Applying Roller Gear Cam Mechanism Technology

Linear drive systems that convert motor rotation into linear motion—such as cam-type rack and pinion, precision ball screws, and timing belts—come in various forms. Among these systems, the liner unit utilizing roller gear cam mechanism technology—renowned for its exceptional precision and high-speed performance—delivers outstanding accuracy, rigidity, and reliability. Developed ten years ago, the liner unit transforms the rotation of a servo motor through a screw-shaped cam, allowing the unit to move smoothly in a straight line along a rail. It is a product of Sankyo Seisakusho, the first company in Japan to domestically produce the roller gear cam mechanism, which has continued to pursue research and development under the theme of providing motion control. By adopting rolling transmission drive using high-rigidity rollers, the liner unit enables high-speed and stable transport even for heavy loads such as robots. It achieves travel speeds exceeding 200 meters per minute, significantly reducing transfer time. The system supports rapid acceleration and deceleration as well as high-speed operation, and by simply connecting rails, it can accommodate long strokes of over 10 meters.

▲Liner unit demonstration

Excellent load balance is another advantage. Thanks to the single integrated cam mechanism, the system operates smoothly, enabling seamless lifting and lowering of pallets, 180° rotation, and efficient transfer of heavy workpieces or robots. Compared with other mechanisms, it can reduce installation space by up to approximately 50%.

Achieving a Well-Balanced Combination of Functions Required for Linear Drive Systems

The most remarkable feature of this liner unit is its well-balanced design. It offers all key performance aspects: high speed, compact size, long stroke, high load capacity, and long service life.

▲Comparison of features with other mechanisms

In typical long-stroke drives, positioning accuracy is around ±50–100 µm, whereas the liner unit achieves ±15 µm. Thanks to the cam mechanism, it maintains high repeatability, stopping precisely at the intended position every time. Other linear drive systems have limitations: rack and pinion mechanisms experience play due to backlash between gear teeth, making precise positioning difficult. Precision ball screws can achieve accurate positioning but are prone to deflection, limiting long strokes to about 3 meters. The liner unit, on the other hand, is widely used in processes such as 10-meter-long vehicle transfers because it simultaneously delivers both long-stroke capability and high precision.