| 摘要 |
PURPOSE:To make a torsional damper of a crank shaft of an internal combustion engine with an appropriate mass when manufacturing the damper by forming a damper pulley with plastic material injection molding and at the same time providing a circumferential elastic body with effective contractive function. CONSTITUTION:A torsional damper 10 consists of a damper pulley 12, a boss part 16 of a small-diametered cylindrical shape in which a metallic sleeve 14 is integrally arranged, a cylindrical part 18, and a connection part 20. When manufacturing the damper pulley 12, an elastic body 30 made of an elastic material such as rubber of a specified thickness is sulfurized and glued on the inner circumference of a damper mass 26 of a ring- or cylindrical shape. Then the mass and the sulfurized and glued elastic body are set in a specified injection mold die, and a specified plastic material is injected inside the mass and sulfurized and glued elastic body 30 to form the damper pulley 12 by injection molding. Simultaneously, it is made so that a specified contractive function is given to the elastic body 30 by means of the injection molding pressure. |
