Ever higher precision and higher speeds: These are key trends for linear actuators. In this context, an important role in the cooling. NSK has developed already in the 80er years ago the first series with integrated cooling. There was a hollow bored spindle shaft (hollow shaft spindle) used, was passed through the cooling liquid. Now the next step of development is done: NSK provides high-speedBall Screws before, in which the parent is cooled.The impetus for the development gave customers the tools and plastic machinery. You must always comply with higher precision requirements, so that the machine can produce, for example, aircraft components with extremely high dimensional accuracy or plastic components such as mobile phone housing with extremely thin walls. A constant temperature in the machine or the tool is one of the prerequisites for this precision because temperature differences can lead to dimensional changes to default or other loss of quality. If particularly high demands are made, push ball screws without cooling limits here. A system in which the mother is cooled, however, allows an even more precise temperature control, especially as the parent record is then cooled.
The well-known problem that is caused by the cooling contraction of the material affects the preload of the nut could be loosened. After extensive experiments, the NSK developers determines a bias level, which is not affected by the cooling. Compared to the cooled hollow shaft spindles, the ball screws have cooled with mother on at least as good, and in many cases significantly better cooling performance. Especially in high-speed applications with short strokes, the cooling effect is considerably higher.
Thus, the new type of cooling is ideal for including machines running relatively small movements at high speeds and short cycle time. Meet this example for many machine tools, edit the automotive components, as well as for injection molding machines that manufacture plastic parts with high demands on the dimensional accuracy.
The series with cooled mother can 1: 1 be exchanged for existing series with cooled spindle, because the dimensions are identical. In addition to the technical advantages offered by the new ball screws a significant economic advantage: they can be manufactured at low cost, because it is much easier to bring in a hole in a mother than to make a hollow spindle shaft design. This advantage will go to the user who will also benefit from the fact that the cooling can be easily integrated into existing cooling systems. The cooled parent body can be supplied in shank diameters 40, 45, 50 and 63 mm. Depending on the spindle shaft slope variants with 16, 20, 25 and 30 mm are available.