| 摘要 |
PROBLEM TO BE SOLVED: To provide an injection molded pulley made of resin, which can reduce filling defects due to degassing ability and suppress the deformation of a cylindrical portion due to the force of a belt to be small by devising an injection molding die and the shape of a flat pulley. SOLUTION: The flat pulley having a cylindrical portion 5 having an outer peripheral surface 2 with a crowning shape is configured as follows. In a first embodiment, a boss 1 and the cylindrical portion 5 are connected with a web 3 at the respective end faces. The connecting portions of the web 3 with the boss 1 and the cylindrical portion 5 are located on the same side on one side, and further the connecting portion of the web 3 with the boss 1 is located inside the cylindrical portion 5 in the direction of its width. The boss 1, the web 3, and the cylindrical portion 5 are integratedly formed with the resin injected from a gate 8 arranged at the end portion of the boss. A gate mark left on the end portion of the boss exists on the end portion of the boss on the opposite side of the end surface connected to the web 3. COPYRIGHT: (C)2007,JPO&INPIT |
