Spacer for a helicopter main rotor shaft

摘要

A spacer (10) for a helicopter main rotor shaft (102) is mounted in combination with the main rotor shaft (102) and is operative to support the inner race (116) of the upper bearing assembly (110) of the main rotor shaft (102) and is concomitantly operative to restrain axial migration of the inner race (116). The spacer (10) comprises a body member (11) having a stepped configuration defined by an upper cylindrical segment (12) and a lower cylindrical segment (20) to accommodate the outer structural envelope of the main rotor shaft (102). The upper cylindrical segment (12) includes an upper annular collar (14), an intermediate annular collar (16), and a lower annular collar (18), and the lower cylindrical segment (20) includes an interface annular collar (22) and a bottom annular collar (24). Structural continuity between the upper and lower cylindrical segments (12, 20) is provided by the lower annular collar (18) and the interface annular collar (22 ) and a plurality of reaction spokes (30) that extend between the upper annular collar (14) and the bottom annular collar (24). The reaction spokes (30) react the bearing migration loading exerted by the inner race (116). The upper annular collar (14) includes an annular shoulder (26) that engages the inner race (116) of the upper bearing assembly (110) to support the inner race (116) and to concomitantly restrain axial migration thereof. The endface surface (24E) of the bottom annular collar (24) selectively abuttingly engages the endface of a planetary carrier (106) to support the spacer (10) in combination with the main rotor shaft (102). A plurality of flats (28) are formed on the inner surface of the bottom annular collar (24) in alignment with corresponding reaction spokes (30). The faces (28F) of the flats (28) provide the mechanical engagement between the spacer (10) and the main rotor shaft (102), and function as a pin joint to prevent bending motion of the main rotor shaft from being inducing loads into the spacer (10).