Ball screw nuts to DIN69051 or special

Precision nuts with recirculating ball system

Servomech ball screw nuts are manufactured in-house on modern machine tools to high precision and the DIN69051 standard.  Two basic types are available - radial linear and frontal deflector.  These are available as single nuts, as single nuts with preload to remove backlash and as double nuts with preload.  Dimensions are to DIN69051, alternatively customised specials are possible

Two basic types

a) Radial Liner where the balls travel for 1 revolution and are then deflected back to the start point by an insert called a liner.  There are typically 3 or 4 tracks of balls inside the nut.

b) Frontal deflector where a single track takes the balls through several revolutions down the length of the nut.  A deflector then diverts the balls into a return tube machined in the nut body.  They pass axially back up the length of the nut and a second deflector returns then to the start position.

Frontal deflector nuts have slightly higher load capacity and they are better suited to large thread pitches and multi-start threads.  However the choice between radial liner and frontal deflector is best left to Servomech.

Main models of ball nuts

Single nut with flange to DIN69051
This is recognisable by the two flats on the flange.
Two versions are offered, for rolled screws of diameter 16 to 40mm and for whirled screws from 20 to 100mm.  Dimensions are the same.  The whirled version has slightly higher load capacity.
Single preloaded nut with flange to DIN69051
The preload removes backlash and is normal practice when the screw is of whirled quality.
Two sets of ball tracks are machined with an offset of a few microns in the pitch
Dimensions are the same as the standard single nut but load capacity is lower.
Diameters are 20 to 63mm
Double preload nut with flange to DIN69051
The double nut removes backlash in a similar way to the single preloaded nut, but the extra length restores the load capacity
Screw diameters 20 to 100mm

Production of ball nut

A new machining centre creates the nuts in a single process.  The nuts are then hardened followed by skimming of the critical dimensions by a special machine tool that achieves micron accuracy.  Hand assembly with different ball options achieves smooth running and zero backlash.

Lubrication of ball nuts

Oil lubrication is recommended for maximum performance, particularly high speeds, and lifetime.  However many applications make use of grease lubrication where the ball nut is pre-loaded with grease.  A grease filling hole is provided in the flange, alternatively a grease nipple can be fitted