The NEFF sliding drives are based on NEFF ball screws. The sliding drive is completed with a sliding nut, manufactured with the negative profile of the ball screw, instead of (using) a ball nut.
The generated sliding drive combines high pitches and dynamic of the ball screw with the lower costs of the trapezoidal threaded spindles.
Choosing high-quality plastics allows the lubricant-free running of the sliding drive – a significant characteristic with advantages in many businesses (e.g. food industry, clean room technology etc.), which excludes many problems in advance.
Ball screws have become indispensable in many industrial environments. They are also called rolling screw drives with balls or rolling elements. Amongst other things, they convert rotational movements into precise linear movements or vice versa and are therefore often used as drive elements for linear movements wherein the screw is usually driven while the nut is connected to the part to be moved.
HOW DO BALL SCREWS WORK?
In a ball screw, the balls inside the nut ensure particularly low-friction movement by transmitting the force evenly between the screw and the nut. These balls move between the screw and the ball nut. In the standard version, the ball screw is not preloaded, thus combining precision with a long service life. The precision can be further increased by preloading the nut on the screw, maximizing precision and travel accuracy. Once the balls reach the end of the nut, they are returned to the other end via a recirculation system. The recirculation ensures smooth movement of the nut even at high load capacities, because the load is distributed over a large number of balls.
These properties make ball screws the perfect candidates for precise linear drive movements. With high repeat accuracy, they ensure precise and fast positioning. Ball screws can also be used in systems with multiple screw drives, where the power transmission and motion conversion of two parallel systems are realised together.
Ball screws are also increasingly used to act as a substitute for hydraulic systems, such as servo-assisted steering, presses, or injection moulding machines.
The biggest difference between these two screw drives is probably their type of friction: In ball screws, rolling friction prevails, whereas classic trapezoidal screw drives operate mainly with dynamic friction. This results in several advantages when using ball screws:
Ball screws have significantly lower friction than trapezoidal screws, therefore they are more efficient and require less energy.
While conventional trapezoidal screws must overcome a breakaway torque during start-up, this is not the case for ball screws: The stick-slip phenomenon does not come into play here, resulting in a reduction in drive torque by about 65 percent. Ball screws do not have self-retainment, thus without external force, there is no movement of the ball nut possible.
Ball screws have a significantly greater potential speed of movement and are therefore ideally suited for dynamic operations with high precision.
Another difference is the adjustability of the thrust movement: Ball screws are significantly more precise than trapezoidal screw drives and can be adjusted without backlash or with preload to further increase the repeat accuracy. This makes ball screws particularly suitable for drive technology, CNC technology as well as for modern robotics projects, where they make possible high feed rates with maximum precision under a wide range of loads.
The interaction of sliding ball nuts (GGM) made from plastics with integrated ball screw negative profiles makes NEFF ball screws to a sliding drive.
Sales Screw drives
Phone +49 7157 53890-13
Email d.sautter[at]neff-gt.de
NEFF Gewindetriebe GmbH
Karl-Benz-Straße 24
D-71093 Weil im Schönbuch
Fon. 07157 53890-0
info[at]neff-gt.de
