US Patent 7587954 Ball screw

Ball screw having a spindle nut (2) arranged on a spindle (1), together with balls (3) which are arranged in a series and are capable of rolling in a helical ball track (4), the helical ball track (4) being defined by a thread groove (5) formed on the spindle (1) and by a thread groove (6) formed on the spindle nut (2), the balls (3) arranged in a series being returned in a return duct (7) from an outlet end to an inlet end of the helical ball track (4), the divided circle end play of the series of balls being less than or equal to 0.3 millimeters or the ratio between the pitch of the helical ball track (4) and the diameter of the balls (3) ranging from 1.02 to 1.2 or the thread grooves (5, 6) of the spindle nut (2) and of the spindle (1) in each case having a gothic profile (8, 9), a pressure angle formed by the balls (3) in contact with the gothic profile (8, 9) ranging from 15 to 35 degrees.