| 摘要 |
PROBLEM TO BE SOLVED: To prevent any crack in plastics, and to improve a ball return hole and a holding part in terms of accuracy by making up a chamfer in a block body square part corresponding to the forming part of an endless circuit through such a method as forming a ball load rolling surface in a metallic block body and a ball endless circuit with a die forming material, respectively. SOLUTION: A moving blocking 4 is made up of a synthetic resin by means of injection molding with a machined metallic block body 8 as a core, and ball load rolling surfaces 43a and 43b or the like are formed in this body 8, while ball return holes 44a, 44b, a ball holding part 45, or the like are formed with a synthetic resin. In addition, a chamfer 50a is formed in both ends in front and in the rear of a skirt part 4b of the body 8, and another chamfer 50b in an opening edge of a through hole 48 of a horizontal part 4a, respectively. When a molten synthetic resin is filled up there, this molten resin is speedily spread over the circumference of this skirt part 4b, quickly flowing into an inner part of the through hole 48 as well. Accordingly, plastic wall thickness forming the ball return holes 441, 44b and the ball holding part 45 is uniformized, and thereby those of deformation, strain and crack are preventable and, what is more, the dimensional accuracy of a ball endless circuit is thus heightened. |
