The gap between the application of the roller screw and the application suitable for the screw is narrowing. It is increasingly difficult for engineers and designers to determine which technology is suitable for them. The advancement of the screw design and materials give them higher load capacity and better positioning accuracy, so that it is not just an ideal choice for low -cost and low -precision applications in the past.
The screw contains a screw and an ordinary nut (no rolling mechanism). They rely on the angle of the thread and the friction between the nut and the screw to produce exercise. Screws are usually made of carbon steel or stainless steel, and the nut can be bronze, plastic or polymer.
The roller screw also contains a screw and a nut, but in this case, the nut is loaded with a circulating ball to carry the load. This design reduces friction in a large limit and provides high efficiency.
The many advantages of the roller screws are attributed to the circulating balls that support the load.
However, although their technical capabilities are becoming more and more overlapping, each technology still has suitable applications. In some cases, the application requirements are only beyond the ability of the screw, and only the roller screw can meet the needs. The following are four common application standards that require rolling screws in most (in most cases).
Heavy object
Use circular steel balls to support the load. The roller screw has higher load capacity than the screw with plastic or polymer nuts of the same size. A screw with a bronze nut can drive heavier loads, but the friction will increase as the load increases. Higher friction means a lower duty cycle.
Also related to the load, the size of the roller screw is based on the L10 bearing life equation. This equation provides a statistical verified screw life estimation, which is based on rice or rotation. The wear characteristics of the screw make the life span almost unpredictable. You can choose a screw with a plastic nut based on the PV value, but this gives the stress and speed range that the screw can withstand.
High -precision requirements
Different from the bars with the gap between the nut and the screw, the roller screw can be pre -loaded to eliminate the gap. This is usually done by using a slight diameter than the roller between the space between the screw roller and the thread.
