A TOCO linear module is only as precise as the connection to its drive motor. In 2026, as high-speed "start-stop" cycles become more aggressive, the choice of shaft coupling—specifically for TGH (Ball Screw) and TGB (Belt) series—can be the difference between sub-micron repeatability and a system that vibrates itself apart.

1. Why Standard Couplings Won't Cut It

In high-precision motion, we must eliminate two primary enemies:

• Backlash: Any "play" or looseness in the connection. If the motor turns 1℃ but the screw doesn't move, your positioning data is a lie.

• Misalignment: No matter how precisely a motor is mounted, there is always a microscopic offset ($\Delta$) between the motor shaft and the module input shaft. A rigid connection would destroy the bearings; a flexible one must absorb this without losing accuracy.

2. The TOCO Preferred Choice: Disk (Leaf) Couplings

For the TGH Ball Screw series, we almost exclusively recommend Single or Double Disk Couplings.

• Construction: These use thin stainless steel springs (disks) to transmit torque.

• The Benefit: They are "Torsionally Rigid" (meaning they don't twist under load) but "Flexibly Compliant" (meaning they can bend to accommodate shaft misalignment).

• Zero Backlash: Because there are no sliding parts, there is zero "slop" in the rotation.

3. The "High-Damping" Choice: Jaw (Spider) Couplings

For the TGB Belt Drive series, where high-speed transport and vibration dampening are more important than absolute sub-micron positioning, Jaw Couplings are the standard.

• Construction: Two metal hubs "sandwich" a curved elastomer insert (the "Spider").

• The Benefit: The elastomer absorbs the shock of rapid direction changes, protecting the motor’s internal bearings and the module’s belt teeth from "snap" forces.

• Fail-Safe: Even if the spider fails, the metal jaws will interlock, preventing a total runaway of the load.

4. Coupling Selection Matrix for TOCO Modules

5. Proper Installation: The "Clamp" vs. "Set Screw"

To ensure the facts of your machine's performance match the technical specs, TOCO recommends Clamping Hubs over Set Screws.

• Set Screws: Can slip over time and mar the motor shaft, making removal difficult.

• Clamping: Distributes the force 360° around the shaft. This provides a much more secure "friction-fit" capable of handling the high torque of 2026-era servo motors without slipping.

Conclusion

The coupling is the final link in the precision chain. By matching a Torsionally Rigid Disk Coupling to your TGH module or a Damping Jaw Coupling to your TGB module, you protect your motor while ensuring that every pulse from the controller results in perfect, predictable motion.