating passage. The extending rib is integrally radial inwardly extended from a curved portion of the circulating body. The curved portion of the circulating body is configured toward an inner direction of the circulating passage by reinforcement of the extending rib to increase a radius of the circulating passage. Moreover, the instant disclosure further provides an end cap-type ball screw assembly.

Abstract: A wiper for screwing on a rolling groove of a screw shaft includes a ring and a plurality of wiping protrusions extended from the inner surface of the ring. The ring has a plurality of dust discharge grooves formed on an inner surface thereof. The inner surface of the ring substantially configured to abut an outer surface of the screw shaft. Each wiping protrusion is arranged between any two adjacent dust discharge grooves. When the wiper screws on the rolling groove of the screw shaft, the wiping protrusions are arranged in and compressed by the rolling groove of the screw shaft, and a portion of the rolling groove touched with the wiping protrusions is arranged in a single pitch of the screw shaft. The instant disclosure also provides a ball screw assembly.

Abstract: A ball screw assembly has a screw shaft, a nut, a plurality of balls, and two end caps. The screw shaft has a spiral rolling groove formed on an outer surface thereof. The nut has a spiral load rolling groove formed on an inner surface thereof. The screw shaft passes through the nut, and the rolling groove aligns with the load rolling groove, and the rolling groove and the load rolling groove jointly define a raceway. The balls are disposed between the rolling groove of the screw shaft and the load rolling groove of the nut. The end caps respectively arranged on two opposite sides of the nut. The screw shaft passes through the end caps, one end surface of each end cap is exposed from the nut, and each one of the end surfaces has a plurality of dust discharge outlets formed thereon.