Method for producing composite material molded article, method for producing retainer and rolling bearing, and method for producing gearbox constituent component

A method for producing a retainer for use in a rolling bearing, the retainer including:

• a pair of annular portions that face each other in an axial direction;
• and a plurality of columnar portions that connect the pair of annular portions, rolling elements being housed in regions surrounded by the pair of columnar portions arranged to face each other in a circumferential direction and the pair of annular portions facing each other in the axial direction, the method comprising:
• to obtain the columnar portions, from a solution in which reinforcing fibers with an average fiber length of 0.5 mm or more and thermosetting resin are dispersed and mixed in a solvent, removing the solvent by paper-making to form a reference preform in which the reinforcing fibers are formed at a first bulk density;
• to obtain the annular portions, from the solution in which the reinforcing fibers and the thermosetting resin are dispersed and mixed in the solvent, removing the solvent by paper-making to form a high density preform in which the reinforcing fibers are formed at a second bulk density higher than the first bulk density;
• placing the high density preform in a cavity of a mold at a portion where the annular portions to be molded;
• placing the reference preform in the cavity at a portion where the columnar portions to be molded;
• and
• clamping and heating the mold and injecting a molten resin into the cavity to perform resin molding.