| Lead Screw |
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Information AboutLead Screw |
| CATEGORIES ABOUT LEADSCREW | |
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A leadscrew nut and screw mate with rubbing surfaces, and consequently they have a relatively high Friction and Stiction compared to mechanical parts which mate with rolling surfaces and bearings. Their efficiency is typically only between 25 and 70%, with higher pitch screws tending to be more efficient. A higher performing, and more expensive, alternative is the Ball Screw . The high internal friction means that leadscrew systems are not usually capable of continuous operation at high speed, as they will overheat. Due to inherently high Stiction , the typical screw is self-locking (ie. when stopped, a linear force on the nut will not apply a Torque to the screw) and are often used in applications where backdriving is unacceptable, like holding vertical loads or in hand cranked machine tools. Leadscrews are typically used well greased, but, with an appropriate nut, it may be run dry with somewhat higher friction. There is often a choice of nuts, and manufacturers will specify screw and nut combinations as a set. Leadscrew threads typically have an Acme profile. Backlash can be reduced with the use of a second nut to create a static loading force known as preload. Leadscrews are manufactured to various tolerances. EXAMPLES OF USE SEE ALSO |
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