Lead Screw Linear Actuators - LSR Series - Non-Captive and External-Nut Assemblies with Anti-Backlash Nuts and NEMA motors

Non-captive and external-nut lead screw actuators in the anti-backlash LSR Series use programmable stepper motors, precision lead screws, and Constant Force Technology™ anti-backlash nuts to move and accurately position loads.

In the non-captive configuration the lead screw passes completely through the motor and the nut is integrated into the motor rotor. The screw is typically fixed at both ends and rotates so the motor and its attached load travel along the screw; alternatively the motor can remain stationary while the screw translates through it and moves a load attached to the end of the screw.

In the external-nut configuration the motor stays fixed, the screw extends from one side of the motor only (it does not pass through), and a separate external Constant Force anti-backlash nut is restrained from rotating so it travels along the rotating screw and moves the attached load.

An anti-backlash lead screw nut minimizes clearance between the nut and screw threads, reducing lost motion when travel reverses. The LSR Series uses PBC Linear’s Constant Force Technology™ nut, which maintains consistent thread engagement for better positioning accuracy and repeatability and provides more than twice the backlash compensation of conventional designs. Available in NEMA 11, 14, 17, and 23 frame sizes, these actuators support lead screw diameters of 3/16 in, 1/4 in, 6 mm, 3/8 in, and 10 mm.

Optional PTFE-coated or uncoated screws suit different friction, wear, and environmental needs. The self-lubricating polymer nut reduces maintenance, and lead accuracy up to three times better than standard supports repeatable positioning in automation, robotics, packaging, and other linear motion applications.

• Integrated lead screw and programmable stepper motor assemblies for controlled linear movement and accurate load positioning.
• Non-captive configurations allow the lead screw to pass completely through the motor assembly.
• External-nut configurations use a rotating lead screw and a separate, non-rotating, load-carrying nut that travels along the screw.
• Non-captive configurations support traveling-motor or traveling-screw arrangements.
• Constant Force Technology™ anti-backlash nuts provide more than twice the backlash compensation of conventional designs.
• Anti-backlash nut technology maintains thread preload and compensates for wear to improve positioning repeatability.
• Available in NEMA 11, 14, 17, and 23 stepper motor frame sizes for non-captive configurations.
• Lead screw diameters include 3/16in, 1/4in, 6mm, 3/8in, and 10mm.
• PTFE-coated and uncoated lead screw options available.
• Self-lubricating polymer nuts reduce maintenance requirements.
• Lead accuracy up to three times better than typical lead screws.

Frequently Asked Questions