Ball spline assembly and ball reflow component thereof

A ball spline assembly, comprising:

• an outer cylinder comprising an inner annular wall, an outer annular wall, a first end portion, and a second end portion axially corresponding to the first end portion, wherein the outer cylinder further comprises a ball groove and a through hole, the ball groove is axially disposed on the inner annular wall, and the through hole is axially passed through the outer cylinder and is between the inner annular wall and the outer annular wall;
• a ball cage comprising a groove, wherein the ball cage is axially inserted into the outer cylinder, and the groove corresponds to the ball groove;
• the ball cage comprises a plurality of first recessed portions, a plurality of second recessed portions, a first side portion, and a second side portion opposite to the first side portion, the plurality of first recessed portions are arranged on the first side portion, and the plurality of second recessed portions are arranged on the second side portion;
• a first end cover disposed on the first end portion of the outer cylinder, wherein the first end cover comprises a first curve and a plurality of first protruding portions, the plurality of first protruding portions are correspondingly arranged in the plurality of first recessed portions;
• a second end cover disposed on the second end portion of the outer cylinder, wherein the second end cover comprises a second curve and a plurality of second protruding portions, the plurality of second protruding portions are correspondingly arranged in the plurality of second recessed portions;
• and
• a plurality of balls, wherein the ball groove corresponds to the groove to form a ball channel, the ball channel, the first curve, the through hole, and the second curve together form a ball circulation channel, and the plurality of balls are accommodated in the ball circulation channel;
• wherein two opposite end portions of the groove are respectively provided with a first guide groove and a second guide groove, the first guide groove is curvedly connected to the first curve, and the second guide groove is curvedly connected to the second curve;
• wherein the first guide groove and the second guide groove extend in a direction deviated from a length direction of the groove.