DFU Nuts

DFU Nuts for Preloaded Ball Screw Assemblies

DLY DFU nuts are flange-type double ball screw nuts used with DFU ball screws. The DFU structure combines a main nut and an auxiliary nut to create preload, reduce axial clearance, and improve rigidity in linear motion systems that require stable positioning and smooth transmission.

Unlike a general single ball nut, a DFU nut is selected when the axis needs better backlash control and stronger axial support. It is commonly used in CNC machinery, automation equipment, industrial robots, packaging machinery, printing equipment, inspection systems, and precision positioning tables.

DLY supplies DFU nuts in common models such as DFU1604, DFU1605, DFU2005, DFU2505, DFU3205, DFU4010, DFU5010, DFU8010, and DFU10020. For reliable performance, the DFU nut should be confirmed together with the matching ball screw shaft, screw lead, preload requirement, flange dimensions, support units, and installation space.

DFU double ball screw nut with flange for preloaded ball screw assemblies.

DFU2005-3 double ball screw nut with flange mounting structure.

DFU4010 double ball screw nut standing view.

 

DFU Double Nut Structure

A DFU nut is built with a double-nut structure. The main nut and auxiliary nut work together to preload the ball screw assembly, helping reduce axial backlash and improve feed rigidity. This makes DFU nuts suitable for machine axes that need more stable positioning than standard single-nut ball screw assemblies.

During operation, steel balls roll between the screw raceway and nut raceway. The internal circulation structure guides the balls back into the loaded area, allowing continuous rolling motion. Because a DFU nut is preloaded, correct screw matching, lubrication, support alignment, and installation accuracy are important for smooth operation.

DFU Model Range

DLY supplies DFU nuts for common ball screw diameters and leads. Typical model names show the nominal screw diameter and lead. For example, DFU2005 is used with a 20mm diameter, 5mm lead ball screw, while DFU4010 is used with a 40mm diameter, 10mm lead ball screw.

Common DFU nut models include DFU1604, DFU1605, DFU1610, DFU2005, DFU2010, DFU2505, DFU3205, DFU3206, DFU3210, DFU4005, DFU4010, DFU5005, DFU5010, DFU5020, DFU6310, DFU6320, DFU8010, DFU8020, and DFU10020. The final model should be confirmed according to the screw shaft, installation drawing, and preload requirement.

DFU flange-type double ball screw nut dimension drawing.

DFU ball screw nut dimension table with lead, ball diameter, load rating, and stiffness reference.

DFU Double Nut Size Reference

The table below reorganizes common DFU model data for easier reading. It can be used for preliminary comparison, but final dimensions should be checked with the official drawing before replacement or production.

DFU Nut Features

The main advantage of a DFU nut is its double-nut preload structure. Preload helps reduce axial clearance between the ball nut and the screw shaft, improving rigidity and making the linear axis more stable during forward and reverse movement.

The flange design allows the nut to be fixed to a moving table, carriage, bracket, or linear module slide. The oil hole position supports lubrication maintenance, while the internal ball circulation path keeps the nut structure compact and suitable for many machine layouts.

FAQ About DFU Nuts

What are DFU nuts?

DFU nuts are flange-type double ball screw nuts used with matching DFU ball screws. They use a double-nut structure to create preload, reduce axial backlash, and improve rigidity in precision linear motion systems.

What is the difference between DFU nuts and standard single ball nuts?

Standard single ball nuts are simpler and more compact, while DFU nuts use a double-nut preload structure. DFU nuts are more suitable when the application needs lower backlash, better rigidity, and more stable positioning.

Can DFU nuts be purchased separately?

Yes, DFU nuts can be supplied separately for replacement or maintenance. However, the new nut must match the existing screw shaft. Screw diameter, lead, raceway condition, nut series, flange size, and preload requirement should be checked before ordering.

Are DFU nuts interchangeable with other brands?

They may be interchangeable when the screw diameter, lead, nut dimensions, ball circulation design, preload condition, and mounting layout are compatible. For reliable replacement, provide the old nut photos, model marking, and screw measurements for confirmation.

What DFU models are available?

Common models include DFU1604, DFU1605, DFU1610, DFU2005, DFU2010, DFU2505, DFU3205, DFU3206, DFU3210, DFU4005, DFU4010, DFU5005, DFU5010, DFU5020, DFU6310, DFU6320, DFU8010, DFU8020, and DFU10020.

How should DFU nuts be maintained?

Keep the ball screw and nut properly lubricated, avoid dust and metal chips entering the raceway, check alignment regularly, and do not disassemble the nut from the screw shaft without a transfer sleeve or proper assembly tool.