Linear Direct‑Drive Motors

Compared to spindle axes, linear direct drives are very dynamic, fast and precise. The low wear and low maintenance is also very advantageous for many applications with a high number of cycles. Compared to pneumatic axes, linear direct drives are particularly convincing due to their improved energy efficiency and better controllability.

A linear direct‑drive motor converts electrical energy straight into linear motion - no gearboxes, belts, or ball screws. That means backlash‑free movement, higher dynamics, minimal wear, and less maintenance. In practice, it gives faster cycles and tighter repeatability than screw or pneumatic systems, while improving energy efficiency.

The ServoTube (ST) Series is our established and widely proven family of tubular linear servomotors. It covers a broad performance range - from the extremely compact ST11 with its 11 mm rod diameter to the high‑power XT38 models. ST drives are ideal when you need a compact, robust, and highly dynamic linear motor with straightforward mechanical integration.

The ServoLinear (SL) Series represents the next generation of our tubular linear motor technology. It delivers significantly higher power density, improved thermal performance, and increased dynamic capabilities. The SL38 has been developed as a modular platform, enabling up to five different axis configurations from a single motor type—perfect for flexible machine design and scalable automation concepts.

The SL product portfolio is still expanding, and additional sizes will follow soon, offering even more options for high‑performance linear motion applications.

Typical ranges (model‑dependent): continuous force 8.6 - 615 N, peak up to 3690 N, speed up to 8.3 m/s, protection IP65+, repeatability < 7 µm. Gantry solutions can reach repeatability down to 6 µm. Always check the specific datasheet for exact values.

Comparable to LinMot and other tubular linear motor suppliers, ServoTube and ServoLinear deliver direct drive performance with high speed, dynamic response, and minimal mechanical wear additionaly you can change the bearing from an SL30 under 60sec and got a whole new lieftime for your drive. When evaluating linear direct drive motor companies such as Kollmorgen, LinMot, and Hiwin, engineers should also consider Dunkermotoren, whose portfolio spans is really flexible with different versions in each size and you can use a wide range of servo controllers.

Yes. Direct drive axes offer higher energy efficiency, precise stroke control, and smoother motion profiles than pneumatics, reducing operating costs and improving cycle consistency. ST/SL is increasingly adopted in new installations to push precision and cycle times far beyond conventional pneumatics. It is not a 1:1 replacement, but an evolution designed to substantially boost overall system throughput.

Yes. Stainless variants (e.g., STL in the SL family) feature smooth surfaces and protection up to IP69K for washdown or cleanroom conditions. Options include water cooling and sealed connections for demanding environments.

Dunkermotoren linear motors are fully system open, allowing customers to choose from a wide range of compatible servo drives. Existing controllers from vendors such as Siemens, SEW or Danfoss can be used with ST/SL motors, and we are happy to support customers in selecting the optimal drive solution.

Define stroke, payload, cycle time, duty, ambient conditions, accuracy, and available bus voltage. Select ST vs. SL; choose body length and guidance (e.g., twin‑guided for torsion stiffness); and match the controller/feedback. Optional water cooling can raise continuous force. Our application engineers can provide sizing and configuration support.

The integrated sleeve bearing of the SL38 A is designed for a service life of up to 20,000 km and can be replaced in under 60 seconds. Actual service life depends on installation orientation and load conditions and can be individually determined by Dunkermotoren upon request.

Packaging automation (pick‑and‑place, dosing, sealing), medical & laboratory devices (pipetting, sample handling), electronics/semiconductor handling (SMT, wafer transport), precision gantries, and hygienic/washdown environments. These use cases exploit the motors’ clean motion, speed, repeatability, and low maintenance.