| 摘要 |
PURPOSE:To remarkably increase the cooling effect for a screw shaft, by communicating the cooling medium passage composed of an air lead hole, a cooling medium passage, an air exhaust hole and air passage with a cooled air feeding pipe combined with a hollow bracket. CONSTITUTION:A refrigerant passage is formed with the passage 33 in the axial direction formed on a ball/screw shaft 27 and a radial hole 42 being directly connected to the refrigerant room 26a of a motor bracket 26 where a cooled air is fed via the side hole 37a, shaft hole 37b of a shaft joint 32. The cooled air exhausted from this radial hole 42 takes the heat away and cools with its direct contact with the surface part performing a screw motion by the engagement with a screw like part 27a, i.e., a ball screw nut 28. The heat taken away area is thus equivalent to the large area of the screw like part surface and the heat taking away effect is improved further. So, the telescopic displacement due to the thermal effect of the ball/screw shaft 27 can effectively be restrained. |
