LINEAR-MOTION DEVICE

To provide a linear-motion device using a highly reliable and eco-friendly separator, which can improve dimensional stability, ductility and the adhesion force of a grease containing a poly-α-olefin oil or the like as a base oil, and can prevent deformation at high speed that are required for a separator.SOLUTION: A linear-motion device includes: a linear-motion body 15 that is externally fitted with a shaft (screw shaft 11) and linearly moves along the shaft (screw shaft 11); a large number of balls B that are held in a ball groove 14 formed on an inner surface side of the linear-motion body 15 and roll between the ball groove 14 and the shaft (screw shaft 11); separators 100 that are interposed between the respective balls B; and a circulation passage 18 that is formed on the linear-motion body 15 and circulates the balls B from one end side to the other end side of the ball groove 14. At least either one of the separator 100 or the circulation passage 18 is made to be a member formed by injection-molding copolymerized polyamide resin of polyamide 6T and polyamide 11.SELECTED DRAWING: Figure 2 【課題】セパレータに求められる寸法安定性、延性、ポリα-オレフィン油等を基油とするグリースの付着力を改善、更に高速での変形防止とを達成した、高信頼性で環境にやさしいセパレータが用いられた直動装置を提供する。【解決手段】本発明は、軸（ねじ軸１１）に外嵌すると共に、当該軸（ねじ軸１１）に沿って直進移動する直動体１５と、この直動体１５の内面側に形成されたボール溝１４に保持され、当該ボール溝１４と前記軸（ねじ軸１１）との間で転動する多数のボールＢと、各ボールＢの間に介装されるセパレータ１００と、直動体１５に形成され、ボール溝１４の一端側から他端側にボールＢを循環させる循環通路１８とを有する直動装置であって、セパレータ１００と循環通路１８の少なくともどちらか一方を、ポリアミド６Ｔとポリアミド１１の共重合ポリアミド樹脂を射出成形で形成した部材とする。【選択図】図２