| 摘要 |
An actuator device comprising a screw shaft(16),a nut member(17),and balls(18),wherein normally under a load in a first axial direction(F1),the nut member(17)moves in the first axial direction(F1)and in a second axial direction(F2)opposite thereto,with respect to the screw shaft(16).A ball thread groove(19)in the screw shaft(16)is formed with a load surface(19a)located on the side of the first axial direction(F1)with a groove bottom(19c)defining a boundary,for pressure contact with the balls(18).A ball thread groove(20)in the nut member(17)is formed with a load surface(20a)located on the side of the second axial direction(F2)with its groove bottom(20c)defining a boundary,for pressure contact with the balls(18).These load surfaces(19a,20a)have a finishing treatment applied thereto to make the surface roughness thereof lower than that of non−load surfaces(19b,20b). |
