| 摘要 |
PURPOSE:To produce economically a small quantity and multiple kinds of gears having high quality and high strength in the stage of producing the gears by preparing the pattern of the gear of a foamed resin, and casting the gear by an expendable pattern molding method using said pattern. CONSTITUTION:A prototype 3 of a gear is fitted onto a revolving shaft 7 of a speed reducing motor 6 and is heated to 150-250 deg.C with a heater 2. The revolution of the shaft 7 is transmitted via a spur gear 9, a horizontal shaft 10 and a bevel gear 11 to a vertical shaft 12 which rotates a foamed body 4 in synchronization with the prototype 3. The revolution of the shaft 10 is further transmitted via a pulley 13 and a belt 14 to a horizontal shaft 15. The body 4 is moved upward via the shaft 12 by a cam 16 fixed thereto and is brought into press contact with the prototype 13, by which a pattern 5 is prepd. A runner, riser, etc. are attached to the pattern 5, and is embedded in molding sand to form an expendable casting mold. A molten metal is cast into such mold and a gear is cast. |
